Advanced Information
CAT522
8-Bit Dual Digital POT With Independent Reference Inputs
FEATURES
s
Buffered Outputs
s
Output settings retained without power
s
Independent Reference Inputs
s
Output range includes both supply rails
s
Programming voltage generated on-chip
s
2 independently addressable outputs
s
Serial
µ
P 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 CAT522 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 CAT522 offers 2 independently programmable DACs
each having its own reference inputs and each capable
of rail to rail output swing. Outputs are buffered by rail
to rail OP AMPS 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. Each output can be dithered to test
new output values without effecting the stored settings
FUNCTIONAL DIAGRAM
V
DD
and stored settings can be read back without disturbing
the DAC’s output.
Control of the CAT522 is accomplished with a simple 3
wire serial interface. A Chip Select pin allows several
CAT522'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 CAT522’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 CAT522 operates from a single 3–5 volt power
supply. The high voltage required for EEPROM Erase/
Write operations is generated on-chip.
The CAT522 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
1
DIP Package (P)
6
DO
SOIC Package (J)
RDY/BSY
3
SERIAL DATA OUTPUT
PROG
7
PROGRAM
CONTROL
14
EEPROM
LATCH
DAC 1
V
REF
H1
VDD
CLK
RDY/BSY
CS
DI
13
V
H2
REF
V
2
OUT
VREF L2
1
2
3
4
14
13
12
VREF H1
VREF H2
VOUT1
V
2
OUT
VREF L2
VREF L1
GND
VDD
CLK
RDY/BSY
CS
DI
DO
PROG
1
2
3
4
14
13
12
VREF H1
VREF H2
VOUT1
V
OUT2
VREF L2
VREF L1
GND
+
–
12
9
1
V
OUT
V REF L1
CLK
2
DATA
CONTROLLER
CS
4
11
CAT522
5
10
6
7
9
8
11
CAT522
5
10
6
7
9
8
DI
5
EEPROM
LATCH
DAC 2
DO
PROG
+
–
11
10
H.V.
CHARGE
PUMP
CAT522
8
GND
© 2000 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
CAT522
ABSOLUTE MAXIMUM RATINGS
Supply Voltage*
V
DD
to GND ...................................... –0.5V to +7V
Inputs
CLK to GND ............................ –0.5V to V
DD
+0.5V
CS to GND .............................. –0.5V to V
DD
+0.5V
DI to GND ............................... –0.5V to V
DD
+0.5V
RDY/BSY to GND ................... –0.5V to V
DD
+0.5V
PROG to GND ........................ –0.5V to V
DD
+0.5V
V
REF
H to GND ........................ –0.5V to V
DD
+0.5V
V
REF
L to GND ......................... –0.5V to V
DD
+0.5V
Outputs
D
0
to GND ............................... –0.5V to V
DD
+0.5V
V
OUT
1– 2 to GND ................... –0.5V to V
DD
+0.5V
RELIABILITY CHARACTERISTICS
Symbol
V
ZAP(1)
I
LTH(1)(2)
Advanced Information
Operating Ambient Temperature
Commercial (‘C’ suffix) .................... 0°C to +70°C
Industrial (‘I’ suffix) ...................... – 40°C to +85°C
Junction Temperature ..................................... +150°C
Storage Temperature ....................... –65°C to +150°C
Lead Soldering (10 sec max) .......................... +300°C
* Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Absolute
Maximum Ratings are limited values applied individually while
other parameters are within specified operating conditions,
and functional operation at any of these conditions is NOT
implied. Device performance and reliability may be impaired by
exposure to absolute rating conditions for extended periods of
time.
Parameter
ESD Susceptibility
Latch-Up
Min
2000
100
Max
Units
Volts
mA
Test Method
MIL-STD-883, Test Method 3015
JEDEC Standard 17
NOTES:
1. This parameter is tested initially and after a design or process change that affects the parameter.
2. Latch-up protection is provided for stresses up to 100mA on address and data pins from –1V to V
CC
+ 1V.
DC ELECTRICAL CHARACTERISTICS:
V
DD
= +2.7V to +5.5V, V
REF
H = V
DD
, V
REF
L = 0V, unless otherwise specified
Symbol
Accuracy
INL
Integral Linearity Error
I
LOAD
= 10
µA,
I
LOAD
= 40
µA,
DNL
Differential Linearity Error
I
LOAD
= 10
µA,
I
LOAD
= 40
µA,
T
R
= C
T
R
= I
T
R
= C
T
R
= I
T
R
= C
T
R
= I
T
R
= C
T
R
= I
—
—
—
—
—
—
—
—
—
—
2
0
2.7
GND
—
—
I
OH
= – 40
µA
I
OL
= 1 mA, V
DD
= +5V
I
OL
= 0.4 mA, V
DD
= +3V
V
DD
–0.3
—
—
0.6
0.6
1.2
1.2
0.25
0.25
0.5
0.5
—
—
—
—
—
—
28K
±
0.5
—
—
—
±
1
±
1
—
—
±
0.5
±
0.5
—
—
10
–10
V
DD
0.8
V
DD
V
DD
-2.7
—
±
1
—
0.4
0.4
LSB
LSB
LSB
LSB
LSB
LSB
LSB
LSB
µA
µA
V
V
V
V
Ω
%
V
V
V
Parameter
Resolution
Conditions
Min
8
Typ
—
Max
—
Units
Bits
Logic Inputs
I
IH
I
IL
V
IH
V
IL
Input Leakage Current
Input Leakage Current
High Level Input Voltage
Low Level Input Voltage
V
REF
H Input Voltage Range
V
REF
L Input Voltage Range
V
REF
H–V
REF
L Resistance
Input Resistance Match
High Level Output Voltage
Low Level Output Voltage
V
IN
= V
DD
V
IN
= 0V
References
V
RH
V
RL
Z
IN
∆V
IN
/ R
IN
V
OH
V
OL
Logic Outputs
8/00
2
Advanced Information
DC ELECTRICAL CHARACTERISTICS
(Cont.):
V
DD
= +2.7V to +5.5V, V
REF
H = V
DD
, V
REF
L = 0V
, unless otherwise specified
Symbol
FSO
ZSO
I
L
R
OUT
PSSR
TC
O
TC
REF
CAT522
Parameter
Full-Scale Output Voltage
Zero-Scale Output Voltage
DAC Output Load Current
DAC Output Impedance
Power Supply Rejection
V
OUT
Temperature Coefficient
Temperature Coefficient of
V
REF
Resistance
Supply Current (Read)
Supply Current (Write)
Operating Voltage Range
Conditions
V
R
= V
REF
H – V
REF
L
V
R
= V
REF
H – V
REF
L
V
DD
= V
REF
H = +5V
V
DD
= V
REF
H = +3V
I
LOAD
= 1
µA
V
DD
= +5V, I
LOAD
= 250nA
V
REF
H= +5V, V
REF
L = 0V
V
REF
H to V
REF
L
Min
0.99 V
R
—
—
—
—
—
—
—
Typ
0.995 V
R
0.005 V
R
—
—
—
—
—
700
Max
—
0.01 V
R
1
1K
1K
1
200
—
Units
V
V
µA
Ω
Ω
LSB / V
µV/ °C
ppm /
°C
Analog Output
Temperature
Power Supply
I
DD1
I
DD2
V
DD
Normal Operating
Programming, V
DD
= 5V
V
DD
= 3V
—
—
—
2.7
0.4
1.6
1.0
—
0.6
2.5
1.6
5.5
mA
mA
mA
V
AC ELECTRICAL CHARACTERISTICS:
V
DD
= +2.7V to +5.5V, V
REF
H = V
DD
, V
REF
L = 0V
, unless otherwise specified
Symbol
Digital
t
CSMIN
t
CSS
t
CSH
t
DIS
t
DIH
t
DO1
t
DO0
t
HZ
t
LZ
t
BUSY
t
PS
t
PROG
t
CLK
H
t
CLK
L
f
C
Minimum CS Low Time
CS Setup Time
CS Hold Time
DI Setup Time
DI Hold Time
Output Delay to 1
Output Delay to 0
Output Delay to High-Z
Output Delay to Low-Z
Erase/Write Cycle Time
PROG Setup Time
Minimum Pulse Width
Minimum CLK High Time
Minimum CLK Low Time
Clock Frequency
DAC Settling Time to 1 LSB
150
100
0
50
50
—
—
—
—
—
150
700
500
300
DC
—
—
—
—
—
—
—
—
—
—
—
400
400
4
—
—
—
—
—
3
6
8
6
—
—
—
—
—
150
150
—
—
5
—
—
—
—
1
10
10
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ms
ns
ns
ns
ns
MHz
µs
µs
pF
pF
Parameter
Conditions
Min
Typ
Max
Units
C
L
= 100 pF,
see note 1
Analog
t
DS
C
LOAD
= 10 pF, V
DD
= +5V
C
LOAD
= 10 pF, V
DD
= +3V
V
IN
= 0V, f = 1 MHz
(2)
V
OUT
= 0V, f = 1 MHz
(2)
Pin Capacitance
C
IN
C
OUT
Input Capacitance
Output Capacitance
NOTES:
1. All timing measurements are defined at the point of signal crossing V
DD
/ 2.
2. These parameters are periodically sampled and are not 100% tested.
3
8/00
CAT522
A. C. TIMING DIAGRAM
Advanced Information
to
1
2
3
4
5
t CLK H
CLK
t CSS
CS
t CLK L
t CSH
t CSMIN
t DIS
DI
t DIH
t LZ
DO
t DO0
t HZ
t DO1
PROG
t PS
t PROG
RDY/BSY
t BUSY
to
1
2
3
4
5
8/00
4
Advanced Information
PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
CAT522
DAC addressing is as follows:
Name
V
DD
CLK
RDY/BSY
CS
DI
DO
PROG
GND
V
REF
L1
V
REF
L2
V
OUT
2
V
OUT
1
V
REF
H2
V
REF
H1
Function
Power supply positive
Clock input pin
Ready/Busy output
Chip select
Serial data input pin
Serial data output pin
EEPROM Programming Enable
Input
Power supply ground
Minimum DAC 1 output voltage
Minimum DAC 2 output voltage
DAC 2 output
DAC 1 output
Maximum DAC 2 output voltage
Maximum DAC 1 output voltage
DAC OUTPUT
V
OUT
1
V
OUT
2
A0
0
1
A1
1
1
DEVICE OPERATION
The CAT522 is a dual 8-bit Digital to Analog Converter
(DAC) whose outputs can be programmed to any one of
256 individual voltage steps. Once programmed, these
output settings are retained in non-volatile EEPROM
memory and will not be lost when power is removed from
the chip. Upon power up the DACs return to the settings
stored in EEPROM memory. Each DAC can be written
to and read from independently without effecting the
output voltage during the read or write cycle. Each
output can also be adjusted without altering the stored
output setting, which is useful for testing new output
settings before storing them in memory.
DIGITAL INTERFACE
The CAT522 employs a standard 3 wire serial control
interface consisting of Clock (CLK), Chip Select (CS)
and Data In (DI) inputs. For all operations, address and
data are shifted in LSB first. In addition, all digital data
must be preceded by a logic “1” as a start bit. The DAC
address and data are clocked into the DI pin on the
clock’s rising edge. When sending multiple blocks of
information a minimum of two clock cycles is required
between the last block sent and the next start bit.
Multiple devices may share a common input data line by
selectively activating the CS control of the desired IC.
Data Outputs (DO) can also share a common line
because the DO pin is Tri-Stated and returns to a high
impedance when not in use.
5
CHIP SELECT
Chip Select (CS) enables and disables the CAT522’s
read and write operations. When CS is high data may be
read to or from the chip, and the Data Output (DO) pin is
active. Data loaded into the DAC control registers will
remain in effect until CS goes low. Bringing CS to a logic
low returns all DAC outputs to the settings stored in
EEPROM memory and switches DO to its high imped-
ance Tri-State mode.
Because CS functions like a reset the CS pin has been
desensitized with a 30 ns to 90 ns filter circuit to prevent
noise spikes from causing unwanted resets and the loss
of volatile data.
CLOCK
The CAT522’s clock controls both data flow in and out of
the IC and EEPROM memory cell programming. Serial
data is shifted into the DI pin and out of the DO pin on the
clock’s rising edge. While it is not necessary for the clock
to be running between data transfers, the clock must be
operating in order to write to EEPROM memory, even
though the data being saved may already be resident in
the DAC control register.
No clock is necessary upon system power-up. The
CAT522’s internal power-on reset circuitry loads data
from EEPROM to the DACs without using the external
clock.
8/00
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
