AVAILABLE
Functional Diagrams
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
General Description
The MAX6126 is an ultra-low-noise, high-precision, low-
dropout voltage reference. This family of voltage refer-
ences feature curvature-correction circuitry and
high-stability, laser-trimmed, thin-film resistors that
result in 3ppm/°C (max) temperature coefficients and
an excellent ±0.02% (max) initial accuracy. The propri-
etary low-noise reference architecture produces a low
flicker noise of 1.3µVP-P and wideband noise as low as
60nV/√Hz (2.048V output) without the increased supply
current usually found in low-noise references. Improve
wideband noise to 35nV/√Hz and AC power-supply
rejection by adding a 0.1µF capacitor at the noise
reduction pin. The MAX6126 series mode reference
operates from a wide 2.7V to 12.6V supply voltage
range and load-regulation specifications are guaran-
teed to be less than 0.025Ωfor sink and source cur-
rents up to 10mA. These devices are available over the
automotive temperature range of -40°C to +125°C.
The MAX6126 typically draws 380µA of supply current
and is available in 2.048V, 2.500V, 2.800V, 3.000V,
4.096V, and 5.000V output voltages. These devices
also feature dropout voltages as low as 200mV. Unlike
conventional shunt-mode (two-terminal) references that
waste supply current and require an external resistor,
the MAX6126 offers supply current that is virtually inde-
pendent of supply voltage and does not require an
external resistor. The MAX6126 is stable with 0.1µF to
10µF of load capacitance.
The MAX6126 is available in the tiny 8-pin µMAX®, as
well as 8-pin SO packages.
Applications
High-Resolution A/D and D/A Converters
ATE Equipment
High-Accuracy Reference Standard
Precision Current Sources
Digital Voltmeters
High-Accuracy Industrial and Process Control
Features
oUltra-Low 1.3µVP-P Noise (0.1Hz to 10Hz, 2.048V
Output)
oUltra-Low 3ppm/°C (max) Temperature Coefficient
o±0.02% (max) Initial Accuracy
oWide (VOUT + 200mV) to 12.6V Supply Voltage
Range
oLow 200mV (max) Dropout Voltage
o380µA Quiescent Supply Current
o10mA Sink/Source-Current Capability
oStable with CLOAD = 0.1µF to 10µF
oLow 20ppm/1000hr Long-Term Stability
o0.025Ω (max) Load Regulation
o20µV/V (max) Line Regulation
oForce and Sense Outputs for Remote Sensing
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
OUTS
I.C.*GNDS
1
2
8
+
7
I.C.*
OUTFIN
GND
NR
SO/µMAX
TOP VIEW
3
4
6
5
MAX6126
*I.C. = INTERNALLY CONNECTED. DO NOT USE.
Pin Configuration
Ordering Information
PART TEMP RANGE PIN-
PACKAGE
OUTPUT
VOLTAGE
(V)
MAXIMUM INITIAL
ACCURACY (%)
MAXIMUM TEMPCO
(-40°C to +85°C)
(ppm/°C)
TOP
MARK
MAX6126AASA21+ -40°C to +125°C 8 SO 2.048 0.02 3 —
MAX6126BASA21+ -40°C to +125°C 8 SO 2.048 0.06 5 —
MAX6126A21+ -40°C to +125°C 8 µMAX 2.048 0.06 3 6126A21
Ordering Information continued at end of data sheet.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
Ordering Information
19-2647; Rev 5; 12/10
MAX6126
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ABSOLUTE MAXIMUM RATINGS
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.
(All voltages referenced to GND)
GNDS ....................................................................-0.3V to +0.3V
IN ........................................................................... -0.3V to +13V
OUTF, OUTS, NR........ -0.3V to the lesser of (VIN + 0.3V) or +6V
Output Short Circuit to GND or IN ..........................................60s
Continuous Power Dissipation (TA= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) ............362mW
8-Pin SO (derate 5.88mW/°C above +70°C) ...............471mW
Operating Temperature Range ........................-40°C to +125°C
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Soldering Temperature (reflow) ......................................+260°C
ELECTRICAL CHARACTERISTICS—MAX6126_21 (VOUT = 2.048V)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 2.048 V
A grade SO -0.02 +0.02
B grade SO -0.06 +0.06
A grade µMAX -0.06 +0.06
Output Voltage Accuracy
Referred to
VOUT,
TA = +25°C
B grade µMAX -0.1 +0.1
%
A grade SO 0.5 3
B grade SO 1 5
A grade µMAX 1 3
TA = -40°C
to +85°C
B grade µMAX 2 7
A grade SO 1 5
B grade SO 2 10
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C
to +125°C
B grade µMAX 3 12
ppm/°C
TA = +25°C220
Line Regulation ∆VOUT/
∆VIN
2.7V ≤ VIN ≤
12.6V TA = -40°C to +125°C40
µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 0.7 25
Load Regulation ∆VOUT/
∆IOUT Sinking: -10mA ≤ IOUT ≤ 0 1.3 25 µV/mA
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
SO 25
Thermal Hysteresis (Note 2) ∆VOUT/
cycle µMAX 80 ppm
SO 20
Long-Term Stability ∆VOUT/
time 1000hr at TA = +25°CµMAX 100
ppm/
1000hr
MAX6126
2
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ELECTRICAL CHARACTERISTICS—MAX6126_21 (VOUT = 2.048V) (continued)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 1.3 µVP-P
f = 1kHz, CNR = 0 60
Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 35 nV/√Hz
CNR = 0 0.8
Turn-On Settling Time tRTo VOUT = 0.01% of
final value CNR = 0.1µF 20 ms
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 2.7 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
ELECTRICAL CHARACTERISTICS—MAX6126_25 (VOUT = 2.500V)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 2.500 V
A grade SO -0.02 +0.02
B grade SO -0.06 +0.06
A grade µMAX -0.06 +0.06
Output Voltage Accuracy Referred to VOUT,
TA = +25°C
B grade µMAX -0.1 +0.1
%
A grade SO 0.5 3
B grade SO 1 5
A grade µMAX 1 3
TA = -40°C to +85°C
B grade µMAX 2 7
A grade SO 1 5
B grade SO 2 10
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C to
+125°C
B grade µMAX 3 12
ppm/°C
TA = +25°C320
Line Regulation ∆VOUT/
∆VIN 2.7V ≤ VIN ≤ 12.6V TA = -40°C to +125°C40
µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 1 25
Load Regulation ∆VOUT/
∆IOUT Sinking: -10mA ≤ IOUT ≤ 0 1.8 25 µV/mA
MAX6126
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IOUT = 5mA 0.06 0.2
Dropout Voltage (Note 3) VIN - VOUT ∆VOUT = 0.1% IOUT = 10mA 0.12 0.4 V
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
SO 35
Thermal Hysteresis (Note 2) ∆VOUT/
cycle µMAX 80 ppm
SO 20
Long-Term Stability ∆VOUT/
time 1000hr at TA = +25°CµMAX 100
ppm/
1000hr
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 1.45 µVP-P
f = 1kHz, CNR = 0 75Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 45 nV/√Hz
CNR = 0 1
Turn-On Settling Time tRTo VOUT = 0.01% of
final value CNR = 0.1µF 20 ms
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 2.7 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
ELECTRICAL CHARACTERISTICS—MAX6126_25 (VOUT = 2.500V) (continued)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDTIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 2.800 V
A grade µMAX -0.06 +0.06
Output Voltage Accuracy Referred to VOUT, TA =
+25°C B grade µMAX -0.10 +0.10 %
A grade µMAX 1 3
TA = -40°C to +85°C B grade µMAX 2 7
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C to +125°C B grade µMAX 3 12
ppm/°C
TA = +25°C 3.5 23
Line Regulation ∆VOUT/∆VIN 3.0V ≤ VIN ≤ 12.6V TA = -40°C to
+125°C 45 µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 1.3 28
Load Regulation ∆VOUT/∆VIN Sinking: -10mA ≤ IOUT ≤ 0 2.4 28 µV/mA
IOUT = 5mA 0.06 0.2
Dropout Voltage (Note 3) VIN - VOUT ∆VOUT = 0.1% IOUT = 10mA 0.12 0.4 V
ELECTRICAL CHARACTERISTICS—MAX6126_28 (VOUT = 2.800V)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX6126
4
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
PARAMETER SYMBOL CONDTIONS MIN TYP MAX UNITS
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
Thermal Hysteresis (Note 2) ∆VOUT/cycle µMAX 80 ppm
Long-Term Stability ∆VOUT/time 1000hr at TA = +25°C µMAX 100 ppm/
1000hr
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 1.45 µVP-P
f = 1kHz, CNR = 0 75
Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 45 nV/√Hz
CNR = 0 1
Turn-On Settling Time tRTo VOUT = 0.01% of
final value CNR = 0.1µF 20 ms
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 3.0 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
ELECTRICAL CHARACTERISTICS—MAX6126_28 (VOUT = 2.800V) (continued)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 3.000 V
A grade SO -0.02 +0.02
B grade SO -0.06 +0.06
A grade µMAX -0.06 +0.06
Output Voltage Accuracy Referred to VOUT,
TA = +25°C
B grade µMAX -0.1 +0.1
%
A grade SO 0.5 3
B grade SO 1 5
A grade µMAX 1 3
TA = -40°C to
+85°C
B grade µMAX 2 7
A grade SO 1 5
B grade SO 2 10
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C to
+125°C
B grade µMAX 3 12
ppm/°C
ELECTRICAL CHARACTERISTICS—MAX6126_30 (VOUT = 3.000V)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX6126
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ELECTRICAL CHARACTERISTICS—MAX6126_30 (VOUT = 3.000V) (continued)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
TA = +25°C425
Line Regulation ∆VOUT/
∆VIN 3.2V ≤ VIN ≤ 12.6V TA = -40°C to +125°C50
µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 1.5 30
Load Regulation ∆VOUT/
∆IOUT Sinking: -10mA ≤ IOUT ≤ 0 2.8 30 µV/mA
IOUT = 5mA 0.06 0.2
Dropout Voltage (Note 3) VIN - VOUT ∆VOUT = 0.1% IOUT = 10mA 0.11 0.4 V
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
SO 20
Thermal Hysteresis (Note 2) ∆VOUT/
cycle µMAX 80 ppm
SO 20
Long-Term Stability ∆VOUT/
time 1000hr at TA = +25°CµMAX 100
ppm/
1000hr
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 1.75 µVP-P
f = 1kHz, CNR = 0 90
Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 55 nV/√Hz
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
CNR = 0 1.2
Turn-On Settling Time tRTo VOUT = 0.01%
of final value CNR = 0.1µF 20 ms
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 3.2 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
ELECTRICAL CHARACTERISTICS—MAX6126_41 (VOUT = 4.096V)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 4.096 V
A grade SO -0.02 +0.02
B grade SO -0.06 +0.06
A grade µMAX -0.06 +0.06
Output Voltage Accuracy Referred to VOUT,
TA = +25°C
B grade µMAX -0.1 +0.1
%
MAX6126
6
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ELECTRICAL CHARACTERISTICS—MAX6126_41 (VOUT = 4.096V) (continued)
(VIN = 5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
A grade SO 0.5 3
B grade SO 1 5
A grade µMAX 1 3
TA = -40°C to
+85°C
B grade µMAX 2 7
A grade SO 1 5
B grade SO 2 10
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C to
+125°C
B grade µMAX 3 12
ppm/°C
TA = +25°C 4.5 30
Line Regulation ∆VOUT/
∆VIN 4.3V ≤ VIN ≤ 12.6V TA = -40°C to +125°C60
µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 2 40
Load Regulation ∆VOUT/
∆IOUT Sinking: -10mA ≤ IOUT ≤ 0 5 40 µV/mA
IOUT = 5mA 0.05 0.2
Dropout Voltage (Note 3) VIN - VOUT ∆VOUT = 0.1% IOUT = 10mA 0.1 0.4 V
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
SO 20
Thermal Hysteresis (Note 2) ∆VOUT/
cycle µMAX 80 ppm
SO 20
Long-Term Stability ∆VOUT/
time 1000hr at TA = + 25°C µMAX 100
ppm/
1000hr
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 2.4 µVP-P
f = 1kHz, CNR = 0 120Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 80 nV/√Hz
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
CNR = 0 1.6
Turn-On Settling Time tRTo VOUT = 0.01% of
final value CNR = 0.1µF 20 ms
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 4.3 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
MAX6126
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ELECTRICAL CHARACTERISTICS—MAX6126_50 (VOUT = 5.000V)
(VIN = 5.5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT
Output Voltage VOUT TA = +25°C 5.000 V
A grade SO -0.02 +0.02
B grade SO -0.06 +0.06
A grade µMAX -0.06 +0.06
Output Voltage Accuracy TA = +25°C
B grade µMAX -0.1 +0.1
%
A grade SO 0.5 3
B grade SO 1 5
A grade µMAX 1 3
TA = -40°C to +85°C
B grade µMAX 2 7
A grade SO 1 5
B grade SO 2 10
A grade µMAX 2 5
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
TA = -40°C to
+125°C
B grade µMAX 3 12
ppm/°C
TA = +25°C340
Line Regulation ∆VOUT/
∆VIN 5.2V ≤ VIN ≤ 12.6V TA = -40°C to +125°C80
µV/V
Sourcing: 0 ≤ IOUT ≤ 10mA 2.5 50
Load Regulation ∆VOUT/
∆IOUT Sinking: -10mA ≤ IOUT ≤ 0 6.5 50 µV/mA
IOUT = 5mA 0.05 0.2
Dropout Voltage (Note 3) VIN - VOUT ∆VOUT = 0.1% IOUT = 10mA 0.1 0.4 V
Short to GND 160
OUT Short-Circuit Current ISC Short to IN 20 mA
SO 15
Thermal Hysteresis (Note 2) ∆VOUT/
cycle µMAX 80 ppm
SO 20
Long-Term Stability ∆VOUT/
time 1000hr at TA = +25°CµMAX 100
ppm/
1000hr
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 2.85 µVP-P
f = 1kHz, CNR = 0 145Noise Voltage eOUT
f = 1kHz, CNR = 0.1µF 95 nV/√Hz
Capacitive-Load Stability Range CLOAD No sustained oscillations 0.1 to 10 µF
MAX6126
8
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
ELECTRICAL CHARACTERISTICS—MAX6126_50 (VOUT = 5.000V) (continued)
(VIN = 5.5V, CLOAD = 0.1µF, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CNR = 0 2
Turn-On Settling Time tRTo VOUT = 0.01% of
final value CNR = 0.1µF 20 ms
INPUT
Supply Voltage Range VIN Guaranteed by line-regulation test 5.2 12.6 V
TA = +25°C 380 550
Quiescent Supply Current IIN TA = -40°C to +125°C 725 µA
Note 1: Temperature coefficient is measured by the “box” method, i.e., the maximum ∆VOUT / VOUT is divided by the maximum ∆T.
Note 2: Thermal hysteresis is defined as the change in +25°C output voltage before and after cycling the device from TMAX to TMIN.
Note 3: Dropout voltage is defined as the minimum differential voltage (VIN - VOUT) at which VOUT decreases by 0.1% from its
original value at VIN = 5.0V (VIN = 5.5V for VOUT = 5.0V).
Typical Operating Characteristics
(VIN = 5V for MAX6126_21/25/30/41, VIN = 5.5V for MAX6126_50, CLOAD = 0.1µF, IOUT = 0, TA= +25°C, unless otherwise specified.)
(Note 5)
MAX6126A_21
OUTPUT VOLTAGE TEMPERATURE DRIFT
(VOUT = 2.048V) (SO)
MAX6126 toc01
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1007550250-25
2.0465
2.0470
2.0475
2.0480
2.0485
2.0490
2.0460
-50 125
THREE TYPICAL PARTS
MAX6126A_21
OUTPUT VOLTAGE TEMPERATURE DRIFT
(VOUT = 2.048V) (µMAX)
MAX6126 toc02
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1007550250-25
2.0480
2.0475
2.0485
2.0490
2.0470
-50 125
THREE TYPICAL PARTS
MAX6126A_50
OUTPUT VOLTAGE TEMPERATURE DRIFT
(VOUT = 5.000V) (SO)
MAX6126 toc03
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1007550250-25
5.000
4.999
5.001
5.002
4.998
-50 125
THREE TYPICAL PARTS
MAX6126
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(VIN = 5V for MAX6126_21/25/30/41, VIN = 5.5V for MAX6126_50, CLOAD = 0.1µF, IOUT = 0, TA= +25°C, unless otherwise specified.)
(Note 5)
MAX6126A_50
OUTPUT VOLTAGE TEMPERATURE DRIFT
(VOUT = 5.000V) (µMAX)
MAX6126 toc04
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1007550250-25
5.000
4.999
5.001
5.002
4.998
-50 125
THREE TYPICAL PARTS
MAX6126_21
LOAD REGULATION
MAX6126 toc05
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
50-5
2.0465
2.0470
2.0475
2.0480
2.0485
2.0460
-10 10
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_50
LOAD REGULATION
MAX6126 toc06
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
50-5
4.997
4.998
4.999
5.000
5.001
4.996
-10 10
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_50
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX6126 toc10
FREQUENCY (kHz)
PSRR (dB)
1001010.10.01
-100
-80
-60
-40
-20
0
-120
0.001 1000
MAX6126_21
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX6126 toc11
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
12108642
100
200
300
400
500
600
0
014
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_50
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX6126 toc12
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
12106 842
100
200
300
400
500
600
700
800
900
0
014
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_25
DROPOUT VOLTAGE
vs. SOURCE CURRENT
MAX6126 toc07
SOURCE CURRENT (mA)
DROPOUT VOLTAGE (mV)
12963
50
100
150
200
250
300
0
015
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_50
DROPOUT VOLTAGE
vs. SOURCE CURRENT
MAX6126 toc08
SOURCE CURRENT (mA)
DROPOUT VOLTAGE (mV)
12963
50
100
150
200
250
0
015
TA = +25°C
TA = -40°C
TA = +125°C
MAX6126_21
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX6126 toc09
FREQUENCY (kHz)
PSRR (dB)
1001010.10.01
-100
-80
-60
-40
-20
0
-120
0.001 1000
MAX6126
10
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(VIN = 5V for MAX6126_21/25/30/41, VIN = 5.5V for MAX6126_50, CLOAD = 0.1µF, IOUT = 0, TA= +25°C, unless otherwise specified.)
(Note 5)
MAX6126_21
OUTPUT NOISE (0.1Hz TO 10Hz)
MAX6126 toc13
1s/div
0.4µV/div
VOUT = 2.048V
MAX6126_50
OUTPUT NOISE (0.1Hz TO 10Hz)
MAX6126 toc14
1s/div
1µV/div
VOUT = 5V
MAX6126_21
LOAD TRANSIENT
MAX6126 toc15
200µs/div
0mA
10mA
VOUT
AC-COUPLED
100mV/div
CLOAD = 0.1µF
VIN = 5V
IOUT
5mA/div
IOUT = 0 TO 10mA
VOUT = 2.048V
MAX6126_21
LOAD TRANSIENT
MAX6126 toc16
200µs/div
CLOAD = 0.1µF
VIN = 5V
IOUT = -100µA TO 1mA
VOUT = 2.048V
-100µA
1mA
VOUT
AC-COUPLED
20mV/div
IOUT
500µA/div
MAX6126_21
LOAD TRANSIENT
MAX6126 toc17
400µs/div
CLOAD = 0.1µF
VIN = 5V
IOUT = -1mA TO -10mA
VOUT = 2.048V
-10mA
-1mA
VOUT
AC-COUPLED
100mV/div
IOUT
5mA/div
MAX6126_21
LOAD TRANSIENT
MAX6126 toc18
1ms/div
CLOAD = 10µF
VIN = 5V
IOUT = 0 TO 10mA
VOUT = 2.048V
0mA
10mA
VOUT
AC-COUPLED
20mV/div
IOUT
5mA/div
MAX6126
Maxim Integrated
11
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(VIN = 5V for MAX6126_21/25/30/41, VIN = 5.5V for MAX6126_50, CLOAD = 0.1µF, IOUT = 0, TA= +25°C, unless otherwise specified.)
(Note 5)
MAX6126_21
LOAD TRANSIENT
MAX6126 toc19
1ms/div
CLOAD = 10µF
VIN = 5V
IOUT = -100µA TO 1mA
VOUT = 2.048V
-100µA
+1mA
VOUT
AC-COUPLED
10mV/div
IOUT
500µA/div
MAX6126_21
LOAD TRANSIENT
MAX6126 toc20
400µs/div
CLOAD = 10µF
VIN = 5V
IOUT = -1mA TO -10mA
VOUT = 2.048V
-10mA
-1mA
VOUT
AC-COUPLED
50mV/div
IOUT
5mA/div
MAX6126_21
LINE TRANSIENT
MAX6126 toc21
2.7V
3.2V
VOUT
AC-COUPLED
20mV/div
VIN
200mV/div
20µs/div
VOUT = 2.048V CLOAD = 0.1µF
MAX6126_50
LINE TRANSIENT
MAX6126 toc22
5.2V
5.7V
VOUT
AC-COUPLED
10mV/div
VIN
200mV/div
400µs/div
VIN = 5.2V TO 5.7V
VOUT = 5V
CLOAD = 0.1µF
MAX6126_21
TURN-ON TRANSIENT
MAX6126 toc23
20µs/div
GND
5.5V
VOUT
1V/div
VIN
2V/div
CLOAD = 0.1µF
VOUT = 2.048V
MAX6126_50
TURN-ON TRANSIENT
MAX6126 toc24
GND
5.5V
VOUT
2V/div
VIN
2V/div
GND
200µs/div
CLOAD = 0.1µF
VOUT = 5V
MAX6126
12
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(VIN = 5V for MAX6126_21/25/30/41, VIN = 5.5V for MAX6126_50, CLOAD = 0.1µF, IOUT = 0, TA= +25°C, unless otherwise specified.)
(Note 5)
MAX6126_21
TURN-ON TRANSIENT
MAX6126 toc25
GND
5.5V
VOUT
1V/div
VIN
2V/div
40µs/div
CLOAD = 10µF
VOUT = 2.048V
MAX6126_50
TURN-ON TRANSIENT
MAX6126 toc26
GND
5.5V
VOUT
2V/div
VIN
2V/div
GND
400µs/div
CLOAD = 10µF
VOUT = 5V
2.4994
2.4998
2.4996
2.5002
2.5000
2.5004
2.5006
0400200 600 800 1000
MAX6126B_25
LONG-TERM STABILITY vs. TIME (SO)
MAX6126 toc27
TIME (hr)
VOUT (V)
TWO TYPICAL PARTS
VOUT = 2.5V
2.5010
2.5005
2.5000
2.4995
2.4990
0 400200 600 800 1000
MAX6126B_25
LONG-TERM STABILITY vs. TIME (µMAX)
MAX6126 toc28
TIME (hr)
VOUT (V)
TWO TYPICAL PARTS
VOUT = 2.5V
4.9994
4.9998
4.9996
5.0002
5.0000
5.0004
5.0006
0 400200 600 800 1000
MAX6126B_50
LONG-TERM STABILITY vs. TIME (SO)
MAX6126 toc29
TIME (hr)
VOUT (V)
TWO TYPICAL PARTS
VOUT = 5V
5.0010
5.0005
5.0000
4.9995
4.9990
0 400200 600 800 1000
MAX6126B_50
LONG-TERM STABILITY vs. TIME (µMAX)
MAX6126 toc30
TIME (hr)
VOUT (V)
TWO TYPICAL PARTS
VOUT = 5V
Note 5: Many of the MAX6126
Typical Operating Characteristics
are extremely similar. The extremes of these characteristics are
found in the MAX6126_21 (2.048V output) and the MAX6126_50 (5.000V output). The
Typical Operating Characteristics
of
the remainder of the MAX6126 family typically lie between those two extremes and can be estimated based on their output
voltages.
MAX6126
Maxim Integrated
13
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Detailed Description
Wideband Noise Reduction
To improve wideband noise and transient power-supply
noise, add a 0.1µF capacitor to NR (Figure 1). Larger
values do not improve noise appreciably. A 0.1µF NR
capacitor reduces the noise from 60nV/√Hz to
35nV/√Hz for the 2.048V output. Noise in the power-
supply input can affect output noise, but can be
reduced by adding an optional bypass capacitor
between IN and GND, as shown in the
Typical
Operating Circuit
.
Output Bypassing
The MAX6126 requires an output capacitor between
0.1µF and 10µF. Locate the output capacitor as close
to OUTF as possible. For applications driving switching
capacitive loads or rapidly changing load currents, it is
advantageous to use a 10µF capacitor in parallel with a
0.1µF capacitor. Larger capacitor values reduce tran-
sients on the reference output.
Supply Current
The quiescent supply current of the series-mode
MAX6126 family is typically 380µA and is virtually inde-
pendent of the supply voltage, with only a 2µA/V (max)
variation with supply voltage.
When the supply voltage is below the minimum speci-
fied input voltage during turn-on, the device can draw
up to 300µA beyond the nominal supply current. The
input voltage source must be capable of providing this
current to ensure reliable turn-on.
Thermal Hysteresis
Thermal hysteresis is the change of output voltage at
TA= +25°C before and after the device is cycled over
its entire operating temperature range. The typical ther-
mal hysteresis value is 20ppm (SO package).
Turn-On Time
These devices typically turn on and settle to within
0.1% of their final value in 200µs to 2ms depending on
the device. The turn-on time can increase up to 4ms
with the device operating at the minimum dropout volt-
age and the maximum load. A noise reduction capaci-
tor of 0.1µF increases the turn-on time to 20ms.
Output Force and Sense
The MAX6126 provides independent connections for the
power-circuit output (OUTF) supplying current into a
load, and for the circuit input regulating the voltage
applied to that load (OUTS). This configuration allows for
the cancellation of the voltage drop on the lines connect-
ing the MAX6126 and the load. When using the Kelvin
connection made possible by the independent current
and voltage connections, take the power connection to
the load from OUTF, and bring a line from OUTS to join
the line from OUTF, at the point where the voltage accu-
Pin Description
PIN NAME FUNCTION
1NR
Noise Reduction. Connect a 0.1µF
capacitor to improve wideband noise.
Leave unconnected if not used (see
Figure 1).
2 IN Positive Power-Supply Input
3 GND Ground
4 GNDS Ground-Sense Connection. Connect to
ground connection at load.
5, 8 I.C. Internally Connected. Do not connect
anything to these pins.
6 OUTS Voltage Reference Sense Output
7 OUTF
Voltage Reference Force Output. Short
OUTF to OUTS as close to the load as
possible. Bypass OUTF with a
capacitor (0.1µF to 10µF) to GND.
NR
OUTF
*OPTIONAL.
0.1µF*
OUTS
REFERENCE
OUTPUT
(VOUT + 200mV) TO 12.6V INPUT
IN
GND GNDS
MAX6126
*
Figure 1. Noise-Reduction Capacitor
MAX6126
14
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
racy is needed. The MAX6126 has the same type of
Kelvin connection to cancel drops in the ground return
line. Connect the load to ground and bring a connection
from GNDS to exactly the same point.
Applications Information
Precision Current Source
Figure 2 shows a typical circuit providing a precision
current source. The OUTF output provides the bias cur-
rent for the bipolar transistor. OUTS and GNDS sense
the voltage across the resistor and adjust the current
sourced by OUTF accordingly. For even higher preci-
sion, use a MOSFET to eliminate base current errors.
High-Resolution DAC and Reference from
a Single Supply
Figure 3 shows a typical circuit providing the reference
for a high-resolution, 16-bit MAX541 D/A converter.
Temperature Coefficient vs. Operating
Temperature Range for a 1 LSB Maximum
Error
In a data converter application, the reference voltage of
the converter must stay within a certain limit to keep the
error in the data converter smaller than the resolution
limit through the operating temperature range. Figure 4
shows the maximum allowable reference voltage tem-
perature coefficient to keep the conversion error to less
than 1 LSB, as a function of the operating temperature
range (TMAX - TMIN) with the converter resolution as a
parameter. The graph assumes the reference voltage
temperature coefficient as the only parameter affecting
accuracy.
In reality, the absolute static accuracy of a data con-
verter is dependent on the combination of many para-
meters such as integral nonlinearity, differential
nonlinearity, offset error, gain error, as well as voltage
reference changes.
OUTF
ISOURCE
R
OUTS
VOUT(NOMINAL) / R = ISOURCE
IN
GND GNDS
MAX6126
Figure 2. Precision Current Source
OUTF
OUTS
IN
GND GNDS
MAX6126
OUT
REF
ANALOG
OUTPUT
VDD
3V SUPPLY
GND
MAX541
DAC
Figure 3. 14-Bit High-Resolution DAC and Positive Reference
from a Single 3V Supply
MAX6126
Maxim Integrated
15
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
TEMPERATURE
COEFFICIENT
(ppm/°C)
110 100
16 BIT
14 BIT
12 BIT
10 BIT
8 BIT
0.01
0.1
10
100
1000
1
10,000
18 BIT
20 BIT
OPERATING TEMPERATURE RANGE (TMAX - TMIN) (°C)
Figure 4. Temperature Coefficient vs. Operating Temperature Range for a 1 LSB Maximum Error
Chip Information
PROCESS: BiCMOS
NR
OUTF
*OPTIONAL.
*
OUTS
REFERENCE
OUTPUT
(VOUT + 200mV) TO 12.6V INPUT
IN
GND GNDS
*
MAX6126
LOAD
Typical Operating Circuit
MAX6126
16
Maxim Integrated
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Ordering Information (continued)
PART TEMP RANGE PIN-
PACKAGE
OUTPUT
VOLTAGE
(V)
MAXIMUM INITIAL
ACCURACY (%)
MAXIMUM TEMPCO
(-40°C to +85°C)
(ppm/°C)
TOP
MARK
MAX6126B21+ -40°C to +125°C 8 µMAX 2.048 0.1 7 6126B21
MAX6126AASA25+ -40°C to +125°C 8 SO 2.500 0.02 3 —
MAX6126BASA25+ -40°C to +125°C 8 SO 2.500 0.06 5 —
MAX6126A25+ -40°C to +125°C 8 µMAX 2.500 0.06 3 6126A25
MAX6126B25+ -40°C to +125°C 8 µMAX 2.500 0.1 7 6126B25
MAX6126A28+ -40°C to +125°C 8 µMAX 2.800 0.06 3 6126A28
MAX6126B28+ -40°C to +125°C 8 µMAX 2.800 0.1 7 6126B28
MAX6126AASA30+ -40°C to +125°C 8 SO 3.000 0.02 3 —
MAX6126BASA30+ -40°C to +125°C 8 SO 3.000 0.06 5 —
MAX6126A30+ -40°C to +125°C 8 µMAX 3.000 0.06 3 6126A30
MAX6126B30+ -40°C to +125°C 8 µMAX 3.000 0.1 7 6126B30
MAX6126AASA41+ -40°C to +125°C 8 SO 4.096 0.02 3 —
MAX6126BASA41+ -40°C to +125°C 8 SO 4.096 0.06 5 —
MAX6126A41+ -40°C to +125°C 8 µMAX 4.096 0.06 3 6126A41
MAX6126B41+ -40°C to +125°C 8 µMAX 4.096 0.1 7 6126B41
MAX6126AASA50+ -40°C to +125°C 8 SO 5.000 0.02 3 —
MAX6126BASA50+ -40°C to +125°C 8 SO 5.000 0.06 5 —
MAX6126A50+ -40°C to +125°C 8 µMAX 5.000 0.06 3 6126A50
MAX6126B50+ -40°C to +125°C 8 µMAX 5.000 0.1 7 6126B50
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND
PATTERN NO.
8 µMAX U8+1 21-0036 90-0092
8 SO S8+4 21-0041 90-0096
+
Denotes a lead(Pb)-free/RoHS-compliant package.
MAX6126
Maxim Integrated
17
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES CHANGED
0 10/02 Initial release —
1 3/03 Remove “future product” and “contact factory” notes 1, 16
2 6/03 Add “A” grade devices 1, 16
3 12/03 Change µMAX part number 1, 16
4 7/04 Add top mark to Ordering Information 1, 16
5 12/10 Add 2.8V option, add lead-free options, update Package Information 1, 2, 4, 15, 16
MAX6126
18 Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
© 2010 Maxim Integrated The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.