19-4782; Rev 2; 9/04
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Multirange, +5V, 8-Channel,
Serial 12-Bit ADCs
Features
The MAX1270/MAX1271 are multirange, 12-bit dataacquisition systems (DAS) that require only a single
+5V supply for operation, yet accept signals at their
analog inputs that can span above the power-supply
rail and below ground. These systems provide eight
analog input channels that are independently software
programmable for a variety of ranges: ±10V, ±5V, 0 to
+10V, 0 to +5V for the MAX1270; ±VREF, ±VREF/2, 0 to
VREF, 0 to VREF/2 for the MAX1271. This range switching increases the effective dynamic range to 14 bits and
provides the flexibility to interface 4–20mA, ±12V, and
±15V powered sensors directly to a single +5V system.
In addition, these converters are fault protected to
±16.5V; a fault condition on any channel will not affect
the conversion result of the selected channel. Other features include a 5MHz bandwidth track/hold, softwareselectable internal/external clock, 110ksps throughput
rate, and internal 4.096V or external reference operation.
♦ 12-Bit Resolution, 0.5 LSB Linearity
The MAX1270/MAX1271 serial interface directly
connects to SPI™/QSPI™ and MICROWIRE™ devices
without external logic.
A hardware shutdown input (SHDN) and two softwareprogrammable power-down modes, standby (STBYPD)
or full power-down (FULLPD), are provided for low-current shutdown between conversions. In standby mode,
the reference buffer remains active, eliminating startup
delays.
♦ Internal or External Clock
♦ +5V Single-Supply Operation
♦ SPI/QSPI and MICROWIRE-Compatible
3-Wire Interface
♦ Four Software-Selectable Input Ranges
MAX1270: 0 to +10V, 0 to +5V, ±10V, ±5V
MAX1271: 0 to VREF, 0 to VREF/2, ±VREF,
±VREF/2
♦ Eight Analog Input Channels
♦ 110ksps Sampling Rate
♦ ±16.5V Overvoltage-Tolerant Input Multiplexer
♦ Internal 4.096V or External Reference
♦ Two Power-Down Modes
♦ 24-Pin Narrow PDIP or 28-Pin SSOP Packages
Typical Operating Circuit
+5V
0.1µF
The MAX1270/MAX1271 are available in 24-pin narrow
PDIP or space-saving 28-pin SSOP packages.
VDD
Applications
SHDN
Industrial Control Systems Automatic Testing
Data-Acquisition Systems Robotics
Battery-Powered
Medical Instruments
Instruments
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
ANALOG
INPUTS
MAX1270
MAX1271
MC68HCXX
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
INL
(LSB)
MAX1270ACNG
0°C to +70°C
24 Narrow PDIP
±0.5
MAX1270BCNG
0°C to +70°C
24 Narrow PDIP
±1
MAX1270ACAI
0°C to +70°C
28 SSOP
MAX1270BCAI
0°C to +70°C 28 SSOP
Ordering Information continued at end of data sheet.
REF
REFADJ
4.7µF
0.01µF
DGND
CS
SCLK
DIN
DOUT
SSTRB
I/O
SCK
MOSI
MISO
AGND
±0.5
±1
Pin Configurations appear at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX1270/MAX1271
General Description
MAX1270/MAX1271
Multirange, +5V, 8-Channel,
Serial 12-Bit ADCs
ABSOLUTE MAXIMUM RATINGS
VDD to AGND............................................................-0.3V to +6V
AGND to DGND.....................................................-0.3V to +0.3V
CH0–CH7 to AGND ......................................................... ±16.5V
REF, REFADJ to AGND ..............................-0.3V to (VDD + 0.3V)
SSTRB, DOUT to DGND.............................-0.3V to (VDD + 0.3V)
SHDN, CS, DIN, SCLK to DGND..............................-0.3V to +6V
Max Current into Any Pin ....................................................50mA
Continuous Power Dissipation (TA = +70°C)
24-Pin Narrow DIP (derate 13.33mW/°C above +70°C)..1067mW
28-Pin SSOP (derate 9.52mW/°C above +70°C) ..........762mW
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
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
(VDD = +5.0V ±5%; unipolar/bipolar range; external reference mode, VREF = +4.096V; 4.7µF at REF; external clock; fCLK = 2.0MHz,
50% duty cycle (MAX127_B); fCLK = 1.8MHz, 50% duty cycle (MAX127_A); 18 clock/conversion cycle, TA = TMIN to TMAX, unless
otherwise noted. Typical values are TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ACCURACY (Note 1)
Resolution
12
Integral Nonlinearity
INL
Differential Nonlinearity
DNL
±0.5
MAX127_B
±1.0
Unipolar
Bipolar
±5
±5
LSB
±10
MAX127_B
Bipolar
±0.3
Bipolar
Gain Error Temperature
Coefficient (Note 2)
MAX127_B
MAX127_A
±0.1
Gain Error (Note 2)
LSB
±3
MAX127_A
Unipolar
Unipolar
LSB
±1
No missing codes over temperature
Offset Error
Channel-to-Channel Offset Error
Matching
Bits
MAX127_A
LSB
MAX127_A
±7
MAX127_B
±10
MAX127_A
±7
LSB
±10
MAX127_B
Unipolar, external reference
±3
Bipolar, external reference
±5
ppm/°C
DYNAMIC SPECIFICATIONS (10kHz sine-wave input, ±10VP-P (MAX1270), or ±4.096VP-P (MAX1271), fSAMPLE = 110ksps
(MAX127_B), fSAMPLE = 100ksps (MAX127_A))
Signal-to-Noise + Distortion Ratio
SINAD
Total Harmonic Distortion
THD
Spurious-Free Dynamic Range
SFDR
Channel-to-Channel Crosstalk
Aperture Delay
Aperture Jitter
2
70
Up to the 5th harmonic
dB
-87
80
-78
dB
dB
50kHz (Note 3)
-86
DC, VIN = ±16.5V
-96
External clock mode
15
ns
External clock mode