© 1999 National Semiconductor Corporation

http://www.national.com

Printed in the U.S.A.

N

General Description

The CLC5957 is a monolithic 12-bit, 70MSPS analog-to-digital

converter. The device has been optimized for use in IF-sampled

digital receivers and other applications where high resolution,

high sampling rate, wide dynamic range, low power dissipation,

and compact size are required. The CLC5957 features differential

analog inputs, low jitter differential universal clock inputs, a low

distortion track-and-hold with 0-300MHz input bandwidth, a band-

gap voltage reference, data valid clock output, TTL compatible

CMOS (3.3V or 2.5V) programmable output logic, and a propri-

etary 12-bit multi-stage quantizer. The CLC5957 is fabricated on

the ABIC-V 0.8 micron BiCMOS process.

The CLC5957 features a 74dBc spurious free dynamic range

(SFDR) and a 67dB signal to noise ratio (SNR). The wideband

track-and-hold allows sampling of IF signals to greater than

250MHz. The part produces two-tone, dithered, SFDR of 83dBFS

at 75MHz input frequency. The differential analog input provides

excellent common mode rejection, while the differential universal

clock inputs minimize jitter. The 48-pin TSSOP package provides

an extremely small footprint for applications where space is a

critical consideration. The CLC5957 operates from a single +5V

power supply. Operation over the industrial temperature range of

-40°C to +85°C is guaranteed. National Semiconductor tests

each part to verify compliance with the guaranteed specifications.

ADC Block Diagram

CLC5957

12-bit, 70MSPS Broadband Monolithic A/D Converter

Features

• 70MSPS

• Wide dynamic range

SFDR: 74dBc

SFDR w/dither: 85dBFS

SNR: 67dB

• IF sampling capability

• Input bandwidth = 0-300MHz

• Low power dissipation: 640mW

• Very small package: 48-pin TSSOP

• Single +5V supply

• Data valid clock output

• Programmable output levels:

3.3V or 2.5V

Applications

• Cellular base-stations

• Digital communications

• Infrared/CCD imaging

• IF sampling

• Electro-optics

• Instrumentation

• Medical imaging

• High definition video

October 1999

3-bit

Q

T/H

3

3-bit

Q

3

3-bit

Q

3

3-bit

Q

3

Bit Align/Error Correct

12

Clock

In

ADC

Out

DAV

12

IF

Saw

IF

Input

~

~

BPF

(150MHz

typ.)

DVGA

(

∆G = 42dB)

CLC5957

12-bit

70MSPS

ADC

Dig.

Tuner/

Filter

AGC

20

3-bit (Gain Control)

Noise

BPF

DAV

CLC5902

First IF Receiver

ME79TG

CL5956

IMTD

N

ME79TG

CL5956

IMTD

N

ME79TG

CL5956

IMTD

N

ME79TG

CLC5957

MTD

N

Actual Size

Frequency (MHz)

0

-10

-100

-90

-80

-70

-60

-50

-40

-30

-20

0

828

4

12

16

20

24

32

Single Tone Output Spectrum w/Dither

Input (dBFS)

90

80

0

10

20

30

40

50

60

70

-125

-50

-25

0

-75

-100

Receiver SINAD vs. Input Amplitude

Decimation/filter = 190/0.8

Output BW = 50M/190 X 0.8 = 210KHz