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LTC1402

Serial 12-Bit, 2.2Msps

Sampling ADC with Shutdown

October 1999

FEATURES

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Sample Rate: 2.2Msps

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72dB S/(N + D) and –89dB THD at Nyquist

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No Missing Codes over Temperature

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Available in 16-Pin Narrow SSOP Package

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Single Supply 5V or

±5V Operation

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Power Dissipation: 90mW (Typ)

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Nap Mode with Instant Wake-Up: 15mW

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Sleep Mode: 10

µW

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True Differential Inputs Reject Common Mode Noise

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80MHz Full Power Bandwidth Sampling

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

±2.048V

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Internal Reference Can Be Overdriven Externally

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3-Wire Interface to DSPs and Processors (SPI and

MICROWIRE

The LTC

verter. This high performance device includes a high dy-

namic range sample-and-hold and a precision reference.

It operates from a single 5V supply or dual

±5V supplies

and draws only 90mW from 5V.

The versatile differential input offers a unipolar range of

4.096V and a bipolar range of

±2.048V for dual supply

systems where high performance op amps perform best,

eliminating the need for special translation circuitry.

The high common mode rejection allows users to elimi-

nate ground loops and common mode noise by measuring

signals differentially from the source.

Outstanding AC performance includes 72dB S/(N + D) and

–93dB SFDR at the Nyquist input frequency of 1.1MHz

with dual

±5V supplies and –84dB SFDR with a single 5V

supply.

The LTC1402 has two power saving modes: Nap and

Sleep. Nap mode consumes only 15mW of power and

Sleep can wake up and convert immediately. In Sleep

mode, it typically consumes 10

µW of power. 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 3-wire serial port allows compact and efficient data

transfer to a wide range of microprocessors, microcon-

trollers and DSPs. A digital output driver power supply pin

allows direct connection to 3V or lower logic.

SAMPLE-

AND-HOLD

BIP/UNI

CONV

SCK

10

8

16

15

112

11

GAIN

7

5

4

3

–5V OR 0V

10

µF

10

µF

4.096V

10

µF

64k

OUTPUT

BUFFER

1402 TA01

2.048

REFERENCE

TIMING

LOGIC

LTC1402

OGND

9

6

2

DGND

5V

3V OR 5V

AGND1

14

13

AGND2

+

–

64k

12-BIT ADC

MICROWIRE is a trademark of National Semiconductor Corp.

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

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Telecommunications

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High Speed Data and Signal Acquisition

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Digitally Multiplexed Data Acquisition Systems

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Digital Radio Receivers

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Spectrum Analysis

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Low Power and Battery-Operated Systems

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Handheld or Portable Instruments

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Imaging Systems

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

Final Electrical Specifications

BLOCK DIAGRA

5 Harmonic THD, 2nd, 3rd and SFDR

vs Input Frequency (Unipolar)

INPUT FREQUENCY (Hz)

–80

–60

–40

1401 G05

–100

–120

0

–20

–90

–70

–50

–110

–10

–30

THD

SFDR

2ND

3RD