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MAX127/MAX128
EVALUATION KIT AVAILABLE
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 ±VREF, ±VREF/2, 0 to +VREF, 0 to +VREF/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 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, 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 multiple devices using SDA and SCL lines.
A hardware shutdown input (SHDN) and two softwareprogrammable power-down modes (standby and full powerdown) are provided for low-current shutdown between conversions. In standby mode, the reference buffer remains active, eliminating startup delays.
The MAX127/MAX128 are available in 24-pin narrow PDIP 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
MAX127ACNG+ 0°C to +70°C 24 Narrow PDIP
MAX127ACNG+ 0°C to +70°C 24 Narrow PDIP +Denotes a lead(Pb)-free/RoHS-compliant package.
INL (LSB)
±1/2
±1
Ordering Information continued at end of data sheet.
Features
●● 12-Bit Resolution, 1/2 LSB Linearity ●● +5V Single-Supply Operation ●● I2C-Compatible, 2-Wire Serial Interface ●● Four Software-Selectable Input Ranges
• MAX127: 0 to +10V, 0 to +5V, ±10V, ±5V • MAX128: 0 to +VREF, 0 to +VREF/2, ±VREF,
±VREF/2 ●● 8 Analog Input Channels ●● 8ksps 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
ANALOG INPUTS
4.7µF
VDD
SHDN
CH0
CH1
CH2
CH3 MAX127
CH4 CH5
MAX128
CH6
CH7
REF REFADJ
SCL SDA
A0 A1 A2
0.01µF
DGND AGND
µC SCL SDA
1kΩ
Pin Configurations appear at end of data sheet.
19-4773; Rev 1; 12/12
MAX127/MAX128
Multirange, +5V, 12-Bit DAS with 2-Wire Serial Interface
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 to AGND............................................ -0.3V to (VDD + 0.3V) REFADJ to AGND..................................... -0.3V to (VDD + 0.3V) A0, A1, A2 to DGND.................................. -0.3V to (VDD + 0.3V) SHDN, SCL, SDA to DGND.....................................-0.3V to +6V Max Current into Any Pin....................................................50mA
Continuous Power Dissipation (TA = +70°C) 24-Pin Narrow PDIP
(derate 13.33mW/°C above +70°C)...........................1067mW 28-Pin SSOP (derate 15mW/°C above +70°C)..........1201mW Operating Temperature Ranges MAX127_ C_ _/MAX128_ C_ _..........................0°C to +70°C MAX127_ E_ _/MAX128_ E_ _....................... -40°C to +85°C Storage Temperature Range ............................-65°C to +150°C Lead Temperature (soldering, 10s).................................. +300°C Soldering Temperature (reflow)........................................+260°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 = +5V ±5%; unipolar/bipolar range; external reference mode, VREF = 4.096V; 4.7μF at REF; external clock, fCLK = 400kHz; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
ACCURACY (Note 1)
Resolution
12
Integral Nonlinearity
MAX127A INL
MAX127B/MAX128B
±1/2 ±1
Differential Nonlinearity
DNL
±1
Offset Error
Unipolar Bipolar
MAX127A MAX127B/MAX128B MAX127A MAX127B/MAX128B
±3 ±5 ±5 ±10
Channel-to-Channel Offset Error Matching
Unipolar Bipolar
±0.1 ±0.3
Gain Error (Note 2)
Unipolar Bipolar
MAX127A MAX127B/MAX1.