1

LTC1400

Complete SO-8, 12-Bit,

400ksps ADC with Shutdown

The LTC

verter which draws only 75mW from a 5V or

± 5Vsupplies.

This easy-to-use device comes complete with a 200ns

sample-and-hold and a precision reference. Unipolar and

bipolar conversion modes add to the flexibility of the ADC.

The LTC1400 has two power saving modes: Nap and

Sleep. In Nap mode, it consumes only 6mW of power and

can wake up and convert immediately. In the Sleep mode,

it consumes 30

µW of power typically. Upon power-up

from Sleep mode, a reference ready (REFRDY) signal is

available in the serial data word to indicate that the

reference has settled and the chip is ready to convert.

The LTC1400 converts 0V to 4.096V unipolar inputs from

a single 5V supply and

±2.048V bipolar inputs from ±5V

supplies. Maximum DC specs include

±1LSB INL, ±1LSB

DNL and 45ppm/

°C drift over temperature. Guaranteed AC

performance includes 70dB S/(N + D) and – 76dB THD at

an input frequency of 100kHz, over temperature.

The 3-wire serial port allows compact and efficient data

transfertoawiderangeofmicroprocessors, microcontrollers

and DSPs.

FEATURES

s

Complete 12-Bit ADC in SO-8

s

Single Supply 5V or

s

Sample Rate: 400ksps

s

Power Dissipation: 75mW (Typ)

s

72dB S/(N + D) and – 80dB THD at Nyquist

s

No Missing Codes over Temperature

s

Nap Mode with Instant Wake-Up: 6mW

s

Sleep Mode: 30

µW

s

High Impedance Analog Input

s

Input Range (1mV/LSB): 0V to 4.096 or

± 2.048V

s

Internal Reference Can Be Overdriven Externally

s

3-Wire Interface to DSPs and Processors (SPI and

MICROWIRE

, LTC and LT are registered trademarks of Linear Technology Corporation.

MICROWIRE is a trademark of National Semiconductor Corp.

s

High Speed Data Acquisition

s

Digital Signal Processing

s

Multiplexed Data Acquisition Systems

s

Audio and Telecom Processing

s

Digital Radio

s

Spectrum Analysis

s

Low Power and Battery-Operated Systems

s

Handheld or Portable Instruments

Single 5V Supply, 400kHz, 12-Bit Sampling A/D Converter

GND

CONV

CLK

MPU

P1.4

P1.3

P1.2

LTC1400

+

0.1

µF

10

µF

+

0.1

µF

10

µF

ANALOG INPUT

(0V TO 4.096V)

4

3

2

1

5

6

7

8

SERIAL

DATA LINK

5V

LTC1400 • TA01

Power Consumption vs Sample Rate

SAMPLE RATE (Hz)

0.01

100

10

1

0.1

0.01

0.001

10

1k

1M

LTC1400 • TA02

0.1

1

100

10k 100k

NORMAL CONVERSION

NAP MODE

BETWEEN CONVERSION

SLEEP AND NAP MODE

BETWEEN CONVERSION

SLEEP MODE BETWEEN

CONVERSION

6.4MHz CLOCK