AD7894

Features:

Fast 14-Bit ADC with 5 ms Conversion Time
8-Lead SOIC Package
Single 5 V Supply Operation
High Speed, Easy-to-Use, Serial Interface
On-Chip Track/Hold Amplifier
Selection of Input Ranges
± 10 V for AD7894-10
± 2.5 V for AD7894-3
0 V to +2.5 V for AD7894-2
High Input Impedance
Low Power: 20 mW Typ
Pin Compatible Upgrade of 12-Bit AD7895




Specifications

(T_A = +25°C unless otherwise noted)
V_DD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V
Analog Input Voltage to GND
AD7894-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±17 V
AD7894-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±7 V
AD7894-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V to +10 V
Reference Input Voltage to GND . . . . 0.3 V to V_DD + 0.3 V
Digital Input Voltage to GND . . . . . . . 0.3 V to V_DD + 0.3 V
Digital Output Voltage to GND . . . . . 0.3 V to V_DD + 0.3 V
Operating Temperature Range
Commercial (A, B Versions) . . . . . . . . 40°C to +85°C
Storage Temperature Range . . . . . . 65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +150°C
SOIC Package, Power Dissipation . . . . . .. . . . . . . . 450 mW
_JA Thermal Impedance . . . . . . . . . . . . . . . . . . 170°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . .. . .. . +215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . .+220°C




Description

The AD7894 is a fast, 14-bit ADC that operates from a single +5 V supply and is housed in a small 8-lead SOIC. The part contains a 5 µs successive approximation A/D converter, an on-chip track/hold amplifier, an on-chip clock and a high speed serial interface.

Output data from the AD7894 is provided via a high speed, serial interface port. This two-wire serial interface has a serial clock input and a serial data output with the external serial clock accessing the serial data from the part.

In addition to the traditional dc accuracy specifications such as linearity, full-scale and offset errors, the AD7894 is also speci- fied for dynamic performance parameters including harmonic distortion and signal-to-noise ratio.

The part accepts an analog input range of ±10 V (AD7894-10), ±2.5 V (AD7894-3), 0 V to +2.5 V (AD7894-2), and operates from a single +5 V supply consuming only 20 mW typical.

The AD7894 features a high sampling rate mode and, for low power applications, a proprietary automatic power-down mode where the part automatically goes into power-down once conversion is complete and "wakes up" before the next conversion cycle.

The part is available in a small outline IC (SOIC).