January 2000 1 LM4040/4041
LM4040/4041 Micrel
LM4040/4041
Precision Micropower Shunt Voltage Reference
General Description
Ideal for space critical applications, the LM4040 and LM4041
precision voltage references are available in the subminia-
ture (3mm × 1.3mm) SOT-23 surface-mount package.
The LM4040 is the available in fixed reverse breakdown
voltages of 2.500V, 4.096V and 5.000V. The LM4041 is
available with a fixed 1.225V or an adjustable reverse break-
down voltage.
The LM4040 and LM4041’s advanced design eliminates the
need for an external stabilizing capacitor while ensuring
stability with any capacitive load, making them easy to use.
The minimum operating current ranges from 60µA for the
LM4041-1.2 to 74µA for the LM4040-5.0. LM4040 versions
have a maximum operating current of 15mA. LM4041
versions have a maximum operating current of 12mA.
The LM4040 and LM4041 utilizes zener-zap reverse break-
down voltage trim during wafer sort to ensure that the prime
parts have an accuracy of better than ±0.1% (A grade) at
25°C. Bandgap reference temperature drift curvature correc-
tion and low dynamic impedance ensure stable reverse
breakdown voltage accuracy over a wide range of operating
temperatures and currents.
Features
• Small SOT-23 package
• No output capacitor required
• Tolerates capacitive loads
• Fixed reverse breakdown voltages of 1.225, 2.500V,
4.096V and 5.000V
• Adjustable reverse breakdown version
• Contact Micrel for parts with extended temperature
range.
Key Specifications
• Output voltage tolerance (A grade, 25°C) .. ±0.1% (max)
• Low output noise (10Hz to 100Hz)
LM4040 ................................................ 35µVRMS (typ)
LM4041 ................................................ 20µVRMS (typ)
• Wide operating current range
LM4040 ................................................ 60µA to 15mA
LM4041 ................................................ 60µA to 12mA
• Industrial temperature range ..................–40°C to +85°C
• Low temperature coefficient ................100ppm/°C (max)
Applications
• Battery-Powered Equipment
• Data Acquisition Systems
• Instrumentation
• Process Control
• Energy Management
• Product Testing
• Automotive Electronics
• Precision Audio Components
Typical Applications
V
S
R
S
V
R
LM4041
Adjustable
R
1
R
2
V
O
VS
RS
VR
IQ + IL
IQ
IL
LM4040
LM4041
VO
Figure 2. LM4041 Adjustable
Shunt Regulator Application
Figure 1. LM4040, LM4041 Fixed
Shunt Regulator Application
VO = 1.233 (R2/R1 + 1)
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
LM4040/4041 Micrel
LM4040/4041 2 January 2000
Part Number * Voltage Accuracy,
Temp. Coefficient
LM4041AIM3-1.2 1.225V ±0.1%, 100ppm/°C
LM4041BIM3-1.2 1.225V ±0.2%, 100ppm/°C
LM4041CIM3-1.2 1.225V ±0.5%, 100ppm/°C
LM4041DIM3-1.2 1.225V ±1.0%, 150ppm/°C
LM4041CIM3-ADJ 1.24V to 10V ±0.5%, 100ppm/°C
LM4041DIM3-ADJ 1.24V to 10V ±1.0%, 150ppm/°C
Pin Configuration
1
2
3 –
FB
+
Adjustable Version
SOT-23 (M3) Package
Top View
Fixed Version
SOT-23 (M3) Package
Top View
1
2
3
+
–
Pin 3 must float or
be connected to pin 2.
Part Number * Voltage Accuracy,
Temp. Coefficient
LM4040AIM3-2.5 2.500V ±0.1%, 100ppm/°C
LM4040BIM3-2.5 2.500V ±0.2%, 100ppm/°C
LM4040CIM3-2.5 2.500V ±0.5%, 100ppm/°C
LM4040DIM3-2.5 2.500V ±1.0%, 150ppm/°C
LM4040AIM3-4.1 4.096V ±0.1%, 100ppm/°C
LM4040BIM3-4.1 4.096V ±0.2%, 100ppm/°C
LM4040CIM3-4.1 4.096V ±0.5%, 100ppm/°C
LM4040DIM3-4.1 4.096V ±1.0%, 150ppm/°C
LM4040AIM3-5.0 5.000V ±0.1%, 100ppm/°C
LM4040BIM3-5.0 5.000V ±0.2%, 100ppm/°C
LM4040CIM3-5.0 5.000V ±0.5%, 100ppm/°C
LM4040DIM3-5.0 5.000V ±1.0%, 150ppm/°C
Example Field Code
_ _ A 3rd Character A = ±0.1%
B = ±0.2%
C = ±0.5%
D = ±1.0%
Example Field Code
_ 2 _ 2nd Character 1 = 1.225V
2 = 2.500V
4 = 4.096V
5 = 5.000V
A = Adjustable
Example: R2C represents
Reference,
2.500V,
±
0.5%
(LM4040CIM3-2.5)
Note: If 3rd character is omitted, container will
indicate tolerance.
SOT-23 Package Markings
Example Field Code
R _ _ 1st Character R = Reference
Ordering Information
January 2000 3 LM4040/4041
LM4040/4041 Micrel
Absolute Maximum Ratings
Reverse Current.........................................................20mA
Forward Current .........................................................10mA
Maximum Output Voltage
LM4041-Adjustable ...................................................15V
Power Dissipation at TA = 25°C (Note 2) ................306mW
Storage Temperature ............................... –65°C to +150°C
Lead Temperature
Vapor phase (60 seconds) .............................. +215°C
Infrared (15 seconds) ...................................... +220°C
ESD Susceptibility
Human Body Model (Note 3).................................2kV
Machine Model (Note 3) ......................................200V
Operating Ratings (Notes 1 and 2)
Temperature Range
(TMIN ≤ TA ≤ TMAX)..........................–40°C ≤ TA ≤ +85°C
Reverse Current
LM4040-2.5 .......................................... 60µA to 15mA
LM4040-4.1 .......................................... 68µA to 15mA
LM4040-5.0 .......................................... 74µA to 15mA
LM4041-1.2 .......................................... 60µA to 12mA
LM4041-ADJ ........................................ 60µA to 12mA
Output Voltage Range
LM4041-ADJ .......................................... 1.24V to 10V
+
Functional Diagram
LM4040, LM4041 Fixed Functional Diagram
LM4041 Adjustable
+
FB
V
REF
LM4040/4041 Micrel
LM4040/4041 4 January 2000
LM4040-2.5 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades A, B, C, and D designate initial Reverse
Breakdown Voltage tolerance of ±0.1%, ±0.2%, ±0.5%, and ±1.0 respectively.
LM4040AIM3 LM4040BIM3 LM4040CIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits Limits (Limit)
(Note 5) (Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 2.500 V
Reverse Breakdown Voltage IR = 100µA±2.5 ±5.0 ±12 mV (max)
Tolerance ±19 ±21 ±29 mV (max)
IRMIN Minimum Operating Current 45 µA
60 60 60 µA (max)
65 65 65 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 20 ppm/°C
Voltage Temperature IR = 1mA 15 100 100 100 ppm/°C (max)
Coefficient IR = 100µA 15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.3 mV
Change with Operating 0.8 0.8 0.8 mV (max)
Current Change 1.0 1.0 1.0 mV (max)
1mA ≤ IR 15mA 2.5 mV
0.6 0.6 0.6 mV (max)
8.0 8.0 8.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.3 Ω
IAC = 0.1 IR0.8 0.8 0.9 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 35 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits (Limit)
(Note 5)
VRReverse Breakdown Voltage IR = 100µA 2.500 V
Reverse Breakdown Voltage IR = 100µA±25 mV (max)
Tolerance ±49 mV (max)
IRMIN Minimum Operating Current 45 µA
65 µA (max)
70 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 20 ppm/°C
Voltage Temperature IR = 1mA 15 150 ppm/°C (max)
Coefficient IR = 100µA 15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.3 mV
Change with Operating 1.0 mV (max)
Current Change 1.2 mV (max)
1mA ≤ IR 15mA 2.5 mV
8.0 mV (max)
10.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.3 Ω
IAC = 0.1 IR1.1 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 35 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
January 2000 5 LM4040/4041
LM4040/4041 Micrel
LM4040-4.1 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades A, B, C, and D designate initial Reverse
Breakdown Voltage tolerance of ±0.1%, ±0.2%, ±0.5%, and ± 1.0% respectively.
LM4040AIM3 LM4040BIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limit)
(Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 4.096 V
Reverse Breakdown Voltage IR = 100µA±4.1 ±8.2 mV (max)
Tolerance ±31 ±35 mV (max)
IRMIN Minimum Operating Current 50 µA
68 68 µA (max)
73 73 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 30 ppm/°C
Voltage Temperature IR = 1mA 20 100 100 ppm/°C (max)
Coefficient IR = 100µA 20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 0.9 0.9 mV (max)
Current Change 1.2 1.2 mV (max)
1mA ≤ IR 15mA 3.5 mV
7.0 7.0 mV (max)
10.0 10.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.0 1.0 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4040CIM3 LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limits)
(Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 4.096 V
Reverse Breakdown Voltage IR = 100µA±20 ±41 mV (max)
Tolerance ±47 ±81 mV (max)
IRMIN Minimum Operating Current 50 µA
68 73 µA (max)
73 78 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 30 ppm/°C
Voltage Temperature IR = 1mA 20 100 150 ppm/°C (max)
Coefficient IR = 100µA 20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 0.9 1.2 mV (max)
Current Change 1.2 1.5 mV (max)
1mA ≤ IR 15mA 3.0 mV
7.0 9.0 mV (max)
10.0 13.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.0 1.3 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4040/4041 Micrel
LM4040/4041 6 January 2000
LM4040-5.0 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades A, B, C, and D designate initial Reverse
Breakdown Voltage tolerance of ±0.1%, ±0.2%, ±0.5%, and ± 1.0% respectively.
LM4040AIM3 LM4040BIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limit)
(Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 5.000 V
Reverse Breakdown Voltage IR = 100µA±5.0 ±10 mV (max)
Tolerance ±38 ±43 mV (max)
IRMIN Minimum Operating Current 54 µA
74 74 µA (max)
80 80 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 30 ppm/°C
Voltage Temperature IR = 1mA 20 100 100 ppm/°C (max)
Coefficient IR = 100µA 20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 1.0 1.0 mV (max)
Current Change 1.4 1.4 mV (max)
1mA ≤ IR 15mA 3.5 mV
8.0 8.0 mV (max)
12.0 12.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.1 1.1 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4040CIM3 LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limits)
(Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 5.000 V
Reverse Breakdown Voltage IR = 100µA±25 ±50 mV (max)
Tolerance ±58 ±99 mV (max)
IRMIN Minimum Operating Current 54 µA
74 79 µA (max)
80 85 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 30 ppm/°C
Voltage Temperature IR = 1mA 20 100 150 ppm/°C (max)
Coefficient IR = 100µA 20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 1.0 1.3 mV (max)
Current Change 1.3 1.8 mV (max)
1mA ≤ IR 15mA 3.5 mV
8.0 10.0 mV (max)
12.0 15.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.1 1.5 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
January 2000 7 LM4040/4041
LM4040/4041 Micrel
LM4040 Typical Characteristics
+0.5
+0.4
+0.3
+0.2
+0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-40
-22ppm/°C
-51ppm/°C
I
R
= 150µA
12ppm/°C
TEMPERATURE (°C)
V
R
CHANGE (%)
Temperature Drift for Different
Average Temperature Coefficient
-200 20406080100
Output Impedance
vs. Frequency
IR = IRMIN + 100 µA
VR = 5V
2.5V
100 1k 10k 100k 1M
FREQUENCY (Hz)
CL
= 1µF
TANTALUM
XCL
1k
100
10
1
0.1
IMPEDANCE (Ω)
T
J
= 25 °C, ∆ I
R
= 0.1 I
R
CL = 0
Output Impedance
vs. Frequency
I
R
= 1mA
T
J
= 25 °C, ∆I
R
= I
R
C
L
= 0
C
L
= 1µF
TANTALUM
V
R
= 5V
2.5V
1k
100
10
1
0.1
100 1k 10k 100k 1M
FREQUENCY (Hz)
IMPEDANCE (Ω)
LM4040-5.0 R
S
= 30k
T
J
= 25°C
10
0
6
4
2
0
0 100 200 300 400
RESPONSE TIME (µs)
V
R
(V) V
IN
(V)
I
J
= 25°C
LM4040-2.5 RS = 30k
0 20 40 60 80
5
0
6
4
2
0
RESPONSE TIME (µs)
V
R
(V) V
IN
(V)
Test Circuit
V
IN
1Hz rate LM4040
R
S
V
R
•
•
•
•
REVERSE VOLTAGE (V)
A, B, C, Suffix
D Suffix
Reverse Characteristics and
Minimum Operating Current
120
100
80
60
40
20
0
0 2 4 6 8 10
T
J
= 25°C
Typical
IRMIN Guaranteed
2.5V
4.1V
5V
REVERSE CURRENT (µA)
10.0
5.0
1 10 100 1k 10k 100k
FREQUENCY (Hz)
2.0
1.0
0.5
0.2
I
R
= 200µA
T
J
= 25°C
5V
2.5V
Noise Voltage
vs. Frequency
0.1
Noise (µV/ Hz )
√
LM4040/4041 Micrel
LM4040/4041 8 January 2000
LM4041-1.2 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades A, B, C, and D designate initial Reverse
Breakdown Voltage tolerance of ±0.1%, ±0.2%, ±0.5%, and ± 1.0%, respectively.
LM4041AIM3 LM4041BIM3 LM4041CIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits Limits (Limit)
(Note 5) (Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 1.225 V
Reverse Breakdown Voltage IR = 100µA±1.2 ±2.4 ±6 mV (max)
Tolerance ±9.2 ±10.4 ±14 mV (max)
IRMIN Minimum Operating Current 45 µA
60 60 60 µA (max)
65 65 65 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 20 ppm/°C
Voltage Temperature IR = 1mA 15 ±100 ±100 ±100 ppm/°C (max)
Coefficient IR = 100µA 15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.7 mV
Change with Operating 1.5 1.5 1.5 mV (max)
Current Change 2.0 2.0 2.0 mV (max)
1mA ≤ IR 15mA 4.0 mV
6.0 6.0 6.0 mV (max)
8.0 8.0 8.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.5 1.5 1.5 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 20 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4041DIM3 LM4041EIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limit)
(Note 5) (Note 5)
VRReverse Breakdown Voltage IR = 100µA 1.225 V
Reverse Breakdown Voltage IR = 100µA±12 ±25 mV (max)
Tolerance ±24 ±36 mV (max)
IRMIN Minimum Operating Current 45 µA
65 65 µA (max)
70 70 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA 20 ppm/°C
Voltage Temperature IR = 1mA 15 ±150 ±150 ppm/°C (max)
Coefficient IR = 100µA 15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.3 mV
Change with Operating 2.0 2.0 mV (max)
Current Change 2.5 2.5 mV (max)
1mA ≤ IR 15mA 2.5 mV
8.0 8.0 mV (max)
10.0 10.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.3 Ω
IAC = 0.1 IR2.0 2.0 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 35 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
January 2000 9 LM4040/4041
LM4040/4041 Micrel
LM4041-Adjustable Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TJ = 25°C unless otherwise specified (SOT-23, see Note 7),
IRMIN ≤ IR < 12mA, VREF ≤ VOUT ≤ 10V. The grades C and D designate initial Reverse Breakdown Voltage tolerance of ±0.5% and
±1%, respectively for VOUT = 5V.
LM4041CIM3 LM4041DIM3
Symbol Parameter Conditions Typical Units
(Note 4) Limits Limits (Limit)
(Note 5) (Note 5)
VREF Reference Breakdown Voltage IR = 100µA 1.233 V
VOUT = 5V
Reference Breakdown Voltage IR = 100µA±6.2 ±12 mV (max)
Tolerance (Note 8) ±14 ±24 mV (max)
IRMIN Minimum Operating Current 45 µA
60 65 µA (max)
65 70 µA (max)
∆VREF Reference Voltage IRMIN ≤ IR 1mA 0.7 mV
/∆IRChange with Operating SOT-23: 1.5 2.0 mV (max)
Current Change VOUT ≥ 1.6V 2.0 2.5 mV (max)
(Note 7)
1mA ≤ IR 15mA 2 mV
SOT-23: 4 6 mV (max)
VOUT ≥ 1.6V 68mV (max)
(Note 7)
∆VREF Reference Voltage Change IR = 1mA –1.3 mV/V
/∆VOwith Output Voltage Change –2.0 –2.5 mV/V (max)
–2.5 –3.0 mV/V (max)
IFB Feedback Current 60 nA
100 150 nA (max)
120 200 nA (max)
∆VREF Average Reference VOUT = 5V
/∆T Voltage Temperature IR = 10mA 20 ppm/°C
Coefficient IR = 1mA 15 ±100 ±150 ppm/°C (max)
(Note 8) IR = 100µA 15 ppm/°C (max)
ZOUT Dynamic Output Impedance IR = 1mA, f = 120Hz
IAC = 0.1 IR
VOUT = VREF 0.3 Ω
VOUT = 10V 2 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 20 µVRMS
∆VREF Reference Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
LM4040/4041 Micrel
LM4040/4041 10 January 2000
+0.5
+0.4
+0.3
+0.2
+0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-40
-22ppm/°C
-51ppm/°C
I
R
= 150µA
LM4041-1.2
12ppm/°C
TEMPERATURE (°C)
V
R
CHANGE (%)
Temperature Drift for Different
Average Temperature Coefficient
-200 20406080100
C
L
= 1µF
TANTALUM
Output Impedence
vs. Frequency
1k
100
10
1
0.1100 1k 10k 100k 1M
FREQUENCY (Hz)
T
J
= 25° C
∆I
R
= 0.1I
R
LM4041-1.2 C
L
= 0
X
C
I
R
= 150µA
I
R
= 1mA
IMPEDANCE (Ω)
Voltage Impedance
1000
800
600
400
200
01 10 100 1k 10k 100k
FREQUENCY (Hz)
I
R
= 200µA
TJ = 25°C
LM4041-1.2
LM4041-ADJ: V
OUT
= V
REF
√
NOISE (nV/ Hz )
Reverse Characteristics and
Minimum Operating Current
REVERSE VOLTAGE (V)
100
80
60
40
20
00 0.4 0.8 1.2 1.6 2.0
Typical
T
J
= 25°C
LM4041-1.2
REVERSE CURRENT (µA)
Reverse Characteristics and
Minimum Operating Current
REVERSE VOLTAGE (V)
100
80
60
40
20
00 0.4 0.8 1.2 1.6 2.0
Typical
T
J
= 25°C
LM4041-1.2
REVERSE CURRENT (µA)
R
S
30k
V
IN
1Hz rate LM4041-1.2 V
R
Test Circuit
Note 1. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the
device is functional, but do not guarantee specific performance limits. For guaranteed specification and test conditions, see the Electrical
Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when
the device is not operated under the listed test conditions.
Note 2. The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature), θJA
(junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is
PDMAX = (TJMAX – TA)/θJA or the number given in the Absolute Maximum Ratings, whichever is lower. For the LM4040 and LM4041,
TJMAX = 125°C, and the typical thermal resistance (θJA), when board mounted, is 326°C/W for the SOT-23 package.
Note 3. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor
discharged directly into each pin.
Note 4. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 5. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 6. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
A-grade: ±0.75% = ±0.1% ±100ppm/°C × 65°C
B-grade: ±0.85% = ±0.2% ±100ppm/°C × 65°C
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The A-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 0.75% = ±19mV.
Note 7. When VOUT ≤ 1.6V, the LM4041-ADJ must operate at reduced IR. This is caused by the series resistance of the die attach between the die (–)
output and the package (–) output pin. See the Output Saturation curve in the Typical Performance Characteristics section.
Note 8. Reference voltage and temperature coefficient will change with output voltage. See Typical Performance Characteristics curves.
LM4040 and LM4041 Electrical Characteristic Notes
LM4041 Typical Characteristics
January 2000 11 LM4040/4041
LM4040/4041 Micrel
LM4041 Typical Characteristics
LM4041-ADJ
85°C
25°C
-40°C
-40°C
85°C
Reference Voltage vs. Output
Voltage and Temperature
1.244
1.240
1.236
1.232
1.228
1.224
1.2200 2 4 6 8 10
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
Reference Voltage vs.
Temperature and Output Voltage
1.244
1.240
1.236
1.232
1.228
1.224
1.220
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
LM4041-ADJ
V
OUT
= V
REF
V
OUT
= 5V
V
OUT
= 10V
I
R
= 1mA
REFERENCE VOLTAGE (V)
T
J
= 85°C
LM4041-ADJ
T
J
= 25°C, -40°C
Feedback Current vs.
Output Voltage and Temperature
0 2 4 6 8 10
OUTPUT VOLTAGE (V)
100
80
60
40
20
0
FEEDBACK (nA)
Output Saturation
0 2 4 6 8 10 12
OUTPUT CURRENT (mA)
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
LM4041-ADJ
V
ADJ
= V
REF
+ 5µV
-40°C
85°C
25°C
OUTPUT SATURATION (V)
LM4041-ADJ
T
J
= 25 °C
I
R
= 1mA
∆I
R
= 0.1I
R
C
L
= 0
C
L
=1µF
X
C
V
OUT
= 10V
5V
2.5V
1.23V
Output Impedence
vs. Frequency *
1K
100
10
1
0100 1k 10k 100k 1M
FREQUENCY (Hz)
IMPEDANCE (Ω)
C
L
= 0
C
L
=1µF
X
C
5V
2.5V
1.23V
FREQUENCY (Hz)
100 1k 10k 100k 1M
1K
100
10
1
0
Output Impedence
vs. Frequency *
IMPEDANCE (Ω)
V
OUT
= 10V
LM4041-ADJ
T
J
= 25 °C
I
R
= 1mA
∆I
R
= 0.1 I
R
FB STEPS (V)
0 2 4 6 8 10
TJ = 25°C
LM4041-ADJ
0 2 4 6 8
100
80
60
40
20
0
Reverse Characteristics
†
OUTPUT VOLTAGE (V)
REVERSE CURRENT (µA)
LM4041-ADJ
TJ = -40°C
25°C
85°C
0 10 20 30 40
-40°C
OUTPUT
INPUT -40°C
Large Signal Response
‡
10
8
6
4
2
0
RESPONSE TIME (µs)
VOLTAGE (V)
* Output Impedance vs. Freq.
Test Circuit
‡ Large Signal Response
Test Circuit
† Reverse Characteristics
Test Circuit
FB
2V / step
VOU
T
I
R
( + )
( – )
LM4041-ADJ
V
VOUT
LM4041 - ADJ
( + )
FB
( - )
100k
INPUT
+ 15V
5.1k
–
+
C
L
120k
FB
I
R
LM4040/4041 Micrel
LM4040/4041 12 January 2000
Applications Information
The LM4040 and LM4041 have been designed for stable
operation without the need of an external capacitor con-
nected between the (+) and (–) pins. If a bypass capacitor is
used, the references remain stable.
Schottky Diode
LM4040-x.x and LM4041-1.2 in the SOT-23 package have a
parasitic Schottky diode between pin 2 (–) and pin 3 (die
attach interface connect). Pin 3 of the SOT-23 package must
float or be connected to pin 1. LM4041-ADJs use pin 3 as the
(–) output.
Conventional Shunt Regulator
In a conventional shunt regulator application (see Figure 1),
an external series resistor (RS) is connected between the
supply voltage and the LM4040-x.x or LM4041-1.2 reference.
RS determines the current that flows through the load (IL) and
the reference (IQ). Since load current and supply voltage may
vary, RS should be small enough to supply at least the
minimum acceptable IQ to the reference even when the
supply voltage is at its minimum and the load current is at its
maximum value. When the supply voltage is at its maximum
and IL is at its minimum, RS should be large enough so that
the current flowing through the LM4040-x.x is less than
15mA, and the current flowing through the LM4041-1.2 or
LM4041-ADJ is less than 12mA.
RS is determined by the supply voltage (VS), the load and
operating current, (IL and IQ), and the reference’s reverse
breakdown voltage (VR).
Rs = (Vs – VR) / (IL + IQ)
Adjustable Regulator
The LM4041-ADJ’s output voltage can be adjusted to any
value in the range of 1.24V through 10V. It is a function of the
internal reference voltage (VREF) and the ratio of the external
feedback resistors as shown in Figure 2. The output is found
using the equation
(1) VO = VREF´ [ (R2/R1) + 1 ]
where VO is the desired output voltage. The actual value of
the internal VREF is a function of VO. The “corrected” VREF is
determined by
(2) VREF´ = VO (∆VREF / ∆VO) + VY
where VO is the desired output voltage. ∆VREF / ∆VO is found
in the Electrical Characteristics and is typically –1.3mV/V and
VY is equal to 1.233V. Replace the value of VREF´ in equation
(1) with the value found using equation (2).
Note that actual output voltage can deviate from that pre-
dicted using the typical ∆VREF / ∆VO in equation (2); for C-
grade parts, the worst-case ∆VREF / ∆VO is –2.5mV/V and
VY = 1.248V.
The following example shows the difference in output voltage
resulting from the typical and worst case values of
∆VREF / ∆VO:
Let VO = +9V. Using the typical values of ∆VREF /∆VO , VREF
is 1.223V. Choosing a value of R1 = 10kΩ, R2 = 63.272kΩ.
Using the worst case ∆VREF / ∆VO for the C-grade and D-
grade parts, the output voltage is actually 8.965V and 8.946V
respectively. This results in possible errors as large as 0.39%
for the C-grade parts and 0.59% for the D-grade parts. Once
again, resistor values found using the typical value of
∆VREF / ∆VO will work in most cases, requiring no further
adjustment.
Figure 4. Voltage Level Detector
R1
120
k
R2
1M
FB
+
–
LM4041-ADJ
D1
λ
< –12V
LED ON
R3
200
–5V
D1 λ
LM4041-
ADJ
R1
120k
R2
1M
FB
–
+
R3
330
> –12V
LED ON
–5V
Figure 3. Voltage Level Detector
January 2000 13 LM4040/4041
LM4040/4041 Micrel
Figure 8. Bidirectional Adjustable Clamp
±2.4 to ±6V
VIN
R1I
LM4041-ADJ
D2
1N457
R3
1M
R2
330k
VOUT
LM4041-ADJ
FB
+
–
FB –
+
D1
1N457 R4
330k
VIN
R1
R2
390k
R3
500k
FB
+
–
LM4041-ADJ
D1
1N457
R4
390k
D2
1N457
LM4041-ADJ
FB
+
–
I
VOUT
Figure 7. Bidirectional Adjustable Clamp
±18V to ±2.4V
0 to 20mA
R1
390Ω
± 2%
1N4002
D2
LM4041-ADJ
+
–
FB
λ
D1* 1
2
3
6
5
4
4N28
N.C.
I
THRESHOLD
=
+
= 3.2mA
1.24V
R1 5µA
4N28 GAIN
N.C.
R2
470k
CMOS
+ 5V
Figure 9. Floating Current Detector
D1
1N457 R3
510k
LM4041-ADJ
D2
1N457
V
OUT
R2
510k
V
IN
R1
I
+FB FB
LM4041-ADJ +
–
–
Figure 6. Bidirectional Clamp
±2.4V
Figure 5. Fast Positive Clamp
2.4V + ∆VD1
V
IN
V
OUT
D1
1N914
D2
1N914
R3
240k
R4
240k
R1
I
R2
50µA
LM4041-ADJ FB
+
–
LM4040/4041 Micrel
LM4040/4041 14 January 2000
+15V
R1
2N2905
2N
3964
R2
120k
LM4041-ADJ FB
+
–
1.24V
R1
IOUT =
1µA < IOUT = 100mA
+5V
R3
100k
CMOS
R4
10M
1
2
3
6
5
4
4N28
N.C.
R2
22k
LM4041-ADJ
+
–
R1
332Ω
±1% FB
1N914
2N2222
D1* λ
I
THRESHOLD
=
= 3.7mA ± 2%
1.24V
R1
D2
1N4002
0 to 20 mA
Figure 10. Current Source
Figure 11. Precision Floating Current Detector
* D1 can be any LED, VF = 1.5V to 2.2V at 3mA. D1 may act as an indicator. D1 will
be on if ITHRESHOLD falls below the threshold current, except with I = O.
January 2000 15 LM4040/4041
LM4040/4041 Micrel
Package Information
0.15 (0.006)
0.076 (0.0030)
0.41 (0.016)
0.13 (0.005)
3.05 (0.120)
2.67 (0.105) 8°
0°
0.445 (0.0175) TYP 3 PLACES
2.50 (0.098)
2.10 (0.083)
1.40 (0.055)
1.19 (0.047)
0.10 (0.004)
0.013 (0.0005)
1.15 (0.045)
0.76 (0.030)
DIMENSIONS:
MM (INCH)
2.36 (0.093)
2.28 (0.090)
C
L
C
L
SOT-23 (M3)
LM4040/4041 Micrel
LM4040/4041 16 January 2000
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 2000 Micrel Incorporated
