2.7 V to 5.5 V, 200 kSPS
8-Bit Sampling ADC
a
AD7819
FEATURES
FUNCTIONAL BLOCK DIAGRAM
8-Bit ADC with 4.5 ꢀs Conversion Time
On-Chip Track and Hold
V
V
REF
AGND
DD
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
AD7819
DB7
DB0
CHARGE
REDISTRIBUTION
DAC
THREE-
STATE
DRIVERS
CLOCK
OSC
Normal Operation
10.5 mW, VDD = 3 V
Automatic Power-Down
57.75 ꢀW @ 1 kSPS, VDD = 3 V
Analog Input Range: 0 V to VREF
Reference Input Range: 1.2 V to VDD
CONTROL
LOGIC
COMP
T/H
V
IN
BUSY
CS RD CONVST
PRODUCT HIGHLIGHTS
1. Low Power, Single Supply Operation
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.
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.)
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.
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.
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).
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 2000