AD7884 Datasheet, PDF (1/16 Pages) Analog Devices – LC2MOS 16-Bit, High Speed Sampling ADCs

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LC²MOS
16-Bit, High Speed Sampling ADCs
AD7884/AD7885
FEATURES
Monolithic Construction
Fast Conversion: 5.3 ␮s
High Throughput: 166 kSPS
Low Power: 250 mW
APPLICATIONS
Automatic Test Equipment
Medical Instrumentation
Industrial Control
Data Acquisition Systems
Robotics
GENERAL DESCRIPTION
The AD7884/AD7885 is a 16-bit monolithic analog-to-digital
converter with internal sample-and-hold and a conversion time
of 5.3 µs. The maximum throughput rate is 166 kSPS. It uses a
two pass flash architecture to achieve this speed. Two input
ranges are available: ± 5 V and ± 3 V. Conversion is initiated by
the CONVST signal. The result can be read into a microproces-
sor using the CS and RD inputs on the device. The AD7884 has
a 16-bit parallel reading structure while the AD7885 has a byte
reading structure. The conversion result is in 2s complement
code.
The AD7884/AD7885 has its own internal oscillator which con-
trols conversion. It runs from ± 5 V supplies and needs a V_REF+
of +3 V.
The AD7884 is available in a 40-pin plastic DIP package and in
a 44-pin PLCC package.
The AD7885 is available in a 28-pin plastic DIP package and
the AD7885A is available in a 44-pin PLCC package.
FUNCTIONAL BLOCK DIAGRAMS
±3V_IN F ±3V_IN S
AGNDS AGNDF AVDD AVSS VDD VSS
±5VIN S
±5V_IN F
R2
3kΩ
R1
5kΩ
R3 3kΩ
C1
SW1
A1
R4 4kΩ
R6
R5
2kΩ
4kΩ
SW2
9-BIT
ADC
V REF–
A2
SW3
16-BIT ₉
ACCURATE
DAC
TIMER
R7
2kΩ
AD7884
OD
9
LATCH
UR
TI
+
ALU
16
PV
UE
16
9
TR
S
DB15
DB0
CS
CONTROL
RD
R8
2kΩ
VREF+ F VREF+ S V INV VREF– GND _{CONVST BUSY}
DGND
±3VIN
AGNDS AGNDF AV_DD AVSS VDD VSS
±5V_IN S
±5V_IN F
R2
3kΩ
R1
5kΩ
R3 3kΩ
C1
SW1
A1
R4 4kΩ
R6
R5
2kΩ
4kΩ
SW2
9-BIT
ADC
VREF–
A2
SW3
16-BIT ₉
ACCURATE
DAC
TIMER
R7
2kΩ
AD7885
9
LATCH
+ 16
ALU
9
OD
UR
TI
PV
UE
8
TR
S
DB7
DB0
CONTROL
CS
RD
HBEN
R8
2kΩ
V_REF+ F V_REF+ S VINV VREF– GND _{CONVST BUSY} DGND
REV. C
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
© Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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