General Description
The MAX6225/MAX6241/MAX6250 are low-noise, preci-
sion voltage references with extremely low 1ppm/°C
temperature coefficients and excellent ±0.02% initial
accuracy. These devices feature buried-zener technolo-
gy for lowest noise performance. Load-regulation speci-
fications are guaranteed for source and sink currents
up to 15mA. Excellent line and load regulation and low
output impedance at high frequency make them ideal
for high-resolution data-conversion systems up to
16 bits.
The MAX6225 is set for 2.500V output, the MAX6241 is
set for 4.096V output, and the MAX6250 is set for
5.000V output. All three provide for the option of exter-
nal trimming and noise reduction.
Applications
High-Resolution Analog-to-Digital
and Digital-to-Analog Converters
High-Accuracy Reference Standard
High-Accuracy Industrial and Process Control
Digital Voltmeters
ATE Equipment
Precision Current Sources
Features
Low 1.0ppm/°C Temperature Coefficient
Very Low 1.5µVp-p Noise (0.1Hz to 10Hz)
±0.02% Initial Accuracy
±15mA Output Source and Sink Current
Low, 18mW Power Consumption (MAX6225)
Industry-Standard Pinout
Optional Noise Reduction and Voltage Trim
Excellent Transient Response
8-Pin SO Package Available
Low 20ppm/1000hr Long-Term Stability
Stable for All Capacitive Loads
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
________________________________________________________________ Maxim Integrated Products 1
REFERENCE OUT
GND
NR
*OPTIONAL
TRIM
OUT
IN
8V TO 36V INPUT
*
2.2µF
*
2.2µF
MAX6225
MAX6241
MAX6250
Typical Operating Circuit
OUT
NR
TRIM
GND
1
2
8
7
I.C.
I.C.
IN
I.C.
MAX6225
MAX6241
MAX6250
DIP/SO
TOP VIEW
I.C. = INTERNALLY CONNECTED; DO NOT USE
3
4
6
5
Pin Configuration
19-1139; Rev 4; 1/01
Ordering Information
Ordering Information continued at end of data sheet.
MAX6225BCSA
MAX6225ACPA
MAX6225BCPA
MAX6225ACSA 0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C5.0
2.0
5.0
2.0
8 SO
8 Plastic DIP
8 Plastic DIP
8 SO
MAX6225AEPA -40°C to +85°C3.08 Plastic DIP
PART TEMP. RANGE
MAX
TEMPCO
(ppm/°C)
PIN-
PACKAGE
MAX6225BEPA -40°C to +85°C7.08 Plastic DIP
MAX6225AESA -40°C to +85°C3.08 SO
MAX6225BESA -40°C to +85°C7.08 SO
MAX6225AMJA -55°C to +125°C5.08 CERDIP
MAX6225BMJA -55°C to +125°C8.08 CERDIP
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.
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICSMAX6225
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
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.
(Voltages Referenced to GND)
IN..............................................................................-0.3V to +40V
OUT, TRIM ...............................................................-0.3V to +12V
NR ..............................................................................-0.3V to +6V
OUT Short-Circuit to GND Duration (VIN 12V)..........Continuous
OUT Short-Circuit to GND Duration (VIN 40V) ........................5s
OUT Short-Circuit to IN Duration (VIN 12V) ..............Continuous
Continuous Power Dissipation (TA= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ......727mW
8-Pin SO (derate 5.88mW/°C above +70°C) ...................471mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C)...........640mW
Operating Temperature Ranges
MAX62_ _ _C_ A.....................................................0°C to +70°C
MAX62_ _ _E_ A ..................................................-40°C to +85°C
MAX62_ _ _MJA ................................................-55°C to +125°C
Storage Temperature Range ..............................-65°C to +150°C
Lead Temperature (soldering, 10s)...................................+300°C
V
836VIN
Input Voltage Range
UNITSMIN TYP MAXSYMBOLPARAMETER
C, E, M
TA
V
2.499 2.500 2.501
VOUT
Output Voltage
C1.0 2.0
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
E1.5 3.0
ppm/°C
Line Regulation (Note 2) VOUT /
VIN
+25°C10 18
ppm/V
MAX6225A
MAX6225AC_A
MAX6225AE_A
CONDITIONS
8V VIN 10V
2.497 2.500 2.503MAX6225B
M2.0 5.0
C2.5 5.0
MAX6225AMJA
MAX6225BC_A
E2.5 7.0
M2.5 8.0
MAX6225BE_A
MAX6225BMJA
C30
E35
M45
10V VIN 36V
+25°C25
C 7
E 8
M10
+25°C
+25°C
Sinking: -15mA IOUT 0mA
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICSMAX6225 (continued)
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
(Note 4) 20 ppmTemperature Hysteresis +25°C
CONDITIONS
C16
E
Long-Term Stability VOUT / t
17
+25°C20
M315
ppm/
1000hr
C16
Figure 1
0.1Hz f 10Hz
E
10Hz f 1kHz
17
M10 30
+25°C1.8 2.7
Supply Current IIN C, E, M 3.0 mA
Trim-Adjustment Range
UNITSMIN TYP MAXSYMBOLPARAMETER
VOUT C, E, M ±15 ±25 mV
1.5 µVp-p
Output Noise Voltage (Note 3) en+25°C1.3 2.8 µVRMS
TA
To ±0.01% of final valueTurn-On Settling Time tON +25°C 5 µs
+25°C
Sourcing: 0mA IOUT 15mA
ppm/mA
VOUT/
IOUT
Load Regulation (Note 2)
Sinking: -15mA IOUT 0mA
ppm/mA
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
4 _______________________________________________________________________________________
(Note 4)
V
4.095 4.096 4.097
VOUT
Output Voltage +25°C
20 ppmTemperature Hysteresis
C1.0 2.0
MAX6241A
Output Voltage Temperature
Coefficient (Note 1) TCVOUT
E1.5 3.0
ppm/°C
+25°C
+25°C10 18
MAX6241AC_A
MAX6241AE_A
CONDITIONS
20 ppm/
1000hr
8V VIN 10V
Long-Term Stability VOUT / t +25°C
Line Regulation (Note 2) VOUT /
VIN ppm/V
Figure 1
0.1Hz f 10Hz
10Hz f 1kHz
V836VIN
Input Voltage Range
+25°C1.9 2.9
IIN C, E, M 3.2 mA
Trim-Adjustment Range
UNITSMIN TYP MAXSYMBOLPARAMETER
VOUT C, E, M ±24 ±40 mV
2.4 µVp-p
Output Noise Voltage (Note 3) en
+25°C
2.0 4.0 µVRMS
C, E, M
TA
ELECTRICAL CHARACTERISTICSMAX6241
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
M2.0 5.0
C2.5 5.0
MAX6241AMJA
MAX6241BC_A
E2.5 7.0
M2.5 8.0
MAX6241BE_A
MAX6241BMJA
4.092 4.096 4.100MAX6241B
To ±0.01% of final valueTurn-On Settling Time tON +25°C 8 µs
C30
E35
M45
+25°C25
10V VIN 36V C 7
E 8
M10
Supply Current
C16
E17
M39
C16
E17
M718
+25°C
+25°C
Sourcing: 0mA IOUT 15mA
Sinking: -15mA IOUT 0mA
VOUT /
IOUT
Load Regulation (Note 2) ppm/mA
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICSMAX6250
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
(Note 4)
V
4.999 5.000 5.001
VOUT
Output Voltage +25°C
20 ppmTemperature Hysteresis
C1.0 2.0
MAX6250A
E1.5 3.0
+25°C
+25°C10 18
MAX6250AC_A
MAX6250AE_A
CONDITIONS
20 ppm/
1000hr
8V VIN 10V
Long-Term Stability VOUT / t +25°C
Line Regulation (Note 2) VOUT /
VIN ppm/V
Figure 1
To ±0.01% of final value
V836VIN
Input Voltage Range
+25°C2.0 3.0
Supply Current IIN C, E, M 3.3 mA
Trim-Adjustment Range
UNITSMIN TYP MAXSYMBOLPARAMETER
VOUT C, E, M ±30 ±50 mV
10 µsTurn-On Settling Time ton +25°C
C, E, M
TA
C30
E35
M45
C 7
+25°C25
E 8
10V VIN 36V
M10
C16
C16
E17
E17
M
M29
615
0.1Hz f 10Hz
10Hz f 1kHz
3.0 µVp-p
Output Noise Voltage (Note 3) en
+25°C
2.5 5.0 µVRMS
4.995 5.000 5.005MAX6250B
Output Voltage Temperature
Coefficient (Note 1) TCVOUT ppm/°C
M2.0 5.0MAX6250AMJA
C2.5 5.0MAX6250BC_A
E2.5 7.0MAX6250BE_A
M2.5 8.0MAX6250BMJA
Note 1: Temperature coefficient is measured by the box method; i.e., the maximum VOUT is divided by T x VOUT.
Note 2: Line regulation (VOUT / (VOUT x VIN)) and load regulation (VOUT / (VOUT x IOUT)) are measured with pulses and do
not include output voltage changes due to die-temperature changes.
Note 3: Noise specifications are guaranteed by design.
Note 4: Temperature hysteresis is specified at TA= +25°C by measuring VOUT before and after changing temperature by +25°C
using the PDIP package.
+25°C
+25°C
Sourcing: 0mA IOUT 15mA
Sinking: -15mA IOUT 0mA
ppm/mA
VOUT /
IOUT
Load Regulation (Note 2)
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
6 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(VIN = +10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
2.0
-1.5
-55 -15 65
MAX6250
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
-1.0
1.0
MAX6225
toc
01
TEMPERATURE (°C)
VOUT (mV)
VOUT (ppm)
25 105-35 5 8545 125
0.5
0
-0.5
1.5
400
-300
-200
200
100
0
-100
300
-20
-10
0
10
20
30
40
50
60
0 5 10 15 20 25 30 35 40
CHANGE IN OUTPUT VOLTAGE
vs. INPUT VOLTAGE
VIN (V)
VOUT (ppm)
MAX6225
toc
07
-55 -15 65
MAX6241
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
-1
1.0
MAX6225
toc
02
TEMPERATURE (°C)
VOUT (mV)
VOUT (ppm)
25 105-35 5 8545 125
0.5
0
-0.5
1.5
-250
-125
0
125
250
375
-0.4
-0.3
-0.2
-0.1
00
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-160
-120
-80
-40
40
80
120
160
200
240
280
-55 -15 65
MAX6225
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
MAX6225
toc
03
TEMPERATURE (°C)
VOUT (mV)
VOUT (ppm)
25 105-35 5 8545 125
-250
-200
-150
-100
-50
0
50
100
150
200
-40 -30 -20 -10 0 10 20 30 40
MAX6225
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
IOUT (mA)
VOUT (µV)
TA = +85°C
TA = -40°CTA = +25°C
MAX6225
toc
06
-300
-200
-100
0
100
200
300
-40 -30 -20 -10 0 10 20 30 40
MAX6241
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6225
toc
05
IOUT (mA)
VOUT (µV)
TA = +25°C
TA = -40°C
TA = +85°C
-400
-300
-200
-100
0
100
200
300
-40 -30 -20 -10 0 10 20 30 40
MAX6250
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6225
toc
04
IOUT (mA)
VOUT (µV)
TA = +25°C
TA = -40°CTA = +85°C
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
0 5 10 15 20 25 30 35 40
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
MAX6225 MAX6241
MAX6250
MAX6225 toc08
1.0
1.5
2.0
2.5
3.0
3.5
-55 -35 -15 5 25 45 65 85 105 125
SUPPLY CURRENT vs. TEMPERATURE
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
MAX6241
MAX6250
MAX6225
MAX6225 toc09
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
_______________________________________________________________________________________ 7
MAX6241
0.1Hz to 10Hz NOISE
VOUT, 1µV/div
1sec/div
COUT = CNR = 0µF
MAX6225 toc14
0
5
10
15
20
25
30
35
40
45
50
10 100 1k 10k
MAX6225
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
FREQUENCY (Hz)
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/÷ Hz)
MAX6225 toc10
MAX6225
0.1Hz to 10Hz NOISE
MAX6225 toc13
VOUT, 0.5µV/div
1sec/div
COUT = CNR = 0µF
0
10
20
30
40
50
60
70
80
90
10 100 1k 10k
MAX6241
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
FREQUENCY (Hz)
MAX6225 toc11
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/÷ Hz)
0
10
20
30
40
50
60
70
80
100
90
10 100 1k 10k
MAX6250
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
FREQUENCY (Hz)
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/÷ Hz)
MAX6225 toc12
MAX6250
0.1Hz to 10Hz NOISE
VOUT, 1µV/div
1sec/div
COUT = CNR = 0µF
MAX6225 toc15
10 1M10k
FREQUENCY (Hz)
100 1k 100k
100
0.01
OUTPUT IMPEDANCE vs. FREQUENCY
0.1
OUTPUT IMPEDANCE ()
1
10
ISINK = 5mA
ISOURCE = 5mA
MAX6225 toc16
60
70
80
90
100
110
120
10 100 1k 10k
RIPPLE REJECTION
vs. FREQUENCY (CNR = 1µF)
FREQUENCY (Hz)
RIPPLE REJECTION (dB)
MAX6241
MAX6225
MAX6250
MAX6225 toc17
60
65
70
75
80
85
90
95
10 100 1k 10k
RIPPLE REJECTION
vs. FREQUENCY (CNR = 0µF)
MAX6607/08 toc18
FREQUENCY (Hz)
RIPPLE REJECTION (dB)
MAX6225
MAX6241
MAX6250
____________________________Typical Operating Characteristics (continued)
(VIN = 10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
8 _______________________________________________________________________________________
2µs/div
LOAD-TRANSIENT RESPONSE (SOURCING)
B
A
A: IOUT, 10mA/div (SOURCING)
B: VOUT, 500µV/div
0mA
-10mA
MAX6225 toc19
2µs/div
LOAD-TRANSIENT RESPONSE (SINKING)
B
A
0mA
10mA
A: IOUT, 10mA/div (SINKING)
B: VOUT, 500µV/div
MAX6225 toc20
____________________________Typical Operating Characteristics (continued)
(VIN = 10V, IOUT =0mA, TA= +25°C, unless otherwise noted.)
1µs/div
LOAD-TRANSIENT RESPONSE
B
A
A: IOUT (±10mA SOURCE AND SINK), 20mA/div, AC COUPLED
B: VOUT, 20mV/div, AC COUPLED
+10mA
-10mA
VIN = 10V
COUT = CNR = 0µF
MAX6225 toc21
1µs/div
MAX6225
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
B
A
A: VIN, 10V/div
B: VOUT, 1V/div
+10V
0
CIN = COUT = CNR = 0µF
MAX6225 toc22
1µs/div
MAX6250
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
B
A
A: VIN, 10V/div
B: VOUT, 1V/div
+10V
0
CIN = COUT = CNR = 0µF
MAX6225 toc24
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
_______________________________________________________________________________________ 9
Detailed Description
Temperature Stability
The MAX6225/MAX6241/MAX6250 are highly stable,
low-noise voltage references that use a low-power tem-
perature-compensation scheme to achieve laboratory-
standard temperature stability. This produces a nearly
flat temperature curve, yet does not require the power
associated with heated references.
The output voltage can be trimmed a minimum of 0.6%
by connecting a 10kpotentiometer between OUT and
GND, and connecting its tap to the TRIM pin, as shown
in Figure 1. The external trimming does not affect tem-
perature stability.
Noise Reduction
To augment wideband noise reduction, add a 1µF
capacitor to the NR pin (Figure 2). Larger values do not
improve noise appreciably (see Typical Operating
Characteristics).
Noise in the power-supply input can affect output
noise, but can be reduced by adding an optional
bypass capacitor to the IN pin and GND.
Bypassing
The MAX6225/MAX6241/MAX6250 are stable with
capacitive load values from 0µF to 100µF, for all values
of load current. Adding an output bypass capacitor can
help reduce noise and output glitching caused by load
transients.
Applications Information
Negative Regulator
Figure 3 shows how both a +5V and -5V precision ref-
erence can be obtained from a single unregulated +5V
supply. A MAX865 generates approximately ±9V to
operate the MAX6250 reference and MAX432 inverting
amplifier. The +5V is inverted by the MAX432 chopper-
stabilized amplifier. Resistor R1 is optional, and may be
used to trim the ±5V references. R2 and R4 should be
matched, both in absolute resistance and temperature
coefficient. R3 is optional, and is adjusted to set the -5V
reference.
_____________________Pin Description
NAME FUNCTION
1, 7, 8 I.C. Internally Connected. Do not use.
2IN Positive Power-Supply Input
PIN
4GND Ground
3 NR
Noise Reduction. Optional capacitor
connection for wideband noise
reduction. Leave open if not used
(Figure 2).
6OUT Voltage Reference Output
5TRIM
External Trim Input. Allows ±1%
output adjustment (Figure 1).
Leave open if not used.
MAX6225
MAX6241
MAX6250
IN
8V TO 36V INPUT
REFERENCE OUT
OUT
TRIM 10k
NR
GND
MAX6225
MAX6241
MAX6250
IN
8V TO 36V INPUT
REFERENCE OUT
OUT
TRIM
NR
*OPTIONAL
*
1µFGND
Figure 1. Output Voltage Adjustment Figure 2. Noise-Reduction Capacitor
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
10 ______________________________________________________________________________________
MAX6250
MAX865
IN
VCC V+
V-
GND
C2-
C2+
C1-
C1+
+5V INPUT
+REFERENCE OUT
-REFERENCE OUT
OUT
TRIM R1
10k
R4
100k
R2
100k
R3
1k
NR
2.2µF
C1
3.3µF
3.3µF
2.2µF
C2
1µF
2.2µF
C3
1µF
C4
GND
MAX432
Figure 3. +5V and -5V References from a Single +5V Supply
Ordering Information (continued) ___________________Chip Information
TRANSISTOR COUNT: 435
MAX6241BCSA
MAX6241ACPA
MAX6241BCPA
MAX6241ACSA 0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C5.0
2.0
5.0
2.0
8 SO
8 Plastic DIP
8 Plastic DIP
8 SO
MAX6241AEPA -40°C to +85°C3.08 Plastic DIP
PART TEMP. RANGE
MAX
TEMPCO
(ppm/°C)
PIN-
PACKAGE
MAX6250BEPA -40°C to +85°C7.08 Plastic DIP
MAX6250AESA -40°C to +85°C3.08 SO
MAX6250BESA -40°C to +85°C7.08 SO
MAX6250AMJA -55°C to +125°C5.08 CERDIP
MAX6241BEPA -40°C to +85°C7.08 Plastic DIP
MAX6241AESA -40°C to +85°C3.08 SO
MAX6241BESA -40°C to +85°C7.08 SO
MAX6241AMJA -55°C to +125°C5.08 CERDIP
MAX6241BMJA -55°C to +125°C8.08 CERDIP
MAX6250ACPA 0°C to +70°C2.08 Plastic DIP
MAX6250BCPA 0°C to +70°C5.08 Plastic DIP
MAX6250ACSA 0°C to +70°C2.08 SO
MAX6250BCSA 0°C to +70°C5.08 SO
MAX6250BMJA -55°C to +125°C8.08 CERDIP
MAX6250AEPA -40°C to +85°C3.08 Plastic DIP
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
______________________________________________________________________________________ 11
________________________________________________________Package Information
PDIPN.EPS
SOICN.EPS
MAX6225/MAX6241/MAX6250
Low-Noise, Precision, +2.5V/+4.096V/+5V
Voltage References
CDIPS.EPS
___________________________________________Package Information (continued)
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.