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,
excellent long-term accuracy and repeatability, and con-
sumes minimal power. These features make this device
ideally suited to applications from process and machine
control to consumer and automotive applications. For
16-channel multiplexer with common output (sample/hold
port) see ADC0816 data sheet. (See AN-247 for more infor-
mation.)
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 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
Block Diagram
00567201
See Ordering
Information
October 2002
ADC0808/ADC0809 8-Bit µP Compatible A/D Converters with 8-Channel Multiplexer
© 2002 National Semiconductor Corporation DS005672 www.national.com
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