MAX146 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – +2.7Low-Power, 8-Channel, Serial 12-Bit ADCs

19-0465; Rev 1; 6/97
EVAALVUAAILTAIOBNLEKIT
+2.7V, Low-Power, 8-Channel,
Serial 12-Bit ADCs
_______________General Description
The MAX146/MAX147 12-bit data-acquisition systems
combine an 8-channel multiplexer, high-bandwidth
track/hold, and serial interface with high conversion
speed and low power consumption. The MAX146 oper-
ates from a single +2.7V to +3.6V supply; the MAX147
operates from a single +2.7V to +5.25V supply. Both
devices’ analog inputs are software configurable for
unipolar/bipolar and single-ended/differential operation.
The 4-wire serial interface connects directly to SPI™/
QSPI™ and Microwire™ devices without external logic. A
serial strobe output allows direct connection to TMS320-
family digital signal processors. The MAX146/MAX147
use either the internal clock or an external serial-interface
clock to perform successive-approximation analog-to-
digital conversions.
The MAX146 has an internal 2.5V reference, while the
MAX147 requires an external reference. Both parts have
a reference-buffer amplifier with a ±1.5% voltage-
adjustment range.
These devices provide 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 con-
version. Accessing the serial interface automatically
powers up the MAX146/MAX147, and the quick turn-on
time allows them to be shut down between all conver-
sions. This technique can cut supply current to under
60µA at reduced sampling rates.
The MAX146/MAX147 are available in 20-pin DIP and
SSOP packages.
For 4-channel versions of these devices, see the
MAX1246/MAX1247 data sheet.
________________________Applications
____________________________Features
o 8-Channel Single-Ended or 4-Channel
Differential Inputs
o Single-Supply Operation:
+2.7V to +3.6V (MAX146)
+2.7V to +5.25V (MAX147)
o Internal 2.5V Reference (MAX146)
o Low Power: 1.2mA (133ksps, 3V supply)
54µA (1ksps, 3V supply)
1µA (power-down mode)
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^†
MAX146ACPP
MAX146BCPP
MAX146ACAP
MAX146BCAP
MAX146BC/D
TEMP. RANGE PIN-PACKAGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
20 Plastic DIP
20 Plastic DIP
20 SSOP
20 SSOP
Dice*
INL
(LSB)
±1/2
±1
±1/2
±1
±1
Ordering Information continued at end of data sheet.
† _{Contact factory for availability of alternate surface-mount}
packages.
*Dice are specified at T_A = +25°C, DC parameters only.
__________Typical Operating Circuit
Portable Data Logging Data Acquisition
Medical Instruments Battery-Powered Instruments
Pen Digitizers
Process Control
Pin Configuration appears at end of data sheet.
SPI and QSPI are registered trademarks of Motorola, Inc.
Microwire is a registered trademark of National Semiconductor Corp.
0V TO
+2.5V
ANALOG
INPUTS
4.7µF
0.047µF
CH0
V_DD
DGND
MAX146 _AGND
CH7
VREF
REFADJ
COM
CS
SCLK
DIN
DOUT
SSTRB
SHDN
+3V
V_DD
0.1µF
CPU
I/O
SCK (SK)
MOSI (SO)
MISO (SI)
V_SS
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