National Semiconductor ADC0820 Manual

ADC0820
8-Bit High Speed µP Compatible A/D Converter with
Track/Hold Function

General Description

By using a half-flash conversion technique, the 8-bit
ADC0820 CMOS A/D offers a 1.5 µs conversion time and
dissipates only 75 mW of power. The half-flash technique
consists of 32 comparators, a most significant 4-bit ADC and
a least significant 4-bit ADC.
The input to the ADC0820 is tracked and held by the input
sampling circuitry eliminating the need for an external
sample-and-hold for signals moving at less than 100 mV/µs.
For ease of interface to microprocessors, the ADC0820 has
been designed to appear as a memory location or I/O port
without the need for external interfacing logic.

Key Specifications

n Resolution
n Conversion Time
n Low Power
n Total Unadjusted
Error
Connection and Functional Diagrams
Dual-In-Line, Small Outline
and SSOP Packages
Top View
TRI-STATE ® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
8 Bits
2.5 µs Max (RD Mode)
1.5 µs Max (WR-RD Mode)
75 mW Max
± ±
1 ⁄ LSB and 1 LSB
2
DS005501-1
DS005501
Features
n Built-in track-and-hold function
n No missing codes
n No external clocking
n Single supply — 5 V
DC
n Easy interface to all microprocessors, or operates
stand-alone
n Latched TRI-STATE ® output
n Logic inputs and outputs meet both MOS and T
voltage level specifications
n Operates ratiometrically or with any reference value
equal to or less than V
CC
n 0V to 5V analog input voltage range with single 5V
supply
n No zero or full-scale adjust required
n Overflow output available for cascading
n 0.3" standard width 20-pin DIP
n 20-pin molded chip carrier package
n 20-pin small outline package
n 20-pin shrink small outline package (SSOP)
Molded Chip Carrier
Package
June 1999
2
L
DS005501-33
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