MAX127 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Multirange, +5V, 12-Bit DAS with 2-Wire Serial Interface

19-4773; Rev 0; 7/98
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Multirange, +5V, 12-Bit DAS with
2-Wire Serial Interface
General Description
The MAX127/MAX128 are multirange, 12-bit data
acquisition systems (DAS) that require only a single
+5V supply for operation, yet accept signals at their
analog inputs that may 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 MAX127; and ±V_REF, ±V_REF/2, 0
to +V_REF, 0 to +V_REF/2 for the MAX128. 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 pro-
tected 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,
an 8ksps throughput rate, and the option of an internal
4.096V or external reference.
The MAX127/MAX128 feature a 2-wire, I²C-compatible
serial interface that allows communication among multi-
ple devices using SDA and SCL lines.
A hardware shutdown input (SHDN) and two software-
programmable power-down modes (standby and full
power-down) are provided for low-current shutdown
between conversions. In standby mode, the reference-
buffer remains active, eliminating start-up delays.
The MAX127/MAX128 are available in 24-pin DIP or
space-saving 28-pin SSOP packages.
Applications
Industrial Control Systems
Data-Acquisition Systems
Robotics
Automatic Testing
Battery-Powered Instruments
Medical Instruments
Ordering Information
PART
TEMP. RANGE PIN-PACKAGE
INL
(LSB)
MAX127ACNG 0°C to +70°C 24 Narrow Plastic DIP ±1/2
MAX127ACNG 0°C to +70°C 24 Narrow Plastic DIP ±1
Ordering Information continued at end of data sheet.
Features
o 12-Bit Resolution, 1/2 LSB Linearity
o +5V Single-Supply Operation
o I²C-Compatible, 2-Wire Serial Interface
o Four Software-Selectable Input Ranges
MAX127: 0 to +10V, 0 to +5V, ±10V, ±5V
MAX128: 0 to +V_REF, 0 to +V_REF/2, ±V_REF,
±V_REF/2
o 8 Analog Input Channels
o 8ksps Sampling Rate
o ±16.5V Overvoltage-Tolerant Input Multiplexer
o Internal 4.096V or External Reference
o Two Power-Down Modes
o 24-Pin Narrow DIP or 28-Pin SSOP Packages
Typical Operating Circuit
+5V
0.1µF
ANALOG
INPUTS
4.7µF
V_DD
SHDN
CH0
CH1
CH2
CH3 ^MAX127
CH4 ^MAX128
CH5
CH6
CH7
SCL
SDA
A0
REF
A1
REFADJ
A2
0.01µF
DGND AGND
µC
SCL SDA
1k
Pin Configurations appear at end of data sheet.
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