General Description
The MAX6129 micropower, low-dropout bandgap volt-
age reference combines ultra-low supply current and
low drift in a miniature 5-pin SOT23 surface-mount
package that uses 70% less board space than compa-
rable devices in an SO package. This series-mode volt-
age reference sources up to 4mA and sinks up to 1mA
of load current. A wide 2.5V to 12.6V supply range,
ultra-low 5.25µA (max) supply current, and a low
200mV dropout voltage make these devices ideal for
battery-operated systems.
An initial accuracy of 0.4% and a 40ppm/°C (max) tem-
perature coefficient make the MAX6129 suitable for
precision applications. Additionally, an internal com-
pensation capacitor eliminates the need for an external
compensation capacitor and ensures stability with load
capacitances up to 10µF.
The MAX6129 provides six output voltages of 2.048V,
2.5V, 3V, 3.3V, 4.096V, and 5V. The MAX6129 is avail-
able in a 5-pin SOT23 package and in die form.
Applications
Battery-Powered Systems
Handheld Instruments
Precision Power Supplies
A/D and D/A Converters
Features
♦Ultra-Low 5.25µA (max) Supply Current
♦4mA Output Source Current
♦1mA Output Sink Current
♦±0.4% (max) Initial Accuracy
♦40ppm/°C (max) Temperature Coefficient
♦2.5V to 12.6V Supply Range
♦Low 200mV Dropout
♦Stable with Capacitive Loads Up to 10µF
♦No External Capacitors Required
♦Miniature 5-Pin SOT23 Package
MAX6129
Ultra-Low-Power Series Voltage Reference
________________________________________________________________ Maxim Integrated Products 1
GND
N.C.N.C.
15OUTIN
MAX6129
SOT23
TOP VIEW
2
34
Pin Configuration
Ordering Information
OUT
GND
IN
MAX6129
VIN = 2.5V TO 12.6V
*
*CAPACITOR IS OPTIONAL
Typical Operating Circuit
19-2507; Rev 2; 3/05
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.
PA R T
TEMP RANGE
PIN -
PA C K A G E
O U TPU T
VO LT A G E
( V)
M AX 6129_E U K21- T
-40°C to +85°C 5 SOT23-5
2.048
M AX 6129AC /D 21
-40°C to +85°C
Dice 2.048
M AX 6129_E U K25- T
-40°C to +85°C 5 SOT23-5
2.500
M AX 6129AC /D 25
-40°C to +85°C
Dice 2.500
M AX 6129_E U K30- T
-40°C to +85°C 5 SOT23-5
3.000
M AX 6129AC /D 30
-40°C to +85°C
Dice 3.000
M AX 6129_E U K33- T
-40°C to +85°C 5 SOT23-5
3.300
M AX 6129AC /D 33
-40°C to +85°C
Dice 3.300
M AX 6129_E U K41- T
-40°C to +85°C 5 SOT23-5
4.096
M AX 6129AC /D 41
-40°C to +85°C
Dice 4.096
M AX 6129_E U K50- T
-40°C to +85°C 5 SOT23-5
5.000
M AX 6129AC /D 50
-40°C to +70°C
Dice 5.000
Note: The MAX6129_EUK is available in A or B grade. Choose
the desired grade from the Selector Guide and insert the suffix
in the blank above to complete the part number.
Selector Guide appears at end of data sheet.
MAX6129
Ultra-Low-Power Series Voltage Reference
2_______________________________________________________________________________________
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.
IN to GND ...............................................................-0.3V to +13V
OUT to GND ..............-0.3V to the lower of +6V and (VIN + 0.3V)
Output to GND Short-Circuit Duration........................Continuous
Continuous Power Dissipation (TA= +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS—MAX6129_21 (VOUT = 2.048V)
(VIN = 2.5V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 2.0398 2.0480 2.0562
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
2.0275 2.0480 2.0685
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B 100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 2.5V to 12.6V 27 200
µV/V
IOUT = 0 to 4mA
0.22
0.7
Load Regulation (Note 4) ∆VOUT/
∆IOUT IOUT = 0 to -1mA 2.4 5.5
µV/µA
Output Short-Circuit Current ISC 60 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 30
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
115
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 2.5V ±200mV, f = 120Hz 43 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value
450
µs
INPUT
Supply Voltage Range VIN 2.5
12.6
V
Supply Current IIN
5.25
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 2.5V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS—MAX6129_25 (VOUT = 2.500V)
(VIN = 2.7V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 2.4900 2.5000 2.5100
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
2.4750 2.5000 2.5250
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B 100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 2.7V to 12.6V 30 230
µV/V
IOUT = 0 to 4mA 0.1 0.6
Load Regulation (Note 4)
∆VOUT/∆IOUT
IOUT = 0 to -1mA 2.5 6.2
µV/µA
IOUT = 0 0.3 100
Dropout Voltage (Notes 4, 6)
VIN - VOUT
IOUT = 4mA
140
200 mV
Output Short-Circuit Current ISC 60 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 39
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
137
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 2.7V ±200mV, f = 120Hz 34 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value
700
ms
INPUT
Supply Voltage Range VIN 2.7
12.6
V
Supply Current IIN
5.75
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 2.7V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
4_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—MAX6129_30 (VOUT = 3.000V)
(VIN = 3.2V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 2.9880 3.0000 3.0120
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
2.9700 3.0000 3.0300
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B 100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 3.2V to 12.6V 15 250
µV/V
IOUT = 0 to 4mA 0.1 0.6
Load Regulation (Note 4) ∆VOUT/
∆IOUT IOUT = 0 to -1mA 2.4 6.5
µV/µA
IOUT = 0 0.2 100
Dropout Voltage (Notes 4, 6)
VIN - VOUT
IOUT = 4mA
140
200 mV
Output Short-Circuit Current ISC 25 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 50
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
161
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 3.2V ±200mV, f = 120Hz 37 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value
775
µs
INPUT
Supply Voltage Range VIN 3.2
12.6
V
Supply Current IIN
6.75
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 3.2V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS—MAX6129_33 (VOUT = 3.300V)
(VIN = 3.5V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 3.2868 3.3000 3.3132
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
3.2670 3.3000 3.3330
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B
100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 3.5V to 12.6V 30
270
µV/V
IOUT = 0 to 4mA 0.1 0.6
Load Regulation (Note 4)
∆VOUT/∆IOUT
IOUT = 0 to -1mA 2.4 7
µV/µA
IOUT = 0 0.2
100
Dropout Voltage (Notes 4, 6)
VIN - VOUT
IOUT = 4mA
140 200
mV
Output Short-Circuit Current ISC 25 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 56
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
174
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 3.5V ±200mV, f = 120Hz 38 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value 1 ms
INPUT
Supply Voltage Range VIN 3.5
12.6
V
Supply Current IIN
7.25
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 3.5V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
6_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—MAX6129_41 (VOUT = 4.096V)
(VIN = 4.3V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS
MIN
MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 4.0796 4.0960 4.1124
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
4.0550 4.0960 4.1370
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B 100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 4.3V to 12.6V 30 310
µV/V
IOUT = 0 to 4mA 0.1 0.6
Load Regulation (Note 4)
∆VOUT/∆IOUT
IOUT = 0 to -1mA 2.5 8.5
µV/µA
IOUT = 0
0.18
100
Dropout Voltage (Notes 4, 6)
VIN - VOUT
IOUT = 4mA
140
200 mV
Output Short-Circuit Current ISC 25 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 72
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
210
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 4.3V ±200mV, f = 120Hz 36 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value 1.2 ms
INPUT
Supply Voltage Range VIN 4.3
12.6
V
Supply Current IIN
8.75
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 4.3V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
_______________________________________________________________________________________ 7
Note 1: MAX6129 is 100% production tested at TA= +25°C and is guaranteed by design for TA= TMIN to TMAX as specified.
Note 2: Temperature coefficient is defined by box method: (VMAX - VMIN)/(∆T ✕V+25°C).
Note 3: Not production tested. Guaranteed by design for both SOT23 and dice.
Note 4: Only the typical values apply to MAX6129A sold in die form (max values apply to packaged parts).
Note 5: Thermal hysteresis is defined as the change in output voltage at TA= +25°C before and after cycling the device from TMAX
to TMIN.
Note 6: Dropout voltage is the minimum input voltage at which VOUT changes by 0.1% from VOUT at rated VIN and is guaranteed by
Load Regulation Test.
ELECTRICAL CHARACTERISTICS—MAX6129_50 (VOUT = 5.000V)
(VIN = 5.2V, IOUT = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
OUTPUT
MAX6129A (±0.4%) 4.9800 5.0000 5.0200
Output Voltage VOUT TA = +25°CMAX6129B (±1%)
4.9500 5.0000 5.0500
V
MAX6129A 40
Output Voltage Temperature
Coefficient (Notes 2, 3) TCVOUT MAX6129B
100
ppm/°C
Line Regulation (Note 4)
∆VOUT/∆VIN
VIN = 5.2V to 12.6V 34
375
µV/V
IOUT = 0 to 4mA 0.3 0.8
Load Regulation (Note 4) ∆VOUT/
∆IOUT IOUT = 0 to -1mA 3.3 9
µV/µA
IOUT = 0
0.175 100
Dropout Voltage (Notes 4, 6)
VIN - VOUT
IOUT = 4mA
140 200
mV
Output Short-Circuit Current ISC 25 mA
Long-Term Stability
∆VOUT/time
1000 hours at +25°C
150
ppm
Thermal Hysteresis (Note 5)
140
ppm
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz 90
µVP-P
Noise Voltage eOUT f = 10Hz to 1kHz
245
µVRMS
Ripple Rejection
∆VOUT/∆VIN
VIN = 5.2V ±200mV, f = 120Hz 38 dB
Turn-On Settling Time tRTo VOUT = 0.1% of final value 1.4 ms
INPUT
Supply Voltage Range VIN 5.2
12.6
V
Supply Current IIN
10.5
µA
Change in Supply Current
(Note 4) IIN/VIN VIN = 5.2V to 12.6V 1.0 1.5
µA/V
MAX6129
Ultra-Low-Power Series Voltage Reference
8_______________________________________________________________________________________
Typical Operating Characteristics
(VIN = 2.5V for MAX_EUK21, VIN = 3.2V for MAX_EUK30, and VIN = 5.2V for MAX_EUK50, IOUT = 0, TA= +25°C, unless otherwise
noted.)
OUTPUT VOLTAGE vs. TEMPERATURE
(VOUT = 2.048V)
MAX6129 toc01
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
603510-15
2.042
2.044
2.046
2.048
2.050
2.040
-40 85
3 TYPICAL UNITS
OUTPUT VOLTAGE vs. TEMPERATURE
(VOUT = 3V)
MAX6129 toc02
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
603510-15
2.993
2.995
2.997
2.999
3.001
3.003
2.991
-40 85
3 TYPICAL UNITS
OUTPUT VOLTAGE vs. TEMPERATURE
(VOUT = 5V)
MAX6129 toc03
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
4.990
4.992
4.994
4.996
4.998
5.000
5.002
5.004
5.006
4.988
603510-15-40 85
3 TYPICAL UNITS
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX6129 toc04
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
121110987654321
2
4
6
8
10
12
14
0
013
VOUT = 3V
VOUT = 5V
VOUT = 2.048V
SUPPLY CURRENT vs. TEMPERATURE
MAX6129 toc05
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
603510-15
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
2.5
-40 85
VOUT = 3V
VOUT = 5V
VOUT = 2.048V
DROPOUT VOLTAGE vs. SOURCE CURRENT
(VOUT = 2.048V)
MAX6129 toc06
SOURCE CURRENT (mA)
DROPOUT VOLTAGE (V)
651 2 3 4
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0
07
DROPOUT VOLTAGE vs. SOURCE CURRENT
(VOUT = 3V)
MAX6129 toc07
SOURCE CURRENT (mA)
DROPOUT VOLTAGE (V)
653 421
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0
07
DROPOUT VOLTAGE vs. SOURCE CURRENT
(VOUT = 5V)
MAX6129 toc08
SOURCE CURRENT (mA)
DROPOUT VOLTAGE (V)
653 421
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0
07
LOAD REGULATION
(VOUT = 2.048V)
MAX6129 toc09
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
653 40 1 2-1
2.0475
2.0480
2.0485
2.0490
2.0495
2.0500
2.0505
2.0510
2.0515
2.0520
2.0470
-2 7
MAX6129
Ultra-Low-Power Series Voltage Reference
_______________________________________________________________________________________ 9
LINE REGULATION
(VOUT = 2.048V)
MAX6129 toc10
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
11.510.07.0 8.55.54.0
2.04774
2.04776
2.04778
2.04780
2.04782
2.04784
2.04786
2.04788
2.04790
2.04792
2.04772
2.5 13.0
LOAD REGULATION
(VOUT = 3V)
MAX6129 toc11
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
653 40 1 2-1
3.0015
3.0020
3.0025
3.0030
3.0035
3.0040
3.0045
3.0050
3.0055
3.0010
-2 7
LINE REGULATION
(VOUT = 3V)
MAX6129 toc12
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
121110987654
3.00160
3.00165
3.00170
3.00175
3.00180
3.00155
313
LOAD REGULATION
(VOUT = 5V)
MAX6129 toc13
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
653 40 1 2-1
5.0015
5.0020
5.0025
5.0030
5.0035
5.0040
5.0045
5.0050
5.0005
5.0010
-2 7
LINE REGULATION
(VOUT = 5V)
MAX6129 toc14
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
12116 7 8 9 10
5.00066
5.00068
5.00070
5.00072
5.00074
5.00076
5.00078
5.00080
5.00064
513
POWER-SUPPLY REJECTION RATIO vs.
FREQUENCY (VOUT = 2.048V)
MAX6129 toc15
FREQUENCY (kHz)
PSRR (dB)
100101
-50
-40
-30
-20
-10
0
-60
0.1 1000
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (VOUT = 3V)
MAX6129 toc16
FREQUENCY (kHz)
PSRR (dB)
100101
-50
-40
-30
-20
-10
0
-60
0.1 1000
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (VOUT = 5V)
MAX6129 toc17
FREQUENCY (kHz)
PSRR (dB)
100101
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
-50
0.1 1000
Typical Operating Characteristics (continued)
(VIN = 2.5V for MAX_EUK21, VIN = 3.2V for MAX_EUK30, and VIN = 5.2V for MAX_EUK50, IOUT = 0, TA= +25°C, unless otherwise
noted.)
LINE-TRANSIENT RESPONSE
(VOUT = 2.048V)
MAX6129 toc18
200µs/div
3V
2.5V
2.048V
VIN
200mV/div
AC-COUPLED
VOUT
200mV/div
AC-COUPLED
MAX6129
Ultra-Low-Power Series Voltage Reference
10 ______________________________________________________________________________________
LINE-TRANSIENT RESPONSE
(VOUT = 3V)
MAX6129 toc19
200µs/div
3.7V
3.2V
3V
VIN
200mV/div
AC-COUPLED
VOUT
200mV/div
AC-COUPLED
LINE-TRANSIENT RESPONSE
(VOUT = 5V)
MAX6129 toc20
200µs/div
5.7V
5.2V
5V
VIN
200mV/div
AC-COUPLED
VOUT
100mV/div
AC-COUPLED
LOAD-TRANSIENT RESPONSE
(SOURCING, VOUT = 2.048V)
MAX6129 toc21
100µs/div
4mA
2.048V
IOUT
10mA/div
VOUT
500mV/div
AC-COUPLED
COUT = 0
0
LOAD-TRANSIENT RESPONSE
(SINKING, VOUT = 2.048V)
MAX6129 toc22
1ms/div
0
-1mA
2.048V
IOUT
2mA/div
VOUT
500mV/div
AC-COUPLED
COUT = 0
LOAD-TRANSIENT RESPONSE
(SOURCING, VOUT = 2.048V)
MAX6129 toc23
400µs/div
4mA
2.048V
IOUT
10mA/div
VOUT
500mV/div
AC-COUPLED
COUT = 1µF
0
LOAD-TRANSIENT RESPONSE
(SINKING, VOUT = 2.048V)
MAX6129 toc24
1ms/div
0
-1mA
2.048V
IOUT
2mA/div
VOUT
500mV/div
AC-COUPLED
COUT = 1µF
Typical Operating Characteristics (continued)
(VIN = 2.5V for MAX_EUK21, VIN = 3.2V for MAX_EUK30, and VIN = 5.2V for MAX_EUK50, IOUT = 0, TA= +25°C, unless otherwise
noted.)
MAX6129
Ultra-Low-Power Series Voltage Reference
______________________________________________________________________________________ 11
LOAD-TRANSIENT RESPONSE
(SINKING, VOUT = 5V)
MAX6129 toc28
2ms/div
0
-1mA
5V
IOUT
1mA/div
VOUT
1V/div
AC-COUPLED
COUT = 1µF
TURN-ON TRANSIENT
(VOUT = 2.048V)
MAX6129 toc29
200µs/div
2.5V
2.048V
VIN
1V/div
VOUT
1V/div
0
0
TURN-ON TRANSIENT
(VOUT = 3V)
MAX6129 toc30
200µs/div
3.2V
3V
VIN
2V/div
VOUT
1V/div
0
0
LOAD-TRANSIENT RESPONSE
(SOURCING, VOUT = 5V)
MAX6129 toc25
400µs/div
4mA
5V
IOUT
10mA/div
VOUT
500mV/div
AC-COUPLED
COUT = 0
0
LOAD-TRANSIENT RESPONSE
(SINKING, VOUT = 5V)
MAX6129 toc26
2ms/div
0
-1mA
5V
IOUT
1mA/div
VOUT
1V/div
AC-COUPLED
COUT = 0
LOAD-TRANSIENT RESPONSE
(SOURCING, VOUT = 5V)
MAX6129 toc27
400µs/div
4mA
6V
IOUT
10mA/div
VOUT
200mV/div
AC-COUPLED
COUT = 1µF
0
Typical Operating Characteristics (continued)
(VIN = 2.5V for MAX_EUK21, VIN = 3.2V for MAX_EUK30, and VIN = 5.2V for MAX_EUK50, IOUT = 0, TA= +25°C, unless otherwise
noted.)
MAX6129
Ultra-Low-Power Series Voltage Reference
12 ______________________________________________________________________________________
NOISE vs. FREQUENCY
(VOUT = 5V)
MAX6129 toc37
FREQUENCY (kHz)
NOISE (µVRMS/√Hz)
40302010
2
4
6
8
10
12
14
16
18
20
0
050
Typical Operating Characteristics (continued)
(VIN = 2.5V for MAX_EUK21, VIN = 3.2V for MAX_EUK30, and VIN = 5.2V for MAX_EUK50, IOUT = 0, TA= +25°C, unless otherwise
noted.)
0.1Hz TO 10Hz OUTPUT NOISE
(VOUT = 5V)
MAX6129 toc34
1s/div
VOUT
20µV/div
NOISE vs. FREQUENCY
(VOUT = 2.048V)
MAX6129 toc35
FREQUENCY (kHz)
NOISE (µVRMS/√Hz)
403010 20
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
050
NOISE vs. FREQUENCY
(VOUT = 3V)
MAX6129 toc36
FREQUENCY (kHz)
NOISE (µVRMS/√Hz)
40302010
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
0
050
0.1Hz TO 10Hz OUTPUT NOISE
(VOUT = 2.048V)
MAX6129 toc32
1s/div
VOUT
10µV/div
0.1Hz TO 10Hz OUTPUT NOISE
(VOUT = 3V)
MAX6129 toc33
1s/div
VOUT
10µV/div
TURN-ON TRANSIENT
(VOUT = 5V)
MAX6129 toc31
400µs/div
5.2V
5V
VIN
2V/div
VOUT
2V/div
0
0
MAX6129
Ultra-Low-Power Series Voltage Reference
______________________________________________________________________________________ 13
Applications Information
Input Bypassing
The MAX6129 does not require an input bypass capac-
itor. For improved transient performance, bypass the
input to ground with a 0.1µF ceramic capacitor. Place
the capacitor as close to IN as possible.
Load Capacitance
The MAX6129 does not require an output capacitor for
stability. The MAX6129 is stable driving capacitive
loads from 0 to 100pF and 0.1µF to 10µF when sourc-
ing current and from 0 to 0.4µF when sinking current. In
applications where the load or the supply can experi-
ence step changes, an output capacitor reduces the
amount of overshoot (undershoot) and improves the cir-
cuit’s transient response. Many applications do not
require an external capacitor, and the MAX6129 offers
a significant advantage in applications where board
space is critical.
Supply Current
The quiescent supply current of the series-mode
MAX6129 is very small, 5.25µA (max), and is very sta-
ble against changes in the supply voltage with only
1.5µA/V (max) variation with supply voltage. The
MAX6129 family draws load current from the input volt-
age source only when required, so supply current is not
wasted and efficiency is maximized at all input volt-
ages. This improved efficiency reduces power dissipa-
tion and extends battery life.
Output Thermal Hysteresis
Output thermal hysteresis is the change of output volt-
age at TA= +25°C before and after the device is
cycled over its entire operating temperature range.
Hysteresis is caused by differential package stress
appearing across the device.
Temperature Coefficient vs. Operating
Temperature Range for a 1LSB
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 1
shows the maximum allowable reference voltage tem-
perature coefficient to keep the conversion error to less
than 1LSB, 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.
Pin Description
PIN
NAME
FUNCTION
1INPositive Voltage Supply
2GND Ground
3, 4 N.C. Internally connected. Leave
unconnected or connect to ground.
5OUT Reference Output
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 1. Temperature Coefficient vs. Operating Temperature Range for a 1LSB Maximum Error
MAX6129
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.
Turn-On Time
These devices typically turn on and settle to within
0.1% of their final value in less than 1.4ms. The turn-on
time increases when heavily loaded and operating
close to dropout.
Positive and Negative Low-Power Voltage
Reference
Figure 2 shows a typical method for developing a bipo-
lar reference. The circuit uses a MAX681 voltage dou-
bler/inverter charge-pump converter to power a
MAX480, creating a positive as well as a negative refer-
ence voltage.
Ultra-Low-Power Series Voltage Reference
14 ______________________________________________________________________________________
MAX681
MAX6129
VIN
VCC
GND
V+
V-
2VIN
GND
IN OUT
1MΩ
1MΩ10nF MAX480
V+
+REF
OUTPUT
-REF
OUTPUT
V-
-2VIN
Figure 2. Positive and Negative References from a Single 3V/5V Supply
MAX6129
Ultra-Low-Power Series Voltage Reference
______________________________________________________________________________________ 15
PART
PIN-PACKAGE
OUTPUT
VOLTAGE (V)
INITIAL
ACCURACY (%)
TEMPERATURE
COEFFICIENT
(ppm/°C)
TOP MARK
MAX6129AEUK21-T 5 SOT23-5 2.048 0.4 40 ADRM
MAX6129AC/D21 Dice 2.048 0.4 40 —
MAX6129BEUK21-T 5 SOT23-5 2.048 1 100 ADRN
MAX6129AEUK25-T 5 SOT23-5 2.500 0.4 40 ADRO
MAX6129AC/D25 Dice 2.500 0.4 40 —
MAX6129BEUK25-T*
5 SOT23-5 2.500 1 100 ADRP
MAX6129AEUK30-T 5 SOT23-5 3.000 0.4 40 ADRQ
MAX6129AC/D30 Dice 3.000 0.4 40 —
MAX6129BEUK30-T 5 SOT23-5 3.000 1 100 ADRR
MAX6129AEUK33-T 5 SOT23-5 3.300 0.4 40 ADRW
MAX6129AC/D33 Dice 3.300 0.4 40 —
MAX6129BEUK33-T 5 SOT23-5 3.300 1 100 ADRX
MAX6129AEUK41-T 5 SOT23-5 4.096 0.4 40 ADRS
MAX6129AC/D41 Dice 4.096 0.4 100 —
MAX6129BEUK41-T 5 SOT23-5 4.096 1 100 ADRT
MAX6129AEUK50-T 5 SOT23-5 5.000 0.4 40 ADRU
MAX6129AC/D50 Dice 5.000 0.4 40 —
MAX6129BEUK50-T 5 SOT23-5 5.000 1 100 ADRV
Selector Guide
*Future product—contact factory for availability.
Chip Topography
N.C.
N.C.
GND
N.C.
N.C.
OUT
N.C.
IN
Chip Information
TRANSISTOR COUNT: 30
PROCESS: BiCMOS
SUBSTRATE CONNECTED TO GND
MAX6129
Ultra-Low-Power Series Voltage Reference
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.
16 ____________________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.
SOT-23 5L .EPS
E
1
1
21-0057
PACKAGE OUTLINE, SOT-23, 5L
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.)