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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 subminiature (3mm x 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 breakdown 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 60A for the LM4041-1.2 to 74A 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 breakdown voltage trim during wafer sort to ensure that the prime parts have an accuracy of better than 0.1% (A grade) at 25C. Bandgap reference temperature drift curvature correction 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, 25C) .. 0.1% (max) * Low output noise (10Hz to 100Hz) LM4040 ................................................ 35VRMS (typ) LM4041 ................................................ 20VRMS (typ) * Wide operating current range LM4040 ................................................ 60A to 15mA LM4041 ................................................ 60A to 12mA * Industrial temperature range .................. -40C to +85C * 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
VS
VS RS VR LM4040 LM4041 I Q + IL IL IQ
RS VR
VO
VO R1
VO = 1.233 (R2/R1 + 1)
LM4041 Adjustable
R2
Figure 1. LM4040, LM4041 Fixed Shunt Regulator Application
Figure 2. LM4041 Adjustable Shunt Regulator Application
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
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LM4040/4041
LM4040/4041
Micrel
Pin Configuration
+ -
1 3
FB +
1 3- 2
2
Pin 3 must float or be connected to pin 2.
Fixed Version SOT-23 (M3) Package Top View
Adjustable Version SOT-23 (M3) Package Top View
Ordering Information
Part Number * LM4040AIM3-2.5 LM4040BIM3-2.5 LM4040CIM3-2.5 LM4040DIM3-2.5 LM4040AIM3-4.1 LM4040BIM3-4.1 LM4040CIM3-4.1 LM4040DIM3-4.1 LM4040AIM3-5.0 LM4040BIM3-5.0 LM4040CIM3-5.0 LM4040DIM3-5.0 Voltage 2.500V 2.500V 2.500V 2.500V 4.096V 4.096V 4.096V 4.096V 5.000V 5.000V 5.000V 5.000V Accuracy, Temp. Coefficient 0.1%, 100ppm/C 0.2%, 100ppm/C 0.5%, 100ppm/C 1.0%, 150ppm/C 0.1%, 100ppm/C 0.2%, 100ppm/C 0.5%, 100ppm/C 1.0%, 150ppm/C 0.1%, 100ppm/C 0.2%, 100ppm/C 0.5%, 100ppm/C 1.0%, 150ppm/C Part Number * LM4041AIM3-1.2 LM4041BIM3-1.2 LM4041CIM3-1.2 LM4041DIM3-1.2 LM4041CIM3-ADJ LM4041DIM3-ADJ Voltage 1.225V 1.225V 1.225V 1.225V 1.24V to 10V 1.24V to 10V Accuracy, Temp. Coefficient 0.1%, 100ppm/C 0.2%, 100ppm/C 0.5%, 100ppm/C 1.0%, 150ppm/C 0.5%, 100ppm/C 1.0%, 150ppm/C
SOT-23 Package Markings
Example R__ Field 1st Character Code R = Reference Example _2_ Field Code Example __A Field 3rd Character Code A = 0.1% B = 0.2% C = 0.5% D = 1.0% 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.
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Functional Diagram LM4040, LM4041 Fixed
Functional Diagram LM4041 Adjustable
+
+
VREF
FB
Absolute Maximum Ratings
Reverse Current ......................................................... 20mA Forward Current ......................................................... 10mA Maximum Output Voltage LM4041-Adjustable ................................................... 15V Power Dissipation at TA = 25C (Note 2) ................ 306mW Storage Temperature ............................... -65C to +150C Lead Temperature Vapor phase (60 seconds) .............................. +215C Infrared (15 seconds) ...................................... +220C ESD Susceptibility Human Body Model (Note 3) ................................. 2kV Machine Model (Note 3) ...................................... 200V
Operating Ratings (Notes 1 and 2)
Temperature Range (TMIN TA TMAX) .......................... -40C TA +85C Reverse Current LM4040-2.5 .......................................... 60A to 15mA LM4040-4.1 .......................................... 68A to 15mA LM4040-5.0 .......................................... 74A to 15mA LM4041-1.2 .......................................... 60A to 12mA LM4041-ADJ ........................................ 60A to 12mA Output Voltage Range LM4041-ADJ .......................................... 1.24V to 10V
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LM4040-2.5 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25C. 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 (Note 4) 2.500 2.5 Limits (Note 5) Limits (Note 5) 5.0 Limits (Note 5) 12 Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
19
60 65
21
60 65 100
29
60 65 100
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
45
VR/T
Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change
IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA
20 15 15 0.3
100
VR/IR
0.8 1.0 2.5 0.6 8.0 0.3 0.8 35 120
0.8 1.0 0.6 8.0 0.8
0.8 1.0 0.6 8.0 0.9
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
LM4040DIM3 Symbol Parameter Conditions Typical (Note 4) 2.500 25 Limits (Note 5) Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
49
65 70
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
45
VR/T
Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change
IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA
20 15 15 0.3
150
VR/IR
1.0 1.2 2.5 8.0 10.0 0.3 1.1 35 120
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
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LM4040-4.1 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25C. 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 Symbol Parameter Conditions Typical (Note 4) 4.096 4.1 Limits (Note 5) LM4040BIM3 Limits (Note 5) 8.2 Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
31
68 73
35
68 73 100
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
50
VR/T
Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change
IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA
30 20 20 0.5
100
VR/IR
0.9 1.2 3.5 7.0 10.0 0.5 1.0 80 120
0.9 1.2 7.0 10.0 1.0
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
LM4040CIM3 Symbol Parameter Conditions Typical (Note 4) 4.096 20 50 68 73 Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA 30 20 20 0.5 0.9 1.2 3.0 7.0 10.0 0.5 1.0 80 120 100 Limits (Note 5)
LM4040DIM3 Limits (Note 5) 41 Units (Limits) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
47
81
73 78 150
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
VR/T
VR/IR
1.2 1.5 9.0 13.0 1.3
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
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LM4040-5.0 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25C. 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 Symbol Parameter Conditions Typical (Note 4) 5.000 5.0 Limits (Note 5) LM4040BIM3 Limits (Note 5) 10 Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
38
74 80
43
74 80 100
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
54
VR/T
Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change
IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA
30 20 20 0.5
100
VR/IR
1.0 1.4 3.5 8.0 12.0 0.5 1.1 80 120
1.0 1.4 8.0 12.0 1.1
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
LM4040CIM3 Symbol Parameter Conditions Typical (Note 4) 5.000 25 54 74 80 Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA 30 20 20 0.5 1.0 1.3 3.5 8.0 12.0 0.5 1.1 80 120 100 Limits (Note 5)
LM4040DIM3 Limits (Note 5) 50 Units (Limits) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
58
99
79 85 150
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
VR/T
VR/IR
1.3 1.8 10.0 15.0 1.5
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
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LM4040 Typical Characteristics
Temperature Drift for Different Average Temperature Coefficient
+0.5 IR = 150A +0.4 +0.3 +0.2 12ppm/C +0.1 0 -0.1 -0.2 -22ppm/C -0.3 -51ppm/C -0.4 -0.5 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
1k
Output Impedance vs. Frequency
TJ = 25 C, IR = 0.1 IR
Output Impedance vs. Frequency
1k IR= 1mA TJ = 25 C, IR = IR CL= 0 VR = 5V 2.5V 1 CL= 1F
TANTALUM
IR = IRMIN + 100 A
VR CHANGE (%)
IMPEDANCE ()
VR = 5V 10 2.5V
CL = 0 CL = 1F
TANTALUM
IMPEDANCE ()
100
100
10
1 XCL 0.1 100 1k 10k 100k FREQUENCY (Hz) 1M
0.1 100
1k
10k
100k
1M
FREQUENCY (Hz)
Reverse Characteristics and Minimum Operating Current
2.5V 4.1V 5V
120 10.0
*
Noise Voltage vs. Frequency
IR = 200A TJ = 25C
REVERSE CURRENT (A)
100 80 60 40 20 0 0
Noise (V/ Hz )
ed nte ara Gu uffix ix IN D S , Suff I RM ,C ,B *A
5.0 2.0 1.0 0.5 0.2 0.1 1
*
*
ical Typ
5V 2.5V
TJ = 25C
2
4
6
8
10
10
100
1k
10k
100k
REVERSE VOLTAGE (V)
FREQUENCY (Hz)
RS VIN 1Hz rate VR
LM4040
Test Circuit
LM4040-2.5
VIN (V)
RS = 30k
VIN (V)
10 0
LM4040-5.0
RS = 30k
5 0 IJ = 25C 6
TJ = 25C
6
VR (V)
2 0 0 20 40 60 RESPONSE TIME (s) 80
VR (V)
4
4 2 0 0 100 200 300 400
RESPONSE TIME (s)
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LM4041-1.2 Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25C. 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 (Note 4) 1.225 1.2 45 60 65 Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA 20 15 15 0.7 1.5 2.0 4.0 6.0 8.0 0.5 1.5 20 120 1.5 1.5 6.0 8.0 6.0 8.0 1.5 2.0 1.5 2.0 60 65 60 65 Limits (Note 5) Limits (Note 5) 2.4 Limits (Note 5) 6 Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
9.2
10.4
14
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
VR/T
100
100
100
VR/IR
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
LM4041DIM3 Symbol Parameter Conditions Typical (Note 4) 1.225 12 45 65 70 Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR = 10mA IR = 1mA IR = 100A IRMIN IR 1mA 20 15 15 0.3 2.0 2.5 2.5 8.0 10.0 0.3 2.0 35 120 Limits (Note 5)
LM4041EIM3 Limits (Note 5) 25 Units (Limit) V
VR
Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance
IR = 100A IR = 100A
24
36
65 70
mV (max) mV (max) A A (max) A (max) ppm/C ppm/C (max) ppm/C (max) mV mV (max) mV (max) mV mV (max) mV (max) (max) VRMS ppm
IRMIN
Minimum Operating Current
VR/T
150
150
VR/IR
2.0 2.5 8.0 10.0 2.0
1mA IR 15mA
ZR eN VR
Reverse Dynamic Impedance Wideband Noise Reverse Breakdown Voltage Long Term Stability
IR = 1mA, f = 120Hz IAC = 0.1 IR IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
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LM4041-Adjustable Electrical Characteristics
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TJ = 25C 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 Symbol Parameter Conditions Typical (Note 4) 1.233 6.2 12 Limits (Note 5) LM4041DIM3 Limits (Note 5) Units (Limit) V mV (max) mV (max) A A (max) A (max) mV mV (max) mV (max) mV mV (max) mV (max) mV/V mV/V (max) mV/V (max) nA nA (max) nA (max) ppm/C ppm/C (max) ppm/C (max)
VREF
Reference Breakdown Voltage Reference Breakdown Voltage Tolerance (Note 8)
IR = 100A VOUT = 5V IR = 100A
14
60 65
24
65 70 2.0 2.5
IRMIN
Minimum Operating Current
45
VREF /IR
Reference Voltage Change with Operating Current Change
IRMIN IR 1mA SOT-23: VOUT 1.6V (Note 7) 1mA IR 15mA SOT-23: VOUT 1.6V (Note 7)
0.7 1.5 2.0 2 4 6 -1.3 -2.0 -2.5 60 100 120 150 200 -2.5 -3.0 6 8
VREF /VO IFB
Reference Voltage Change with Output Voltage Change Feedback Current
IR = 1mA
VREF /T
Average Reference Voltage Temperature Coefficient (Note 8) Dynamic Output Impedance
VOUT = 5V IR = 10mA IR = 1mA IR = 100A IR = 1mA, f = 120Hz IAC = 0.1 IR VOUT = VREF VOUT = 10V IR = 100A 10Hz f 10kHz t = 1000hrs T = 25C 0.1C IR = 100A
20 15 15
100
150
ZOUT
0.3 2 20 120
(max) VRMS ppm
eN VREF
Wideband Noise Reference Voltage Long Term Stability
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LM4040 and LM4041 Electrical Characteristic Notes
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. The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature), JA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDMAX = (TJMAX - TA)/JA or the number given in the Absolute Maximum Ratings, whichever is lower. For the LM4040 and LM4041, TJMAX = 125C, and the typical thermal resistance (JA), when board mounted, is 326C/W for the SOT-23 package. The human body model is a 100pF capacitor discharged through a 1.5k resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. Typicals are at TJ = 25C and represent most likely parametric norm. Limits are 100% production tested at 25C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL) methods. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown Voltage Tolerance [(VR/T)(65C)(VR)]. VR/T is the VR temperature coefficient, 65C is the temperature range from -40C to the reference point of 25C, 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 x 65C B-grade: 0.85% = 0.2% 100ppm/C x 65C C-grade: 1.15% = 0.5% 100ppm/C x 65C D-grade: 1.98% = 1.0% 150ppm/C x 65C Example: The A-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of 2.5 x 0.75% = 19mV. Note 7. Note 8. 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. Reference voltage and temperature coefficient will change with output voltage. See Typical Performance Characteristics curves.
Note 2.
Note 3. Note 4. Note 5. Note 6.
LM4041 Typical Characteristics
Temperature Drift for Different Average Temperature Coefficient
+0.5 IR = 150A +0.4 LM4041-1.2 +0.3 +0.2 12ppm/C +0.1 0 -0.1 -0.2 -22ppm/C -0.3 -51ppm/C -0.4 -0.5 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 1k
Output Impedence vs. Frequency
TJ = 25 C IR = 0.1IR LM4041-1.2 1000 800 600 400 200 XC 100 1k 10k 100k FREQUENCY (Hz) 1M 0 1
Voltage Impedance
IR = 200A TJ = 25C LM4041-1.2 LM4041-ADJ: VOUT = VREF
VR CHANGE (%)
IMPEDANCE ()
CL= 0
10 IR = 150A 1 I = 1mA R 0.1
CL= 1F
TANTALUM
NOISE (nV/ Hz )
100
10
100
1k
10k
100k
FREQUENCY (Hz)
Reverse Characteristics and Minimum Operating Current
100 100
Reverse Characteristics and Minimum Operating Current
REVERSE CURRENT (A)
REVERSE CURRENT (A)
RS 30k
80 60 40 20 0 Typical TJ = 25C LM4041-1.2 0 0.4 0.8 1.2 1.6 2.0
80 60 40 20 0 Typical TJ = 25C LM4041-1.2 0 0.4 0.8 1.2 1.6 2.0
VIN 1Hz rate
V LM4041-1.2
R
Test Circuit
REVERSE VOLTAGE (V)
REVERSE VOLTAGE (V)
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LM4041 Typical Characteristics
Reference Voltage vs. Output Voltage and Temperature
1.244
REFERENCE VOLTAGE (V)
Reference Voltage vs. Temperature and Output Voltage
1.244
REFERENCE VOLTAGE (V)
Feedback Current vs. Output Voltage and Temperature
100 80
FEEDBACK (nA)
25C
1.240 1.236 -40C 1.232 1.228 1.224 1.220 0
85C
LM4041-ADJ
1.240 1.236 1.232 1.228 1.224
LM4041-ADJ IR = 1mA VOUT = VREF
LM4041-ADJ
TJ = 85C 60 40 20 0 0 2 4 6 8 OUTPUT VOLTAGE (V) 10 TJ = 25C, -40C
-40C
VOUT = 5V VOUT = 10V
85C
2 4 6 8 OUTPUT VOLTAGE (V)
10
1.220 -40 -20
0
20
40
60 80 100
TEMPERATURE (C)
Output Saturation
1.7
Output Impedence vs. Frequency *
1K
Output Impedence vs. Frequency *
1K
LM4041-ADJ TJ = 25 C IR = 1mA IR = 0.1 IR
OUTPUT SATURATION (V)
LM4041-ADJ 1.6 VADJ = VREF + 5V
IMPEDANCE ()
1.5 1.4 1.3 1.2 25C 1.1 1.0 0 2 4 6 8 10 12 -40C 85C
IMPEDANCE ()
100
LM4041-ADJ TJ = 25 C IR = 1mA IR = 0.1IR
CL = 0
VOUT = 10V
CL = 0
100
VOUT = 10V
10
5V 2.5V 1.23V
10
CL=1F XC
5V 2.5V 1.23V
CL=1F
1
1 XC
0
100
1k
10k
100k
1M
0 100
1k
10k
100k
1M
OUTPUT CURRENT (mA)
FREQUENCY (Hz)
FREQUENCY (Hz)
Reverse Characteristics
0
100
REVERSE CURRENT (A)
FB STEPS (V) 2 4 6
8
IR
80 60 40 20 0
(+) LM4041-ADJ
FB V OUT ( - ) 2V / step V
CL
IR
+ -
120k FB
TJ = 25C LM4041-ADJ
0 2 4 6 8 10 OUTPUT VOLTAGE (V)
Reverse Characteristics Test Circuit
* Output Impedance vs. Freq. Test Circuit
Large Signal Response
-40C 10 LM4041-ADJ TJ = -40C OUTPUT 25C 85C INPUT -40C
+ 15V 5.1k INPUT 100k FB (+) LM4041 - ADJ VOUT (-)
VOLTAGE (V)
8 6 4 2 0 0
10 20 30 40 RESPONSE TIME (s)
Large Signal Response Test Circuit
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LM4040/4041
Micrel
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 predicted using the typical VREF / VO in equation (2); for Cgrade 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 = 10k, R2 = 63.272k. Using the worst case VREF / VO for the C-grade and Dgrade 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.
Applications Information
The LM4040 and LM4041 have been designed for stable operation without the need of an external capacitor connected 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)
+ FB 120k
LM4041-ADJ D1
D1
R1
+ FB
R1 120k R2 1M
-
R2 1M
LM4041- ADJ
< -12V R3 LED ON 200
-5V
> -12V R3 LED ON 330 -5V
Figure 3. Voltage Level Detector
Figure 4. Voltage Level Detector
LM4040/4041
12
January 2000
LM4040/4041
VIN I R2 50A R1 VOUT D1 1N914 D2 1N914 + LM4041-ADJ - FB R3 240k
LM4041-ADJ + FB
Micrel
VIN I R1 R2 510k - FB + R3 510k VOUT D2 1N457 LM4041-ADJ
R4 240k
- D1 1N457
Figure 5. Fast Positive Clamp 2.4V + VD1
Figure 6. Bidirectional Clamp
2.4V
VIN I R1 VOUT R2 390k R3 500k FB R4 390k D1 1N457 FB - + D2 1N457 LM4041-ADJ LM4041-ADJ + - I
VIN R1 VOUT R2 330k FB R3 1M D2 1N457
+ LM4041-ADJ -
FB - +
LM4041-ADJ
D1 1N457
R4 330k
Figure 7. Bidirectional Adjustable Clamp 18V to 2.4V
0 to 20mA
Figure 8. Bidirectional Adjustable Clamp 2.4 to 6V
+ 5V R1 390 2% D1* + FB LM4041-ADJ - 1 2 3 6 5 4 N.C. CMOS R2 470k
1N4002 D2
N.C. I THRESHOLD =
4N28
1.24V 5A + = 3.2mA R1 4N28 GAIN
Figure 9. Floating Current Detector
January 2000
13
LM4040/4041
LM4040/4041
Micrel
+15V
+ LM4041-ADJ -
R1 FB 2N2905
R2 120k
2N 3964
1A < IOUT = 100mA 1.24V I OUT = R1
Figure 10. Current Source
0 to 20 mA R1 332 1% D2 1N4002 +5V + FB 1N914
2N2222
LM4041-ADJ - R3 100k 1 6 5 4 4N28 R4 10M
R2 22k D1*
2
CMOS
3 N.C. 1.24V = 3.7mA 2% I THRESHOLD = R1
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.
LM4040/4041
14
January 2000
LM4040/4041
Micrel
Package Information
C L C L
1.40 (0.055) 2.50 (0.098) 1.19 (0.047) 2.10 (0.083)
2.36 (0.093) 2.28 (0.090) 3.05 (0.120) 2.67 (0.105)
DIMENSIONS: MM (INCH) 1.15 (0.045) 0.76 (0.030) 8 0 0.15 (0.006) 0.076 (0.0030)
0.445 (0.0175) TYP 3 PLACES
0.10 (0.004) 0.013 (0.0005)
0.41 (0.016) 0.13 (0.005)
SOT-23 (M3)
January 2000
15
LM4040/4041
LM4040/4041
Micrel
MICREL INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131
FAX
USA
+ 1 (408) 944-0800
+ 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. (c) 2000 Micrel Incorporated
LM4040/4041
16
January 2000

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