a
FEATURES
12-Bit Monolithic A/D Converter
66 kHz Throughput Rate
12 s Conversion Time
3 s On-Chip Track/Hold Amplifier
Low Power
Power Save Mode: 2 mW typ
Normal Operation: 25 mW typ
70 dB SNR
Fast Data Access Time: 57 ns
Small 24-Lead SOIC and 0.3" DIP Packages
APPLICATIONS
Battery Powered Portable Systems
Digital Signal Processing
Speech Recognition and Synthesis
High Speed Modems
Control and Instrumentation
LC MOS Single +5 V Supply,
Low Power, 12-Bit Sampling ADC
AD7880
FUNCTIONAL BLOCK DIAGRAM
V
DD
R
V
INA
V
INB
V
REF
AGND
CS
CLKIN
CONVST
RD
BUSY
THREE
STATE
BUFFERS
DB11 DB0
CONTROL
LOGIC
R
SAMPLING
COMPARATOR
+
–
2
LOW POWER
CONTROL
CIRCUIT
MODE
12-BIT DAC
SAR +
COUNTER
AD7880
DGND
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD7880 is a high speed, low power, 12-bit A/D converter
which operates from a single +5 V supply. It consists of a 3
µs
track/hold amplifier, a 12
µs
successive-approximation ADC,
versatile interface logic and a multiple-input-range circuit. The
part also includes a power save feature.
An internal resistor network allows the part to accept both uni-
polar and bipolar input signals while operating from a single
+5 V supply. Fast bus access times and standard control inputs
ensure easy interfacing to modern microprocessors and digital
signal processors.
The AD7880 features a total throughput time of 15
µs
and can
convert full power signals up to 33 kHz with a sampling fre-
quency of 66 kHz.
In addition to the traditional dc accuracy specifications such as
linearity, full-scale and offset errors, the AD7880 is also fully
specified for dynamic performance parameters including har-
monic distortion and signal-to-noise ratio.
The AD7880 is fabricated in Analog Devices’ Linear Compat-
ible CMOS (LC
2
MOS) process, a mixed technology process
that combines precision bipolar circuits with low power CMOS
logic. The part is available in a 24-pin, 0.3 inch-wide, plastic or
hermetic dual-in-line package (DIP) as well as a small 24-lead
SOIC package.
1. Fast Conversion Time.
12
µs
conversion time and 3
µs
acquisition time allow for
large input signal bandwidth. This performance is ideally
suited for applications in areas such as telecommunications,
audio, sonar and radar signal processing.
2. Low Power Consumption.
2 mW power consumption in the power-down mode makes
the part ideally suited for portable, hand held, battery pow-
ered applications.
3. Multiple Input Ranges.
The part features three user-determined input ranges, 0 V to
+5 V, 0 V to 10 V and
±
5 V. These unipolar and bipolar
ranges are achieved with a 5 V only power supply.
REV. 0
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
which 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: 617/329-4700
Fax: 617/326-8703
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