19-2921; Rev 1; 12/03
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
General Description
The MAX1272/MAX1273 multirange 12-bit data-acquisi-
tion systems (DAS) operate with a single 5V supply. The
software-programmable analog input accepts a variety
of voltage ranges: ±10V, ±5V, 0 to 10V, 0 to 5V for the
MAX1272; ±V
REF
, ±V
REF
/ 2, 0 to V
REF
, 0 to V
REF
/ 2 for
the MAX1273. The software-selectable extended analog
input range increases the effective dynamic range to 14
bits and provides the flexibility to interface 4–20mA pow-
ered sensors directly to a single 5V system. In addition,
the MAX1272 provides fault protection to ±12V. Other
features include a 5MHz track/hold (T/H) bandwidth,
87ksps throughput rate, and internal (4.096V) or external
(2.40V to 4.18V) reference.
The MAX1272/MAX1273 serial interfaces connect
directly to SPI™/QSPI™/MICROWIRE™-compatible
devices without any external logic.
Four software-programmable power-down modes
(delayed standby, immediate standby, delayed full power-
down, and immediate full power-down) provide low-cur-
rent shutdown between conversions. In standby mode, the
internal reference buffer remains active, thus eliminating
startup delay.
The MAX1272/MAX1273 are available in 8-pin PDIP
and µMAX packages. Both devices are available in the
commercial (0°C to +70°C) or extended (-40°C to
+85°C) temperature range.
Features
o
Four Software-Selectable Input Ranges
MAX1272: 0 to 10V, 0 to 5V, ±10V, ±5V
MAX1273: 0 to V
REF
, 0 to V
REF
/ 2, ±V
REF
,
±V
REF
/ 2
o
12-Bit Resolution, No Missing Codes
o
5V Single-Supply Operation
o
SPI/QSPI/MICROWIRE-Compatible 3-Wire
Interface
o
87ksps Sampling Rate
o
±12V Fault-Protected Analog Input (MAX1272)
o
Internal (4.096V) or External (2.4V to 4.18V)
Reference
o
Low Power
1.5mA at 87ksps
0.4mA at 10ksps
0.2mA at 1ksps
o
Four Power-Down Modes
o
8-Pin µMAX and PDIP Packages
MAX1272/MAX1273
Ordering Information
PART
MAX1272CPA
MAX1272CUA
MAX1272EPA
MAX1272EUA
MAX1273CPA
MAX1273CUA
MAX1273EPA
MAX1273EUA
TEMP
RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
8 Plastic DIP
8 µMAX
8 Plastic DIP
8 µMAX
8 Plastic DIP
8 µMAX
8 Plastic DIP
8 µMAX
INL
(LSB)
±1
±1
±1
±1
±1
±1
±1
±1
Applications
Industrial Control Systems
Data-Acquisition Systems
Robotics
Automatic Testing
Battery-Powered Instruments
Medical Instruments
Pin Configuration
TOP VIEW
SCLK
DIN
1
2
3
8
7
DOUT
CS
REF
AIN
Typical Application Circuit appears at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
V
DD
MAX1272
MAX1273
6
5
GND
4
PDIP/µMAX
________________________________________________________________
Maxim Integrated Products
1
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.
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
MAX1272/MAX1273
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ..............................................................-0.3V to +6V
AIN to GND (MAX1272) ...................................................... ±12V
AIN to GND (MAX1273) ........................................................ ±6V
DOUT,
CS,
DIN, SCLK, REF to GND..........-0.3V to (V
DD
+ 0.3V)
Maximum Current into Any Pin............................................50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Plastic DIP (derate 9.1mW/°C above +70°C) ......727mW
8-Pin µMAX (derate 4.5mW/°C above +70°C) ..............362mW
Operating Temperature Ranges
MAX127_ C_ _ .....................................................0°C to +70°C
MAX127_ E_ _...................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Junction Temperature .....................................................+150°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
(V
DD
= 4.75V to 5.25V, unipolar/bipolar input range, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, C
LOAD
= 50pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETERS
ACCURACY (Note 1)
Resolution
Integral Nonlinearity
Differential Nonlinearity
Offset Error
Gain Error (Note 2)
Gain Error Temperature
Coefficient (Note 2)
Signal-to-Noise + Distortion Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
Aperture Delay
Aperture Jitter
ANALOG INPUT
T/H Acquisition Time
t
ACQ
2.85
µs
SINAD
THD
SFDR
t
AD
t
AJ
Up to the 5th harmonic
80
INL
DNL
No missing codes over temperature
Unipolar
Bipolar
Unipolar
Bipolar
Unipolar
Bipolar
69
±3
±5
72
-87
88
15
<50
-78
SYMBOL
CONDITIONS
MIN
12
±0.3
±0.35
±1.0
±1.00
±5
±10
±10
±10
LSB
ppm/°C
TYP
MAX
UNITS
Bits
LSB
LSB
LSB
DYNAMIC SPECIFICATIONS (10kHz sine-wave input,
±10V
P-P
(MAX1272), or
±4.096V
P-P
(MAX1273), f
SAMPLE
= 87ksps)
dB
dB
dB
ns
ps
2
_______________________________________________________________________________________
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 4.75V to 5.25V, unipolar/bipolar input range, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, C
LOAD
= 50pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETERS
SYMBOL
CONDITIONS
±10V (MAX1272) or ±V
REF
(MAX1273)
range
±5V (MAX1272) or ±V
REF
/ 2 (MAX1273)
range
Small-Signal Bandwidth
BW
-3dB
0 to 10V (MAX1272) or 0 to V
REF
(MAX1273)
range
0 to 5V (MAX1272) or 0 to V
REF
/ 2
(MAX1273) range
MAX1272
Unipolar
MAX1273
Input Voltage Range
(Tables 2, 3)
V
IN
MAX1272
Bipolar
MAX1273
MAX1272
Unipolar
MAX1273
Input Current
I
IN
MAX1272
Bipolar
MAX1273
Input Capacitance
INTERNAL REFERENCE
REF Output Voltage
REF Output Tempco
Output Short-Circuit Current
Load Regulation
Capacitive Bypass at REF
REFERENCE INPUT (Reference buffer disabled, reference input applied to REF)
Input Voltage Range
V
REF
TC V
REF
MAX127_ C
MAX127_ E
REF shorted to GND
0 to 0.5mA output current
1
2.40
4.18
4.036
4.096
±15
±30
40
0.7
10
4.156
V
ppm/°C
mA
mV
µF
V
RNG = 1
RNG = 0
RNG = 1
RNG = 0
RNG = 1
RNG = 0
RNG = 1
RNG = 0
0 to 10V range
0 to 5V range
0 to V
REF
range
0 to V
REF
/ 2 range
±10V range
±5V range
±V
REF
range
±V
REF
/ 2 range
0
0
0
0
-10
-5
-V
REF
-V
REF
/ 2
-10
-10
-10
-10
-1400
-720
-1400
-720
40
MIN
TYP
5
2.5
MHz
2.5
1.25
10
5
V
REF
V
REF
/ 2
+10
+5
+V
REF
+V
REF
/ 2
+860
+430
+10
+10
+860
+430
+10
+10
pF
µA
V
MAX
UNITS
MAX1272/MAX1273
_______________________________________________________________________________________
3
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
MAX1272/MAX1273
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 4.75V to 5.25V, unipolar/bipolar input range, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, C
LOAD
= 50pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETERS
SYMBOL
CONDITIONS
Converting
V
REF
= 4.096V
Standby power-down
mode
Full power-down mode
POWER REQUIREMENTS
Supply Voltage
Supply Current
(Internal Reference Mode)
V
DD
Converting
I
DD
Bipolar
Unipolar
4.75
5
2.4
2.2
400
1
1.5
1.2
200
1
±0.3
±0.5
0.1
(Note 4)
(Note 4)
REF bypass capacitor initially discharged
External reference mode
V
IH
V
IL
V
HYS
I
IN
C
IN
I
SINK
= 10mA
I
SINK
= 16mA
I
SOURCE
= 0.5mA
CS
= V
DD
CS
= V
DD
V
DD
- 0.5
-10
15
+10
0.6
V
IN
= 0 to V
DD
-10
15
0.4
0.8
0.2
+10
2.85
8.57
87.5
2
10
2.4
1.4
±1.0
2.5
2.0
450
MIN
TYP
400
5
MAX
850
10
1
5.25
4
3
700
V
mA
µA
mA
µA
LSB
UNITS
Input Current
µA
Standby power-down mode
Full power-down mode
Converting
Bipolar
Unipolar
Supply Current
(External Reference Mode)
I
DD
Standby power-down mode
Full power-down mode
External reference = 4.096V
Internal reference
Power-Supply Rejection
Ratio (Note 3)
TIMING
Clock Frequency Range
T/H Acquisition Time
Conversion Time
Throughput Rate
Internal Reference Settling Time
Device Power-Up Time
PSRR
f
SCLK
t
ACQ
t
CONV
MHz
µs
µs
ksps
ms
µs
V
V
V
µA
pF
DIGITAL INPUTS (DIN, SCLK, and
CS)
Input High-Threshold Voltage
Input Low-Threshold Voltage
Input Hysteresis
Input Leakage Current
Input Capacitance
DIGITAL OUTPUT (DOUT)
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Output Capacitance
V
OL
V
OH
I
L
C
OUT
V
V
µA
pF
4
_______________________________________________________________________________________
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
TIMING CHARACTERISTICS
(V
DD
= 4.75V to 5.25V, unipolar/bipolar input range, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, C
LOAD
= 50pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Figures 1 and 4)
PARAMETERS
DIN to SCLK Setup
DIN to SCLK Hold
SCLK Fall to Output Data Valid
CS
Fall to Output Enable
CS
Rise to Output Disable
CS
to SCLK Rise Setup
CS
to SCLK Rise Hold
SCLK Pulse Width High
SCLK Pulse Width Low
SYMBOL
t
DS
t
DH
t
DO
t
DV
t
TR
t
CSS
t
CSH
t
CH
t
CL
100
0
200
200
20
CONDITIONS
MIN
100
0
250
100
100
TYP
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
MAX1272/MAX1273
Note 1:
Accuracy specifications tested at V
DD
= 5V. Performance at power-supply tolerance limit is guaranteed by power-supply
rejection test.
Note 2:
Offset error nulled. The ideal last-code transition is (FS - 1.5 LSB).
Note 3:
PSRR measured at full scale. Tested at ±10V (MAX1272) and ±4.096V (MAX1273) input ranges.
Note 4:
Acquisition and conversion times are dependent on the clock speed.
Typical Operating Characteristics
(Typical operating circuit, BIP = RNG = 1, V
DD
= 5V, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, 87ksps, T
A
= +25°C, unless otherwise noted.)
CONVERTING SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1272/73 toc01
CONVERTING SUPPLY CURRENT
vs. TEMPERATURE
MAX1272/73 toc02
STANDBY SUPPLY CURRENT
vs. TEMPERATURE
0.9
STANDBY SUPPLY CURRENT (mA)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
INTERNAL
REFERENCE
EXTERNAL
REFERENCE
V
AIN
= 0
MAX1272/73 toc03
5.0
4.5
4.0
SUPPLY CURRENT (mA)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
EXTERNAL
REFERENCE
INTERNAL
REFERENCE
V
AIN
= 0
5.0
4.5
4.0
V
AIN
= 0
1.0
SUPPLY CURRENT (mA)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
EXTERNAL
REFERENCE
INTERNAL
REFERENCE
4.75 4.80 4.85 4.90 4.95 5.00 5.05 5.10 5.15 5.20 5.25
SUPPLY VOLTAGE (V)
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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