AAT3697IWP-4.2-T1 - SKYWORKS SOLUTIONS

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

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General Description

The AAT3697 BatteryManager is a highly integrated sin-

gle-cell lithium-ion/polymer battery charger IC designed

to operate with AC adapter inputs. It requires a minimum

number of external components. The AAT3697 precisely

regulates battery charge voltage and current for 4.2V

lithium-ion/polymer battery cells. Adapter charge current

rates can be programmed up to 2.0A. An active thermal

management system regulates the fast charge constant

current for all ambient temperature and input vs. output

voltage conditions.

Battery temperature and charge state are fully moni-

tored for fault conditions. In the event of an over-voltage

or over-temperature failure, the device will automati-

cally shut down, thus protecting the charging device,

control system, and the battery under charge. Status

monitor output pins are provided to indicate the battery

charge status by directly driving two external LEDs. A

serial interface output is available to report 12 various

charging status states to a microcontroller.

The AAT3697 is available in a Pb-free, thermally-enhanced,

space-saving 12-pin TDFN 3x3mm package and is rated

over the -40°C to +85°C temperature range.

Features

• Input Voltage Range: 4.0V to 5.5V

• Up to 2.0A Charging Current

• Adapter Present Indicator (ADPP#)

• High Level of Integration with Internal:

▪ Charging Device

▪ Reverse Blocking Diode

▪ Current Sensing

• Active Thermal Loop Charge Reduction

• Automatic Recharge Sequencing

• Battery Temperature Monitoring

• Full Battery Charge Auto Turn-Off / Sleep Mode

• Over-Voltage, Over-Current, and Over-Temperature

Protection

• Power On Reset and Soft Start

• Serial Interface Status Report

• 12-Pin 3x3mm TDFN Package

• -40°C to +85°C Temperature Range

Applications

• Cellular Telephones

• Digital Still Cameras

• Hand Held PCs

• MP3 Players

• Personal Data Assistants (PDAs)

• Other Lithium-Ion/Polymer Battery-Powered Devices

Typical Application

AAT3697

COUT

10μF

BATT-

TEMP

Battery

Pack

ADP

ADPSET

GND

BAT

BATT+

RSET

RB1 RB2

CIN

10μF

0.1μF

dapter

STAT1

LED1

LED2

STAT2

DATA

Serial Interface

ENEnable

ADPP#

Adapter

Present

RT1

VADP

RT2

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Pin Descriptions

Pin # Name Type Function

1 BAT Out Battery charging and sensing.

2 ADP In Adapter input.

3 GND Ground Ground connection.

4 EN In Enable pin. Logic high enables the IC.

5 ADPP# Out Adapter present indicator. This pin is open drain until ADP pin reaches threshold.

6 TS In/Out Battery temperature sense input.

7 DATA Out Status report to microcontroller via serial interface; open drain.

8 STAT2 Out Battery charge status indicator pin to drive an LED; active low, open drain.

9 STAT1 Out Battery charge status indicator pin to drive an LED; active low, open drain.

10 CT In/Out Timing capacitor to adjust internal watchdog timer. Set maximum charge time for adapter powered

trickle, CC, and CV charge modes. If timing function is not needed, terminate this pin to ground.

11 N/C No connection.

12 ADPSET In/Out Use resistor at this pin to set adapter charging current.

EP Exposed paddle (bottom); connect to GND directly beneath package.

Pin Configuration

TDFN33-12

(Top View)

BAT

ADP

GND

DPP#

ADPSE

N/C

STAT1

STAT2

DATA

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Absolute Maximum Ratings1

Symbol Description Value Units

VPADP Input Voltage, <30ms, Duty Cycle <10% -0.3 to 7.0 V

VPADP Input Voltage, Continuous -0.3 to 6.0 V

VNBAT, TS, ADPSET, ADPP#, DATA, CT, EN, STAT1, STAT2 -0.3 to VP + 0.3 V

TJOperating Junction Temperature Range -40 to 150 °C

TLEAD Maximum Soldering Temperature (at leads) 300 °C

Thermal Information

Symbol Description Value Units

JA Maximum Thermal Resistance250 °C/W

PDMaximum Power Dissipation 2.0 W

1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions

specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.

2. Mounted on an FR4 board.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

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Electrical Characteristics1

VADP = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.

Symbol Description Conditions Min Typ Max Units

Operation

ADP Adapter Voltage Range 4.0 5.5 V

VADPP Adapter Present Threshold Voltage 3.0 V

VUVLO

Under-Voltage Lockout (UVLO) Rising Edge 3.0 V

UVLO Hysteresis 150 mV

IOP Operating Current Charge Current = 100mA 0.3 1.5 mA

ISLEEP Sleep Mode Current VBAT = 4.25V 0.3 1.0 μA

ILeakage Reverse Leakage Current from BAT Pin VBAT = 4V, ADP Pin Open 1.0 μA

Voltage Regulation

VBAT_EOC1End of Charge Voltage Accuracy 4.158 4.20 4.242 V

VCH/VCH Output Charge Voltage Tolerance 0.5 %

VMIN Preconditioning Voltage Threshold 2.8 3.0 3.15 V

VRCH Battery Recharge Voltage Threshold VBAT_EOC

- 0.1 V

Current Regulation

ICH Charge Current 100 2000 mA

ICH/ICH Charge Current Regulation Tolerance 10 %

VADPSET ADPSET Pin Voltage CC Mode 2.0 V

KIA Current Set Factor: ICH/IADPSET 4000

Charging Devices

RDS(ON) Adapter Charging Transistor On Resistance VIN = 5.5V 0.2 0.25 0.35 

Logic Control / Protection

VEN(H) Input High Threshold 1.6 V

VEN(L) Input Low Threshold 0.4 V

VADPP# Output Low Voltage ADPP# Pin Sinks 500μA 0.4 V

Preconditioning Plus Constant Current Mode Time Out

CT = 0.1μF, VADP = 5.5V 3.0 Hour

TPPreconditioning Time Out CT = 0.1μF, VADP = 5.5V 25 Minute

TVConstant Voltage Mode Time Out CT = 0.1μF, VADP = 5.5V 3.0 Hour

VSTAT Output Low Voltage STAT Pin Sinks 4mA 0.4 V

ISTAT STAT Pin Current Sink Capability 8.0 mA

VOVP Over-Voltage Protection Threshold 4.4 V

ITK/ICH Pre-Charge Current 10 %

ITERM/ICH Charge Termination Threshold Current 7.5 %

VTS1 High Temperature Threshold VADP = 5.5V 29.1 30 30.9 %VADP

VTS2 Low Temperature Threshold VADP = 5.5V 58.2 60 61.8 %VADP

IDATA DATA Pin Sink Current DATA Pin is Active Low State 3 mA

IADPP# ADPP# Current Sink ADPP# Pin is Active Low

State 8mA

VDATA(H) Input High Threshold 1.6 V

VDATA(L) Input Low Threshold 0.4 V

SQPULSE Status Request Pulse Width Status Request 200 ns

tPERIOD System Clock Period 50 μs

fDATA Data Output Frequency 20 kHz

TREG Thermal Loop Regulation 90 °C

TLOOP_IN Thermal Loop Entering Threshold 110 °C

TLOOP_OUT Thermal Loop Exiting Threshold 85 °C

TOVSD Over-Temperature Shutdown Threshold 145 °C

1. The AAT3697 output charge voltage is specified over the 0° to 70°C ambient temperature range; operation over the -40°C to +85°C temperature range is guaranteed by design.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Typical Characteristics

Charge Current vs. RSET

RSET (kΩ

)

ICH (mA)

100

1000

10000

1 10 100

Battery Voltage vs. Supply Voltage

Supply Voltage (V)

VBAT (V)

4.158

4.179

4.200

4.221

4.242

4.5 4.75 5.0 5.25 5.5

End of Charge Voltage Regulation

vs. Temperature

Temperature (°

VBAT_EOC (V)

4.158

4.179

4.200

4.221

4.242

-50 -25 0 25 50 75 100

Preconditioning Threshold

Voltage vs. Temperature

Temperature (°

VMIN (V)

2.95

2.96

2.97

2.98

2.99

3.00

3.01

3.02

3.03

3.04

3.05

-50 -25 0 25 50 75 100

Pre-Charge Current vs. Temperature

(ADPSET = 8.06kΩ

)

Temperature (

ITK (mA)

100

110

120

-50 -25 0 25 50 75 100

Charge Current vs. Temperature

(ADPSET = 8.06kΩ

)

Temperature (

ICH (mA)

900

920

940

960

980

1000

1020

1040

1060

1080

1100

-50 -25 0 25 50 75 100

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Typical Characteristics

Charge Current vs. Battery Voltage

(ADPSET = 8.06kΩ

; VIN = 5.0V)

Battery Voltage (V)

ICH (A)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2.5 2.9 3.3 3.7 4.1 4.5

Charge Current vs. Supply Voltage

(ADPSET = 8.06kΩ

)

Supply Voltage (V)

ICH (mA)

200

400

600

800

1000

1200

4.5 4.75 5.0 5.25 5.5 5.75 6.0

VBAT = 3.3V

VBAT = 3.5V

VBAT = 3.9V

VIH vs. Supply Voltage

EN Pin (Rising)

Supply Voltage (V)

VIH (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C +25°C

+85°C

VIL vs. Supply Voltage

EN Pin (Falling)

Supply Voltage (V)

VIH (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C +25°C

+85°C

Operating Current vs. ADPSET Resistor

ADPSET Resistor (kΩ

)

IOP (mA)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1 10 100 1000

Pre-Conditioning

Constant Current

Counter Timeout vs. Temperature

(CT = 0.1µF)

Temperature (°

Counter Timeout (%)

-10

-8

-6

-4

-2

-50 -25 0 25 50 75 100

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Typical Characteristics

CT Pin Capacitance vs. Counter Timeout

Time (hours)

Capacitance (μ

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0246810

Precondition Timeout

Precondition + Constant Current Timeout

or Constant Voltage Timeout

High and Low Temperature

Threshold vs. Temperature

Temperature (°

VTS (% VADP)

100

-50 -25 0 25 50 75 100

VTS2

VTS1

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Functional Description

The AAT3697 is a highly integrated single-cell lithium-

ion/polymer battery charger IC designed to operate with

standard AC adapter input sources, while requiring a

minimum number of external components. The AAT3697

precisely regulates battery charge voltage and current

for 4.2V lithium-ion/polymer battery cells.

The adapter charge input constant current level can be

programmed up to 2.0A for rapid charging applications.

The AAT3697 is rated for operation from -40°C to

+85°C. In the event of operating ambient temperatures

exceeding the power dissipation abilities of the device

package for a given constant current charge level, the

charge control will enter into thermal regulation. When

the system thermal regulation becomes active, the pro-

grammed constant current charge amplitude will be

automatically reduced to a safe level for the current

operating condition. Should the ambient operating tem-

perature drop below the thermal loop threshold, the

system will automatically resume charging at the full

programmed constant current level. This intelligent ther-

mal management system permits the AAT3697 to oper-

ate and safely charge a battery cell over a wide range of

ambient conditions while maximizing the greatest pos-

sible charge current for the given set of conditions.

Status monitor output pins are provided to indicate the

battery charge state by directly driving two external LEDs.

A serial interface output is also available to report any one

of 12 distinct charge states to the system microcontroller.

Battery temperature and charge state are fully monitored

for fault conditions. In the event of an over-voltage or

over-temperature failure, the device will automatically

shut down, thus protecting the charging device, control

system, and the battery under charge. In addition to

internal charge controller thermal protection, the AAT3697

also provides a temperature sense feedback function (TS

pin) from the battery to shut down the device in the

event the battery exceeds its own thermal limit during

charging. All fault events are reported to the user either

by the simple status LEDs or via the DATA pin function.

Functional Block Diagram

Charge

Control

Reverse Blocking

CV/

Precharge

Constant

Current

Compare

ADP

BAT

DPSET

UVLO

Over-

Temperature

Protection

Charge

Status

STAT2

STAT1

4.2V

Serial

Data

DATA Watchdog

Timer CT

Voltage

Sense

ADPP#

GND

IC enable

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Charging Operation

The AAT3697 has four basic modes for the battery

charge cycle: pre-conditioning/trickle charge; constant

current/fast charge; constant voltage; and end of charge

(see Figure 1).

Battery Preconditioning

Before the start of charging, the AAT3697 checks sev-

eral conditions in order to assure a safe charging envi-

ronment. The input supply must be above the minimum

operating voltage, or under-voltage lockout threshold

(VUVLO), for the charging sequence to begin. Also, the cell

temperature, as reported by a thermistor connected to

the TS pin from the battery, must be within the proper

window for safe charging. When these conditions have

been met and a battery is connected to the BAT pin, the

AAT3697 checks the state of the battery. If the cell volt-

age is below the preconditioning voltage threshold

(VMIN), the charge control begins preconditioning the cell.

The battery preconditioning trickle charge current is equal

to the fast charge constant current divided by 10. For

example, if the programmed fast charge current is 1.5A,

then the preconditioning mode (trickle charge) current

will be 150mA. Cell preconditioning is a safety precaution

for deeply discharged battery cells and also aids in limit-

ing power dissipation in the pass transistor when the volt-

age across the device is at the greatest potential.

Fast Charge / Constant Current Charging

Battery cell preconditioning continues until the voltage

on the BAT pin exceeds the preconditioning voltage

threshold (VMIN). At this point, the AAT3697 begins the

constant current fast charging phase. The fast charge

constant current (ICH) amplitude is programmed by the

user via the RSET resistor. The AAT3697 remains in the

constant current charge mode until the battery reaches

the voltage regulation point, VBAT_EOC.

Constant Voltage Charging

The system transitions to a constant voltage charging

mode when the battery voltage reaches the output

charge regulation threshold (VBAT_EOC) during the con-

stant current fast charge phase. The regulation voltage

level is factory programmed to 4.2V (±1%). Charge cur-

rent in the constant voltage mode drops as the battery

cell under charge reaches its maximum capacity.

End of Charge Cycle Termination

and Recharge Sequence

When the charge current drops to 7.5% of the pro-

grammed fast charge current level in the constant volt-

age mode, the device terminates charging and goes into

a sleep state. The charger will remain in a sleep state

until the battery voltage decreases to a level below the

battery recharge voltage threshold (VRCH).

When the input supply is disconnected, the charger will

automatically transition into a power-saving sleep mode.

Only consuming an ultra-low 0.3μA in sleep mode, the

AAT3697 minimizes battery drain when it is not charging.

This feature is particularly useful in applications where

the input supply level may fall below the battery charge

or under-voltage lockout level. In such cases where the

AAT3697 input voltage drops, the device will enter sleep

mode and automatically resume charging once the input

supply has recovered from the fault condition.

Constant Current

Charge Phase

Constant Voltage

Charge Phase

Preconditioning

Trickle Charge

Phase

Charge Complete Voltage

Constant Current Mode

Voltage Threshold

Regulated Current

Trickle Charge and

Termination Threshold

I = CC / 10

I = Max CC

Figure 1: Current vs. Voltage Profile During Charging Phases.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

System Operation Flow Chart

Yes Yes

Yes

Set

Enable

Timing

Expire

TERM

BAT_EOC

Yes

ADP

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

Application Information

Adapter Power Input

Constant current charge levels up to 2.0A may be pro-

grammed by the user when powered from a sufficient

input power source. The AAT3697 will operate from the

adapter input over a 4.0V to 5.5V range.

The constant current fast charge current for the adapter

input is set by the RSET resistor connected between the

ADPSET pin and ground. Refer to Table 1 for recom-

mended RSET values for a desired constant current

charge level. The presence of voltage on the adapter

input is indicated by the ADPP# pin function. This indica-

tor pin uses an internal open drain device that will pull

the ADPP# pin low when voltage is detected on the ADP

pin. The precise charging function of the AAT3697 may

be read from the DATA pin and/or status LEDs. Please

refer to the Battery Charge Status Indication discussion

for further details on data reporting.

Thermal Loop Control

Due to the integrated nature of the linear charging con-

trol pass device for the adapter input, a special thermal

loop control system has been employed to maximize

charging current under all operating conditions. The

thermal management system measures the internal cir-

cuit die temperature and reduces the fast charge current

when the device exceeds a preset internal temperature

control threshold. Once the thermal loop control becomes

active, the fast charge current is initially reduced by a

factor of 0.44.

The initial thermal loop current can be estimated by the

following equation:

Eq. 1: ITLOOP = ICH · 0.44

The thermal loop control re-evaluates the circuit die tem-

perature in 330ms intervals and adjusts the fast charge

current back up in small steps to the full fast charge cur-

rent level or until an equilibrium current is discovered

and maximized for the given ambient temperature condi-

tion. The thermal loop controls the system charge level;

therefore, the AAT3697 will always provide the highest

level of constant current in the fast charge mode possible

for any given ambient temperature condition.

Adapter Input Charge Inhibit and Resume

The AAT3697 has a UVLO and power on reset feature so

that the charger will suspend charging and shut down if

the input supply to the adapter pin drops below the

UVLO threshold. When power is re-applied to the adapt-

er pin or the UVLO conditions recovers, the system

charge control will assess the state of charge on the

battery cell and will automatically resume charging in

the appropriate mode for the condition of the battery.

Enable / Disable

The AAT3697 provides an enable function to control the

charger IC on and off. The enable (EN) pin is active high.

When pulled to a logic low level, the AAT3697 will be shut

down and forced into the sleep state. Charging will be

halted regardless of the battery voltage or charging state.

When the device is re-enabled, the charge control circuit

will automatically reset and resume charging functions

with the appropriate charging mode based on the battery

charge state and measured cell voltage on the BAT pin.

Programming Charge Current

The fast charge constant current charge level is user

programmed with a set resistor placed between the

ADPSET pin and ground. The accuracy of the fast charge,

as well as the preconditioning trickle charge current, is

dominated by the tolerance of the set resistor used. For

this reason, a 1% tolerance metal film resistor is recom-

mended for the set resistor function.

Fast charge constant current levels from 50mA to 2.0A

can be set by selecting the appropriate resistor value

from Table 1.

ICH (mA) RSET (kΩ)I

CH (mA) RSET (kΩ)

100 84.5 1100 7.32

200 43.2 1200 6.65

300 28.0 1300 6.04

400 21.0 1400 5.62

500 16.9 1500 5.36

600 13.3 1600 4.87

700 11.5 1700 4.53

800 10.2 1800 4.22

900 90.9 1900 3.92

1000 8.06 2000 3.65

Table 1: Recommended RSET Values.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201901B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012

RSET (kΩ

)

IFASTCHARGE (mA)

100

1000

10000

1 10 100

Figure 2: ICH vs. RSET.

Protection Circuitry

Programmable Watchdog Timer

The AAT3697 contains a watchdog timing circuit to shut

down charging functions in the event of a defective bat-

tery cell not accepting a charge over a preset period of

time. Typically, a 0.1μF ceramic capacitor is connected

between the CT pin and ground. When a 0.1μF ceramic

capacitor is used, the device will time out a shutdown

condition if the trickle charge mode exceeds 25 minutes

and a combined trickle charge plus fast charge mode of

3 hours. When the device transitions to the constant

voltage mode, the timing counter is reset and will time

out after an additional 3 hours if the charge current does

not drop to the charge termination level.

Mode Time

Trickle Charge (TC) Time Out 25 minutes

Trickle Charge (TC) + Fast Charge (CC) Time Out

3 hours

Constant Voltage (VC) Mode Time Out 3 hours

Table 2: Summary for a 0.1μF Ceramic Capacitor

Used for the Timing Capacitor.

The CT pin is driven by a constant current source and will

provide a linear response to increases in the timing

capacitor value. Thus, if the timing capacitor were to be

doubled from the nominal 0.1μF value, the time-out

periods would be doubled.

If the programmable watchdog timer function is not

needed, it can be disabled by terminating the CT pin to

ground. The CT pin should not be left floating or un-

terminated, as this will cause errors in the internal tim-

ing control circuit.

The constant current provided to charge the timing

capacitor is very small, and this pin is susceptible to

noise and changes in capacitance value. Therefore, the

timing capacitor should be physically located on the

printed circuit board layout as close as possible to the CT

pin. Since the accuracy of the internal timer is domi-

nated by the capacitance value, a 10% tolerance or bet-

ter ceramic capacitor is recommended. Ceramic capaci-

tor materials, such as X7R and X5R types, are a good

choice for this application.

Over-Voltage Protection

An over-voltage event is defined as a condition where the

voltage on the BAT pin exceeds the maximum battery

charge voltage and is set by the over-voltage protection

threshold (VOVP). If an over-voltage condition occurs, the

AAT3697 charge control will shut down the device until the

voltage on the BAT pin drops below VOVP

. The AAT3697 will

resume normal charging operation after the over-voltage

condition is removed. During an over-voltage event, the

STAT LEDs will report a system fault, and the actual fault

condition can be read via the DATA pin signal.

Over-Temperature Shutdown

The AAT3697 has a thermal protection control circuit

which will shut down charging functions should the inter-

nal die temperature exceed the preset thermal limit

threshold.

Battery Temperature Fault Monitoring

In the event of a battery over-temperature condition, the

charge control will turn off the internal pass device and

report a battery temperature fault on the DATA pin func-

tion. The STAT LEDs will also display a system fault. After

the system recovers from a temperature fault, the

device will resume charging operation.

The AAT3697 checks battery temperature before starting

the charge cycle, as well as during all stages of charging.

This is accomplished by monitoring the voltage at the TS

pin. Either a negative temperature coefficient thermistor

(NTC) or positive temperature coefficient thermistor

(PTC) can be used because the AAT3697 checks to see

that the voltage at TS is within a voltage window bound-

ed by VTS1 and VTS2. Please see the equations below for

specifying resistors:

RT1 and RT2 for use with NTC Thermistor

Eq. 2:

5 ⋅ R

⋅ R

3 ⋅ (R

- R

)

5 ⋅ R

⋅ R

(2 ⋅ R

) - (7 ⋅ R

)

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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RT1 and RT2 for use with PTC Thermistor

Eq. 3:

5 ⋅ R

⋅ R

3 ⋅ (R

- R

)

5 ⋅ R

⋅ R

(2 ⋅ R

) - (7 ⋅ R

)

Where RTC is the thermistor’s cold temperature resistance

and RTH is the thermistor’s hot temperature resistance.

See thermistor specifications for information. To ensure

there is no dependence on the input supply changes,

connect the divider between VADP and GND. Disabling the

temperature-monitoring function is achieved by applying

a voltage between VTS1 and VTS2 on the TS pin.

Battery Charge Status Indication

The AAT3697 indicates the status of the battery under

charge with two different systems. First, the device has

two status LED driver outputs. These two LEDs can indi-

cate simple functions such as no battery charge activity,

battery charging, charge complete, and charge fault. The

AAT3697 also provides a bi-directional data reporting

function so that a system microcontroller can interrogate

the DATA pin and read any one of 12 system states.

Status Indicator Display

Simple system charging status states can be displayed

using one or two LEDs in conjunction with the STAT1 and

STAT2 pins on the AAT3697. These two pins are simple

open drain switches used to connect the LED cathodes

to ground. It is not necessary to use both display LEDs

if a user simply wants to have a single lamp to show

“charging” or “not charging.”

This can be accomplished by using the STAT1 pin and a

single LED. Using two LEDs and both STAT pins simply

gives the user more information to the charging states.

Refer to Table 3 for LED display definitions. The LED

anodes should be connected to VADP

The LEDs should be biased with as little current as nec-

essary to create reasonable illumination; therefore, a

ballast resistor should be placed between the LED cath-

odes and the STAT1/2 pins. LED current consumption

will add to the overall thermal power budget for the

device package, hence it is good to keep the LED drive

current to a minimum. 2mA should be sufficient to drive

most low-cost green or red LEDs. It is not recommended

to exceed 8mA for driving an individual status LED.

The required ballast resistor values can be estimated

using the following formulas:

Eq. 4:

ADP -

F(LED)

)

B(STAT1/2)

= I

LED(STAT1/2)

Example:

Eq. 5:

(5.5V

- 2.0

B(STAT1)

= = 1.75kΩ

2mA

Note: Red LED forward voltage (VF) is typically 2.0V @

2mA.

Event Description STAT1 STAT2

Charge Disabled or Low Supply Off Off

Charge Enabled Without Battery Flash1Flash1

Battery Charging On Off

Charge Completed Off On

Fault On On

Table 3: LED Status Indicator.

Digital Charge Status Reporting

The AAT3697 has a comprehensive digital data reporting

system by use of the DATA pin feature. This function can

provide detailed information regarding the status of the

charging system. The DATA pin is a bi-directional port

which will read back a series of data pulses when the

system microcontroller asserts a request pulse. This sin-

gle strobe request protocol will invoke one of 12 possible

return pulse counts that the system microcontroller can

look up based on the serial report data listed in Table 4.

N DATA Report Status

1 Chip Over-Temperature Shutdown.

2 Battery Temperature Fault.

3 Over-Voltage Turn Off.

4 Not Used.

5 ADP Watchdog Time-Out in Battery Condition Mode.

6 ADP Battery Condition Mode.

7 ADP Watchdog Time-Out in Constant Current Mode.

ADP Thermal Loop Regulation in Constant Current Mode.

9 ADP Constant Current Mode.

10 ADP Watchdog Time-Out in Constant Voltage Mode.

11 ADP Constant Voltage Mode.

12 ADP End of Charging.

23 Data Report Error.

Table 4: Serial Data Report Table.

1. Flashing rate depends on output capacitance.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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The DATA pin function logic is active low and should nor-

mally be pulled high to VADP

. This data line can also be

pulled high to the same level as the high state for the logic

I/O port on the system microcontroller. In order for the

DATA pin control circuit to generate clean, sharp edges for

the data output, and to maintain the integrity of the data

timing for the system, the pull-up resistor on the data line

should be low enough in value so that the DATA signal

returns to the high state without delay. If the pull-up

resistor is too high, the strobe pulse from the system

microcontroller could exceed the maximum pulse time and

the DATA output control could issue false status reports. A

1.5k resistor is recommended when pulling the DATA pin

high to 5.0V on the VADP input. If the data line is pulled

high to a voltage level less than 5.0V, the pull-up resistor

can be calculated based on a recommended minimum

pull-up current of 3mA. Use the following formula:

Eq. 6:

PULL-UP

≤3mA

Data Timing

The system microcontroller should assert an active low

data request pulse for minimum duration of 200ns; this

is specified by TLO(DATA). Upon sensing the rising edge of

the end of the data request pulse, the AAT3697 status

data control will reply the data word back to the system

microcontroller after a delay specified by the data report

time specification TDATA(RPT). The period of the following

group of data pulses will be specified by TDATA.

AAT3697

Status

Control

1.8V to 5.0V

DATA Pin

PULL_UP

μP GPIO

Port

GPIO

OUT

Figure 3: Data Pin Application Circuit.

Timing Diagram

PULSE

Data

System Reset

System Start

SYNC

LAT

N=1 N=2 N=3

OFF

DATA(RPT)

= T

SYNC

+ T

LAT

< 2.5 P

DATA

OFF

> 2 P

DATA

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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Thermal Considerations

The AAT3697 is offered in a 3x3mm TDFN package which

can provide up to 2.0W of power dissipation when it is

properly bonded to a printed circuit board and has a

maximum thermal resistance of 50°C/W. Many consider-

ations should be taken into account when designing the

printed circuit board layout, as well as the placement of

the charger IC package in proximity to other heat gen-

erating devices in a given application design. The ambi-

ent temperature around the charger IC will also have an

effect on the thermal limits of a battery charging applica-

tion. The maximum limits that can be expected for a

given ambient condition can be estimated by the follow-

ing discussion.

First, the maximum power dissipation for a given situa-

tion should be calculated:

Eq. 7: PD = [(VIN - VBAT) · ICC + (VIN · IOP)]

Where:

PD = Total Power Dissipation by the Device

VIN = Input Voltage Amplitude, VADP

VBAT = Battery Voltage as Seen at the BAT Pin

ICC = Maximum Constant Fast Charge Current Programmed

for the Application

IOP = Quiescent Current Consumed by the Charger IC for

Normal Operation

Next, the maximum operating ambient temperature for

a given application can be estimated based on the ther-

mal resistance of the 3x3mm TDFN package when suf-

ficiently mounted to a PCB layout and the internal ther-

mal loop temperature threshold.

Eq. 8: TA = TJ - (θJA · PD)

Where:

TA = Ambient Temperature in °C

TJ = -Maximum Device Junction Temperature Below the

Thermal Loop Threshold

PD = Total Power Dissipation by the Device

JA = Package Thermal Resistance in °C/W

Example:

For an application where the fast charge current for the

adapter mode is set to 1A, VADP = 5.0V and the battery

voltage at 3.6V, what is the maximum ambient tempera-

ture at which the thermal loop will become active?

Given:

VADP = 5.0V

VBAT = 3.6V

ICC = 1A

IOP = 0.75mA

TJ = 110°C

JA = 50°C/W

Using Equation 7, calculate the device power dissipation

for the stated condition:

Eq. 9: PD = (5.0V - 3.6V)(1A) + (5.0V · 0.75mA)

= 1.40375W

The maximum ambient temperature before the AAT3697

thermal loop becomes active can now be calculated

using Equation 8:

Eq. 10: TA = 110°C - (50°C/W · 1.40375W)

= 39.8125°C

Therefore, under the stated conditions for this worst

case power dissipation example, the AAT3697 will enter

the thermal loop and lower the fast charge constant cur-

rent when the ambient operating temperature rises

above 39.8°C.

Capacitor Selection

Input Capacitor

In general, it is good design practice to place a decou-

pling capacitor between the ADP pin and ground. An

input capacitor in the range of 1μF to 22μF is recom-

mended. If the source supply is unregulated, it may be

necessary to increase the capacitance to keep the input

voltage above the under-voltage lockout threshold during

device enable and when battery charging is initiated.

If the AAT3697 adapter input is to be used in a system

with an external power supply source, such as a typical

AC-to-DC wall adapter, then a CIN capacitor in the range

of 10μF should be used. A larger input capacitor in this

application will minimize switching or power transient

effects when the power supply is “hot plugged” in.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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Output Capacitor

The AAT3697 only requires a 1μF ceramic capacitor on

the BAT pin to maintain circuit stability. This value should

be increased to 10μF or more if the battery connection is

made any distance from the charger output. If the

AAT3697 is to be used in applications where the battery

can be removed from the charger, such as with desktop

charging cradles, an output capacitor greater than 10μF

may be required to prevent the device from cycling on

and off when no battery is present.

Printed Circuit Board

Layout Considerations

For the best results, it is recommended to physically

place the battery pack as close as possible to the

AAT3697 BAT pin. To minimize voltage drops on the PCB,

keep the high current carrying traces adequately wide.

For maximum power dissipation of the AAT3697 3x3mm

TDFN package, the metal substrate should be solder

bonded to the board. It is also recommended to maxi-

mize the substrate contact to the PCB ground plane layer

to further increase local heat dissipation. Refer to the

AAT3697 evaluation board for a good layout example

(see Figures 4 and 5).

AAT3697 Evaluation Board Layout

Figure 4: AAT3697 Evaluation Board Figure 5: AAT3697 Evaluation Board

Component Side Layout. Solder Side Layout.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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AAT3697 Evaluation Board Schematic Diagram

D2 D1D3

8.06K

1.5K

10μF

0.1μF

SW1

DAT

1 2 3

ON/OFF

ADP

BAT

GND

(TDFN33-12)

BAT

ADP

GND

4ADPP# 5

DATA 7

STAT2 8

STAT1 9

ADPSET 12

10k

AAT3697

RED

LED

RED

LED

GRN

LED

AAT3697 Evaluation Board Bill of Materials (BOM)

Quantity Description Desig. Footprint Manufacturer Part Number

1 Test Pin DATA PAD Mill-Max 6821-0-0001-00-00-08-0

1Connecting Terminal Block,

2.54mm, 2 Position ADP, GND TBLOK2 Phoenix Contact 277-1274-ND

1Connecting Terminal Block,

2.54mm, 3 Position

BAT,

GND, TS TBLOK3 Phoenix Contact 277-1273-ND

2Capacitor, Ceramic, 10μF

6.3V 10% X5R 0805 C1, C2 0805 Murata GRM219R60J106KE19

1Capacitor, Ceramic, 0.1μF

10% 16V X7R 0603 C3 0603 Murata GRM188R71C104KA01D

2Typical Red LED, Ultra-

Bright D1, D3 1206LED Chicago Miniature Lamp CMD15-21SRC/TR8

1 Typical Green LED D2 1206LED Chicago Miniature Lamp CMD15-21VGC/TR8

1 Header, 3-Pin J1 HEADER2MM-3 Sullins 6821-0-0001-00-00-08-0

1Resistor, 10k, 1/16W

1% 0603 SMD R1, R2 0603 Panasonic/ECG P10KCFCT-ND

1Resistor, 8.06k, 1/16W

1% 0603 SMD R6 0603 Panasonic/ECG P8.06KHCT-ND

4Resistor, 1.5k, 1/16W

5% 0603 SMD

R3, R4,

R5, R7 0603 Panasonic/ECG P1.5KCGCT-ND

1Switch Tact 6mm SPST

H = 5.0mm SW1 Switch ITT Industries/ C&K Div CKN9012-ND

1AAT3697 2A Lithium-Ion/

Polymer Battery Charger U1 TDFN33-12 Skyworks AAT3697IWP-4.2

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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Ordering Information

Trickle Charge Package Marking1Part Number (Tape and Reel)2

Yes TDFN33-12 VCXYY AAT3697IWP-4.2-T1

Skyworks Green™ products are compliant with

all applicable legislation and are halogen-free.

For additional information, refer to Skyworks

Deﬁnition of Green™, document number

SQ04-0074.

Package Information3

TDFN33-12

Top View Bottom View

Detail "A"

Side View

3.00

0.05

Index Area Detail "A"

1.70

0.05

3.00

0.05

0.23

0.05

0.75

0.05

2.40

0.05

0.43

0.05

0.45

0.050.23

0.05

0.1 REF

Pin 1 Indicator

(optional)

C0.3

All dimensions in millimeters.

1. XYY = assembly and date code.

2. Sample stock is generally held on part numbers listed in BOLD.

3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing

process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.

AAT3697

DATA SHEET

2A Li-Ion/Polymer Battery Charge

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