CAT5271, CAT5273
Dual 256‐position I2C
Compatible Digital
Potentiometers (POTs)
The CAT5271 and CAT5273 are dual 256-position digital
programmable linear taper potentiometers ideally suited for replacing
mechanical potentiometers and variable resistors.
The wiper settings are controlled through an I2C-compatible digital
interface. Upon power-up, the wiper assumes a midscale position and
may be repositioned anytime after the power is stable. The devices can
be programmed to go to a shutdown state during operation.
The CAT5271 and CAT5273 operate from 2.7 V to 5.5 V, while
consuming less than 2 mA. This low operating current, combined with
a small package footprint, makes them ideal for battery-powered
portable applications.
The CAT5271 and CAT5273, designed as pin for pin replacements
for the AD5243 and AD5248, are offered in the 10-lead MSOP
package and operate over the −40C to +85C industrial temperature
range.
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MSOP−10
Z SUFFIX
CASE 846AE
MARKING DIAGRAMS
ANCC
YMR
Features
Dual 256-position
End-to-End Resistance: 50 kW, 100 kW
I2C Compatible Interface*
Power-on Preset to Midscale
Single Supply 2.7 V to 5.5 V
Low Temperature Coefficient 100 ppm/C
Low Power, IDD 2 mA max
Wide Operating Temperature −40C to +85C
MSOP−10 Package (3 mm 4.9 mm)
These Devices are Pb-Free, Halogen Free/BFR Free and are
RoHS Compliant
Typical Applications
ANCC = CAT5721 − 50 kW
ANCE = CAT5721 − 100 kW
PA = CAT5273 − 50 kW*
Y = Production Year (Last Digit)
M = Production Month (1−9, O, N, D)
R = Revision
L = Assembly Location
XX = Last Two Digits of Assembly Lot Number
*Contact factory for availability of CAT5273 − 100 kW
PIN CONNECTIONS
B1
Potentiometer Replacement
Transducer Adjustment of Pressure, Temperature, Position,
Chemical, and Optical Sensors
1
1
1
PAYM
LXX
ANCE
YMR
1
A1
W2
GND
CAT5271
SCL
VDD
RF Amplifier Biasing
Gain Control and Offset Adjustment
B1
AD0
W2
GND
*Two address decode pins (CAT5273 only) allowing
multiple devices on the same bus
W1
B2
A2
SDA
1
CAT5273
W1
B2
AD1
SDA
SCL
VDD
(Top Views)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 12 of this data sheet.
Semiconductor Components Industries, LLC, 2013
July, 2013 − Rev. 3
1
Publication Order Number:
CAT5271/D
CAT5271, CAT5273
SDA
I2C Interface
SCL
A1
Wiper Control
Register 1
VCC
Wiper Control
Register 1
W1
SCL
B1
SDA
A2
Wiper Control
Register 2
I2C Interface
VCC
W2
B2
GND
AD0
Figure 1. CAT5271 Functional Block Diagram
B1
Wiper Control
Register 2
Control Logic
GND
W1
W2
B2
AD1
Figure 2. CAT5273 Functional Block Diagram
Table 1. PIN FUNCTION DESCRIPTION
CAT5271
CAT5273
Pin No.
Pin Name
Description
Pin Name
Description
1
B1
B1 Terminal
B1
2
A1
A1 Terminal
AD0
Device Address Bit 0
3
W2
W2 Terminal
W2
W2 Terminal
4
GND
Digital Ground
GND
Digital Ground
5
VDD
Positive Power Supply
VDD
Positive Power Supply
6
SCL
Serial Clock Input
SCL
Serial Clock Input
7
SDA
Serial Data Input / Output
SDA
Serial Data Input / Output
8
A2
A2 Terminal
AD1
Device Address Bit 1
9
B2
B2 Terminal
B2
B2 Terminal
10
W1
W1 Terminal
W1
W1 Terminal
B1 Terminal
Table 2. ABSOLUTE MAXIMUM RATINGS (Note 1)
Rating
VDD to GND
Value
Unit
−0.3 to 6.5
V
A1, B1, W1, A2, B2, W2 Voltage to GND
VDD
IMAX
20
mA
0 to 6.5
V
−40 to +85
C
150
C
−65 to +150
C
300
C
Digital Inputs and Output Voltage to GND
Operating Temperature Range
Maximum Junction Temperature (TJMAX)
Storage Temperature
Lead Temperature (Soldering, 10 sec)
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Maximum terminal current is bounded by the maximum current handling of the switches, maximum power dissipation of the package, and
maximum applied voltage across any two of the A, B, and W terminals at a given resistance.
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CAT5271, CAT5273
Table 3. ELECTRICAL CHARACTERISTICS: 50 kW and 100 kW Versions
VDD = 2.7 V to 5.5 V; VA = VDD; VB = 0 V; –40C < TA < +85C; unless otherwise noted. (Note 2)
Test Conditions
Symbol
Min
Typ
(Note 3)
Max
Unit
Resistor Differential Nonlinearity (Note 4)
RWB, VA = no connection (CAT5271)
R−DNL
−1
0.1
+1
LSB
Resistor Integral Nonlinearity (Note 4)
0.4
+2
LSB
Parameter
DC CHARACTERISTICS − RHEOSTAT MODE
RWB, VA = no connection (CAT5271)
R−INL
−2
Nominal Resistor Tolerance (Note 5)
TA = 25C
nRAB
−20
Resistance Temperature Coefficient
VAB = VDD, Wiper = no connection
nRAB/nT
VDD = 5 V, IW = 3 mA
RW
Wiper Resistance
+20
100
VDD = 3 V, IW = 3 mA
%
ppm/C
50
120
100
250
W
DC CHARACTERISTICS − POTENTIOMETER DIVIDER MODE
N
Resolution
8
Bits
LSB
Differential Nonlinearity (Note 6)
DNL
−1
0.1
+1
Integral Nonlinearity (Note 6)
INL
−1
0.4
+1
100
LSB
Voltage Divider Temperature Coefficient
Code = 0x80
nVW/nT
ppm/C
Full-scale Error
Code = 0xFF
VWFSE
−3
−1
0
LSB
Zero-scale Error
Code = 0x00
VWZSE
0
1
3
LSB
VA,B,W
GND
VDD
V
RESISTOR TERMINALS
Voltage Range (Note 7)
Capacitance (Note 8) A, B
f = 1 MHz, measured to GND,
Code = 0 x 80
CA,B
45
pF
Capacitance (Note 8) W
f = 1 MHz, measured to GND,
Code = 0 x 80
CW
60
pF
VA = VB = VDD/2
ICM
1
nA
Input Logic High
VDD = 5 V
VIH
Input Logic Low
VDD = 5 V
VIL
Input Logic High
VDD = 3 V
VIH
VDD = 3 V
VIL
0.3VDD
V
VIN = 0 V or 5 V
IIL
1
mA
5.5
V
Common-mode Leakage (Note 8)
DIGITAL INPUTS
Input Logic Low
Input Current
0.7 x VDD
V
0.3VDD
0.7 x VDD
V
V
POWER SUPPLIES
VDD RANGE
Power Supply Range
Supply Current
Power Dissipation (Note 8)
Power Supply Sensitivity
2.7
VIH = 5 V or VIL = 0 V
IDD
2
mA
VIH = 5 V or VIL = 0 V, VDD = 5 V
PDISS
0.3
0.2
mW
nVDD = +5 V 10%, Code = Midscale
PSS
0.05
%/%
DYNAMIC CHARACTERISTICS (Notes 8 and 10)
Bandwidth –3 dB
Total Harmonic Distortion
VW Settling Time (50 kW/100 kW)
RAB = 50 kW / 100 kW, Code = 0x80
BW
100/40
kHz
VA =1 V rms, VB = 0 V,
f = 1 kHz, RAB = 10 kW
THDW
0.05
%
VA = 5 V, VB = 0 V, 1 LSB error band
tS
2
ms
2. VA applies to both A1 and A2, VB applies to both B1 and B2.
3. Typical specifications represent average readings at +25C and VDD = 5 V.
4. Resistor position nonlinearity error R−INL is the deviation from an ideal value measured between the maximum resistance and the
minimum resistance wiper positions. R−DNL measures the relative step change from ideal between successive tap positions. Parts are
guaranteed monotonic.
5. CAT5271: VAB = VDD, Wiper (VW) = no connect. CAT5273: VWB = VDD.
6. INL and DNL are measured at VW with the digital potentiometer configured as a potentiometer divider similar to a voltage output D/A
converter. VA = VDD and VB = 0 V. DNL specification limits of 1 LSB maximum are guaranteed monotonic operating conditions.
7. Resistor terminals A, B, W have no limitations on polarity with respect to each other.
8. Guaranteed by design and not subject to production test.
9. Maximum terminal current is bounded by the maximum current handling of the switches, maximum power dissipation of the package, and
maximum applied voltage across any two of the A, B, and W terminals at a given resistance.
10. All dynamic characteristics use VDD = 5 V.
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CAT5271, CAT5273
Table 4. CAPACITANCE
TA = 25C, f = 1.0 MHz, VDD = 5 V
Symbol
CI/O
(Note 11)
Test
Input/Output Capacitance (SDA, SCL)
Conditions
Max
Units
VI/O = 0 V
8
pF
Max
Units
Table 5. POWER UP TIMING (Notes 11 and 12)
Symbol
Parameter
tPUR
Power-up to Read Operation
1
ms
tPUW
Power-up to Write Operation
1
ms
11. This parameter is tested initially and after a design or process change that affects the parameter.
12. tPUR and t PUW are delays required from the time VCC is stable until the specified operation can be initiated.
Table 6. DIGITAL POTENTIOMETER TIMING
Symbol
tWRPO
tWR
Max
Units
Wiper Response Time After Power Supply Stable
Parameter
Min
50
ms
Wiper Response Time: SCL falling edge after last bit of wiper position data byte to
wiper change
20
ms
Max
Units
400
kHz
Table 7. A.C. CHARACTERISTICS
VDD = +2.7 V to +5.5 V, −40C to +85C unless otherwise specified.
Parameter
Symbol
Min
Typ
fSCL
Clock Frequency
tHIGH
Clock High Period
600
ns
tLOW
Clock Low Period
1300
ns
tSU:STA
Start Condition Setup Time (for a Repeated Start Condition)
600
ns
tHD:STA
Start Condition Hold Time
600
ns
tSU:DAT
Data in Setup Time
100
ns
tHD:DAT
Data in Hold Time
0
ns
tSU:STO
Stop Condition Setup Time
600
ns
Time the bus must be free before a new transmission can start
1300
ns
tBUF
tR
SDA and SCL Rise Time
300
ns
tF
SDA and SCL Fall Time
300
ns
tDH
Data Out Hold Time
100
ns
TI
Noise Suppression Time Constant at SCL, SDA Inputs
50
ns
tAA
SCL Low to SDA Data Out and ACK Out
1
ms
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CAT5271, CAT5273
TYPICAL CHARACTERISTICS
0.03
0.1
0.02
0
DNL
ERROR (LSB)
ERROR (LSB)
0.01
0
−0.01
−0.02
−0.1
INL
−0.2
−0.3
−0.03
−0.4
−0.04
−0.05
0
32
64
96
128
160
192
224
−0.5
256
64
96
128
160
192
224 256
TAP
Figure 3. Potentiometer Divider Differential
Non-linearity, VDD = 5.6 V
Figure 4. Potentiometer Divider Integral
Non-linearity, VDD = 5.6 V
0.16
0.14
0.08
0.12
0.06
ERROR (LSB)
ERROR (LSB)
32
TAP
0.10
0.04
0.02
0
0.10
0.08
0.06
0.04
0.02
0
−0.02
−0.04
0
0
32
64
96
128
160
192
224
−0.02
−0.04
256
0
32
64
96
128
160
192
224 256
TAP
TAP
Figure 5. Rheostat Differential Non-linearity,
VDD = 5.6 V
Figure 6. Rheostat Integral Non-linearity,
VDD = 5.6 V
120
6
100
5
5.6 V
VDD = 2.6 V
60
3.3 V
40
4.0 V
3
3.3 V
2
20
0
5.0 V
4
Vw (V)
Rw (W)
80
5.6 V
4.0 V
0
50
100
VDD = 2.6 V
1
150
200
0
250
0
52
104
156
TAP
TAP
Figure 7. Wiper Resistance at Room
Temperature
Figure 8. Wiper Voltage
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208
260
CAT5271, CAT5273
TYPICAL CHARACTERISTICS
400
350
T = 90C
ISB (nA)
300
T = −45C
250
T = 25C
200
150
100
2
3
4
5
6
VDD (V)
Figure 9. Standby Current
102.15
0.4
102.10
102.05
0.2
D (%)
R (kW)
102.00
101.95
101.90
0
101.85
101.80
−0.2
−50
−20
10
40
70
101.75
−50
100
−20
10
40
70
TEMPERATURE (C)
TEMPERATURE (C)
Figure 10. Change in End-to-End Resistance
Figure 11. End-to-End Resistance vs.
Temperature
0
100
30
−6
25
VDD = 5 V
PSRR (dB)
A (dB)
−12
VDD = 3 V
−18
−24
−30
−36
20
VDD = 5 V
15
VDD = 3 V
10
5
1
10
100
1000
0
1
10
100
f (KHz)
f (KHz)
Figure 12. Gain vs. Bandwidth (Tap 0x80)
Figure 13. PSRR
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1000
CAT5271, CAT5273
BASIC OPERATION
The CAT5271 and CAT5273 are dual 256-position
digitally controlled potentiometers. When power is first
applied, the wipers assume a mid-scale position. Once the
power supply is stable, the wipers may be repositioned via
the I2C compatible interface.
PROGRAMMING: VARIABLE RESISTOR
Rheostat Mode
The equation for determining the digitally programmed
output resistance between W and B is
(The following section refers to CAT5271. The behavior of
CAT5273 is identical, but for this device terminal A of the
resistor is not accessible.)
The resistance between terminals A and B, RAB, has a
nominal value of 50 kW or 100 kW and has 256 contact
points accessed by the wiper terminal, plus the B terminal
contact. Data in the 8-bit Wiper register is decoded to select
one of these 256 possible settings.
The wiper’s first connection is at the B terminal,
corresponding to control position 0x00. Ideally this would
present a 0 W between the Wiper and B, but just as with a
mechanical rheostat there is a small amount of contact
resistance to be considered, there is a wiper resistance
comprised of the RON of the FET switch connecting the
wiper output with its respective contact point. In CAT5271/
CAT5273 this ‘contact’ resistance is typically 50 W. Thus a
connection setting of 0x00 yields a minimum resistance of
50 W between terminals W and B.
For a 100 kW device, the second connection, or the first tap
point, corresponds to 441 W (RWB = RAB/256 + RW = 390.6
+ 50 W) for data 0x01. The third connection is the next tap
point, is 831 W (2 x 390.6 + 50 W) for data 0x02, and so on.
Figure 14 shows a simplified equivalent circuit where the
last resistor string will not be accessed; therefore, there is
1 LSB less of the nominal resistance at full scale in addition
to the wiper resistance.
R WB + D R AB ) R W
256
where D is the decimal equivalent of the binary code loaded
in the 8-bit Wiper register, RAB is the end-to-end resistance,
and RW is the wiper resistance contributed by the on
resistance of the internal switch.
In summary, if RAB = 100 kW and the A terminal is open
circuited, the following output resistance RWB will be set for
the indicated Wiper register codes:
Table 8. CODES AND CORRESPONDING RWB
RESISTANCE FOR RAB = 100 kW, VDD = 5 V
D (Dec.)
RWB (W)
Output State
255
99,559
Full Scale (RAB – 1 LSB + RW)
128
50,050
Midscale
1
441
1 LSB
0
50
Zero Scale
(Wiper Contact Resistance)
Be aware that in the zero-scale position, the wiper
resistance of 50 W is still present. Current flow between W
and B in this condition should be limited to a maximum
pulsed current of no more than 20 mA. Failure to heed this
restriction can cause degradation or possible destruction of
the internal switch contact.
Similar to the mechanical potentiometer, the resistance of
the digital POT between the wiper W and terminal A also
produces a digitally controlled complementary resistance
RWA. When these terminals are used, the B terminal can be
opened. Setting the resistance value for RWA starts at a
maximum value of resistance and decreases as the data
loaded in the latch increases in value. The general equation
for this operation is
A
RS
RS
Wiper
Register
and
Decoder
RS
R WA(D) + 256 * D R AB ) R W
256
W
RS
(eq. 1)
(eq. 2)
For RAB = 100 kW and the B terminal open circuited, the
following output resistance RWA will be set for the indicated
Wiper register codes.
B
Figure 14. CAT5271 Equivalent Digital POT Circuit
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CAT5271, CAT5273
VDD
Table 9. CODES AND CORRESPONDING RWA
RESISTANCE FOR RAB = 100 kW, VDD = 5 V
D (Dec.)
RWA (W)
Output State
255
441
Full Scale
128
50,050
Midscale
1
99,659
1 LSB
0
100,050
Zero Scale
W, A, B
CAT5271
LOGIC
Typical device to device resistance matching is lot
dependent and may vary by up to 20%.
GND
Figure 16.
ESD Protection
Power-up Sequence
Digital
Input
Because ESD protection diodes limit the voltage
compliance at terminals A, B, and W (see Figure 15), it is
recommended that VDD/GND be powered before applying
any voltage to terminals A, B, and W. The ideal power-up
sequence is: GND, VDD, digital inputs, and then VA/B/W. The
order of powering VA, VB, VW, and the digital inputs is not
important as long as they are powered after VDD/GND.
LOGIC
GND
Power Supply Bypassing
Good design practice employs compact, minimum lead
length layout design. Leads should be as direct as possible.
It is also recommended to bypass the power supplies with
quality low ESR Ceramic chip capacitors of 0.01 mF to
0.1 mF. Low ESR 1 mF to 10 mF tantalum or electrolytic
capacitors can also be applied at the supplies to suppress
transient disturbances and low frequency ripple. As a further
precaution digital ground should be joined remotely to the
analog ground at one point to minimize the ground bounce.
W, A, B
Potentiometer
GND
Figure 15. ESD Protection Networks
VDD
Terminal Voltage Operating Range
VDD
C3
10 mF
The CAT5271/CAT5273 VDD and GND power supply
define the limits for proper 3-terminal digital potentiometer
operation. Signals or potentials applied to terminals A, B or
the wiper must remain inside the span of VDD and GND.
Signals which attempt to go outside these boundaries will be
clamped by the internal forward biased diodes.
+
C1
0.1 mF
CAT5271
GND
Figure 17. Power Supply Bypassing
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CAT5271, CAT5273
I2C BUS PROTOCOL
START Condition
The following defines the features of the I2C bus protocol:
1. Data transfer may be initiated only when the bus is
not busy.
2. During a data transfer, the data line must remain
stable whenever the clock line is high. Any
changes in the data line while the clock is high
will be interpreted as a START or STOP condition.
The START condition precedes all commands to the
device, and is defined as a high to low transition of SDA
when SCL is high. The CAT5271/CAT5273 monitors the
SDA and SCL lines and will not respond until this condition
is met.
STOP Condition
A low to high transition of SDA when SCL is high
determines the STOP condition. All operations must end
with a STOP condition.
The device controlling the transfer is a master, typically a
processor or controller, and the device being controlled is the
slave. The master will always initiate data transfers and
provide the clock for both transmit and receive operations.
Therefore, CAT5271/CAT5273 will be considered a slave
device in all applications.
DEVICE ADDRESSING
Acknowledge
The bus Master begins a transmission by sending a
START condition. The Master then sends the address of the
particular slave device it is requesting. The seven most
significant bits of the 8-bit slave address are fixed as
0101111 for the CAT5271. For CAT5273 the first five bits
are fixed as 01011, and the next two bits are
pin-programmable device address bits (AD1 and AD0). The
next bit (R/W) selects between the type of the instruction
Read or Write. If the bit is logic high, then a Read instruction
is performed. If the bit is logic low, then the Write command
is executed.
After the Master sends a START condition and the slave
address byte, the CAT5271/CAT5273 monitors the bus and
responds with an acknowledge (on the SDA line) when its
address matches the transmitted slave address.
After a successful data transfer, each receiving device is
required to generate an acknowledge. The Acknowledging
device pulls down the SDA line during the ninth clock cycle,
signaling that it received the 8 bits of data.
The CAT5271/CAT5273 responds with an acknowledge
after receiving a START condition and its slave address. If
the device has been selected along with a write operation, it
responds with an acknowledge after receiving each 8-bit
byte.
When the CAT5271/CAT5273 is in a READ mode it
transmits 8 bits of data, releases the SDA line, and monitors
the line for an acknowledge. Once it receives this
acknowledge, the CAT5271/CAT5273 will continue to
transmit data. If no acknowledge is sent by the Master, the
device terminates data transmission and waits for a STOP
condition.
WRITE OPERATION
acknowledge from the Slave, the Master device transmits
the data to be written into the wiper register. The CAT5271/
CAT5273 acknowledges once more and the Master
generates the STOP condition.
In the Write mode, the Master device sends the START
condition and the slave address information to the Slave
device. After the Slave generates an acknowledge, the
Master sends the instruction byte. After receiving another
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CAT5271, CAT5273
tF
tHIGH
tLOW
tR
tLOW
SCL
tSU:STA
tHD:STA
tHD:DAT
tSU:DAT
tSU:STO
SDA IN
tAA
tBUF
tDH
SDA OUT
Figure 18. Bus Timing Diagram
SDA
SCL
START CONDITION
STOP CONDITION
Figure 19. Start/Stop Condition
SCL FROM
MASTER
1
8
9
DATA OUTPUT
FROM TRANSMITTER
DATA OUTPUT
FROM RECEIVER
START
ACKNOWLEDGE
Figure 20. Acknowledge Condition
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CAT5271, CAT5273
INSTRUCTION AND REGISTER DESCRIPTION
Slave Address Byte
The remainder of the bits in the instruction byte are don’t
care bits.
The first byte sent to the CAT5271 from the master/processor
is called the Slave Address Byte. The most significant seven
bits of the slave address are a device type identifier. For the
CAT5271, these bits are fixed at 0101111. For CAT5273, the
first five bits are fixed as 01011, and the next two bits of the
device identifier are determined by the logic levels on the
AD1 and AD0 pins. The following bit (R/W) selects
between a Read or a Write operation. If the bit is logic high,
then a Read instruction is performed. If the bit is low, then
the Write command is executed.
Read Operation
In the read mode, the data byte follows immediately after
the acknowledgment of the slave address byte. Data is
transmitted over the serial bus in sequences.
There is no potentiometer channel selection bit in the
Read command. The addressed channel is the one that is
previously selected in the write mode. If it desired to read the
potentiometer wiper register values of both channels, the
first potentiometer must be addressed in write mode and
then change to read mode to read the first channel value.
After that, the user must return the device to write mode with
the second potentiometer selected and read the second
potentiometer wiper register value in read mode. It is not
necessary for users to issue the third data byte in write mode
for subsequent read operation.
Instruction Byte
Write and Read instructions are respectively three and two
bytes in length. The basic sequence of the two instructions
is illustrated in Table 10 and 11.
Write Operation
In the write instruction, the second byte first bit (A0)
selects between the potentiometer 1 and 2: a logic low is for
the potentiometer 1, and a logic high is for potentiometer 2.
The following bit (SD) is the shutdown bit. A logic high
causes an open circuit at terminal A while shorting the wiper
terminal W to terminal B. The “shutdown” operation does
not change the contents of the wiper register. When the
shutdown bit, SD, goes back to a logic low, the previous
wiper position is restored. Also during shutdown, new
settings can be programmed. As soon as the device is
returned from shutdown, the wiper position is set according
to the wiper register value.
Wiper Control
The CAT5271/CAT5273 contains two 8-bit Wiper
Control Register (WCR). The Wiper Control Register
output is decoded to select one of 256 switches along its
resistor array. The contents of the WCR may be written by
the host via Write instruction.
The Wiper Control Registers are a volatile register that
loses its contents when the CAT5271/CAT5273 is
powered-down. Upon power-up, the wiper is set to midscale
and may be repositioned anytime after the power has
become stable.
Table 10. CAT5271 Write
S
0
1
0
1
1
1
1
W
A
A0
SD
Slave Address Byte
X
X
X
X
X
X
A
D7
D6
D5
Instruction Byte
D4
D3
D2
D1
D0
D2
D1
D0
A
P
Data Byte
SDA
0
S
T
A
R
T
1 0
1 1
1
1
SD
A0
R/W
X X
X
X
D7
X X
A
C
K
D6
D5
D4
D3
A S
C T
K O
P
A
C
K
Instruction Byte
Slave Address Byte
Data Byte
Table 11. CAT5271 READ
S
0
1
0
1
1
1
1
R
A
D7
D6
D5
D4
Slave Address Byte
SDA
S
T
A
R
T
0
1
0
1
1
D3
D2
D1
D0
D2
D1
D0
A
P
N
A
C
K
S
T
O
P
Data Byte
1 1 R/W
D7
D6
D5
D4
D3
A
C
K
Data Byte
Slave Address Byte
Legend
S=
P=
A=
D=
R=
W=
Start
Stop
Acknowledge
Data bit
Read (bit is 1 for Read instruction)
Write (bit is 0 for Write instruction)
A0 =
SD =
X=
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Potentiometer Channel (1 or 2) Select Bit
Shut Down:
0: normal operation
1: wiper is parked at B terminal and
terminal A is open circuit.
Don’t Care
CAT5271, CAT5273
Table 12. CAT5273 Write
S
0
1
0
1
1 AD1 AD0
W
A
A0
Slave Address Byte
SD
X
X
X
X
X
X
A
D7
D6
D5
Instruction Byte
D4
D3
D2
D1
D0
D2
D1
D0
A
P
Data Byte
SDA
0
1
0
S
T
A
R
T
1 1 AD1 AD0 R/W
A0
SD
X
X X
X
D7
X X
A
C
K
D6
D5
D4
D3
A S
C T
K O
P
A
C
K
Instruction Byte
Slave Address Byte
Data Byte
Table 13. CAT5273 READ
S
0
1
0
1
1 AD1 AD0
R
A
D7
D6
D5
Slave Address Byte
SDA
0
S
T
A
R
T
1
0
D4
D3
D2
D1
D0
D2
D1
D0
A
P
N
A
C
K
S
T
O
P
Data Byte
1 1 AD1 AD0 R/W
D7
D6
D5
D4
D3
A
C
K
Data Byte
Slave Address Byte
Legend
S=
P=
A=
D=
R=
W=
A0 =
Start
Stop
Acknowledge
Data bit
Read (bit is 1 for Read instruction)
Write (bit is 0 for Write instruction)
Potentiometer Channel (1 or 2) Select Bit
SD =
X=
AD1, AD0 =
Shut Down:
0: normal operation
1: wiper is parked at B terminal
and terminal A is open circuit.
Don’t Care
Bits that must match the logic levels
on pins AD1 and AD0
Table 14. ORDERING PART NUMBER
Part Number
Resistance
CAT5271ZI−50−GT3
50 kW
CAT5271ZI−00−GT3
100 kW
CAT5273ZI−50−GT3
50 kW
Package
Lead Finish
MSOP−10
NiPdAu
MSOP−10
NiPdAu
Shipping†
3000 / Tape & Reel
3000 / Tape & Reel
3000 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
13. For detailed information and a breakdown of device nomenclature and numbering systems, please see the ON Semiconductor Device
Nomenclature document, TND310/D, available at www.onsemi.com.
14. All packages are RoHS-compliant (Lead-free, Halogen-free).
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, and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates
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A listing of onsemi’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. onsemi reserves the right to make changes at any time to any
products or information herein, without notice. The information herein is provided “as−is” and onsemi makes no warranty, representation or guarantee regarding the accuracy of the
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