_______________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

o 4-Channel Single-Ended or 2-Channel

Differential Inputs

o Single +2.7V to +5.25V Operation

o Internal 2.5V Reference (MAX1248)

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 16-Pin QSOP Package (same area as 8-pin SO)

+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

†

MAX1248ACPE

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.

I/O

SCK (SK)

MOSI (SO)

MISO (SI)

SHDN

SSTRB

DOUT

DIN

SCLK

CS

COM

AGND

DGND

CH3

C1

4.7

µF

C2

0.01

µF

C3

0.1

µF

CH0

0V TO

+2.5V

ANALOG

INPUTS

MAX1248

CPU

+3V

VREF

REFADJ

__________Typical Operating Circuit

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.