May 1997
ML2281, ML2282*,
ML2284#, ML2288#
Serial I/O 8-Bit A/D Converters with
Multiplexer Options
GENERAL DESCRIPTION
The ML2281 family are 8-bit successive approximation
A/D converters with serial I/O and configurable input
multiplexers with up to 8 input channels.
All errors of the sample-and-hold, incorporated on the
ML2281 family are accounted for in the analog-to-digital
converters accuracy specification.
The voltage reference can be externally set to any value
between GND and V
CC
, thus allowing a full conversion
over a relatively small voltage span if desired.
The ML2281 family is an enhanced double polysilicon
CMOS pin compatible second source for the ADC0831,
ADC0832, ADC0834, and ADC0838 A/D converters. The
ML2281 series enhancements are faster conversion time,
true sample-and-hold function, superior power supply
rejection, improved AC common mode rejection, faster
digital timing, and lower power dissipation. All parameters
are guaranteed over temperature with a power supply
voltage of 5V ±10%.
FEATURES
s
Conversion time: 6µs
s
Total unadjusted error: ±1/2LSB or ±1LSB
s
Sample-and-hold: 375ns acquisition
s
2, 4 or 8-input multiplexer options
s
0 to 5V analog input range with single 5V
power supply
s
Operates ratiometrically or with up to 5V
voltage reference
s
No zero or full-scale adjust required
s
ML2281 capable of digitizing a 5V, 40kHz sine wave
s
Low power: 12.5mW MAX
s
Superior pin compatible replacement for ADC0831,
ADC0832, ADC0834, and ADC0838
s
Analog input protection: 25mA (min) per input
s
Now in 8-Pin SOIC Package (ML2281, ML2282)
(* Indicates Part is Obsolete)
(# Indicates Part is End Of Life as Of July 1, 2000)
BLOCK DIAGRAM
ML2281
CONTROL
AND
TIMING
CS
CLK
ML2288
(8-Channel SE or 4-Channel Diff Multiplexer)
ML2284
(4-Channel SE or 2-Channel Diff Multiplexer)
ML2284
(2-Channel SE or 1-Channel Diff Multiplexer)
DI
INPUT
SHIFT-REGISTER
SARS
OUTPUT
SHIFT-REGISTER
DO
4-BIT
CONTROL
AND
TIMING
CLK
CS
V
IN+
A/D WITH SAMPLE & HOLD FUNCTION
+
SUCCESSIVE
+
APPROXIMATION
COMP
–
–
REGISTER
8pF
Σ
OUTPUT
SHIFT-REGISTER
CH0
CH2
CH3
CH4
CH5
CH6
CH7
MULTIPLEXER
(ML2288 SHOWN)
DO
CH1
V
REF
SE
V
IN–
D/A
CONVERTER
8pF
A/D
CONVERTER
WITH
SAMPLE & HOLD
FUNCTION
DGND
SHUNT
REGULATOR
AGND
V
REF
V
CC
V+
V
CC
GND
COMMON
1
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
