REV. B
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a
AD7819
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2000
2.7 V to 5.5 V, 200 kSPS
8-Bit Sampling ADC
FUNCTIONAL BLOCK DIAGRAM
CLOCK
OSC
CHARGE
REDISTRIBUTION
DAC
THREE-
STATE
DRIVERS
CONTROL
LOGIC
BUSY
CS RD CONVST
V
IN
V
DD
AGND
V
REF
DB7
DB0
COMP
T/H
AD7819
FEATURES
8-Bit ADC with 4.5 s Conversion Time
On-Chip Track and Hold
Operating Supply Range: 2.7 V to 5.5 V
Specifications at 2.7 V – 3.6 V and 5 V 10%
8-Bit Parallel Interface
8-Bit Read
Power Performance
Normal Operation
10.5 mW, V
DD
= 3 V
Automatic Power-Down
57.75 W @ 1 kSPS, V
DD
= 3 V
Analog Input Range: 0 V to V
REF
Reference Input Range: 1.2 V to V
DD
GENERAL DESCRIPTION
The AD7819 is a high speed, microprocessor-compatible, 8-bit
analog-to-digital converter with a maximum throughput of
200 kSPS. The converter operates off a single 2.7 V to 5.5 V
supply and contains a 4.5 µs successive approximation A/D
converter, track/hold circuitry, on-chip clock oscillator and 8-bit
wide parallel interface. The parallel interface is designed to
allow easy interfacing to microprocessors and DSPs. Using only
address decoding logic the AD7819 is easily mapped into the
microprocessor address space.
When used in its power-down mode, the AD7819 automatically
powers down at the end of a conversion and powers up at the
start of a new conversion. This feature significantly reduces the
power consumption of the part at lower throughput rates. The
AD7819 can also operate in a high speed mode where the part is
not powered down between conversions. In this mode of opera-
tion the part is capable of providing 200 kSPS throughput.
The part is available in a small, 16-lead 0.3" wide, plastic dual-
in-line package (DIP); in a 16-lead, 0.15" wide, narrow body
small outline IC (SOIC) and in a 16-lead, narrow body, thin
shrink small outline package (TSSOP).
PRODUCT HIGHLIGHTS
1. Low Power, Single Supply Operation
The AD7819 operates from a single 2.7 V to 5.5 V supply
and typically consumes only 10.5 mW of power. The power
dissipation can be significantly reduced at lower through-
put rates by using the automatic power-down mode.
2. Automatic Power-Down
The automatic power-down mode, whereby the AD7819
goes into power-down mode at the end of a conversion and
powers up before the next conversion, means the AD7819
is ideal for battery powered applications; e.g., 57.75 µW
@ 1 kSPS. (See Power vs. Throughput Rate section.)
3. Parallel Interface
An easy to use 8-bit wide parallel interface allows interfacing
to most popular microprocessors and DSPs with minimal
external circuitry.
4. Dynamic Specifications for DSP Users
In addition to the traditional ADC specifications, the AD7819
is specified for ac parameters, including signal-to-noise ratio
and distortion.
