FUNCTIONAL BLOCK DIAGRAM

REV. 0

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a

8-Bit 20 MSPS, 60 mW

Sampling A/D Converter

AD775

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

FEATURES

CMOS 8-Bit 20 MSPS Sampling A/D Converter

Low Power Dissipation: 60 mW

+5 V Single Supply Operation

Differential Nonlinearity: 0.3 LSB

Differential Gain: 1%

Differential Phase: 0.5 Degrees

Three-State Outputs

On-Chip Reference Bias Resistors

Adjustable Reference Input

Video Industry Standard Pinout

Small Packages:

24-Pin 300 Mil SOIC Surface Mount

24-Pin 400 Mil Plastic DIP

PRODUCT DESCRIPTION

The AD775 is a CMOS, low power, 8-bit, 20 MSPS sampling

analog-to-digital converter (ADC). The AD775 features a built-

in sampling function and on-chip reference bias resistors to pro-

vide a complete 8-bit ADC solution. The AD775 utilizes a

pipelined/ping pong two-step flash architecture to provide high

sampling rates (up to 35 MHz) while maintaining very low

power consumption (60 mW).

Its combination of excellent DNL, fast sampling rate, low dif-

ferential gain and phase errors, extremely low power dissipation,

and single +5 V supply operation make it ideally suited for a

variety of video and image acquisition applications, including

portable equipment. The AD775’s reference ladder may be con-

nected in a variety of configurations to accommodate different

input ranges. The low input capacitance (11 pF typical) provides

an easy-to-drive input load compared to conventional flash

converters.

The AD775 is offered in both 300 mil SOIC and 400 mil DIP

plastic packages, and is designed to operate over an extended

commercial temperature range (–20

°C to +75°C).

PRODUCT HIGHLIGHTS

Low Power: The AD775 has a typical supply current of 12 mA,

for a power consumption of 60 mW. Reference ladder current

is also low: 6.6 mA typical, minimizing the reference power

consumption.

Complete Solution: The AD775’s switched capacitor design

features an inherent sample/hold function: no external SHA is

required. On-chip reference bias resistors are included to allow

a supply-based reference to be generated without any external

resistors.

Excellent Differential Nonlinearity: The AD775 features a

typical DNL of 0.3 LSBs, with a maximum limit of 0.5 LSBs.

No missing codes is guaranteed.

Single +5 V Supply Operation: The AD775 is designed to oper-

ate on a single +5 V supply, and the reference ladder may be

configured to accommodate analog inputs inclusive of ground.

Low Input Capacitance: The 11 pF input capacitance of the

AD775 can significantly decrease the cost and complexity of

input driving circuitry, compared with conventional 8-bit flash

ADCs.

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CLOCK LOGIC

FINE COMPARATORS

BANK B

FINE COMPARATORS

BANK A

COARSE

COMPARATORS

D7 (MSB)

D0 (LSB)

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OE

CLK

AD775

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