MAX1245 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – +2.375V, Low-Power, 8-Channel, Serial 12-Bit ADC

19-1066; Rev 0; 6/96
+2.375V, Low-Power, 8-Channel,
Serial 12-Bit ADC
________________General Description
The MAX1245 12-bit data-acquisition system combines
an 8-channel multiplexer, high-bandwidth track/hold, and
serial interface with high conversion speed and ultra-low
power consumption. It operates from a single +2.375V to
+3.3V supply, and its analog inputs are software config-
urable for unipolar/bipolar and single-ended/differential
operation.
The 4-wire serial interface directly connects to SPI™,
QSPI™, and Microwire™ devices without external logic.
A serial strobe output allows direct connection to
TMS320-family digital signal processors. The MAX1245
works with an external reference, and uses either the
internal clock or an external serial-interface clock to
perform successive-approximation analog-to-digital
conversions.
This device provides a hard-wired SHDN pin and a
software-selectable power-down, and can be pro-
grammed to automatically shut down at the end of a
conversion. Accessing the serial interface powers up
the MAX1245, and the quick turn-on time allows it to be
shut down between conversions. This technique can
cut supply current to under 10µA at reduced sampling
rates.
The MAX1245 is available in a 20-pin DIP package and
an SSOP that occupies 30% less area than an 8-pin DIP.
For supply voltages from +2.7V to +5.25V, use the pin-
compatible MAX147.
________________________Applications
Portable Data Logging
Medical Instruments
Battery-Powered Instruments Data Acquisition
___________Typical Operating Circuit
0V to
+2.048V
ANALOG
INPUTS
+2.048V
0.1µF
CH0
V_DD
DGND
AGND
CH7
COM
MAX1245
CS
SCLK
VREF
DIN
DOUT
SSTRB
SHDN
+2.5V
VDD
0.1µF
CPU
I/O
SCK (SK)*
MOSI (SO)
MISO (SI)
V_SS
____________________________Features
o Single +2.375V to +3.3V Operation
o 8-Channel Single-Ended or 4-Channel
Differential Analog Inputs
o Low Power: 0.8mA (100ksps)
10µA (1ksps)
1µA (power-down mode)
o Internal Track/Hold, 100kHz Sampling Rate
o SPI/QSPI/Microwire/TMS320-Compatible
4-Wire Serial Interface
o Software-Configurable Unipolar or Bipolar Inputs
o 20-Pin DIP/SSOP Packages
________________Ordering Information
PART^†
TEMP. RANGE
PIN-PACKAGE
INL
(LSB)
MAX1245ACPP 0°C to +70°C 20 Plastic DIP ±1/2
MAX1245BCPP
MAX1245ACAP
MAX1245BCAP
0°C to +70°C
0°C to +70°C
0°C to +70°C
20 Plastic DIP
20 SSOP
20 SSOP
±1
±1/2
±1
MAX1245BC/D 0°C to +70°C Dice*
±1
Ordering Information continued at end of data sheet.
† Contact factory for availability of alternate surface-mount
packages.
* Contact factory for availability.
___________________Pin Configuration
TOP VIEW
CH0 1
CH1 2
CH2 3
CH3 4
CH4 5
CH5 6
CH6 7
CH7 8
COM 9
SHDN 10
MAX1245
20 V_DD
19 SCLK
18 CS
17 DIN
16 SSTRB
15 DOUT
14 DGND
13 AGND
12 VDD
11 VREF
DIP/SSOP
SPI and QSPI are registered trademarks of Motorola, Inc. Microwire is a registered trademark of National Semiconductor Corp.
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