Rainbow Electronics ADC0809 - Manual

ADC0808/ADC0809
8-Bit µP Compatible A/D Converters with 8-Channel
Multiplexer
General Description
The ADC0808, ADC0809 data acquisition component is a
monolithic CMOS device with an 8-bit analog-to-digital con-
verter, 8-channel multiplexer and microprocessor compatible
control logic. The 8-bit A/D converter uses successive ap-
proximation as the conversion technique. The converter fea-
tures a high impedance chopper stabilized comparator, a
256R voltage divider with analog switch tree and a succes-
sive approximation register. The 8-channel multiplexer can
directly access any of 8-single-ended analog signals.
The device eliminates the need for external zero and
full-scale adjustments. Easy interfacing to microprocessors
is provided by the latched and decoded multiplexer address
inputs and latched TTL TRI-STATE
® outputs.
The design of the ADC0808, ADC0809 has been optimized
by incorporating the most desirable aspects of several A/D
conversion techniques. The ADC0808, ADC0809 offers high
speed, high accuracy, minimal temperature dependence, ex-
cellent long-term accuracy and repeatability, and consumes
minimal power. These features make this device ideally
suited to applications from process and machine control to
consumer and automotive applications. For 16-channel mul-
tiplexer
with common output (sample/hold port) see
ADC0816 data sheet. (See AN-247 for more information.)
Features
n Easy interface to all microprocessors
n Operates ratiometrically or with 5 V
DC
or analog span
adjusted voltage reference
n No zero or full-scale adjust required
n 8-channel multiplexer with address logic
n 0V to 5V input range with single 5V power supply
n Outputs meet TTL voltage level specifications
n Standard hermetic or molded 28-pin DIP package
n 28-pin molded chip carrier package
n ADC0808 equivalent to MM74C949
n ADC0809 equivalent to MM74C949-1
Key Specifications
n Resolution: 8 Bits
n Total Unadjusted Error: ± 1 ⁄ 2 LSB and ± 1 LSB
n Single Supply: 5 V
DC
n Low Power: 15 mW
n Conversion Time: 100 µs
TRI-STATE ® is a registered trademark of National Semiconductor Corp.
November 1995
ADC0808/ADC0809
8-Bit
µP
Compatible
A/D
Converters
with
8-Channel
Multiplexer
© 1997 National Semiconductor Corporation DS005672 www.national.com