SPT7855

10-BIT, 25 MSPS, 135 mW A/D CONVERTER

TECHNICAL DATA

MAY 25, 2001

FEATURES

• Monolithic 25 MSPS converter

• 135 mW power dissipation

• On-chip track-and-hold

• Single +5 V power supply

• TTL/CMOS outputs

• 5 pF input capacitance

• Low cost

• Tri-state output buffers

• High ESD protection: 3,500 V minimum

• Selectable +3 V or +5 V logic I/O

APPLICATIONS

• All high-speed applications where low power

dissipation is required

• Video imaging

• Medical imaging

• IR imaging

• Digital communications

GENERAL DESCRIPTION

The SPT7855 is a 10-bit monolithic, low-cost, ultralow-

power analog-to-digital converter capable of minimum

word rates of 25 MSPS. The on-chip track-and-hold func-

tion assures very good dynamic performance without the

need for external components. The input drive require-

ments are minimized due to the SPT7855’s low input

capacitance of only 5 pF.

Power dissipation is extremely low at only 135 mW typical

at 25 MSPS with a power supply of +5.0 V. The digital out-

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

SPT7855 is pin-compatible with an entire family of 10-bit,

CMOS converters (SPT7835/40/50/55/60/61), which sim-

plifies upgrades. The SPT7855 has incorporated propri-

etary circuit design* and CMOS processing technologies

to achieve its advanced performance. Inputs and outputs

are TTL/CMOS-compatible to interface with TTL/CMOS

logic systems. Output data format is straight binary.

The SPT7855 is available in 28-lead SOIC and 32-lead

small (7 mm square) TQFP packages over the commer-

cial and industrial temperature ranges.

*Patent pending

11-Bit

SAR

DAC

ADC Section 1

T/H

11

11-Bit

SAR

DAC

ADC Section 16

Auto-

Zero

CMP

Auto-

Zero

CMP

T/H

11

1:16

Mux

11

11

11

11

11-Bit

16:1

Mux/

Error

Correction

Timing

and

Control

P1

P2

P15

P16

ADC Section 2

ADC Section 15

Reference Ladder

Ref

In

Enable

CLK In

Data

Valid

D10 Overrange

D9 (MSB)

D8

D7

D6

D5

D4

D3

D2

D1

D0 (LSB)

...

...

...

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BLOCK DIAGRAM