MP8785
CMOS
8-Bit High Speed
Analog-to-Digital Converter
FEATURES
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8-Bit Resolution
20 MHz Sampling Rate
DNL = +1/2 LSB, INL = +1 LSB (typ)
Internal S/H Function
Single Supply: 5 V
V
IN
DC Range: 0 V to V
DD
V
REF
DC Range: 1 V to V
DD
Low Power: 85 mW typ. (excluding reference)
Latch-Up Free
ESD Protection: 2000 V Minimum
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FEATURES (CONT’D)
Monotonic. No Missing Codes
20 Pin Package Available: MP8775
Power Down Available: MP8786
3 V Version: MP87L85
March 1998-3
APPLICATIONS
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Digital Color Copiers
Cellular Telephones
CCD’s and Scanners
Video Capture Boards
GENERAL DESCRIPTION
The MP8785 is an 8-bit Analog-to-Digital Converter.
Designed using an advanced 5 V CMOS process, this part
offers excellent performance, low power consumption and
latch-up free operation.
This device uses a two-step flash architecture to maintain
low power consumption at high conversion rates. The
input circuitry of the MP8785 includes an on-chip S/H
function which allows the user to digitize analog input
signals between AGND and AV
DD
. Careful design and
chip layout have achieved a low analog input capacitance.
This reduces “kickback” and eases the requirements of the
buffer/amplifier used to drive the MP8785.
The designer can choose the internally generated
reference voltages by connecting V
RB
to V
RBS
and V
RT
to
V
RTS
, or provide external reference voltages to the V
RB
and V
RT
pins. The internal reference generates 0.6 V at
V
RB
and 2.6 V at V
RT
. Providing external reference
voltages allows easy interface to any input signal range
between AGND and AV
DD
. This also allows the system to
adjust these voltages to cancel zero scale and full scale
errors, or to change the input range as needed.
The device operates from a single +5 V supply. Power
consumption is 85 mW at FS = 20 MHz.
Specified for operation over the commercial / industrial
(-40 to +85°C)
temperature range, the MP8785 is
available in Plastic dual-in-line (PDIP) and Surface Mount
(SOIC) packages in EIAJ and Jedec.
SIMPLIFIED BLOCK AND TIMING DIAGRAM
AV
DD
V
RTS
V
RT
MSB
Comparators
LSB
Comparators
V
RB
V
RBS
GND
GND
S/H
V
IN
Clock Logic
CLK
GND
OE
GND
CLK
DB7-
DB0
Latch
DB7 (MSB)
F/F
DB0 (LSB)
Sample
N
N-3
N-2
N-1
N
AV
DD
DV
DD
DV
DD
Latch
Encoder
+
Error
Correction
Rev. 3.00
E1998
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538
z
(510) 668-7000
z
(510) 668-7017
EXAR [ EXAR CORPORATION ]
