a
2.7 V to 5.25 V, Micropower, 8-Channel,
125 kSPS, 12-Bit ADC in 16-Lead TSSOP
AD7888
FEATURES
Specified for VDD of 2.7 V to 5.25 V
Flexible Power/Throughput Rate Management
Shutdown Mode: 1 A Max
Eight Single-Ended Inputs
Serial Interface: SPI™/QSPI™/MICROWIRE™/DSP
Compatible
16-Lead Narrow SOIC and TSSOP Packages
APPLICATIONS
Battery-Powered Systems (Personal Digital Assistants,
Medical Instruments, Mobile Communications)
Instrumentation and Control Systems
High-Speed Modems
FUNCTIONAL BLOCK DIAGRAM
AIN1
AD7888
I/P
MUX
T/H
VDD
AIN8
2.5V
REF
REF IN/REF OUT
COMP
BUF
CHARGE
REDISTRIBUTION
DAC
SAR + ADC
CONTROL LOGIC
GENERAL DESCRIPTION
The AD7888 is a high speed, low power, 12-bit ADC that operates from a single 2.7 V to 5.25 V power supply. The AD7888 is
capable of a 125 kSPS throughput rate. The input track-andhold acquires a signal in 500 ns and features a single-ended
sampling scheme. The AD7888 contains eight single-ended
analog inputs, AIN1 through AIN8. The analog input on each
of these channels is from 0 to VREF. The part is capable of converting full power signals up to 2.5 MHz.
The AD7888 features an on-chip 2.5 V reference that can be
used as the reference source for the A/D converter. The REF
IN/REF OUT pin allows the user access to this reference. Alternatively, this pin can be overdriven to provide an external reference voltage for the AD7888. The voltage range for this external
reference is from 1.2 V to VDD.
CMOS construction ensures low power dissipation of typically
2 mW for normal operation and 3 µW in power-down mode.
The part is available in a 16-lead narrow body small outline
(SOIC) and a 16-lead thin shrink small outline (TSSOP) package.
AGND
AGND
SPORT
CS
DIN
DOUT
SCLK
PRODUCT HIGHLIGHTS
1. Smallest 12-bit 8-channel ADC; 16-lead TSSOP is the same
area as an 8-lead SOIC and less than half the height.
2. Lowest Power 12-bit 8-channel ADC.
3. Flexible power management options including automatic
power-down after conversion.
4. Analog input range from 0 V to VREF (VDD).
5. Versatile serial I/O port (SPI/QSPI/MICROWIRE/DSP
Compatible).
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corporation.
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001
