X9268
®
Dual Supply/Low Power/256-Tap/2-Wire Bus
Data Sheet
June 21, 2005
Dual Digitally-Controlled (XDCP™)
Potentiometers
FN8172.1
DESCRIPTION
The X9268 integrates 2 digitally controlled
potentiometer (XDCP) on a monolithic CMOS
integrated circuit.
FEATURES
• Dual–Two separate potentiometers
• 256 resistor taps/pot–0.4% resolution
• 2-Wire Serial Interface for write, read, and
transfer operations of the potentiometer
• Wiper Resistance, 100Ω typical @ V+ = 5V,
V- = -5V
• 16 Nonvolatile Data Registers for Each
Potentiometer
• Nonvolatile Storage of Multiple Wiper Positions
• Power-on Recall. Loads Saved Wiper Position
on Power-up.
• Standby Current < 5µA Max
• VCC: ±2.7V to ±5.5V Operation
• 50kΩ, 100kΩ versions of End to End Pot
Resistance
• Endurance: 100,000 Data Changes per Bit per
Register
• 100 yr. Data Retention
• 24-Lead SOIC, 24-Lead TSSOP
• Low Power CMOS
• Power Supply VCC = ±2.7V to ±5.5V
V+ = 2.7V to 5.5V
V- = -2.7V to -5.5V
The digital controlled potentiometer is implemented
using 255 resistive elements in a series array.
Between each element are tap points connected to the
wiper terminal through switches. The position of the
wiper on the array is controlled by the user through the
2-Wire bus interface. Each potentiometer has
associated with it a volatile Wiper Counter Register
(WCR) and a four nonvolatile Data Registers that can
be directly written to and read by the user. The
contents of the WCR controls the position of the wiper
on the resistor array though the switches. Powerup
recalls the contents of the default Data Register (DR0)
to the WCR.
The XDCP can be used as a three-terminal
potentiometer or as a two terminal variable resistor in
a wide variety of applications including control,
parameter adjustments, and signal processing.
FUNCTIONAL DIAGRAM
VCC
2-Wire
Bus
Interface
Address
Data
Status
Write
Read
Transfer
Inc/Dec
Bus
Interface
and Control
Power-on Recall
Wiper Counter
Registers (WCR)
Control
VSS
RH1
RH0
V+
Data Registers
(DR0–DR3)
V-
RW0
RL0
RW1
RL1
50kΩ or 100kΩ versions
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
XDCP is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
X9268
DETAILED FUNCTIONAL DIAGRAM
RH0 RL0 RW0
VCC
V+
Power-on
Recall
R0 R1
R2 R3
SCL
INTERFACE
AND
CONTROL
CIRCUITRY
SDA
A3
A2
Wiper
Counter
Register
(WCR)
50kΩ and 100kΩ
256-taps
8
A1
A0
Pot 0
Data
WP
Power-on
Recall
R0 R1
R2 R3
VSS
V-
Wiper
Counter
Register
(WCR)
Resistor
Array
Pot 1
RL1 RH1 RW1
CIRCUIT LEVEL APPLICATIONS
SYSTEM LEVEL APPLICATIONS
• Vary the gain of a voltage amplifier
• Adjust the contrast in LCD displays
• Provide programmable dc reference voltages for
comparators and detectors
• Control the power level of LED transmitters in
communication systems
• Control the volume in audio circuits
• Set and regulate the DC biasing point in an RF
power amplifier in wireless systems
• Trim out the offset voltage error in a voltage amplifier circuit
• Set the output voltage of a voltage regulator
• Trim the resistance in Wheatstone bridge circuits
• Control the gain, characteristic frequency and
Q-factor in filter circuits
• Set the scale factor and zero point in sensor signal
conditioning circuits
• Vary the frequency and duty cycle of timer ICs
• Vary the dc biasing of a pin diode attenuator in RF
circuits
• Control the gain in audio and home entertainment
systems
• Provide the variable DC bias for tuners in RF wireless systems
• Set the operating points in temperature control
systems
• Control the operating point for sensors in industrial
systems
• Trim offset and gain errors in artificial intelligent
systems
• Provide a control variable (I, V, or R) in feedback
circuits
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FN8172.1
June 21, 2005
X9268
PIN CONFIGURATION
SOIC, TSSOP
NC
1
24
A3
A0
NC
2
23
SCL
3
22
NC
NC
4
21
NC
NC
5
20
NC
V+
6
19
V-
X9268
VCC
7
18
VSS
RL0
8
17
RW1
RH0
9
16
RH1
RW0
10
15
RL1
A2
11
14
A1
WP
12
13
SDA
PIN ASSIGNMENTS
Pin
(SOIC,
TSSOP)
Symbol
1
NC
Function
No Connect
2
A0
Device Address for 2-Wire bus.
3
NC
No Connect
4
NC
No Connect
5
NC
No Connect
6
V+
Analog Suppy Pin (Positive)
7
VCC
System Supply Voltage
8
RL0
Low Terminal for Potentiometer 0.
9
RH0
High Terminal for Potentiometer 0.
10
RW0
11
A2
Device Address for 2-Wire bus.
12
WP
Hardware Write Protect
13
SDA
Serial Data Input/Output for 2-Wire bus.
14
A1
Device Address for 2-Wire bus.
15
RL1
Low Terminal for Potentiometer 1.
16
RH1
High Terminal for Potentiometer 1.
17
RW1
Wiper Terminal for Potentiometer 1.
18
VSS
System Ground
19
V-
Analog Supply Pin (Negative)
20
NC
No Connect
21
NC
No Connect
Wiper Terminal for Potentiometer 0.
22
NC
No Connect
23
SCL
Serial Clock for 2-Wire bus.
24
A3
Device Address for 2-Wire bus.
3
FN8172.1
June 21, 2005
X9268
RW
PIN DESCRIPTIONS
Bus Interface Pins
SERIAL DATA INPUT/OUTPUT (SDA)
The SDA is a bidirectional serial data input/output pin
for a 2-Wire slave device and is used to transfer data
into and out of the device. It receives device address,
opcode, wiper register address and data sent from an
2-Wire master at the rising edge of the serial clock
SCL, and it shifts out data after each falling edge of
the serial clock SCL.
It is an open drain output and may be wire-ORed with
any number of open drain or open collector outputs.
An open drain output requires the use of a pull-up
resistor. For selecting typical values, refer to the
guidelines for calculating typical values on the bus
pull-up resistors graph.
SERIAL CLOCK (SCL)
This input is used by 2-Wire master to supply 2-Wire
serial clock to the X9268.
DEVICE ADDRESS (A3 - A0)
The address inputs are used to set the least significant
3 bits of the 8-bit slave address. A match in the slave
address serial data stream must be made with the
Address input in order to initiate communication with
the X9268. A maximum of 8 devices may occupy the
2-Wire serial bus.
The wiper pin are equivalent to the wiper terminal of a
mechanical potentiometer. Since there are 4
potentiometers, there are 2 sets of RW such that RW0
is the terminal of POT 0 and so on.
Bias Supply Pins
SYSTEM SUPPLY VOLTAGE (VCC) AND SUPPLY
GROUND (VSS)
The VCC pin is the system supply voltage. The VSS
pin is the system ground.
Analog Supply Voltages (V+ and V-)
These supplies are the analog voltage supplies for the
potentiometer. The V+ supply is tied to the wiper
switches while the V- supply is used to bias the
switches and the internal P+ substrate of the
integrated circuit. Both of these supplies set the
voltage limits of the potentiometer.
Other Pins
NO CONNECT
No connect pins should be left open. This pins are
used for Intersil manufacturing and testing purposes.
HARDWARE WRITE PROTECT INPUT (WP)
The WP pin when LOW prevents nonvolatile writes to
the Data Registers.
Potentiometer Pins
RH, RL
The RH and RL pins are equivalent to the terminal
connections on a mechanical potentiometer. Since
there are 2 potentiometers, there are 2 sets of RH and
RL such that RH0 and RL0 are the terminals of POT 0
and so on.
4
FN8172.1
June 21, 2005
X9268
At both ends of each array and between each resistor
segment is a CMOS switch connected to the wiper
(RW) output. Within each individual array only one
switch may be turned on at a time.
PRINCIPLES OF OPERATION
The X9268 is a integrated microcircuit incorporating
four resistor arrays and their associated registers and
counters and the serial interface logic providing direct
communication between the host and the digitally
controlled potentiometers. This section provides detail
description of the following:
These switches are controlled by a Wiper Counter
Register (WCR). The 8-bits of the WCR (WCR[7:0])
are decoded to select, and enable, one of 256
switches (See Table 1).
– Resistor Array Description
The WCR may be written directly. These Data
Registers can the WCR can be read and written by the
host system.
– Serial Interface Description
– Instruction and Register Description.
Array Description
The X9268 is comprised of a resistor array (See
Figure 1). Each array contains 255 discrete resistive
segments that are connected in series. The physical
ends of each array are equivalent to the fixed
terminals of a mechanical potentiometer (RH and RL
inputs).
Power-up and Down Requirements.
At all times, the voltages on the potentiometer pins
must be less than V+ and more than V-. During powerup and power-down, VCC, V+, and V- must reach their
final values within 1msecs of each other. The VCC
ramp rate spec is always in effect.
Figure 1. Detailed Potentiometer Block Diagram
One of Two Potentiometers
SERIAL DATA PATH
SERIAL
BUS
INPUT
FROM INTERFACE
CIRCUITRY
REGISTER 0
(DR0)
REGISTER 1
(DR1)
8
REGISTER 2
(DR2)
8
REGISTER 3
(DR3)
PARALLEL
BUS
INPUT
WIPER
COUNTER
REGISTER
(WCR)
RH
C
O
U
N
T
E
R
D
E
C
O
D
E
INC/DEC
LOGIC
IF WCR = 00[H] THEN RW = RL
IF WCR = FF[H] THEN RW = RH
UP/DN
MODIFIED SCL
UP/DN
CLK
RL
RW
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FN8172.1
June 21, 2005
X9268
SERIAL INTERFACE DESCRIPTION
Serial Interface
The X9268 supports a bidirectional bus oriented
protocol. The protocol defines any device that sends
data onto the bus as a transmitter and the receiving
device as the receiver. The device controlling the
transfer is a master 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, the X9268 will be considered a
slave device in all applications.
Clock and Data Conventions
Data states on the SDA line can change only during
SCL LOW periods. SDA state changes during SCL
HIGH are reserved for indicating start and stop
conditions. See Figure 2.
Start Condition
All commands to the X9268 are preceded by the start
condition, which is a HIGH to LOW transition of SDA
while SCL is HIGH. The X9268 continuously monitors
the SDA and SCL lines for the start condition and will
not respond to any command until this condition is
met. See Figure 2.
Stop Condition
All communications must be terminated by a stop
condition, which is a LOW to HIGH transition of SDA
while SCL is HIGH. See Figure 2.
Acknowledge
Acknowledge is a software convention used to provide
a positive handshake between the master and slave
devices on the bus to indicate the successful receipt of
data. The transmitting device, either the master or the
slave, will release the SDA bus after transmitting eight
bits. The master generates a ninth clock cycle and
during this period the receiver pulls the SDA line LOW
to acknowledge that it successfully received the eight
bits of data.
The X9268 will respond with an acknowledge after
recognition of a start condition and its slave address
and once again after successful receipt of the
command byte. If the command is followed by a data
byte the X9268 will respond with a final acknowledge.
See Figure 2.
Figure 2. Acknowledge Response from Receiver
SCL FROM
MASTER
1
8
9
DATA
OUTPUT
FROM
TRANSMITTER
DATA
OUTPUT
FROM
RECEIVER
START
6
ACKNOWLEDGE
FN8172.1
June 21, 2005
X9268
Acknowledge Polling
The disabling of the inputs, during the internal
nonvolatile write operation, can be used to take
advantage of the typical 5ms nonvolatile write cycle
time. Once the stop condition is issued to indicate the
end of the nonvolatile write command the X9268
initiates the internal write cycle. ACK polling, Flow 1,
can be initiated immediately. This involves issuing the
start condition followed by the device slave address. If
the X9268 is still busy with the write operation no ACK
will be returned. If the X9268 has completed the write
operation an ACK will be returned and the master can
then proceed with the next operation.
FLOW 1: ACK Polling Sequence
Nonvolatile Write
Command Completed
EnterACK Polling
Issue
START
Issue STOP
No
Yes
Further
Operation?
Instructions
DEVICE ADDRESSING: IDENTIFICATION BYTE (ID AND A)
The first byte sent to the X9268 from the host is called
the Identification Byte. The most significant four bits of
the slave address are a device type identifier. The
ID[3:0] bits is the device id for the X9268; this is fixed
as 0101[B] (refer to Table 1).
The A[3:0] bits in the ID byte is the internal slave
address. The physical device address is defined by
the state of the A3 - A0 input pins. The slave address
is externally specified by the user. The X9268
compares the serial data stream with the address
input state; a successful compare of both address
bits is required for the X9268 to successfully continue
the command sequence. Only the device which slave
address matches the incoming device address sent
by the master executes the instruction. The A3 - A0
inputs can be actively driven by CMOS input signals
or tied to VCC or VSS.
INSTRUCTION BYTE (I)
Issue Slave
Address
ACK
Returned?
INSTRUCTION AND REGISTER DESCRIPTION
The next byte sent to the X9268 contains the
instruction and register pointer information. The three
most significant bits are used provide the instruction
opcode I [3:0]. The RB and RA bits point to one of the
four Data Registers of each associated XDCP. The
least significant bit points to one of two Wiper Counter
Registers or Pots. The format is shown in Table 2.
No
Register Selection
Yes
Issue
Instruction
Issue STOP
Proceed
Proceed
7
Register Selected
RB
RA
DR0
0
0
DR1
0
1
DR2
1
0
DR3
1
1
FN8172.1
June 21, 2005
X9268
Table 1. Identification Byte Format
Device Type
Identifier
Slave Address
ID3
ID2
ID1
ID0
0
1
0
1
A3
A2
A1
(MSB)
A0
(LSB)
Table 2. Instruction Byte Format
Data
Register
Selection
Instruction
Opcode
I3
I2
I1
I0
RB
Pot Selection
(WCR Selection)
RA
0
(MSB)
P0
(LSB)
Table 3. Instruction Set
I3
1
I2
0
Instruction Set
I1 I0 RB RA
0
1
0
0
1
0
1
0
0
0
0
1/0
Read Data Register
1
0
1
1
1/0
1/0
0
1/0
Write Data Register
1
1
0
0
1/0
1/0
0
1/0
XFR Data Register to Wiper
Counter Register
1
1
0
1
1/0
1/0
0
1/0
XFR Wiper Counter Register
to Data Register
1
1
1
0
1/0
1/0
0
1/0
Global XFR Data Registers to
Wiper Counter Registers
0
0
0
1
1/0
1/0
0
0
Global XFR Wiper Counter
Registers to Data Register
1
0
0
0
1/0
1/0
0
0
Increment/Decrement Wiper
Counter Register
0
0
1
0
0
0
0
1/0
Instruction
Read Wiper Counter
Register
Write Wiper Counter Register
0
0
P0
Operation
1/0
Read the contents of the Wiper Counter
Register pointed to by P0
Write new value to the Wiper Counter
Register pointed to by P0
Read the contents of the Data Register
pointed to by P0 and RB - RA
Write new value to the Data Register
pointed to by P0 and RB - RA
Transfer the contents of the Data Register
pointed to by P0 and RB - RA to its
associated Wiper Counter Register
Transfer the contents of the Wiper Counter
Register pointed to by P0 to the Data
Register pointed to by RB - RA
Transfer the contents of the Data Registers
pointed to by RB - RA of all four pots to their
respective Wiper Counter Registers
Transfer the contents of both Wiper Counter
Registers to their respective data Registers
pointed to by RB - RA of all four pots
Enable Increment/decrement of the Control
Latch pointed to by P0
Note: 1/0 = data is one or zero
8
FN8172.1
June 21, 2005
X9268
DEVICE DESCRIPTION
Wiper Counter Register (WCR)
The X9268 contains two Wiper Counter Registers, one
for each DCP potentiometer. The Wiper Counter
Register can be envisioned as a 8-bit parallel and
serial load counter with its outputs decoded to select
one of 256 switches along its resistor array. The
contents of the WCR can be altered in four ways: it
may be written directly by the host via the Write Wiper
Counter Register instruction (serial load); it may be
written indirectly by transferring the contents of one of
four associated data registers via the XFR Data
Register instruction (parallel load); it can be modified
one step at a time by the Increment/Decrement
instruction (See Instruction section for more details).
Finally, it is loaded with the contents of its Data
Register zero (DR0) upon power-up.
The Wiper Counter Register is a volatile register; that
is, its contents are lost when the X9268 is powereddown. Although the register is automatically loaded
with the value in DR0 upon power-up, this may be
different from the value present at power-down.
Power-up guidelines are recommended to ensure
proper loadings of the DR0 value into the WCR (See
Design Considerations Section).
Data Registers (DR)
Each potentiometer has four 8-bit nonvolatile Data
Registers. These can be read or written directly by the
host. Data can also be transferred between any of the
four Data Registers and the associated Wiper Counter
Register. All operations changing data in one of the
data registers is a nonvolatile operation and will take a
maximum of 10ms.
If the application does not require storage of multiple
settings for the potentiometer, the Data Registers can
be used as regular memory locations for system
parameters or user preference data.
Bit [7:0] are used to store one of the 256 wiper
positions (0~255).
Table 4. Wiper counter Register, WCR (8-bit), WCR[7:0]: Used to store the current wiper position (Volatile, V).
WCR7
WCR6
WCR5
WCR4
WCR3
WCR2
WCR1
WCR0
V
V
V
V
V
V
V
V
(MSB)
(LSB)
Table 5. Data Register, DR (8-bit), Bit [7:0]: Used to store wiper positions or data (Nonvolatile, NV).
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
NV
NV
NV
MSB
NV
NV
NV
NV
Bit 0
NV
LSB
9
FN8172.1
June 21, 2005
X9268
DEVICE DESCRIPTION
Instructions
Four of the nine instructions are three bytes in length.
These instructions are:
– Read Wiper Counter Register – read the current
wiper position of the selected potentiometer,
– Write Wiper Counter Register – change current
wiper position of the selected potentiometer,
– Read Data Register – read the contents of the
selected Data Register;
– Write Data Register – write a new value to the
selected Data Register.
The basic sequence of the three byte instructions is
illustrated in Figure 4. These three-byte instructions
exchange data between the WCR and one of the Data
Registers. A transfer from a Data Register to a WCR is
essentially a write to a static RAM, with the static RAM
controlling the wiper position. The response of the
wiper to this action will be delayed by tWRL. A transfer
from the WCR (current wiper position), to a Data
Register is a write to nonvolatile memory and takes a
minimum of tWR to complete. The transfer can occur
between one of the four potentiometers and one of its
associated registers; or it may occur globally, where
the transfer occurs between all potentiometers and
one associated register
Four instructions require a two-byte sequence to
complete. These instructions transfer data between the
host and the X9268; either between the host and one of
the data registers or directly between the host and the
Wiper Counter Register. These instructions are:
10
– XFR Data Register to Wiper Counter Register –
This transfers the contents of one specified Data
Register to the associated Wiper Counter Register.
– XFR Wiper Counter Register to Data Register –
This transfers the contents of the specified Wiper
Counter Register to the specified associated Data
Register.
– Global XFR Data Register to Wiper Counter
Register – This transfers the contents of all specified Data Registers to the associated Wiper Counter
Registers.
– Global XFR Wiper Counter Register to Data
Register – This transfers the contents of all Wiper
Counter Registers to the specified associated Data
Registers.
INCREMENT/DECREMENT COMMAND
The final command is Increment/Decrement (Figure 5
and 6). The Increment/Decrement command is
different from the other commands. Once the
command is issued and the X9268 has responded
with an acknowledge, the master can clock the
selected wiper up and/or down in one segment steps;
thereby, providing a fine tuning capability to the host.
For each SCL clock pulse (tHIGH) while SDA is HIGH,
the selected wiper will move one resistor segment
towards the RH terminal. Similarly, for each SCL clock
pulse while SDA is LOW, the selected wiper will move
one resistor segment towards the RL terminal.
See Instruction format for more details.
FN8172.1
June 21, 2005
X9268
Figure 3. Two-Byte Instruction Sequence
SCL
SDA
0
1
0
1
S ID3 ID2 ID1 ID0 A3 A2 A1 A0
T
A
Internal
R
Device ID
Address
T
A I3
C
K
I2
I1
I0
Instruction
Opcode
RB RA 0
Register
Address
P0
A
C
K
Pot/WCR
Address
S
T
O
P
Figure 4. Three-Byte Instruction Sequence
SCL
SDA
0
1
0
1
0
S ID3 ID2 ID1 ID0 A3
T
A
Device ID
R
T
A2
A0 A I3
C
K
Internal
Address
I2
A1
I1 I0
Instruction
Opcode
RB RA 0
P0 A
C
K
Register Pot/WCR
Address Address
D7 D6 D5 D4 D3 D2 D1 D0
WCR[7:0]
or
Data Register D[7:0]
A
C
K
S
T
O
P
Figure 5. Increment/Decrement Instruction Sequence
SCL
0
SDA
S
T
A
R
T
1
0
1
ID3 ID2 ID1 ID0
0
A3
A2 A1 A0
Internal
Address
Device ID
A
C
K
I3
I2
I1
Instruction
Opcode
I0
RB RA 0
P0
A
C
Register Pot/WCR K
Address Address
I
N
C
1
I
N
C
2
I
N
C
n
D
E
C
1
D
E
C
n
S
T
O
P
Figure 6. Increment/Decrement Timing Limits
INC/DEC
CMD
Issued
tWRID
SCL
SDA
Voltage Out
RW
11
FN8172.1
June 21, 2005
X9268
INSTRUCTION FORMAT
Read Wiper Counter Register (WCR)
Device Type
Device
S
Identifier
Addresses
T
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
K 1 0 0 1 0 0 0 P0
S
A
C
K
Wiper Position
(Sent by X9268 on SDA) M
W W W W W W W W A
C C C C C C C C C
R R R R R R R R K
7 6 5 4 3 2 1 0
S
T
O
P
S
A
C
K
Wiper Position
(Sent by Master on SDA) S
W W W W W W W W A
C C C C C C C C C
R R R R R R R R K
7 6 5 4 3 2 1 0
S
T
O
P
Write Wiper Counter Register (WCR)
Device Type
Device
S
Identifier
Addresses
T
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
K 1 0 1 0 0 0 0 P0
Read Data Register (DR)
Device Type
Device
S
Identifier
Addresses
T
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
K 1 0 1 1 RB RA 0 P0
S
A
C
K
Wiper Position
(Sent by X9268 on SDA) M
W W W W W W W W A
C C C C C C C C C
R R R R R R R R K
7 6 5 4 3 2 1 0
S
T
O
P
Device Type
Device
S
Identifier
Addresses
T
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
1 1 0 0 RB RA 0 P0
K
S
A
C
K
Wiper Position
(Sent by Master on SDA) S
W W W W W W W W A
C C C C C C C C C
R R R R R R R R K
7 6 5 4 3 2 1 0
S
T
O
P
HIGH-VOLTAGE
WRITE CYCLE
Write Data Register (DR)
Global XFR Data Register (DR) to Wiper Counter Register (WCR)
S
T
A
R
T
Device Type
Identifier
0
1
0
Device
Addresses
Instruction
DR/WCR
S
Opcode
Addresses
A
C
1 A3 A2 A1 A0 K 0 0 0 1 RB RA 0
0
12
S
A
C
K
S
T
O
P
FN8172.1
June 21, 2005
X9268
Global XFR Wiper Counter Register (WCR) to Data Register (DR)
S Device Type
Device
T
Identifier
Addresses
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
1 0 0 0 RB RA 0 0
K
S
A
C
K
S
T
O
P
HIGH-VOLTAGE
WRITE CYCLE
Transfer Wiper Counter Register (WCR) to Data Register (DR)
S Device Type
Device
T
Identifier
Addresses
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
K 1 1 1 0 RB RA 0 P0
S
A
C
K
S
T
O
P
S
A
C
K
S
T
O
P
HIGH-VOLTAGE
WRITE CYCLE
Transfer Data Register (DR) to Wiper Counter Register (WCR)
S Device Type
Device
T
Identifier
Addresses
A
R 0 1 0 1 A3 A2 A1 A0
T
Instruction
DR/WCR
S
Opcode
Addresses
A
C
K 1 1 0 1 RB RA 0 P0
Increment/Decrement Wiper Counter Register (WCR)
S Device Type
Device
T
Identifier
Addresses
A
R 0 1 0 1 A3 A2 A1 A0
T
Notes: (1)
(2)
(3)
(4)
(5)
Instruction
DR/WCR
S
Opcode
Addresses
A
C
P0
K 0 0 1 0 0 0 0
Increment/Decrement
S
(Sent by Master on SDA)
A
C
K I/D I/D . . . . I/D I/D
S
T
O
P
“MACK”/”SACK”: stands for the acknowledge sent by the master/slave.
“A3 ~ A0”: stands for the device addresses sent by the master.
“X”: indicates that it is a “0” for testing purpose but physically it is a “don’t care” condition.
“I”: stands for the increment operation, SDA held high during active SCL phase (high).
“D”: stands for the decrement operation, SDA held low during active SCL phase (high).
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FN8172.1
June 21, 2005
X9268
ABSOLUTE MAXIMUM RATINGS
COMMENT
Temperature under bias .................... -65°C to +135°C
Storage temperature ......................... -65°C to +150°C
Voltage on SDA, SCL or any address input
with respect to VSS ................................. -1V to +7V
Voltage on V+ (referenced to VSS)........................ 10V
Voltage on V- (referenced to VSS)........................-10V
(V+) - (V-) .............................................................. 12V
Any VH/RH ..............................................................V+
Any VL/RL.................................................................VLead temperature (soldering, 10 seconds) ........ 300°C
IW (10 seconds)..................................................±6mA
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; the functional operation of
the device (at these or any other conditions above
those listed in the operational sections of this
specification) is not implied. Exposure to absolute
maximum rating conditions for extended periods may
affect device reliability.
RECOMMENDED OPERATING CONDITIONS
Temp
Commercial
Industrial
Min.
0°C
-40°C
14
Max.
+70°C
+85°C
Device
X9268
X9268-2.7
Supply Voltage (VCC)(4) Limits
5V ± 10%
2.7V to 5.5V
V+
V-
2.7V to 5.5V
-2.7V to -5.5V
FN8172.1
June 21, 2005
X9268
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
Parameter
Min.
Typ.
Max.
Unit
Test Conditions
RTOTAL
End to End Resistance
100
kΩ
T version
RTOTAL
End to EndResistance
50
kΩ
U version
End to end resistance tolerance
±20
%
Power rating
50
mW
25°C, each pot
IW
Wiper current
±3
mA
RW
Wiper resistance
250
Ω
IW = ± 1mA, V+ = 3V; V- = -3V
RW
Wiper resistance
150
Ω
IW = ± 1mA, V+ = 5V; V- = -5V
V+
Voltage on V+ Pin
V
VVTERM
Voltage on V- Pin
X9268
+4.5
+5.5
X9268-2.7
+2.7
+5.5
X9268
-5.5
-4.5
X9268 -2.7
-5.5
-2.7
V-
V+
Voltage on any VH/RH or VL/RL pin
V
V
Noise
-120
dBV
Resolution (4)
0.4
%
Absolute linearity (1)
Relative linearity (2)
Temperature coefficient of resistance
CH/CL/CW Potentiometer Capacitance
±1
MI(3)
Vw(n)(actual) - Vw(n)(expected)
±0.6
MI(3)
Vw(n + 1) - [Vw(n) + MI]
±300
Ratiometric Temperature Coefficient
ppm/°C
±20
10/10/25
Ref: 1kHz
ppm/°C
pF
See Circuit #3
Notes: (1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage as determined by wiper position when used as a
potentiometer.
(2) Relative linearity is utilized to determine the actual change in voltage between two successive tap positions when used as a
potentiometer. It is a measure of the error in step size.
(3) MI = RTOT / 255 or (RH - RL) / 255, single pot
(4) During power-up VCC > VH, VL, and VW.
(5) n = 0, 1, 2, …,255; m =0, 1, 2, …, 254.
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June 21, 2005
X9268
D.C. OPERATING CHARACTERISTICS (Over the recommended operating conditions unless otherwise specified.)
Limits
Symbol
ICC1
Parameter
VCC supply current
(active)
ICC2
Min.
Typ.
Max.
3
Units
mA
Test Conditions
fSCL = 400kHz; VCC = +6V;
SDA = Open; (for 2-Wire, Active, Read and
Volatile Write States only)
fSCL = 400kHz; VCC = +6V;
SDA = Open; (for 2-Wire, Active,
Nonvolatile Write State only)
VCC supply current
(nonvolatile write)
5
mA
ISB
VCC current (standby)
5
µA
VCC = +6V; VIN = VSS or VCC;
SDA = VCC; (for 2-Wire, Standby State only)
ILI
Input leakage current
10
µA
VIN = VSS to VCC
ILO
Output leakage current
10
µA
VOUT = VSS to VCC
VIH
Input HIGH voltage
VCC x 0.7
VCC + 1
V
VIL
Input LOW voltage
-1
VCC x 0.3
V
VOL
Output LOW voltage
0.4
V
VOH
Output HIGH voltage
IOL = 3mA
ENDURANCE AND DATA RETENTION
Parameter
Min.
Units
Minimum endurance
100,000
Data changes per bit per register
Data retention
100
years
CAPACITANCE
Max.
Units
Test Conditions
CIN/OUT(6)
Symbol
Input / Output capacitance (SDA)
Test
8
pF
VOUT = 0V
CIN(6)
Input capacitance (SCL, WP, A3, A2, A1 and A0)
6
pF
VIN = 0V
POWER-UP TIMING
Symbol
Parameter
tr VCC(6)
VCC Power-up rate
tPUR(7)
Power-up to initiation of read operation
Min.
Max.
Units
0.2
50
V/ms
1
ms
POWER-UP AND DOWN REQUIREMENTS
The are no restrictions on the sequencing of the bias supplies VCC, V+, and V- provided that all three supplies reach
their final values within 1msec of each other. At all times, the voltages on the potentiometer pins must be less than V+
and more than V-. The recall of the wiper position from nonvolatile memory is not in effect until all supplies reach their
final value. The VCC ramp rate spec is always in effect.
A.C. TEST CONDITIONS
VCC x 0.1 to VCC x 0.9
Input Pulse Levels
Input rise and fall times
10ns
Input and output timing level
VCC x 0.5
Notes: (6) This parameter is not 100% tested
(7) tPUR and tPUW are the delays required from the time the (last) power supply (VCC-) is stable until the specific instruction can be issued.
These parameters are periodically sampled and not 100% tested.
16
FN8172.1
June 21, 2005
X9268
EQUIVALENT A.C. LOAD CIRCUIT
5V
3V
1533Ω
SPICE Macromodel
867Ω
RTOTAL
RH
SDA pin
RL
SDA pin
CW
CL
100pF
100pF
CL
10pF
25pF
10pF
RW
AC TIMING
Symbol
Parameter
fSCL
Clock Frequency
tCYC
Clock Cycle Time
tHIGH
tLOW
Min.
Max.
Units
400
kHz
2500
ns
Clock High Time
600
ns
Clock Low Time
1300
ns
tSU:STA
Start Setup Time
600
ns
tHD:STA
Start Hold Time
600
ns
tSU:STO
Stop Setup Time
600
ns
tSU:DAT
SDA Data Input Setup Time
100
ns
tHD:DAT
SDA Data Input Hold Time
30
ns
tR
SCL and SDA Rise Time
300
tF
SCL and SDA Fall Time
300
ns
tAA
SCL Low to SDA Data Output Valid Time
0.9
µs
tDH
SDA Data Output Hold Time
0
ns
TI
Noise Suppression Time Constant at SCL and SDA inputs
50
ns
tBUF
Bus Free Time (Prior to Any Transmission)
1200
ns
tSU:WPA
A0, A1 Setup Time
0
ns
tHD:WPA
A0, A1 Hold Time
0
ns
ns
HIGH-VOLTAGE WRITE CYCLE TIMING
Symbol
Parameter
tWR
High-voltage write cycle time (store instructions)
Typ.
Max.
Units
5
10
ms
XDCP TIMING
Symbol
Parameter
Min.
Max. Units
tWRPO
Wiper response time after the third (last) power supply is stable
5
10
µs
tWRL
Wiper response time after instruction issued (all load instructions)
5
10
µs
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FN8172.1
June 21, 2005
X9268
TIMING DIAGRAMS
Start and Stop Timing
(START)
(STOP)
tR
tF
SCL
tSU:STA
tHD:STA
tSU:STO
tR
tF
SDA
Input Timing
tCYC
tHIGH
SCL
tLOW
SDA
tSU:DAT
tHD:DAT
tBUF
Output Timing
SCL
SDA
tAA
18
tDH
FN8172.1
June 21, 2005
X9268
XDCP Timing (for All Load Instructions)
(STOP)
SCL
LSB
SDA
tWRL
VWx
Write Protect and Device Address Pins Timing
(START)
SCL
(STOP)
...
(Any Instruction)
...
SDA
...
tSU:WPA
tHD:WPA
WP
A0, A1
19
FN8172.1
June 21, 2005
X9268
APPLICATIONS INFORMATION
Basic Configurations of Electronic Potentiometers
+VR
VR
RW
I
Three terminal Potentiometer;
Variable voltage divider
Two terminal Variable Resistor;
Variable current
Application Circuits
Noninverting Amplifier
VS
Voltage Regulator
+
VO
–
VIN
VO (REG)
317
R1
R2
Iadj
R1
R2
VO = (1+R2/R1)VS
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
Offset Voltage Adjustment
R1
Comparator with Hysterisis
R2
VS
VS
–
+
VO
100kΩ
–
VO
+
}
}
TL072
R1
R2
10kΩ
10kΩ
+12V
10kΩ
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
-12V
20
FN8172.1
June 21, 2005
X9268
Application Circuits (continued)
Attenuator
Filter
C
VS
+
R2
R1
VS
VO
–
–
R
VO
+
R3
R4
R2
R1 = R2 = R3 = R4 = 10kΩ
R1
GO = 1 + R2/R1
fc = 1/(2πRC)
V O = G VS
-1/2 ≤ G ≤ +1/2
R1
R2
}
}
Inverting Amplifier
Equivalent L-R Circuit
VS
R2
C1
–
VS
VO
+
+
–
R1
ZIN
V O = G VS
G = - R2/R1
R3
ZIN = R2 + s R2 (R1 + R3) C1 = R2 + s Leq
(R1 + R3) >> R2
Function Generator
C
R2
–
+
R1
–
} RA
+
} RB
frequency ∝ R1, R2, C
amplitude ∝ RA, RB
21
FN8172.1
June 21, 2005
X9268
PACKAGING INFORMATION
24-Lead Plastic, TSSOP, Package Code V24
.026 (.65) BSC
.169 (4.3)
.252 (6.4) BSC
.177 (4.5)
.303 (7.70)
.311 (7.90)
.041 (1.05)
.0075 (.19)
.0118 (.30)
0.002 (0.05)
0.005 (0.15)
.010 (.25)
Gage Plane
0°–8°
(4.16) (7.72)
Seating Plane
.020 (.50)
.030 (.75)
(1.78)
Detail A (20X)
(0.42)
(0.65)
.031 (.80)
.041 (1.05)
ALL MEASUREMENTS ARE TYPICAL
See Detail “A”
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
22
FN8172.1
June 21, 2005
X9268
PACKAGING INFORMATION
24-Lead Plastic Small Outline Gull Wing Package Type S
0.290 (7.37) 0.393 (10.00)
0.299 (7.60) 0.420 (10.65)
Pin 1 Index
Pin 1
0.014 (0.35)
0.020 (0.50)
0.598 (15.20)
0.610 (15.49)
(4X) 7°
0.092 (2.35)
0.105 (2.65)
0.003 (0.10)
0.012 (0.30)
0.050 (1.27)
0.050" Typical
0.010 (0.25)
X 45°
0.020 (0.50)
0.050"
Typical
0° - 8°
0.009 (0.22)
0.013 (0.33)
0.420"
0.015 (0.40)
0.050 (1.27)
FOOTPRINT
0.030" Typical
24 Places
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
23
FN8172.1
June 21, 2005
X9268
ORDERING INFORMATION
X9268
Y
P
T
V
VCC Limits
Blank = 5V ± 10%
-2.7 = 2.7 to 5.5V
Device
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = -40°C to +85°C
Package
S24 = 24-Lead SOIC
T24= 24-Lead TSSOP
Potentiometer Organization
Pot
U=
50kΩ
T=
100kΩ
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries 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 Intersil or its subsidiaries.
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24
FN8172.1
June 21, 2005