Rainbow Electronics MAX1249 - Manual

_______________General Description
The MAX1248/MAX1249 10-bit data-acquisition sys-
tems combine a 4-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 their 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
MAX1248/MAX1249 use either the internal clock or an
external serial-interface clock to perform successive-
approximation analog-to-digital conversions.
The MAX1248 has an internal 2.5V reference, while the
MAX1249 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
conversion. Accessing the serial interface automatically
powers up the MAX1248/MAX1249, and the quick
turn-on time allows them to be shut down between all
conversions. This technique can cut supply current to
under 60µA at reduced sampling rates.
The MAX1248/MAX1249 are available in a 16-pin DIP
and a very small QSOP that occupies the same board
area as an 8-pin SO.
For 8-channel versions of these devices, see the
MAX148/MAX149 data sheet.
________________________Applications
Portable Data Logging Data Acquisition
Medical Instruments Battery-Powered Instruments
Pen Digitizers System Supervision
____________________________Features
♦ 4-Channel Single-Ended or 2-Channel
Differential Inputs
♦ Single +2.7V to +5.25V Operation
♦ Internal 2.5V Reference (MAX1248)
♦ Low Power: 1.2mA (133ksps, +3V supply)
54µA (1ksps, +3V supply)
1µA (power-down mode)
♦ SPI/QSPI/MICROWIRE/TMS320-Compatible
4-Wire Serial Interface
♦ Software-Configurable Unipolar or Bipolar Inputs
♦ 16-Pin QSOP Package (same area as 8-pin SO)
MAX1248/MAX1249
+2.7V to +5.25V, Low-Power, 4-Channel,
Serial 10-Bit ADCs in QSOP-16
________________________________________________________________ Maxim Integrated Products 1
19-1072; Rev 2; 5/98
PART †
MAX1248 ACPE
MAX1248BCPE
MAX1248ACEE 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
16 Plastic DIP
16 Plastic DIP
16 QSOP
_____________Ordering Information
Ordering Information continued at end of data sheet.
† Contact factory for availability of alternate surface-mount
packages.
Pin Configuration appears at end of data sheet.
MAX1248BCEE 0°C to +70°C 16 QSOP
INL
(LSB)
±1/2
±1
±1/2
±1
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
V DD
I/O
SCK (SK)
MOSI (SO)
MISO (SI)
V SS
SHDN
SSTRB
DOUT
DIN
SCLK
CS
COM
AGND
DGND
V DD
CH3
C1
4.7 µ F
C2
0.01 µ F
C3
0.1 µ F
CH0
0V TO
+2.5V
ANALOG
INPUTS
MAX1248
CPU
+3V
VREF
REFADJ
__________Typical Operating Circuit
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For small orders, phone 408-737-7600 ext. 3468.