________________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

____________________________Features

♦♦ Single +2.375V to +3.3V Operation

♦♦ 8-Channel Single-Ended or 4-Channel

Differential Analog Inputs

♦♦ Low Power: 0.8mA (100ksps)

10µA (1ksps)

1µA (power-down mode)

♦♦ Internal Track/Hold, 100kHz Sampling Rate

♦♦ SPI/QSPI/MICROWIRE/TMS320-Compatible

4-Wire Serial Interface

♦♦ Software-Configurable Unipolar or Bipolar Inputs

♦♦ 20-Pin DIP/SSOP Packages

+2.375V, Low-Power, 8-Channel,

Serial 12-Bit ADC

20

19

18

17

16

15

14

13

12

11

1

2

3

4

5

6

7

8

9

10

TOP VIEW

DIP/SSOP

SCLK

CS

DIN

SSTRB

DOUT

DGND

AGND

VREF

SHDN

COM

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

MAX1245

___________________Pin Configuration

I/O

SCK (SK)*

MOSI (SO)

MISO (SI)

SHDN

SSTRB

DOUT

DIN

SCLK

CS

COM

AGND

DGND

CH7

0.1

μF

0.1

μF

CH0

0V to

+2.048V

ANALOG

INPUTS

MAX1245

CPU

+2.5V

VREF

+2.048V

___________Typical Operating Circuit

19-1066; Rev 1; 11/09

________________________________________________________________

Maxim Integrated Products

1

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

________________Ordering Information

*

Contact factory for availability of alternate surface-mount packages.

SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.

PART*

TEMP RANGE

PIN-PACKAGE

INL

(LSB)

MAX1245ACPP

0

°C to +70°C

20 Plastic DIP

±1/2

MAX1245BCPP

0

°C to +70°C

20 Plastic DIP

±1

MAX1245ACAP

0

°C to +70°C

20 SSOP

±1/2

MAX1245BCAP

0

°C to +70°C

20 SSOP

±1

MAX1245AEPP

-40

°C to +85°C 20 Plastic DIP

±1/2

MAX1245BEPP

-40

°C to +85°C 20 Plastic DIP

±1

MAX1245AEAP

-40

°C to +85°C 20 SSOP

±1/2

MAX1245BEAP

-40

°C to +85°C 20 SSOP

±1