1 MSPS, 12-/10-/8-Bit ADCs

in 6-Lead SOT-23

AD7476/AD7477/AD7478

Rev. F

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FEATURES

Fast throughput rate: 1 MSPS

Low power

3.6 mW at 1 MSPS with 3 V supplies

15 mW at 1 MSPS with 5 V supplies

Wide input bandwidth

70 dB SNR at 100 kHz input frequency

Flexible power/serial clock speed management

No pipeline delays

High speed serial interface

SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible

Standby mode: 1 μA maximum

6-lead SOT-23 package

APPLICATIONS

Battery-powered systems

Personal digital assistants

Medical instruments

Mobile communications

Instrumentation and control systems

Data acquisition systems

High speed modems

Optical sensors

FUNCTIONAL BLOCK DIAGRAM

CONTROL

LOGIC

12-/10-/8-BIT

SUCCESSIVE-

APPROXIMATION

ADC

SCLK

SDATA

CS

GND

AD7476/AD7477/AD7478

Figure 1.

GENERAL DESCRIPTION

The AD7476/AD7477/AD74781 are, respectively, 12-bit, 10-bit,

and 8-bit, high speed, low power, successive approximation

ADCs. The parts operate from a single 2.35 V to 5.25 V power

supply and feature throughput rates up to 1 MSPS. Each part

contains a low noise, wide bandwidth track-and-hold amplifier

that can handle input frequencies in excess of 6 MHz.

The conversion process and data acquisition are controlled

using CS and the serial clock, allowing the devices to interface

with microprocessors or DSPs. The input signal is sampled on

the falling edge of CS and the conversion is initiated at this

point. There are no pipeline delays associated with these parts.

The AD7476/AD7477/AD7478 use advanced design techniques

to achieve very low power dissipation at high throughput rates.

allows the widest dynamic input range to the ADC. Thus, the

rate is determined by the SCLK.

PRODUCT HIGHLIGHTS

1.

First 12-/10-/8-Bit ADCs in SOT-23 Packages.

2.

High Throughput with Low Power Consumption.

3.

Flexible Power/Serial Clock Speed Management. The

conversion rate is determined by the serial clock, allowing

the conversion time to be reduced through the serial clock

speed increase. This allows the average power consumption

to be reduced while not converting. The parts also feature a

shutdown mode to maximize power efficiency at lower

throughput rates. Current consumption is 1 μA maximum

when in shutdown mode.

4.

Reference Derived from the Power Supply.

5.

No Pipeline Delay. The parts feature a standard successive-

approximation ADC with accurate control of the sampling

instant via a CS input and once-off conversion control.