MAX148_09 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – +2.7V to +5.25V, Low-Power, 8-Channel, Serial 10-Bit ADCs

19-0464; Rev 3; 5/09
+2.7V to +5.25V, Low-Power, 8-Channel,
Serial 10-Bit ADCs
General Description
The MAX148/MAX149 10-bit data-acquisition systems
combine an 8-channel multiplexer, high-bandwidth
track/hold, and serial interface with high conversion
speed and low power consumption. They operate from a
single +2.7V to +5.25V supply, and sample to 133ksps.
Both devices’ analog inputs are software configurable for
unipolar/bipolar and single-ended/differential operation.
The 4-wire serial interface connects directly to SPIK/
QSPIK and MICROWIREK devices without external
logic. A serial-strobe output allows direct connection to
TMS320-family digital signal processors. The MAX148/
MAX149 use either the internal clock or an external seri-
al-interface clock to perform successive-approximation
analog-to-digital conversions.
The MAX149 has an internal 2.5V reference, while the
MAX148 requires an external reference. Both parts
have a reference-buffer amplifier with a Q1.5% 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
conversion. Accessing the serial interface automatically
powers up the MAX148/MAX149, and the quick turn-on
time allows them to be shut down between all conver-
sions. This technique can cut supply current to under
60FA at reduced sampling rates.
The MAX148/MAX149 are available in a 20-pin DIP and
a 20-pin SSOP.
For 4-channel versions of these devices, see the
MAX1248/MAX1249 data sheet.
Applications
Portable Data Logging
Data Acquisition
Medical Instruments
Battery-Powered Instruments
Pen Digitizers
Process Control
Pin Configuration appears at end of data sheet.
Features
S 8-Channel Single-Ended or 4-Channel Differential
Inputs
S Single-Supply Operation: +2.7V to +5.25V
S Internal 2.5V Reference (MAX149)
S Low Power: 1.2mA (133ksps, 3V Supply)

54µA (1ksps, 3V Supply)

1µA (Power-Down Mode)
S SPI/QSPI/MICROWIRE/TMS320-Compatible 4-Wire
Serial Interface
S Software-Configurable Unipolar or Bipolar Inputs
S 20-Pin DIP/SSOP Packages
Ordering Information
PART†
MAX148ACPP
MAX148BCPP
MAX148ACAP
MAX148BCAP
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
PIN-
PACKAGE
20 Plastic DIP
20 Plastic DIP
20 SSOP
20 SSOP
INL
(LSB)
±1/2
±1
±1/2
±1
Ordering Information continued at end of data sheet.
†_{Contact factory for availability of alternate surface-mount}
package. Specify lead-free by placing + by the part number
when ordering.
*Contact factory for availability of CERDIP package, and for
processing to MIL-STD-883B. Not available in lead-free.
O TO
+2.5V
ANALOG
INPUTS
4.7FF
0.01FF
Typical Operating Circuit
+3V
CH0
V_DD
V_DD
0.1FF
DGND
MAX149
CH7
AGND
VREF
COM
READJ
CS
SCLK
DIN
DOUT
SSTRB
SHDN
CPU
I/O
SCK (SK)
MOSI (SO)
MISO (SI)
V_SS
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.
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