MAX6325/MAX6341/MAX6350
LE
AVAILAB
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
General Description
The MAX6325/MAX6341/MAX6350 are low-noise, precision 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-regulation 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.
____________________________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
19-1203; Rev 1; 1/01
Ordering Information
________________________Applications
High-Resolution Analog-to-Digital
and Digital-to-Analog Converters
PART
TEMP. RANGE
PINPACKAGE
MAX
TEMPCO
(ppm/°C)
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 CERDIP
1.0
1.0
1.5
1.5
2.5
High-Accuracy Reference Standard
High-Accuracy Industrial and Process Control
Digital Voltmeters
ATE Equipment
Precision Current
Sources
Functional
Diagrams
MAX6325CPA
MAX6325CSA
MAX6325EPA
MAX6325ESA
MAX6325MJA
Ordering Information continued at end of data sheet.
PinConfiguration
Configuration
Pin
Typical Operating Circuit
TOP VIEW
8V TO 36V INPUT
IN
OUT
2.2µF *
NR
MAX6325
MAX6341
MAX6350
REFERENCE OUT
I.C. 1
IN 2
NR 3
TRIM
2.2µF *
MAX6325
MAX6341
MAX6350
GND 4
8
I.C.
7
I.C.
6
OUT
5
TRIM
GND
DIP/SO
Pin Configurations appear at end of data sheet.
Functional
Diagrams continued at end of data sheet.
*OPTIONAL
UCSP is a trademark of Maxim Integrated Products, Inc.
I.C. = INTERNALLY CONNECTED; DO NOT USE
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-1203; Rev 1; 1/01
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
ABSOLUTE MAXIMUM RATINGS
(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
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.
ELECTRICAL CHARACTERISTICS—MAX6325
(VIN = +10V, IOUT = 0mA, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Input Voltage Range
Output Voltage
SYMBOL
CONDITIONS
MAX
UNITS
36
V
2.500
2.501
V
C
0.5
1.0
MAX6325E_A
E
0.75
1.5
MAX6325MJA
M
1.0
2.5
+25°C
10
18
VIN
VOUT
MAX6325
MAX6325C_A
Output Voltage Temperature
Coefficient (Note 1)
TCVOUT
8V ≤ VIN ≤ 10V
Line Regulation (Note 2)
∆VOUT/
∆VIN
∆VOUT/
∆IOUT
Sinking: -15mA ≤ IOUT ≤ 0mA
Trim-Adjustment Range
IIN
∆VOUT
Turn-On Settling Time
tON
Output Noise Voltage (Note 3)
en
Temperature Hysteresis
Long-Term Stability
2
∆VOUT/t
8
+25°C
2.499
TYP
C
30
E
35
45
+25°C
Sourcing: 0mA ≤ IOUT ≤ 15mA
Supply Current
MIN
M
10V ≤ VIN ≤ 36V
Load Regulation (Note 2)
TA
C, E, M
2
C
5
ppm/°C
ppm/V
7
E
8
M
10
C
1
E
1
6
7
M
3
15
C
1
6
E
1
7
M
10
30
+25°C
1.8
2.7
C, E, M
3.0
±15
ppm/mA
mA
(Figure 1)
C, E, M
±25
mV
To ±0.01% of final value
+25°C
5
µs
0.1Hz ≤ f ≤ 10Hz
+25°C
1.5
10Hz ≤ f ≤ 1kHz
+25°C
1.3
(Note 4)
+25°C
20
ppm
+25°C
30
ppm/
1000hr
µVp-p
2.8
µVRMS
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
ELECTRICAL CHARACTERISTICS—MAX6341
(VIN = +10V, IOUT = 0mA, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Input Voltage Range
Output Voltage
SYMBOL
CONDITIONS
TYP
MAX
UNITS
36
V
4.096
4.097
V
C
0.5
1.0
MAX6341E_A
E
0.75
1.5
MAX6341MJA
M
1.0
2.5
+25°C
10
18
VIN
VOUT
MAX6341
MAX6341C_A
Output Voltage Temperature
Coefficient (Note 1)
TCVOUT
8V ≤ VIN ≤ 10V
Line Regulation (Note 2)
∆VOUT/
∆VIN
∆VOUT/
∆IOUT
Sinking: -15mA ≤ IOUT ≤ 0mA
Trim-Adjustment Range
IIN
∆VOUT
Turn-On Settling Time
tON
Output Noise Voltage (Note 3)
en
Temperature Hysteresis
Long-Term Stability
Maxim Integrated
∆VOUT/t
C, E, M
8
+25°C
4.095
C
30
E
35
45
+25°C
Sourcing: 0mA ≤ IOUT ≤ 15mA
Supply Current
MIN
M
10V ≤ VIN ≤ 36V
Load Regulation (Note 2)
TA
2
C
5
ppm/°C
ppm/V
7
E
8
M
10
C
1
6
E
1
7
M
3
9
C
1
6
E
1
7
M
7
18
+25°C
1.9
2.9
C, E, M
3.2
±24
ppm/mA
mA
(Figure 1)
C, E, M
±40
mV
To ±0.01% of final value
+25°C
8
µs
0.1Hz ≤ f ≤ 10Hz
+25°C
2.4
10Hz ≤ f ≤ 1kHz
+25°C
2.0
(Note 4)
+25°C
20
ppm
+25°C
30
ppm/
1000hr
µVp-p
4.0
µVRMS
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.)
PARAMETER
Input Voltage Range
Output Voltage
SYMBOL
CONDITIONS
VIN
VOUT
MAX6350
TCVOUT
Turn-On Settling Time
Output Noise Voltage (Note 3)
E
0.75
1.5
M
1.0
2.5
+25°C
10
Temperature Hysteresis
Long-Term Stability
∆VOUT/t
30
E
35
M
45
2
C
ppm/°C
18
C
+25°C
IIN
en
V
MAX6350MJA
∆VOUT/
∆IOUT
tON
V
MAX6350E_A
∆VOUT/
∆VIN
∆VOUT
UNITS
36
1.0
Sinking: -15mA ≤ IOUT ≤ 0mA
Trim-Adjustment Range
4.999
MAX
5.001
Sourcing: 0mA ≤ IOUT ≤ 15mA
Supply Current
+25°C
TYP
0.5
10V ≤ VIN ≤ 36V
Load Regulation (Note 2)
8
5.000
8V ≤ VIN ≤ 10V
Line Regulation (Note 2)
MIN
C
MAX6350C_A
Output Voltage Temperature
Coefficient (Note 1)
TA
C, E, M
5
ppm/V
7
E
8
M
10
C
1
6
E
1
7
M
2
9
C
1
6
E
1
7
M
6
15
+25°C
2.0
3.0
C, E, M
3.3
±50
mA
(Figure 1)
C, E, M
To ±0.01% of final value
+25°C
10
µs
0.1Hz ≤ f ≤ 10Hz
+25°C
3.0
µVp-p
10Hz ≤ f ≤ 1kHz
+25°C
2.5
(Note 4)
+25°C
20
ppm
30
ppm/
1000hr
+25°C
±30
ppm/mA
mV
5.0
µVRMS
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.
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.)
MAX6341
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
200
0.5
100
0
0
250
-0.5
-100
-1.0
-200
0.5
125
0
0
-0.5
-1.5
-55 -35 -15
5
25 45
5
200
0.4
160
0.3
120
0.2
80
0.1
40
0
0
-0.1
-40
-0.2
-80
-0.3
-120
-0.4
-55 -35 -15
5
-160
65 85 105 125
25 45
TEMPERATURE (°C)
CHANGE IN OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX6325
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX6341
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
150
MAX6325-06
300
MAX6325-05
MAX6325-04
200
TA = +85°C
200
100
30
20
10
50
TA = -40°C
0
∆VOUT (µV)
∆VOUT (µV)
40
TA = +25°C
-50
-300
-250
10
15
20
25
30
35
-40 -30 -20 -10
40
10
20
30
-40 -30 -20 -10
40
MAX6350
CHANGE IN OUTPUT VOLTAGE
vs. OUTPUT CURRENT
100
TA = +85°C
TA = -40°C
-100
-200
2.6
MAX6350
2.4
MAX6341
MAX6325
2.2
2.0
1.8
1.6
2.5
MAX6350
MAX6341
2.0
MAX6325
1.0
1.0
-40 -30 -20 -10
0
10
IOUT (mA)
Maxim Integrated
20
30
40
40
3.0
1.2
-400
30
1.5
1.4
TA = +25°C
20
3.5
MAX6325-08
2.8
SUPPLY CURRENT (mA)
200
10
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
3.0
MAX6325-07
300
0
IOUT (mA)
IOUT (mA)
VIN (V)
-300
0
MAX6325-09
5
SUPPLY CURRENT (mA)
0
0
-200
TA = +85°C
-200
-20
TA = +25°C
TA = -40°C
-150
-10
100
-100
-100
0
∆VOUT (µV)
25 45
240
0.5
TEMPERATURE (°C)
50
0
-250
65 85 105 125
280
0.6
TEMPERATURE (°C)
60
∆VOUT (ppm)
-125
-1.0
-55 -35 -15
-300
65 85 105 125
∆VOUT (mV)
1.0
MAX6325 03
0.7
375
1.0
∆VOUT (mV)
300
∆VOUT (ppm)
∆VOUT (mV)
1.5
MAX6325 -02
1.5
400
∆VOUT (ppm)
MAX6325 -01
2.0
MAX6325
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
∆VOUT (ppm)
MAX6350
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
0
5
10
15
20
25
30
SUPPLY VOLTAGE (V)
35
40
-55 -35 -15
5
25 45
65 85 105 125
TEMPERATURE (°C)
5
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
____________________________Typical Operating Characteristics (continued)
(VIN = +10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
MAX6341
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
CNR = 0µF
35
30
25
20
CNR = 1µF
15
10
5
70
CNR = 0µF
60
50
40
30
CNR = 1µF
20
10
10
100
1k
100
1k
CNR = 0µF
70
60
50
40
30
CNR = 1µF
20
10
10k
10
100
1k
10k
FREQUENCY (Hz)
FREQUENCY (Hz)
RIPPLE REJECTION
vs. FREQUENCY (CNR = 1µF)
OUTPUT IMPEDANCE vs. FREQUENCY
RIPPLE REJECTION
vs. FREQUENCY (CNR = 0µF)
MAX6341
MAX6350
80
10
1
0.1
ISINK = 5mA
MAX6325
MAX6341
90
RIPPLE REJECTION (dB)
OUTPUT IMPEDANCE (Ω)
100
95
MAX6325-14
MAX6325-13
MAX6325
90
100
70
85
MAX6350
80
75
70
65
ISOURCE = 5mA
0.01
60
10
100
1k
10
10k
100
FREQUENCY (Hz)
1k
10k
100k
FREQUENCY (Hz)
60
10
1M
MAX6325-18
VOUT, 1µV/div
COUT = CNR = 0µF
VOUT, 1µV/div
COUT = CNR = 0µF
10k
MAX6350
0.1Hz to 10Hz NOISE
COUT = CNR = 0µF
VOUT, 0.5µV/div
1k
MAX6325-17
MAX6325-16
1s/div
100
FREQUENCY (Hz)
MAX6341
0.1Hz to 10Hz NOISE
MAX6325
0.1Hz to 10Hz NOISE
6
80
FREQUENCY (Hz)
120
110
90
0
10
10k
MAX6325-12
100
0
0
RIPPLE REJECTION (dB)
80
MAX6325-15
40
90
MAX6325-11
45
OUTPUT NOISE DENSITY (nV/√ Hz)
MAX6325-10
OUTPUT NOISE DENSITY (nV/√ Hz)
50
MAX6350
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
OUTPUT NOISE DENSITY (nV/√ Hz)
MAX6325
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
1s/div
1s/div
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
____________________________Typical Operating Characteristics (continued)
(VIN = +10V, IOUT = 0mA, TA = +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE (SOURCING)
LOAD-TRANSIENT RESPONSE (SINKING)
MAX6325-19
MAX6325-20
0mA
A
10mA
A
-10mA
0mA
B
B
2µs/div
2µs/div
A: IOUT, 10mA/div (SINKING)
B: VOUT, 500µV/div
A: IOUT, 10mA/div (SOURCING)
B: VOUT, 500µV/div
MAX6325
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
MAX6325-21
MAX6325-22
-10mA
A
+10mA
+10V
A
0
B
VIN = 10V
COUT = CNR = 0µF
B
CIN = COUT = CNR = 0µF
1µs/div
1µs/div
A: IOUT (±10mA SOURCE AND SINK), 20mA/div, AC COUPLED
B: VOUT, 20mV/div, AC COUPLED
A: VIN, 10V/div
B: VOUT, 1V/div
MAX6350
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
MAX6341
TURN-ON AND TURN-OFF TRANSIENT RESPONSE
MAX6325-24
MAX6325-23
+10V
+10V
0
A
A
0
B
B
CIN = COUT = CNR = 0µF
CIN = COUT = CNR = 0µF
1µs/div
1µs/div
A: VIN, 10V/div
B: VOUT, 1V/div
Maxim Integrated
A: VIN, 10V/div
B: VOUT, 1V/div
7
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
_____________________Pin Description
PIN
NAME
1, 7, 8
I.C.
Internally Connected. Do not use.
2
IN
Positive Power-Supply Input
NR
Noise Reduction. Optional capacitor
connection for wideband noise
reduction. Leave open if not used
(Figure 2).
3
FUNCTION
4
GND
Ground
5
TRIM
External Trim Input. Allows ±1%
output adjustment (Figure 1).
Leave open if not used.
6
OUT
Voltage Reference Output
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
_______________Detailed Description
Temperature Stability
The MAX6325/MAX6341/MAX6350 are highly stable,
low-noise voltage references that use a low-power temperature-compensation scheme to achieve laboratorystandard 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 10kΩ potentiometer between OUT and
GND, and connecting its tap to the TRIM pin, as shown
in Figure 1. The external trimming does not affect temperature stability.
Figure 3 shows how both a +5V and -5V precision reference 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.
8V TO 36V INPUT
8V TO 36V INPUT
IN
IN
REFERENCE OUT
OUT
NR
MAX6325
MAX6341
MAX6350
*
TRIM
GND
REFERENCE OUT
OUT
10kΩ
NR
1µF
MAX6325
MAX6341
MAX6350
TRIM
GND
*OPTIONAL
Figure 1. Output Voltage Adjustment
8
Figure 2. Noise-Reduction Capacitor
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
+5V INPUT
3.3µF
C1+
VCC
V+
+REFERENCE OUT
IN
C1-
OUT
R2
100kΩ
MAX865
3.3µF
C1
2.2µF
C2+
C2-
GND
MAX6350
V-
NR
TRIM
GND
0.1µF
R1
10kΩ
C3
2.2µF
C2
1µF
2.2µF
R3
1kΩ
C4
1µF
R4
100kΩ
MAX400
0.1µF
-REFERENCE OUT
Figure 3. +5V and -5V References from a Single +5V Supply
Ordering Information (continued)
PART
MAX6341CPA
MAX6341CSA
MAX6341EPA
MAX6341ESA
MAX6341MJA
MAX6350CPA
MAX6350CSA
MAX6350EPA
MAX6350ESA
MAX6350MJA
Maxim Integrated
TEMP. RANGE
PINPACKAGE
MAX.
TEMPCO
(ppm/°C)
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 CERDIP
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 CERDIP
1.0
1.0
1.5
1.5
2.5
1.0
1.0
1.5
1.5
2.5
___________________Chip Information
TRANSISTOR COUNT: 435
9
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +2.5V/+4.096V/+5V
Voltage References
PDIPN.EPS
SOICN.EPS
________________________________________________________Package Information
10
Maxim Integrated
MAX6325/MAX6341/MAX6350
1ppm/°C, Low-Noise, +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. 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.
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