SPT7938

12-BIT, 40 MSPS, 170 mW A/D CONVERTER

APPLICATIONS

• All High-Speed Applications Where

Low Power Dissipation Is Required

• Video Imaging

• Medical Imaging

• Radar Receivers

• IR Imaging

• Digital Communications

GENERAL DESCRIPTION

The SPT7938 is a 12-bit monolithic, low-cost, low-power

analog-to-digital converter capable of minimum word rates

of 40 MSPS. The on-chip track-and-hold function assures

very good dynamic performance without the need for exter-

nal components. The input drive requirements are mini-

mized due to the SPT7938’s low input capacitance of only

20 pF.

Power dissipation is extremely low at only 170 mW typical at

40 MSPS with a power supply of +5.0 V. The digital outputs

are +3 V or +5 V, and are user selectable. The SPT7938 has

incorporated proprietary circuit design and CMOS process-

ing technologies to achieve its advanced performance. In-

puts and outputs are TTL/CMOS compatible to interface

with TTL/CMOS logic systems. Output data format is

straight binary.

The SPT7938 is available in a 28-lead SSOP package over

the industrial temperature range.

BLOCK DIAGRAM

FEATURES

• Monolithic 40 MSPS Analog-to-Digital Converter

• 170 mW Power Dissipation

• On-Chip Track-and-Hold

• Single +5 V Power Supply

• TTL/CMOS Outputs

• 20 pF Input Capacitance

• Selectable +3 V or +5 V Logic I/O

CLK In

13-Bit

SAR

DAC

ADC Section 1

T/H

13

13-Bit

SAR

DAC

ADC Section 18

Auto-

Zero

CMP

Auto-

Zero

CMP

T/H

13

1:18

Mux

13

13

13

13

13-Bit

18:1

Mux/

Error

Correction

Timing

and

Control

P1

P2

P17

P18

ADC Section 2

ADC Section 17

Reference Ladder

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

DØ (LSB)

D11 (MSB)

D12 Out of Range

VRLS

VRHF

VRLF

VRHS

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