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 MAX6325/MAX6341/MAX6350 are low-noise, preci-
sion voltage references with extremely low, 0.5ppm/°C
typical temperature coefficients and excellent, ±0.02%
initial accuracy. These devices feature buried-zener
technology for lowest noise performance. Load-regula-
tion specifications are guaranteed for source and sink
currents up to 15mA. Excellent line and load regulation
and low output impedance at high frequencies make
them ideal for high-resolution data-conversion systems
up to 16 bits.
The MAX6325 is set for a 2.5V output, the MAX6341 is
set for a 4.096V output, and the MAX6350 is set for a
5V output. All three provide for the option of external
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
♦Ultra Low, 1ppm/°C Max Tempco
♦Very Low, 1.5µVp-p Noise (0.1Hz to 10Hz)
(MAX6325)
♦±0.02% Initial Accuracy (MAX6350)
♦±15mA Output Source and Sink Current
♦Low, 18mW Power Consumption (MAX6325)
♦Industry-Standard Pinout
♦Optional Noise Reduction and Voltage Trim
♦Excellent Transient Response
♦8-Pin SO Package Available
♦Low, 30ppm/1000hr Long-Term Stability
♦Stable for All Capacitive Loads
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
REFERENCE OUT
GND
NR
*OPTIONAL
TRIM
OUT
IN
8V TO 36V INPUT
*
2.2µF
*
2.2µF
MAX6325
MAX6341
MAX6350
Typical Operating Circuit
OUT
NR
TRIM
GND
1
2
8
7
I.C.
I.C.
IN
I.C.
MAX6325
MAX6341
MAX6350
DIP/SO
TOP VIEW
I.C. = INTERNALLY CONNECTED; DO NOT USE
3
4
6
5
Pin Configuration
19-1203; Rev 1; 1/01
Ordering Information
Ordering Information continued at end of data sheet.
MAX6325CPA
MAX6325CSA 0°C to +70°C
0°C to +70°C1.0
1.0
8 Plastic DIP
8 SO
MAX6325EPA -40°C to +85°C1.58 Plastic DIP
PART TEMP. RANGE
MAX
TEMPCO
(ppm/°C)
PIN-
PACKAGE
MAX6325ESA -40°C to +85°C1.58 SO
MAX6325MJA -55°C to +125°C2.58 CERDIP
Pin Configuration
19-1203; Rev 1; 1/01
Pin Configuration
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—MAX6325
(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
MAX63_ _ C_ A.......................................................0°C to +70°C
MAX63_ _ E_ A....................................................-40°C to +85°C
MAX63_ _ MJA ..................................................-55°C to +125°C
Storage Temperature Range ..............................-65°C to +150°C
Lead Temperature (soldering, 10s)...................................+300°C
Load Regulation (Note 2) ∆VOUT/
∆IOUT ppm/mA
+25°C
+25°C
µs5+25°CtON
Turn-On Settling Time To ±0.01% of final value
µVRMS
1.3 2.8+25°C
en
Output Noise Voltage (Note 3) µVp-p1.5
mV±15 ±25C, E, M∆VOUT
Trim-Adjustment Range
mA
3.0C, E, M
IIN
Supply Current 1.8 2.7+25°C
10 30M
17
10Hz ≤f ≤1kHz
E
0.1Hz ≤f ≤10Hz
(Figure 1)
16C
ppm/
1000hr
315M
30+25°C
17
∆VOUT/tLong-Term Stability
E
16C
+25°CTemperature Hysteresis ppm20(Note 4)
10M
8E
7C
25+25°C
10V ≤VIN ≤36V
45M
35E
30C
MAX6325MJA 1.0 2.5M
8V ≤VIN ≤10V
CONDITIONS
MAX6325E_A
MAX6325C_A
MAX6325
ppm/V
10 18+25°C
∆VOUT/
∆VIN
Line Regulation (Note 2)
ppm/°C0.75 1.5ETCVOUT
Output Voltage Temperature
Coefficient (Note 1)
0.5 1.0C
Output Voltage VOUT 2.499 2.500 2.501 V
TA
C, E, M
PARAMETER SYMBOL MIN TYP MAX UNITS
Input Voltage Range VIN 836V
Sourcing: 0mA ≤IOUT ≤15mA
Sinking: -15mA ≤IOUT ≤0mA
MAX6325/MAX6341/MAX6350
2
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
(Note 4)
V4.095 4.096 4.097VOUT
Output Voltage +25°C
20 ppmTemperature Hysteresis
C0.5 1.0
MAX6341
Output Voltage Temperature
Coefficient (Note 1) TCVOUT E0.75 1.5
ppm/°C
+25°C
+25°C10 18
MAX6341C_A
MAX6341E_A
CONDITIONS
30 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 CHARACTERISTICS—MAX6341
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
M1.0 2.5MAX6341MJA
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
Sourcing: 0mA ≤IOUT ≤15mA
Sinking: -15mA ≤IOUT ≤0mA
∆VOUT/
∆IOUT
Load Regulation (Note 2) ppm/mA
MAX6325/MAX6341/MAX6350
Maxim Integrated
3
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
ELECTRICAL CHARACTERISTICS—MAX6350
(VIN = +10V, IOUT = 0mA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
(Note 4)
V4.999 5.000 5.001VOUT
Output Voltage +25°C
20 ppmTemperature Hysteresis
C0.5 1.0
MAX6350
E0.75 1.5
+25°C
+25°C10 18
MAX6350C_A
MAX6350E_A
CONDITIONS
30 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
Output Voltage Temperature
Coefficient (Note 1) TCVOUT ppm/°C
M1.0 2.5MAX6350MJA
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 plastic DIP package.
+25°C
Sourcing: 0mA ≤IOUT ≤15mA
Sinking: -15mA ≤IOUT ≤0mA
ppm/mA
∆VOUT/
∆IOUT
Load Regulation (Note 2)
MAX6325/MAX6341/MAX6350
4
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
__________________________________________Typical Operating Characteristics
(VIN = +10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
2.0
-1.5
-55 -15 65
MAX6350
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
-1.0
1.0
MAX6325 -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
-400
-300
-200
-100
0
100
200
300
-40 -30 -20 -10 0 10 20 30 40
MAX6350
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6325-07
IOUT (mA)
∆VOUT (µV)
TA = +25°C
TA = -40°CTA = +85°C
-55 -15 65
MAX6341
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
-1.0
1.0
MAX6325 -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
MAX6325
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
MAX6325 03
TEMPERATURE (°C)
∆VOUT (mV)
∆VOUT (ppm)
25 105-35 5 8545 125
-300
-200
-100
0
100
200
300
-40 -30 -20 -10 0 10 20 30 40
MAX6341
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6325-06
IOUT (mA)
∆VOUT (µV)
TA = +25°C
TA = -40°C
TA = +85°C
-250
-200
-150
-100
-50
0
50
100
150
200
-40 -30 -20 -10 0 10 20 30 40
MAX6325
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6325-05
IOUT (mA)
∆VOUT (µV)
TA = +85°C
TA = -40°CTA = +25°C
-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
MAX6325-04
VIN (V)
∆VOUT (ppm)
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
MAX6325-08
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
MAX6325 MAX6341
MAX6350
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
MAX6325-09
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
MAX6341
MAX6350
MAX6325
MAX6325/MAX6341/MAX6350
Maxim Integrated
5
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
10 1M10k
FREQUENCY (Hz)
100 1k 100k
100
0.01
OUTPUT IMPEDANCE vs. FREQUENCY
0.1
MAX6325-14
OUTPUT IMPEDANCE (Ω)
1
10
ISINK = 5mA
ISOURCE = 5mA
0
5
10
15
20
25
30
35
40
45
50
10 100 1k 10k
MAX6325
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
MAX6325-10
FREQUENCY (Hz)
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/√ Hz)
60
70
80
90
100
110
120
10 100 1k 10k
RIPPLE REJECTION
vs. FREQUENCY (CNR = 1µF)
MAX6325-13
FREQUENCY (Hz)
RIPPLE REJECTION (dB)
MAX6341
MAX6325
MAX6350
0
10
20
30
40
50
60
70
80
90
10 100 1k 10k
MAX6341
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
MAX6325-11
FREQUENCY (Hz)
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/√ Hz)
0
10
20
30
40
50
60
70
80
100
90
10 100 1k 10k
MAX6350
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
MAX6325-12
FREQUENCY (Hz)
CNR = 0µF
CNR = 1µF
OUTPUT NOISE DENSITY (nV/√ Hz)
60
65
70
75
80
85
90
95
10 100 1k 10k
RIPPLE REJECTION
vs. FREQUENCY (CNR = 0µF)
MAX6325-15
FREQUENCY (Hz)
RIPPLE REJECTION (dB)
MAX6325
MAX6341
MAX6350
MAX6325
0.1Hz to 10Hz NOISE
VOUT, 0.5µV/div
MAX6325-16
1s/div
COUT = CNR = 0µF
MAX6341
0.1Hz to 10Hz NOISE
VOUT, 1µV/div
MAX6325-17
1s/div
COUT = CNR = 0µF
MAX6350
0.1Hz to 10Hz NOISE
VOUT, 1µV/div
1s/div
MAX6325-18
COUT = CNR = 0µF
____________________________Typical Operating Characteristics (continued)
(VIN = +10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
MAX6325/MAX6341/MAX6350
6
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
2µs/div
LOAD-TRANSIENT RESPONSE (SOURCING)
B
A
A: IOUT, 10mA/div (SOURCING)
B: VOUT, 500µV/div
MAX6325-19
0mA
-10mA
2µs/div
LOAD-TRANSIENT RESPONSE (SINKING)
B
A
0mA
10mA
A: IOUT, 10mA/div (SINKING)
B: VOUT, 500µV/div
MAX6325-20
____________________________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
MAX6325-21
+10mA
-10mA
VIN = 10V
COUT = CNR = 0µF
1µs/div
MAX6341
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
B
A
A: VIN, 10V/div
B: VOUT, 1V/div
MAX6325-23
+10V
0
CIN = COUT = CNR = 0µF
1µs/div
MAX6325
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
B
A
A: VIN, 10V/div
B: VOUT, 1V/div
MAX6325-22
+10V
0
CIN = COUT = CNR = 0µF
1µs/div
MAX6350
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
B
A
A: VIN, 10V/div
B: VOUT, 1V/div
MAX6325-24
+10V
0
CIN = COUT = CNR = 0µF
MAX6325/MAX6341/MAX6350
Maxim Integrated
7
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
_______________Detailed Description
Temperature Stability
The MAX6325/MAX6341/MAX6350 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 10kΩpotentiometer 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 MAX6325/MAX6341/MAX6350 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 MAX6350 reference and MAX400 inverting
amplifier. The +5V is inverted by the ultra-low offset
MAX400 op amp. 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
3NR
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.
MAX6325
MAX6341
MAX6350
IN
8V TO 36V INPUT
REFERENCE OUT
OUT
TRIM 10kΩ
NR
GND
MAX6325
MAX6341
MAX6350
IN
8V TO 36V INPUT
REFERENCE OUT
OUT
TRIM
NR
*OPTIONAL
*
1µFGND
Figure 1. Output Voltage Adjustment Figure 2. Noise-Reduction Capacitor
MAX6325/MAX6341/MAX6350
8
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
MAX6350
MAX865
IN
VCC V+
V-
GND
C2-
C2+
C1-
C1+
+5V INPUT
+REFERENCE OUT
-REFERENCE OUT
OUT
TRIM 10kΩ
R1
100kΩ
R4
R2
100kΩ
R3
1kΩ
NR
2.2µF
C1
3.3µF
3.3µF
2.2µF
C2
1µF
2.2µF
0.1µF
0.1µF
C3
1µF
C4
GND
MAX400
Figure 3. +5V and -5V References from a Single +5V Supply
Ordering Information (continued) ___________________Chip Information
TRANSISTOR COUNT: 435
MAX6341CPA
MAX6341CSA 0°C to +70°C
0°C to +70°C1.0
1.0
8 Plastic DIP
8 SO
MAX6341EPA -40°C to +85°C1.58 Plastic DIP
PART TEMP. RANGE
MAX.
TEMPCO
(ppm/°C)
PIN-
PACKAGE
MAX6350ESA -40°C to +85°C1.58 SO
MAX6350MJA -55°C to +125°C2.58 CERDIP
MAX6341ESA -40°C to +85°C1.58 SO
MAX6341MJA -55°C to +125°C2.58 CERDIP
MAX6350CPA 0°C to +70°C1.08 Plastic DIP
MAX6350CSA 0°C to +70°C1.08 SO
MAX6350EPA -40°C to +85°C1.58 Plastic DIP
MAX6325/MAX6341/MAX6350
Maxim Integrated
9
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
________________________________________________________Package Information
PDIPN.EPS
SOICN.EPS
MAX6325/MAX6341/MAX6350
10
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
CDIPS.EPS
___________________________________________Package Information (continued)
MAX6325/MAX6341/MAX6350
11
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.
© 2001 Maxim Integrated The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
MAX6325/MAX6341/MAX6350
