General Description
The LM4040 is a precision two-terminal shunt mode,
bandgap voltage reference available in fixed reverse
breakdown voltages of 2.048V, 2.500V, 3.000V, 3.3V,
4.096V, and 5.000V. Ideal for space-critical applica-
tions, the LM4040 is offered in the subminiature 3-pin
SC70 surface-mount package (1.8mm ✕1.8mm), 50%
smaller than comparable devices in SOT23 surface-
mount packages (SOT23 versions are also available).
Laser-trimmed resistors ensure precise initial accuracy.
With a 100ppm/°C temperature coefficient, the device
is offered in four grades of initial accuracy ranging from
0.1% to 1%. The LM4040 has a 60µA to 15mA shunt
current capability with low dynamic impedance, ensur-
ing stable reverse breakdown voltage accuracy over a
wide range of operating temperatures and currents.
The LM4040 does not require an external stabilizing
capacitor while ensuring stability with any capacitive
load.
The LM4040 is guaranteed over the temperature range
of -40°C to +125°C.
For a 1.225V output version, refer to the LM4041 data
sheet.
________________________Applications
Portable, Battery-Powered Equipment
Notebook Computers
Cell Phones
Industrial Process Controls
Features
♦Ultra-Small 3-Pin SC70 Package
♦0.1% (max) Initial Accuracy
♦100ppm/°C (max) Temperature Coefficient
Guaranteed over -40°C to +125°C Temperature
Range
♦Wide Operating Current Range: 60µA to 15mA
♦Low 28µVRMS Output Noise (10Hz to 10kHz)
♦2.048V, 2.500V, 3.000V, 3.3V, 4.096V, and 5.000V
Fixed Reverse Breakdown Voltages
♦No Output Capacitors Required
♦Tolerates Capacitive Loads
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
________________________________________________________________ Maxim Integrated Products 1
-
1
3N.C.*
+
LM4040
SC70-3/SOT23-3
TOP VIEW
2
*PIN 3 MUST BE LEFT FLOATING
OR CONNECTED TO PIN 2.
PART TEMP RANGE PIN-
PACKAGE
OUTPUT
VOLTAGE
(V)
LM4040_IM3-2.1 -40°C to +85°C 3 SOT23-3 2.048
LM4040_IX3-2.1 -40°C to +85°C 3 SC70-3 2.048
LM4040_EM3-2.1 -40°C to +125°C 3 SOT23-3 2.048
LM4040_EX3-2.1 -40°C to +125°C 3 SC70-3 2.048
LM4040_IM3-2.5 -40°C to +85°C 3 SOT23-3 2.500
LM4040_IX3-2.5 -40°C to +85°C 3 SC70-3 2.500
LM4040_EM3-2.5 -40°C to +125°C 3 SOT23-3 2.500
LM4040_EX3-2.5 -40°C to +125°C 3 SC70-3 2.500
LM4040_IM3-3.0 -40°C to +85°C 3 SOT23-3 3.000
LM4040_IX3-3.0 -40°C to +85°C 3 SC70-3 3.000
LM4040_EM3-3.0 -40°C to +125°C 3 SOT23-3 3.000
LM4040_EX3-3.0 -40°C to +125°C 3 SC70-3 3.000
LM4040_EX3-3.3 -40°C to +125°C 3 SC70-3 3.300
LM4040_IM3-4.1 -40°C to +85°C 3 SOT23-3 4.096
LM4040_IX3-4.1 -40°C to +85°C 3 SC70-3 4.096
LM4040_EM3-4.1 -40°C to +125°C 3 SOT23-3 4.096
LM4040_EX3-4.1 -40°C to +125°C 3 SC70-3 4.096
LM4040_IM3-5.0 -40°C to +85°C 3 SOT23-3 5.000
LM4040_IX3-5.0 -40°C to +85°C 3 SC70-3 5.000
LM4040_EM3-5.0 -40°C to +125°C 3 SOT23-3 5.000
LM4040_EX3-5.0 -40°C to +125°C 3 SC70-3 5.000
Pin Configuration
Selector Guide
19-1787; Rev 5; 7/05
Ordering Information appears at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—2.048V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Reverse Current (cathode to anode) ..................................20mA
Forward Current (anode to cathode) ..................................10mA
Continuous Power Dissipation (TA= +70°C)
3-Pin SC70 (derate 2.17mW/°C above +70°C)............174mW
3-Pin SOT23 (derate 4.01mW/°C above +70°C)..........320mW
Operating Temperature Range
LM4040_I_ _ _..................................................-40°C to +85°C
LM4040_E_ _ _ ..............................................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s)..................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LM4040A (0.1%)
2.046 2.048 2.050
LM4040B (0.2%)
2.044 2.048 2.052
LM4040C (0.5%)
2.038 2.048 2.058
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
2.028 2.048 2.068
V
LM4040A
±2.0
±15
LM4040B
±4.0
±17
LM4040C ±10 ±23
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±20 ±41
mV
LM4040A/B/C 45 65
Minimum Operating Current IRMIN LM4040D 45 70 µA
IR = 10mA ±20
LM4040A/B/C ±15
±100
IR = 1mA LM4040D ±15
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
ppm/°C
LM4040A/B/C 0.3 1.0
IRMIN ≤ IR ≤ 1mA LM4040D 0.3 1.2
LM4040A/B/C 2.5 8.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 2.5
10.0
mV
LM4040A/B 0.3 0.8
LM4040C 0.3 0.9
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.3 1.1
Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 28
µVRMS
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
ppm
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS—2.500V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
LM4040A (0.1%)
2.4975 2.5000 2.5025
LM4040B (0.2%)
2.4950 2.5000 2.5050
LM4040C (0.5%)
2.4875 2.5000 2.5125
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
2.4750 2.5000 2.5250
V
LM4040A
±2.0
±19
LM4040B
±4.0
±21
LM4040C ±10 ±29
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±20 ±49
mV
LM4040A/B/C 45 65
Minimum Operating Current IRMIN LM4040D 45 70 µA
IR = 10mA ±20
LM4040A/B/C ±15
±100
IR = 1mA LM4040D ±15
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
LM4040A/B/C 0.3 1.0
IRMIN ≤ IR ≤ 1mA LM4040D 0.4 1.2
LM4040A/B/C 2.5 8.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 2.5
10.0
mV
LM4040A/B 0.3 0.8
LM4040C 0.3 0.9
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.3 1.1
Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 35
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
4_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—3.000V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LM4040A (0.1%)
2.997 3.000 3.003
LM4040B (0.2%)
2.994 3.000 3.006
LM4040C (0.5%)
2.985 3.000 3.015
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
2.970 3.000 3.030
V
LM4040A
±3.0
±22
LM4040B
±6.0
±26
LM4040C ±15 ±34
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±30 ±59
mV
LM4040A/B/C 45 67
Minimum Operating Current IRMIN LM4040D 45 70 µA
IR = 10mA ±20
LM4040A/B/C ±15
±100
IR = 1mA LM4040D ±15
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
ppm/°C
LM4040A/B/C 0.3 1.0
IRMIN ≤ IR ≤ 1mA LM4040D 0.3 1.2
LM4040A/B/C 2.5 8.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 2.5
10.0
mV
LM4040A/B 0.3 0.8
LM4040C 0.3 0.9
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.3 1.1
Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 45
µVRMS
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
ppm
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS—3.300V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LM4040A (0.1%)
3.2967 3.3000 3.3033
LM4040B (0.2%)
3.2934 3.3000 3.3066
LM4040C (0.5%)
3.2835 3.3000 3.3165
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
3.2670 3.3000 3.3330
V
LM4040A
±3.0
±22
LM4040B
±6.0
±26
LM4040C ±15 ±34
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±30 ±59
mV
LM4040A/B/C 45 67
Minimum Operating Current IRMIN LM4040D 45 70 µA
IR = 10mA ±20
LM4040A/B/C ±15
±100
IR = 1mA LM4040D ±15
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
ppm/°C
LM4040A/B/C 0.3 1.0
IRMIN ≤ IR ≤ 1mA LM4040D 0.3 1.2
LM4040A/B/C 2.5 8.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 2.5
10.0
mV
LM4040A/B 0.3 0.8
LM4040C 0.3 0.9
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.3 1.1
Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 50
µVRMS
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
ppm
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
6_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—4.096V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LM4040A (0.1%)
4.092 4.096 4.100
LM4040B (0.2%)
4.088 4.096 4.104
LM4040C (0.5%)
4.076 4.096 4.116
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
4.055 4.096 4.137
V
LM4040A
±4.1
±31
LM4040B
±8.2
±35
LM4040C ±20 ±47
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±41 ±81
mV
LM4040A/B/C 50 73
Minimum Operating Current IRMIN LM4040D 50 78 µA
IR = 10mA ±30
LM4040A/B/C ±20
±100
IR = 1mA LM4040D ±20
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
ppm/°C
LM4040A/B/C 0.5 1.2
IRMIN ≤ IR ≤ 1mA LM4040D 0.5 1.5
LM4040A/B/C 3.0
10.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 3.0
13.0
mV
LM4040A/B/C 0.5 1.0
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.5 1.3 Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 64
µVRMS
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
ppm
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
_______________________________________________________________________________________ 7
Note 1: All devices are 100% production tested at +25°C and are guaranteed by design for TA= TMIN to TMAX, as specified.
Note 2: The overtemperature limit for Reverse Breakdown Voltage Tolerance is defined as the room-temperature Reverse
Breakdown Voltage Tolerance ±[(∆VR/ ∆T)(max∆T)(VR)], where ∆VR/ ∆T is the VRtemperature coefficient, max∆T is the
maximum difference in temperature from the reference point of +25°C to TMIN or TMAX, and VRis the reverse breakdown
voltage. The total overtemperature tolerance for the different grades in the temperature range where max∆T = +65°C is
shown below:
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
The total over-temperature tolerance for the different grades in the extended temperature range where max ∆T = +100°C is
shown below:
A grade: ±1.1% = ±0.1% ±100ppm/°C ✕100°C
B grade: ±1.2% = ±0.2% ±100ppm/°C ✕100°C
C grade: ±1.5% = ±0.5% ±100ppm/°C ✕100°C
D grade: ±2.5% = ±1.0% ±150ppm/°C ✕100°C
Therefore, as an example, the A-grade LM4040-2.5 has an over-temperature reverse breakdown voltage tolerance of ±2.5V
✕0.75% = ±19mV.
Note 3: Guaranteed by design.
ELECTRICAL CHARACTERISTICS—5.000V
(IR= 100µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LM4040A (0.1%)
4.995 5.000 5.005
LM4040B (0.2%)
4.990 5.000 5.010
LM4040C (0.5%)
4.975 5.000 5.025
Reverse Breakdown Voltage VRTA = +25°C
LM4040D (1.0%)
4.950 5.000 5.050
V
LM4040A
±5.0
±38
LM4040B ±10 ±43
LM4040C ±25 ±58
Reverse Breakdown Voltage
Tolerance (Note 2) VR
LM4040D ±50 ±99
mV
LM4040A/B/C 54 80
Minimum Operating Current IRMIN LM4040D 54 85 µA
IR = 10mA ±30
LM4040A/B/C ±20
±100
IR = 1mA LM4040D ±20
±150
Average Reverse Voltage
Temperature Coefficient
(Notes 2 and 3)
∆VR/∆T
IR = 100µA ±15
ppm/°C
LM4040A/B/C 0.5 1.4
IRMIN ≤ IR ≤ 1mA LM4040D 0.5 1.8
LM4040A/B/C 3.5
12.0
Reverse Breakdown Voltage
Change with Operating
Current Change 1mA ≤ IR ≤ 15mA LM4040D 3.5
15.0
mV
LM4040A/B/C 0.5 1.1
Reverse Dynamic
Impedance (Note 3) ZRIR = 1mA, f = 120Hz,
IAC = 0.1IRLM4040D 0.5 1.5 Ω
Wideband Noise eNIR = 100µA, 10Hz ≤ f ≤ 10kHz 80
µVRMS
Reverse Breakdown Voltage
Long-Term Stability ∆VRT = 1000h 120
ppm
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
8_______________________________________________________________________________________
LM4040-2.5V
TEMPERATURE DRIFT
LM4040-02
TEMPERATURE (°C)
REFERENCE VOLTAGE CHANGE (mV)
1007550250-25
-4
-3
-2
-1
0
1
-5
-50 125
LM4040-5.0V
TEMPERATURE DRIFT
LM4040 toc03
TEMPERATURE (°C)
REFERENCE VOLTAGE CHANGE (mV)
1007550250-25
-15
-10
-5
0
5
-20
-50 125
Typical Operating Characteristics
(IR= 100µA, SC70-3 package, TA= +25°C, unless otherwise noted.)
0
1
2
3
4
5
6
050100
REVERSE CHARACTERISTICS AND
MINIMUM OPERATING CURRENT
LM4040-01
REVERSE CURRENT (µA)
REVERSE VOLTAGE (V)
LM4040_I_3-5.0
LM4040_I_3-4.1
LM4040_I_3-3.0
LM4040_I_3-2.5
LM4040_I_3-2.1
LM4040-5.0V
REVERSE VOLTAGE vs. ISHUNT
LM4040 toc05
ISHUNT (mA)
REVERSE VOLTAGE CHANGE (mV)
15105
1
2
3
4
5
6
0
020
TA = -40°C
TA = +125°C
TA = +85°C
TA = +25°C
LM4040-2.5V
REVERSE VOLTAGE vs. ISHUNT
LM4040-04
ISHUNT (mA)
REVERSE VOLTAGE CHANGE (mV)
15105
1
2
3
4
5
0
020
TA = +125°C
TA = -40°C
TA = +25°C
TA = +85°C
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
_______________________________________________________________________________________ 9
VGEN
VR AC-COUPLED
+25µA
-25µA
10mV/div
LM4040-5.0V
LOAD-TRANSIENT RESPONSE
LM4040-07
40µs/div
ISHUNT = 100µA ± 25µA
RL = 100kΩ, SEE FIGURE 1
VGEN
VR AC-COUPLED
+250µA
-250µA
10mV/div
LM4040-2.5V
LOAD-TRANSIENT RESPONSE
LM4040-08
10µs/div
ISHUNT = 1mA ± 250µA
RL = 10kΩ, SEE FIGURE 1
Typical Operating Characteristics (continued)
(IR= 100µA, SC70-3 package, TA= +25°C, unless otherwise noted.)
VGEN
VR AC-COUPLED
+25µA
-25µA
2mV/div
LM4040-2.5V
LOAD-TRANSIENT RESPONSE
LM4040-06
10µs/div
CH1: VGEN 2V/div
CH2: VR AC-COUPLED 2mV/div
ISHUNT = 100µA ± 25µA, RL = 100kΩ, SEE FIGURE 1
VGEN
VR AC-COUPLED
+2.5mA
-2.5mA
20mV/div
LM4040-2.5V
LOAD-TRANSIENT RESPONSE
LM4040-10
10µs/div
ISHUNT = 10mA ± 2.5mA
RL = 1kΩ, SEE FIGURE 1
VGEN
VR AC-COUPLED
+2.5mA
-2.5mA
20mV/div
LM4040-5.0V
LOAD-TRANSIENT RESPONSE
LM4040-11
10µs/div
ISHUNT = 10mA ± 2.5mA
RL = 1kΩ, SEE FIGURE 1
VGEN
VR AC-COUPLED
+250µA
-250µA
10mV/div
LM4040-5.0V
LOAD-TRANSIENT RESPONSE
LM4040-09
10µs/div
ISHUNT = 1mA ± 250µA
RL = 10kΩ, SEE FIGURE 1
1kΩ
VB
+
-
ISHUNT
VR
RL
VGEN
Figure 1. Load-Transient Test Circuit
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
10 ______________________________________________________________________________________
VIN
VOUT
LM4040-5.0V
STARTUP CHARACTERISTICS
LM4040-13
0405020 3010 60 70 80 90
RESPONSE TIME (µs)
5V
0V
0V
4V
2V
RS = 16kΩ
SEE FIGURE 2
0.1k 10k1k 100k 1M
LM4040-2.5V
OUTPUT IMPEDANCE vs. FREQUENCY
LM4040-14
FREQUENCY (Hz)
IMPEDANCE (Ω)
1000
0.1
1
10
100
IR = 150µA
IR = 1mA
C1 = 1µF
C1 = 0
Typical Operating Characteristics (continued)
(IR= 100µA, SC70-3 package, TA= +25°C, unless otherwise noted.)
VIN
VOUT
LM4040-2.5V
STARTUP CHARACTERISTICS
LM4040-12
01620812424283236
RESPONSE TIME (µs)
5V
0V
0V
2V
1V
RS = 30kΩ
SEE FIGURE 2
1 10010 1k 10k
LM4040-2.5V
NOISE vs. FREQUENCY
LM4040-16
FREQUENCY (Hz)
10,000
100
1000
NOISE (nV/√Hz)
1 10010 1k 10k
LM4040-5.0V
NOISE vs. FREQUENCY
LM4040-17
FREQUENCY (Hz)
10,000
100
1000
NOISE (nV/√Hz)
0.1k 10k1k 100k 1M
LM4040-5.0V
OUTPUT IMPEDANCE vs. FREQUENCY
LM4040-15
FREQUENCY (Hz)
IMPEDANCE (Ω)
100
0.1
1
10 IR = 150µA
IR = 1mA
C1 = 0
C1 = 1µF
RS
VIN
1Hz RATE
50%
DUTY CYCLE
VR
Figure 2. Startup Characteristics Test Circuit
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
______________________________________________________________________________________ 11
Detailed Description
The LM4040 shunt references use the bandgap princi-
ple to produce a stable, accurate voltage. The device
behaves similarly to an ideal zener diode; a fixed volt-
age is maintained across its output terminals when
biased with 60µA to 15mA of reverse current. The
LM4040 behaves similarly to a silicon diode when
biased with forward currents up 10mA.
Figure 3 shows a typical operating circuit. The LM4040
is ideal for providing a stable reference from a high-
voltage power supply.
Applications Information
The LM4040’s internal pass transistor is used to maintain a
constant output voltage (VSHUNT) by sinking the necessary
amount of current across a source resistor. The source
resistance (RS) is determined from the load current (ILOAD)
range, supply voltage (VS) variations, VSHUNT, and desired
quiescent current.
Choose the value of RSwhen VSis at a minimum and ILOAD
is at a maximum. Maintain a minimum ISHUNT of 60µA at all
times. The RSvalue should be large enough to keep
ISHUNT less than 15mA for proper regulation when VSis
maximum and ILOAD is at a minimum. To prevent damage
to the device, ISHUNT should never exceed 20mA.
Therefore, the value of RSis bounded by the following
equation:
[VS(MIN) - VR] / [60µA + ILOAD(MAX)] > RS>
[VS(MAX) - VR] / [20mA + ILOAD(MIN)]
Choosing a larger resistance minimizes the total power dis-
sipation in the circuit by reducing the shunt current
(PD(TOTAL) = VS✕ISHUNT). Provide a safety margin to
incorporate the worst-case tolerance of the resistor used.
Ensure that the resistor’s power rating is adequate, using
the following general power equation:
PDR= ISHUNT ✕(VS(MAX) - VSHUNT)
Output Capacitance
The LM4040 does not require an external capacitor for fre-
quency stability and is stable for any output capacitance.
Temperature Performance
The LM4040 typically exhibits an output voltage tem-
perature coefficient within ±15ppm/°C. The polarity of
the temperature coefficient may be different from one
device to another; some may have positive coefficients,
and others may have negative coefficients.
High Temperature Operation
The maximum junction temperature of the LM4040 is
+150°C. The maximum operating temperature for the
LM4040_E_ is +125°C. At a maximum load current of 15mA
and a maximum output voltage of 5V, the part will dissipate
75mW of power. The power dissipation limits of the 3-pin
SC70 call for a derating value of 2.17mW/°C above +70°C
and thus for 75mW of power dissipation, the part will self-
heat to 35.56°C above ambient temperature. If the ambient
temperature is +125°C, the part operates at 159.56°C,
thereby exceeding the maximum junction temperature
value of +150°C. For high-temperature operation, care must
be taken to ensure the combination of ambient temperature,
output power dissipation and package thermal resistance
does not conspire to raise the device temperature beyond
that listed in the Absolute Maximum Ratings. Either reduce
the output load current or the ambient temperature to keep
the part within the limits.
Figure 3. Typical Operating Circuit
LM4040
ILOAD
ISHUNT
RS
VS
VR
ISHUNT + ILOAD
Pin Description
PIN
NAME
FUNCTION
1+Positive Terminal of the Shunt Reference
2−Negative Terminal of the Shunt Reference
3N.C. No connection. Leave this pin unconnected or connected to pin 2.
Chip Information
TRANSISTOR COUNT: 60
PROCESS: BiCMOS
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
12 ______________________________________________________________________________________
PART OUTPUT
VOLTAGE (V)
INITIAL
ACCURACY (%)
TEMPCO
(ppm/°C) TEMP RANGE
PIN-PACKAGE
TOP
MARK
LM4040AIM3-2.1-T 2.048 0.1 100 -40°C to +85°C 3 SOT23-3
FZEF
LM4040AIX3-2.1-T 2.048 0.1 100 -40°C to +85°C 3 SC70-3 ABJ
LM4040BIM3-2.1-T 2.048 0.2 100 -40°C to +85°C 3 SOT23-3
FZEG
LM4040BIX3-2.1-T 2.048 0.2 100 -40°C to +85°C 3 SC70-3 ABK
LM4040CIM3-2.1-T 2.048 0.5 100 -40°C to +85°C 3 SOT23-3
FZEH
LM4040CIX3-2.1-T 2.048 0.5 100 -40°C to +85°C 3 SC70-3 ABL
LM4040DIM3-2.1-T 2.048 1.0 150 -40°C to +85°C 3 SOT23-3 FZEI
LM4040DIX3-2.1-T 2.048 1.0 150 -40°C to +85°C 3 SC70-3 ABM
LM4040AEM3-2.1-T 2.048 0.1 100 -40°C to +125°C 3 SOT23-3
FZNG
LM4040AEX3-2.1-T 2.048 0.1 100 -40°C to +125°C 3 SC70-3 ALF
LM4040BEM3-2.1-T 2.048 0.2 100 -40°C to +125°C 3 SOT23-3
FZNH
LM4040BEX3-2.1-T 2.048 0.2 100 -40°C to +125°C 3 SC70-3 ALG
LM4040CEM3-2.1-T 2.048 0.5 100 -40°C to +125°C 3 SOT23-3 FZNI
LM4040CEX3-2.1-T 2.048 0.5 100 -40°C to +125°C 3 SC70-3 ALH
LM4040DEM3-2.1-T 2.048 1.0 150 -40°C to +125°C 3 SOT23-3
FZNJ
LM4040DEX3-2.1-T 2.048 1.0 150 -40°C to +125°C 3 SC70-3 ALI
LM4040AIM3-2.5-T 2.500 0.1 100 -40°C to +85°C 3 SOT23-3 FZEJ
LM4040AIX3-2.5-T 2.500 0.1 100 -40°C to +85°C 3 SC70-3 ABN
LM4040BIM3-2.5-T 2.500 0.2 100 -40°C to +85°C 3 SOT23-3
FZEK
LM4040BIX3-2.5-T 2.500 0.2 100 -40°C to +85°C 3 SC70-3 ABO
LM4040CIM3-2.5-T 2.500 0.5 100 -40°C to +85°C 3 SOT23-3
FZEL
LM4040CIX3-2.5-T 2.500 0.5 100 -40°C to +85°C 3 SC70-3 ABP
LM4040DIM3-2.5-T 2.500 1.0 150 -40°C to +85°C 3 SOT23-3
FZEM
LM4040DIX3-2.5-T 2.500 1.0 150 -40°C to +85°C 3 SC70-3 ABQ
LM4040AEM3-2.5-T 2.500 0.1 100 -40°C to +125°C 3 SOT23-3
FZNK
LM4040AEX3-2.5-T 2.500 0.1 100 -40°C to +125°C 3 SC70-3 ALJ
LM4040BEM3-2.5-T 2.500 0.2 100 -40°C to +125°C 3 SOT23-3
FZNL
LM4040BEX3-2.5-T 2.500 0.2 100 -40°C to +125°C 3 SC70-3 ALK
LM4040CEM3-2.5-T 2.500 0.5 100 -40°C to +125°C 3 SOT23-3
FZNM
LM4040CEX3-2.5-T 2.500 0.5 100 -40°C to +125°C 3 SC70-3 ALL
LM4040DEM3-2.5-T 2.500 1.0 150 -40°C to +125°C 3 SOT23-3
FZNN
LM4040DEX3-2.5-T 2.500 1.0 150 -40°C to +125°C 3 SC70-3 ALM
LM4040AIM3-3.0-T 3.000 0.1 100 -40°C to +85°C 3 SOT23-3
FZEN
LM4040AIX3-3.0-T 3.000 0.1 100 -40°C to +85°C 3 SC70-3 ABR
LM4040BIM3-3.0-T 3.000 0.2 100 -40°C to +85°C 3 SOT23-3
FZEO
LM4040BIX3-3.0-T 3.000 0.2 100 -40°C to +85°C 3 SC70-3 ABS
LM4040CIM3-3.0-T 3.000 0.5 100 -40°C to +85°C 3 SOT23-3
FZEP
LM4040CIX3-3.0-T 3.000 0.5 100 -40°C to +85°C 3 SC70-3 ABT
LM4040DIM3-3.0-T 3.000 1.0 150 -40°C to +85°C 3 SOT23-3
FZEQ
LM4040DIX3-3.0-T 3.000 1.0 150 -40°C to +85°C 3 SC70-3 ABU
LM4040AEM3-3.0-T 3.000 0.1 100 -40°C to +125°C 3 SOT23-3
FZNO
LM4040AEX3-3.0-T 3.000 0.1 100 -40°C to +125°C 3 SC70-3 ALN
LM4040BEM3-3.0-T 3.000 0.2 100 -40°C to +125°C 3 SOT23-3
FZNP
LM4040BEX3-3.0-T 3.000 0.2 100 -40°C to +125°C 3 SC70-3 ALO
LM4040CEM3-3.0-T 3.000 0.5 100 -40°C to +125°C 3 SOT23-3
FZNQ
Ordering Information
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
______________________________________________________________________________________ 13
PART OUTPUT
VOLTAGE (V)
INITIAL
ACCURACY (%)
TEMPCO
(ppm/°C) TEMP RANGE
PIN-PACKAGE
TOP
MARK
LM4040CEX3-3.0-T 3.000 0.5 100 -40°C to +125°C 3 SC70-3 ALP
LM4040DEM3-3.0-T 3.000 1.0 150 -40°C to +125°C 3 SOT23-3
FZNR
LM4040DEX3-3.0-T 3.000 1.0 150 -40°C to +125°C 3 SC70-3 ALQ
LM4040AEX3-3.3-T 3.300 0.1 100 -40°C to +125°C 3 SC70-3 ANY
LM4040BEX3-3.3-T 3.300 0.2 100 -40°C to +125°C 3 SC70-3 ANZ
LM4040CEX3-3.3-T 3.300 0.5 100 -40°C to +125°C 3 SC70-3 AOA
LM4040DEX3-3.3-T 3.300 1.0 150 -40°C to +125°C 3 SC70-3 AOB
LM4040AIM3-4.1-T 4.096 0.1 100 -40°C to +85°C 3 SOT23-3
FZER
LM4040AIX3-4.1-T 4.096 0.1 100 -40°C to +85°C 3 SC70-3 ABV
LM4040BIM3-4.1-T 4.096 0.2 100 -40°C to +85°C 3 SOT23-3
FZES
LM4040BIX3-4.1-T 4.096 0.2 100 -40°C to +85°C 3 SC70-3 ABW
LM4040CIM3-4.1-T 4.096 0.5 100 -40°C to +85°C 3 SOT23-3
FZET
LM4040CIX3-4.1-T 4.096 0.5 100 -40°C to +85°C 3 SC70-3 ABX
LM4040DIM3-4.1-T 4.096 1.0 150 -40°C to +85°C 3 SOT23-3
FZEU
LM4040DIX3-4.1-T 4.096 1.0 150 -40°C to +85°C 3 SC70-3 ABY
LM4040AEM3-4.1-T 4.096 0.1 100 -40°C to +125°C 3 SOT23-3
FZNS
LM4040AEX3-4.1-T 4.096 0.1 100 -40°C to +125°C 3 SC70-3 ALR
LM4040BEM3-4.1-T 4.096 0.2 100 -40°C to +125°C 3 SOT23-3
FZNT
LM4040BEX3-4.1-T 4.096 0.2 100 -40°C to +125°C 3 SC70-3 ALS
LM4040CEM3-4.1-T 4.096 0.5 100 -40°C to +125°C 3 SOT23-3
FZNU
LM4040CEX3-4.1-T 4.096 0.5 100 -40°C to +125°C 3 SC70-3 ALT
LM4040DEM3-4.1-T 4.096 1.0 150 -40°C to +125°C 3 SOT23-3
FZNV
LM4040DEX3-4.1-T 4.096 1.0 150 -40°C to +125°C 3 SC70-3 ALU
LM4040AIM3-5.0-T 5.000 0.1 100 -40°C to +85°C 3 SOT23-3
FZEV
LM4040AIX3-5.0-T 5.000 0.1 100 -40°C to +85°C 3 SC70-3 ABZ
LM4040BIM3-5.0-T 5.000 0.2 100 -40°C to +85°C 3 SOT23-3
FZEW
LM4040BIX3-5.0-T 5.000 0.2 100 -40°C to +85°C 3 SC70-3 ACA
LM4040CIM3-5.0-T 5.000 0.5 100 -40°C to +85°C 3 SOT23-3
FZEX
LM4040CIX3-5.0-T 5.000 0.5 100 -40°C to +85°C 3 SC70-3 ACB
LM4040DIM3-5.0-T 5.000 1.0 150 -40°C to +85°C 3 SOT23-3
FZEY
LM4040DIX3-5.0-T 5.000 1.0 150 -40°C to +85°C 3 SC70-3 ACC
LM4040AEM3-5.0-T 5.000 0.1 100 -40°C to +125°C 3 SOT23-3
FZNW
LM4040AEX3-5.0-T 5.000 0.1 100 -40°C to +125°C 3 SC70-3 ALV
LM4040BEM3-5.0-T 5.000 0.2 100 -40°C to +125°C 3 SOT23-3
FZNX
LM4040BEX3-5.0-T 5.000 0.2 100 -40°C to +125°C 3 SC70-3 ALW
LM4040CEM3-5.0-T 5.000 0.5 100 -40°C to +125°C 3 SOT23-3
FZNY
LM4040CEX3-5.0-T 5.000 0.5 100 -40°C to +125°C 3 SC70-3 ALX
Ordering Information (continued)
LM4040
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
14 ______________________________________________________________________________________
SOT23 L.EPS
F
1
1
21-0051
PACKAGE OUTLINE, 3L SOT-23
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
15 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
©2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
SC70, 3L.EPS
PACKAGE OUTLINE, 3L SC70
21-0075
1
1
C
Improved Precision Micropower Shunt Voltage
Reference with Multiple Reverse Breakdown Voltages
LM4040