CAT521 Datasheet, PDF (1/9 Pages) Catalyst Semiconductor – 8-Bit Digital POT With Independent Reference Inputs

Advanced Information
CAT521
8-Bit Digital POT With Independent Reference Inputs
FEATURES
s Buffered Outputs
s Output settings retained without power
s Output range includes both supply rails
s Programming voltage generated on-chip
s Serial µP interface
s Single supply operation: 2.7V-5.5V
APPLICATIONS
s Automated product calibration.
s Remote control adjustment of equipment
s Offset, gain and zero adjustments in Self-
Calibrating and Adaptive Control systems.
s Tamper-proof calibrations.
DESCRIPTION
The CAT521 is a dual 8-Bit Memory DAC designed as an
electronic replacement for mechanical potentiometers
and trim pots. Intended for final calibration of products
such as camcorders, fax machines and cellular tele-
phones on automated high volume production lines and
systems capable of self calibration, it is also well suited
for applications were equipment requiring periodic ad-
justment is either difficult to access or located in a
hazardous environment.
The CAT521 consists of a programmable DAC with
independent high and low reference inputs and is ca-
pable of a rail to rail output swing. The output is buffered
by a rail to rail OP AMP. Output settings, stored in non-
volatile EEPROM memory, are not lost when the device
is powered down and are automatically reinstated when
power is returned. The output can be dithered to test
new output values without effecting the stored settings
FUNCTIONAL DIAGRAM
VDD
1
RDY/BSY
3
SERIAL DATA OUTPUT
6
DO
7
PROG
PROGRAM
CONTROL
CLK
2
4
CS
DI
5
DATA
CONTROLLER
EEPROM
LATCH
DAC 1
14
VREF H1
+
–
12
VOUT 1
9
VREF L1
and stored settings can be read back without disturbing
the DAC’s output.
Control of the CAT521 is accomplished with a simple 3
wire serial interface. A Chip Select pin allows several
CAT521's to share a common serial interface and com-
munications back to the host controller is via a single
serial data line thanks to the CAT521’s Tri-Stated Data
Output pin. A RDY/BSY output working in concert with
an internal low voltage detector signals proper operation
of EEPROM Erase/Write cycle.
The CAT521 operates from a single 3–5 volt power
supply. The high voltage required for EEPROM Erase/
Write operations is generated on-chip.
The CAT521 is available in the 0°C to 70°C Commercial
and –40°C to +85°C Industrial operating temperature
ranges and offered in 14-pin plastic DIP and Surface
mount packages.
PIN CONFIGURATION
DIP Package (P)
SOIC Package (J)
VDD
CLK
RDY/BSY
CS
DI
DO
PROG
1
14
2
13
3
12
CAT521
4
11
5
10
6
9
7
8
VREF ^H1
NC
VOUT1
NC
NC
VREF ^L1
GND
VDD
CLK
RDY/BSY
CS
DI
DO
PROG
1
14
2
13
3
12
CAT521
4
11
5
10
6
9
7
8
VREF ^H1
NC
VOUT1
NC
NC
VREF ^L1
GND
H.V.
CHARGE
PUMP
CAT521
8
GND
© 2001 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1