GENERAL DESCRIPTION

The AD4684/AD4685 are 16-bit, dual, simultaneous sampling, high

speed, successive approximation register (SAR), analog-to-digital

converters (ADCs) that operate from a 3.0 V to 3.6 V power supply

and feature throughput rates of up to 1 MSPS for the AD4684 and

500 kSPS for the AD4685. The analog input types are single-ended

and are sampled and converted on the falling edge of CS.

The AD4684/AD4685 have an on-chip sequencer and integrated

on-chip oversampling block to improve dynamic range and reduce

noise at lower bandwidths. A buffered internal 2.5 V reference is

included. Alternatively, an external reference up to 3.3 V can be

used. The conversion process and data acquisition use standard

control inputs, allowing interfacing to microprocessors or digital

signal processors (DSPs). The AD4684/AD4685 is compatible with

1.8 V, 2.5 V, and 3.3 V interfaces by using the separate logic supply.

The AD4684/AD4685 are available in a 16-lead, 3 mm × 3 mm lead

frame chip scale package (LFCSP) with operation specified from

−40°C to +125°C.

FEATURES

► 16-bit dual simultaneous sampling SAR ADC

► Single-ended analog inputs

► 4-channel with 2:1 multiplexers

► Channel sequencer mode

► Throughput rate

► 1 MSPS (AD4684)

► 500 kSPS (AD4685)

► SNR (typical)

► 87.5 dB with VREF = 3.3 V external

► 93 dB with OSR_MODE = 1, OSR = 8, RES = 1, VREF = 2.5 V

internal

► On-chip oversampling functions

► INL ±1.5 LSB (typical)

► Resolution boost function

► 2.5 V internal reference at 10 ppm/°C (maximum)

► Alert function

► −40°C to +125°C temperature range

► 16-lead, 3 mm × 3 mm LFCSP

APPLICATIONS

► Motor control position feedback

► Motor control current sense

► Sonars

► Power quality

► Data acquisition systems

► Erbium doped fiber amplifier (EDFA) applications

► Inphase and quadrature demodulation