MP8820
8-Bit Analog-to-Digital Converter
with an 8-Channel MUX
FEATURES
•
•
•
•
•
•
•
Precision 7–Bit Plus Sign ADC
8 Channel Analog Mux
Single Reference to GND
Input Referenced to User Supplied V
MID
DNL=
±1/2
LSB, INL=± 1 LSB
Single Supply: 5 V
ESD Protection: 2000 V
APPLICATIONS
•
Servo Control
•
Low Cost Audio Control
•
Voice Acquisition
GENERAL DESCRIPTION
The MP8820 is a precision 1.6 MHz sampling 7-bit plus sign
Analog-to-Digital Converter with an eight channel input mux and
µP
interface. The device has internal circuitry which receives
the user supplied reference voltages V
REF(+)
and V
REF(–)
, and
generates the ADC reference voltages V
MID
(V
REF(+)
–
V
REF(–)
). Since V
REF(+)
is internally buffered and V
REF(–)
is gen-
erally ground, this structure allows the user to easily generate an
input range biased about a user-supplied V
MID
from a grounded
reference source.
The internal ADC reference voltages are capable of swinging
to within 0.5 V of the supply rails, giving the MP8820 a wide
range over which the effective channel gain can be adjusted.
The MP8820 uses a two-step flash conversion technique.
The first section determines the sign and the 3 MSBs while the
second segment converts the 4 LSBs. The ADC conversion be-
gins when WR goes low and the data is valid 500 ns after the
rising edge of WR. The MP8820 operates from a single 5V sup-
ply and consumes only 175mW of power.
Specified for operation over the industrial (–40 to +85°C)
temperature range, the MP8820 is available in Surface Mount
(SOIC) and Shrunk Small Outline (SSOP) packages.
SIMPLIFIED BLOCK DIAGRAM
V
DD
A
IN
0-A
IN
7
8
8:1 MUX
+
3
A0-A2
T/H
G=1
V
RT
A
IN
8
DB0-DB7
V
MID
V
REF(+)
V
REF(–)
+
–
G=1
–
V
MID
8-Bit
ADC
V
RB
+
–
G=1
Control
GND
WR
Rev. 1.00
1
EXAR [ EXAR CORPORATION ]
