16-Bit, 6 MSPS, PulSAR

Differential ADC

Data Sheet

AD7625

Rev. A

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FEATURES

Throughput: 6 MSPS

SNR: 93 dB

INL: ±0.45 LSB typical, ±1 LSB maximum

DNL: ±0.3 LSB typical, ±0.5 LSB maximum

Power dissipation: 135 mW

32-lead LFCSP (5 mm × 5 mm)

SAR architecture

No latency/no pipeline delay

16-bit resolution with no missing codes

Zero error: ±1.5 LSB

Differential input voltage: ±4.096 V

Serial LVDS interface

Self-clocked mode

Echoed-clock mode

Can use LVDS or CMOS for conversion control (CNV signal)

Reference options

Internal: 4.096 V

External (1.2 V) buffered to 4.096 V

External: 4.096 V

APPLICATIONS

High dynamic range telecommunications

Receivers

Digital imaging systems

High speed data acquisition

Spectrum analysis

Test equipment

FUNCTIONAL BLOCK DIAGRAM

AD7625

CLOCK

LOGIC

SERIAL

LVDS

IN–

IN+

REFIN

REF VCM

SAR

÷2

CNV+, CNV–

VIO

D+, D–

DCO+, DCO–

CLK+, CLK–

1.2V

BAND GAP

CAP

DAC

Figure 1.

GENERAL DESCRIPTION

The AD7625 is a 16-bit, 6 MSPS, charge redistribution successive

approximation register (SAR) based architecture analog-to-digital

converter (ADC). SAR architecture allows unmatched perfor-

mance both in noise (93 dB SNR) and in linearity (1 LSB). The

AD7625 contains a high speed, 16-bit sampling ADC, an internal

conversion clock, and an internal buffered reference. On the

CNV± rising edge, it samples the voltage difference between the

IN+ and IN− pins. The voltages on these pins swing in opposite

phase between 0 V and REF. The 4.096 V reference voltage, REF,

can be generated internally or applied externally.

All converted results are available on a single LVDS self-clocked

or echoed-clock serial interface, reducing external hardware

connections.

The AD7625 is housed in a 32-lead, 5 mm × 5 mm LFCSP with

operation specified from −40°C to +85°C.

Table 1. Fast PulSAR® ADC Selection

Input Type

Resolution (Bits)

1 MSPS to <2 MSPS

2 MSPS to 3 MSPS

6 MSPS

Differential (Ground Sense)

16

AD7653

16

AD7667

16

AD7980

16

AD7983

True Bipolar

16

AD7671

Differential (Antiphase)

16

AD7677

AD7621

AD7625

16

AD7623

AD7622

18

AD7643

AD7641

18

AD7982

18

AD7984