CAT525
Configured Digitally Programmable Potentiometer (DPP™): Programmable Voltage Applications
FEATURES
s
Four 8-bit DPPs configured as programmable
APPLICATIONS
s
Automated product calibration
s
Remote control adjustment of equipment
s
Offset, gain and zero adjustments in
voltage sources in DAC-like applications
s
Independent reference inputs
s
Buffered wiper outputs
s
Non-volatile NVRAM memory wiper storage
s
Output voltage range includes both supply rails
s
4 independently addressable buffered
self-calibrating and adaptive control systems
s
Tamper-proof calibrations
s
DAC (with memory) substitute
output wipers
s
1 LSB accuracy, high resolution
s
Serial
µ
P interface
s
Single supply operation: 2.7V-5.5V
s
Setting read-back without effecting outputs
DESCRIPTION
The CAT525 is a quad 8-Bit digitally programmable
potentiometer (DPP™) configured for programmable
voltage and DAC-like applications. Intended for final
calibration of products such as camcorders, fax ma-
chines and cellular telephones on automated high vol-
ume production lines and systems capable of self cali-
bration, it is also well suited for applications were equip-
ment requiring periodic adjustment is either difficult to
access or located in a hazardous environment.
The CAT525 offers four independently programmable
DPPs each having its own reference inputs and each
capable of rail to rail output swing. The wipers are
buffered by rail to rail op amps. Wiper settings, stored in
non-volatile NVRAM memory, are not lost when the
device is powered down and are automatically rein-
FUNCTIONAL DIAGRAM
V
H1
REF
V
H3
REF
V
H4
REF
19
V
H2
REF
2
1
20
stated when power is returned. Each wiper can be
dithered to test new output values without effecting the
stored settings and stored settings can be read back
without disturbing the DPP’s output.
Control of the CAT525 is accomplished with a simple 3
wire serial interface. A Chip Select pin allows several
CAT525's to share a common serial interface and
communications back to the host controller is via a single
serial data line thanks to the CAT525’s Tri-Stated Data
Output pin. A RDY/BSY output working in concert with
an internal low voltage detector signals proper operation
of non-volatile NVRAM Memory Erase/Write cycle.
The CAT525 is available in the 0°C to 70°C commercial
and –40°C to 85°C industrial operating temperature
ranges and offered in 20-pin plastic DIP and Surface
mount packages.
PIN CONFIGURATION
DIP Package (P)
SOIC Package (J)
VREF H2
VREF H1
DVD
CLK
RDY/BSY
CS
DI
DO
PROG
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
VREF H3
VREF H4
VOUT1
VOUT2
VOUT3
VOUT4
VREF L4
VREF L3
VREF L2
VREF L1
RDY/BSY
5
+
PROG
9
PROGRAM
CONTROL
–
18
VOUT1
VREF H2
VREF H1
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
VREF H3
VREF H4
VOUT1
VOUT2
VOUT3
VOUT4
VREF L4
VREF L3
VREF L2
VREF L1
+
–
17
VOUT2
DVD
CLK
CLK
4
DATA
CONTROLLER
NVRAM
+
–
16
V
3
OUT
CS
6
RDY/BSY
7
+
–
7K
(ea)
15
VOUT4
CS
DI
DO
CAT525
14
13
12
11
CAT525
14
13
12
11
H.V.
CHARGE
PUMP
SERIAL
DATA
OUTPUT
REGISTER
8
DO
PROG
11
12
13
14
VREFL4
CAT525
GND
VREFL2
V
L1
REF
VREFL3
© 2001 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. 25078-00 4/01-A M-1
CAT525
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– 4 to GND ................... –0.5V to V
DD
+0.5V
RELIABILITY CHARACTERISTICS
Symbol
V
ZAP(1)
I
LTH(1)(2)
Operating Ambient Temperature
Commercial (‘C’ or Blank 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
= 10
µA
I
LOAD
= 40
µA
I
LOAD
= 40
µA
I
LOAD
= 10
µA
I
LOAD
= 10
µA
I
LOAD
= 40
µA
I
LOAD
= 40
µA
V
IN
= V
DD
V
IN
= 0V
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
—
—
—
—
—
—
28
±
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
kΩ
%
V
V
V
Parameter
Resolution
Conditions
Min
8
Typ
—
Max
—
Units
Bits
DNL
Differential Linearity Error
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
References
V
RH
V
RL
Z
IN
∆V
IN
/ R
IN
V
OH
V
OL
Logic Outputs
Doc. No. 25078-00 4/01 - A M-1
2
CAT525
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
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
1
1
1
200
—
Units
V
V
µA
kΩ
kΩ
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
400
1600
1000
—
600
2500
1600
5.5
µA
µA
µA
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
Doc. No. 25078-00 4/01 - A M-1
TIMING
MIN/MAX
FROM
TO
CAT525
to
2
3
4
5
1
PARAM
NAME
A. C. TIMING DIAGRAM
Doc. No. 25078-00 4/01 - A M-1
t CLK H
t CLK H
Rising CLK edge to falling CLK edge
Min
CLK
t CLK L
Falling CLK edge to CLK rising edge
t CSH
t CLK L
t CSS
t CSH
Falling CLK edge for last data bit (DI)
to falling CS edge
Rising CS edge to next rising CLK edge
Min
Min
t CSS
Min
CS
t CSMIN
t CSMIN
Falling CS edge to rising CS edge
t DIS
Data valid to first rising CLK
edge after CS = high
Min
Min
t DIS
DI
t DIH
t DO0
t LZ
t DO0
Rising CLK edge to end of data valid
Min
4
t HZ
t DO1
t HZ
t PS
t PS
t PROG
t BUSY
2
3
4
5
t DIH
Rising CLK edge to D0 = low
Rising CS edge to D0 becoming high
low impedance (active output)
Max
(Max)
t LZ
DO
Rising CLK edge to D0 = high
Falling CS edge to D0 becoming high
impedance (Tri-State)
Max
(Max)
t DO1
PROG
Rising PROG edge to next rising
CLK edge
t PROG
Rising PROG edge to falling
PROG edge
t BUSY
Falling CLK edge after PROG=H to
rising RDY/BSY edge
Min
Min
RDY/BSY
Max
to
1
CAT525
PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
DAC addressing is as follows:
Function
Maximum DAC 2 output voltage
Maximum DAC 1 output voltage
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
Minimum DAC 3 output voltage
Minimum DAC 4 output voltage
DAC 4 output
DAC 3 output
DAC 2 output
DAC 1 output
Maximum DAC 4 output voltage
Maximum DAC 3 output voltage
Name
V
REF
H2
V
REF
H1
V
DD
CLK
RDY/BSY
CS
DI
DO
PROG
GND
V
REF
L1
V
REF
L2
V
REF
L3
V
REF
L4
V
OUT
4
V
OUT
3
V
OUT
2
V
OUT
1
V
REF
H4
V
REF
H3
DAC OUTPUT
V
OUT
1
V
OUT
2
V
OUT
3
V
OUT
4
A0
0
1
0
1
A1
0
0
1
1
DEVICE OPERATION
The CAT525 is a quad 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 CAT525 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 CAT525’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 CAT525’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
CAT525’s internal power-on reset circuitry loads data
from EEPROM to the DACs without using the external
clock.
Doc. No. 25078-00 4/01 - A M-1
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