NOT RECOMMENDED FOR NEW DESIGNS
INTERSIL SUGGESTS THE
ISL22316 OR ISL22319
DATASHEET
X9428 Low Noise/Low Power/2-Wire Bus
FN8197
Rev 1.00
April 26, 2006
Single Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
• Solid state potentiometer
• 2-wire serial interface
• Register oriented format
—Direct Read/Write/Transfer wiper position
—Store as many as four positions per
potentiometer
• Power supplies
—VCC = 2.7V to 5.5V
—V+ = 2.7V to 5.5V
—V– = -2.7V to -5.5V
• Low power CMOS
—Standby current < 1µA
—Ideal for battery operated applications
• High reliability
—Endurance–100,000 Data changes per bit per
register
—Register data retention–100 years
• 4-bytes of nonvolatile memory
• 10k resistor array
• Resolution: 64 taps each potentiometer
• 16 Ld SOIC, 14 Ld TSSOP packages
• Pb-free plus anneal available (RoHS compliant)
The X9428 integrates a digitally controlled
potentiometers (XDCP) on a monolithic CMOS
integrated microcircuit.
The digitally controlled potentiometer is implemented
using 63 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 4
nonvolatile Data Registers (DR0:DR3) 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 through the switches. Power-up recalls
the contents of 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.
BLOCK DIAGRAM
VCC
VSS
V+
V–
SCL
SDA
A0
A2
A3
R0 R1
Interface
and
Control
Circuitry
8
Data
R2 R3
Wiper
Counter
Register
(WCR)
VH/RH
VL/RL
VW/RW
WP
FN8197 Rev 1.00
April 26, 2006
Page 1 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Ordering Information
PART NUMBER
PART
MARKING
VCC LIMITS (V)
POTENTIOMETER
ORGANIZATION (k)
TEMP. RANGE
(°C)
5 to ±10%
10
0 to +70
16 Ld SOIC (300 mil) M16.3
PACKAGE
PKG. DWG. #
X9428WS16*
X9428WS
X9428WS16Z* (Note)
X9428WS Z
0 to +70
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428WS16I*
X9428WS I
-40 to +85
16 Ld SOIC (300 mil) M16.3
-40 to +85
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428WS16IZ* (Note) X9428WS ZI
X9428WV14*
X9428 W
0 to +70
14 Ld TSSOP
(4.4mm)
M14.173
X9428WV14Z* (Note)
X9428 Z
0 to +70
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428WV14I*
X9428 WI
-40 to +85
14 Ld TSSOP
(4.4mm)
M14.173
-40 to +85
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428WV14IZ* (Note) X9428 ZI
X9428YS16*
X9428YS
X9428YS16Z* (Note)
2
0 to +70
16 Ld SOIC (300 mil) M16.3
X9428YS Z
0 to +70
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428YS16I*
X9428YS I
-40 to +85
16 Ld SOIC (300 mil) M16.3
X9428YS16IZ* (Note)
X9428YS ZI
-40 to +85
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428YV14*
X9428 Y
0 to +70
14 Ld TSSOP
(4.4mm)
M14.173
X9428YV14Z* (Note)
X9428 YZ
0 to +70
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428YV14I*
X9428 YI
-40 to +85
14 Ld TSSOP
(4.4mm)
M14.173
X9428YV14IZ* (Note)
X9428 YZI
-40 to +85
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428WS16-2.7*
X9428WS F
X9428WS16Z-2.7*
(Note)
0 to +70
16 Ld SOIC (300 mil) M16.3
X9428WS ZF
0 to +70
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428WS16I-2.7*
X9428WS G
-40 to +85
16 Ld SOIC (300 mil) M16.3
X9428WS16IZ-2.7*
(Note)
X9428WS ZG
-40 to +85
16 Ld SOIC (300 mil) M16.3
(Pb-free)
X9428WV14-2.7*
X9428 WF
0 to +70
14 Ld TSSOP
(4.4mm)
M14.173
X9428WV14Z-2.7*
(Note)
X9428 ZF
0 to +70
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428WV14I-2.7*
X9428 WG
-40 to +85
14 Ld TSSOP
(4.4mm)
M14.173
X9428WV14IZ-2.7*
(Note)
X9428 ZG
-40 to +85
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428YS16-2.7*
X9428YS F
X9428YS16Z-2.7*
(Note)
X9428YS ZF
FN8197 Rev 1.00
April 26, 2006
2.7 to 5.5
10
2
0 to +70
16 Ld SOIC (300 mil) M16.3
0 to +70
16 Ld SOIC (300 mil) M16.3
(Pb-free)
Page 2 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Ordering Information (Continued)
PART NUMBER
PART
MARKING
VCC LIMITS (V)
POTENTIOMETER
ORGANIZATION (k)
TEMP. RANGE
(°C)
2.7 to 5.5
2
-40 to +85
16 Ld SOIC (300 mil) M16.3
-40 to +85
16 Ld SOIC (300 mil) M16.3
(Pb-free)
PACKAGE
PKG. DWG. #
X9428YS16I-2.7*
X9428YS G
X9428YS16IZ-2.7*
(Note)
X9428YS ZG
X9428YV14-2.7*
X9428 YF
0 to +70
14 Ld TSSOP
(4.4mm)
M14.173
X9428YV14Z-2.7*
(Note)
X9428 YZF
0 to +70
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
X9428YV14I-2.7*
X9428 YG
-40 to +85
14 Ld TSSOP
(4.4mm)
M14.173
X9428YV14IZ-2.7*
(Note)
X9428 YZG
-40 to +85
14 Ld TSSOP
(4.4mm) (Pb-free)
M14.173
*Add "T1" suffix for tape and reel.
NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
FN8197 Rev 1.00
April 26, 2006
Page 3 of 21
X9428 Low Noise/Low Power/2-Wire Bus
PIN DESCRIPTIONS
PIN CONFIGURATION
Host Interface Pins
DIP/SOIC
VCC
1
16
V+
A2
2
15
NC
RL/VL
3
14
A0
RH/VH
4
13
NC
RW/VW
5
12
A3
SDA
6
11
SCL
WP
VSS
7
10
NC
8
9
V-
Serial Clock (SCL)
The SCL input is used to clock data into and out of the
X9428.
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into and
out of the device. 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.
X9428
TSSOP
Device Address (A0, A2, A3)
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
X9428. A maximum of 8 devices may occupy the 2-wire
serial bus.
A2
1
14
VCC
RL
2
13
V+
RH
3
12
A0
RW
4
11
NC
SDA
5
10
A3
WP
6
9
SCL
VSS
7
8
V-
X9428
Potentiometer Pins
RH/VH, RL/VL
The RH/VH and RL/VL inputs are equivalent to the
terminal connections on either end of a mechanical
potentiometer.
RW/VW
The wiper outputs are equivalent to the wiper output of a
mechanical potentiometer.
Hardware Write Protect Input WP
The WP pin when low prevents nonvolatile writes to the
Data Registers.
Analog Supply V+, VThe Analog Supply V+, V- are the supply voltages for
the XDCP analog section.
FN8197 Rev 1.00
April 26, 2006
PIN NAMES
Symbol
Description
SCL
Serial clock
SDA
Serial data
A0, A2, A3
RH/VH, VL/RH
RW/VW
WP
Device address
Potentiometer Pins
(terminal equivalent)
Potentiometer Pin (wiper equivalent)
Hardware write protection
V+,V-
Analog and voltage follower
VCC
System supply voltage
VSS
System ground
NC
No connection
Page 4 of 21
X9428 Low Noise/Low Power/2-Wire Bus
PRINCIPLES OF OPERATION
The X9428 is a highly integrated microcircuit
incorporating a resistor array and its associated
registers and counters and the serial interface logic
providing direct communication between the host and
the XDCP potentiometers.
Serial Interface
The X9428 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 X9428 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 (tLOW). SDA state changes during SCL
HIGH are reserved for indicating start and stop
conditions.
Start Condition
All commands to the X9428 are preceded by the start
condition, which is a HIGH to LOW transition of SDA
while SCL is HIGH (tHIGH). The X9428 continuously
monitors the SDA and SCL lines for the start condition
and will not respond to any command until this condition
is met.
Stop Condition
The X9428 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
X9428 will respond with a final acknowledge.
Array Description
The X9428 is comprised of a resistor array. The array
contains 63 discrete resistive segments that are
connected in series. The physical ends of the array are
equivalent to the fixed terminals of a mechanical
potentiometer (VH/RH and VL/RL inputs).
At both ends of the array and between each resistor
segment is a CMOS switch connected to the wiper
(VW/RW) output. Within each individual array only one
switch may be turned on at a time. These switches are
controlled by the Wiper Counter Register (WCR). The
six bits of the WCR are decoded to select, and enable,
one of sixty-four switches.
The WCR may be written directly, or it can be changed by
transferring the contents of one of four associated Data
Registers into the WCR. These Data Registers and the
WCR can be read and written by the host system.
Device Addressing
Following a start condition the master must output the
address of the slave it is accessing. The most significant
four bits of the slave address are the device type
identifier (refer to Figure 1 below). For the X9428 this is
fixed as 0101[B].
Figure 1. Slave Address
All communications must be terminated by a stop
condition, which is a LOW to HIGH transition of SDA
while SCL is HIGH.
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.
FN8197 Rev 1.00
April 26, 2006
Device Type
Identifier
0
1
0
1
A3
A2
0
A0
Device Address
The next four bits of the slave address are the device
address. The physical device address is defined by the
state of the A0, A2, A3 inputs. The X9428 compares the
serial data stream with the address input state; a
successful compare of all four address bits is required
for the X9428 to respond with an acknowledge. The A0,
A2, A3 inputs can be actively driven by CMOS input
signals or tied to VCC or VSS.
Page 5 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Figure 2. Instruction Byte Format
Acknowledge Polling
The disabling of the inputs, during the internal
nonvolatile write operation, can be used to take
advantage of the typical 5ms EEPROM write cycle time.
Once the stop condition is issued to indicate the end of
the nonvolatile write command the X9428 initiates the
internal write cycle. ACK polling can be initiated
immediately. This involves issuing the start condition
followed by the device slave address. If the X9428 is still
busy with the write operation no ACK will be returned. If
the X9428 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
Issue
START
ACK
Returned?
Issue STOP
NO
YES
Further
Operation?
I3
I2
I1
I0
R1
R0
0
0
Instructions
The four high order bits define the instruction. The next
two bits (R1 and R0) select one of the four registers that is
to be acted upon when a register oriented instruction is
issued. Bits 0 and 1 are defined to be 0.
Four of the seven instructions end with the transmission
of the instruction byte. The basic sequence is illustrated in
Figure 3. These two-byte instructions exchange data
between the Wiper Counter Register and one of the Data
Registers. A transfer from a Data Register to a Wiper
Counter Register is essentially a write to a static RAM.
The response of the wiper to this action will be delayed
tWRL. A transfer from the Wiper Counter Register (current
wiper position), to a Data Register is a write to nonvolatile
memory and takes a minimum of tWR to complete.
Nonvolatile Write
Command Completed
Enter ACK Polling
Issue Slave
Address
Register
Select
NO
YES
Issue
Instruction
Issue STOP
Proceed
Proceed
Four instructions require a three-byte sequence to
complete. These instructions transfer data between the
host and the X9428; either between the host and one of
the Data Registers or directly between the host and the
Wiper Counter Register. These instructions are: Read
Wiper Counter Register (read the current wiper position of
the selected pot), write Wiper Counter Register (change
current wiper position of the selected pot), read Data
Register (read the contents of the selected nonvolatile
register) and write Data Register (write a new value to the
selected Data Register). The sequence of operations is
shown in Figure 4.
Instruction Structure
The next byte sent to the X9428 contains the instruction
and register pointer information. The four most significant
bits are the instruction. The next four bits point to one of
four associated registers. The format is shown below in
Figure 2.
FN8197 Rev 1.00
April 26, 2006
Page 6 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Figure 3. Two-Byte Instruction Sequence
SCL
SDA
S
T
A
R
T
0
1
0
1
A3
A2
0
A0
A
C
K
The Increment/Decrement command is different from
the other commands. Once the command is issued and
the X9428 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
I3
I2
I1
I0
R1 R0 0
0
A
C
K
S
T
O
P
resistor segment towards the VH/RH terminal. Similarly,
for each SCL clock pulse while SDA is LOW, the
selected wiper will move one resistor segment towards
the VL/RL terminal. A detailed illustration of the
sequence and timing for this operation are shown in
Figures 5 and 6 respectively.
Table 1. Instruction Set
I3
1
I2
0
Instruction Set
I1 I0 R1 R0
0
1
0
0
1
0
1
0
1
0
1
1
Write Data Register
1
1
0
XFR Data Register to
Wiper Counter Register
XFR Wiper Counter
Register to Data Register
Increment/Decrement
Wiper Counter Register
1
1
1
0
Instruction
Read Wiper Counter
Register
Write Wiper Counter
Register
Read Data Register
Note:
X1
0
X0
0
0
0
1/0 1/0
0
0
0
1/0 1/0
0
0
1
1/0 1/0
0
1
1
0
1/0 1/0
0
0
1
0
0
0
0
0
0
Operation
Read the contents of the Wiper Counter Register
Write new value to the Wiper Counter Register
Read the contents of the Data Register pointed to by
R1 - R0
0 Write new value to the Data Register pointed to by
R1 - R0
0 Transfer the contents of the Data Register pointed to
by R1 - R0 to its Wiper Counter Register
0 Transfer the contents of the Wiper Counter Register
to the Data Register pointed to by R1 - R0
1/0 Enable Increment/decrement of the Wiper Counter
Register
(7) 1/0 = data is one or zero
FN8197 Rev 1.00
April 26, 2006
Page 7 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Figure 4. Three-Byte Instruction Sequence
SCL
SDA
S
T
A
R
T
0
1
0
1
A3 A2 0
A0 A
C
K
I3
I2
I1 I0
R1 R0 0
0
A
C
K
0
0
D5 D4 D3 D2 D1 D0
A
C
K
S
T
O
P
Figure 5. Increment/Decrement Instruction Sequence
SCL
SDA
X
S
T
A
R
T
0
1
0
1
A3 A2 0
A0
A
C
K
I3
I2
I1
I0
X
R1 R0
0
0
A
C
K
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
VW/RW
FN8197 Rev 1.00
April 26, 2006
Voltage Out
Page 8 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Figure 7. Acknowledge Response from Receiver
SCL from
Master
1
8
9
Data Output
from Transmitter
Data Output
from Receiver
START
Acknowledge
Figure 8. Detailed Potentiometer Block Diagram
Serial Data Path
Serial
Bus
Input
From Interface
Circuitry
Register 0
Register 1
8
Register 2
If WCR = 00[H] then VW/RW = VL/RL
If WCR = 3F[H] then VW/RW = VH/RH
6
Parallel
Bus
Input
Wiper
Counter
Register
(WCR)
Register 3
UP/DN
Modified SCL
VH/RH
C
o
u
n
t
e
r
D
e
c
o
d
e
INC/DEC
Logic
UP/DN
CLK
VL/RL
VW/RW
FN8197 Rev 1.00
April 26, 2006
Page 9 of 21
X9428 Low Noise/Low Power/2-Wire Bus
DETAILED OPERATION
The potentiometer has a Wiper Counter Register and
four Data Registers. A detailed discussion of the register
organization and array operation follows.
Wiper Counter Register
The X9428 contains a Wiper Counter Register. The
Wiper Counter Register can be envisioned as a 6-bit
parallel and serial load counter with its outputs decoded
to select one of sixty-four 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. Finally, it is loaded with the contents of its
Data Register zero (DR0) upon power-up.
The WCR is a volatile register; that is, its contents are
lost when the X9428 is powered-down. Although the
register is automatically loaded with the value in DR0
upon power-up, it should be noted this may be different
from the value present at power-down.
Data Registers
The potentiometer has four nonvolatile Data Registers.
These can be read or written directly by the host and
data can be transferred between any of the four Data
Registers and the Wiper Counter Register. It should be
noted all operations changing data in one of these
registers is a nonvolatile operation and will take a
maximum of 10ms.
Register Descriptions
Data Registers, (6-Bit), Nonvolatile
D5
D4
D3
D2
D1
D0
NV
NV
NV
NV
NV
NV
(MSB)
(LSB)
Four 6-bit Data Registers for each XDCP. (eight 6-bit
registers in total).
– {D5~D0}: These bits are for general purpose not
volatile data storage or for storage of up to four
different wiper values. The contents of Data Register 0
are automatically moved to the Wiper Counter
Register on power-up.
Wiper Counter Register, (6-Bit), Volatile
WP5
WP4
WP3
WP2
WP1
WP0
V
V
V
V
V
V
(MSB)
(LSB)
One 6-bit wiper counter register for each XDCP. (Four 6bit registers in total.)
– {D5~D0}: These bits specify the wiper position of the
respective XDCP. The Wiper Counter Register is
loaded on power-up by the value in Data Register 0.
The contents of the WCR can be loaded from any of
the other Data Register or directly. The contents of the
WCR can be saved in a DR.
If the application does not require storage of multiple
settings for the potentiometer, these registers can be
used as regular memory locations that could possibly
store system parameters or user preference data.
FN8197 Rev 1.00
April 26, 2006
Page 10 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Instruction Format
Notes: (1)
(2)
(3)
(4)
(5)
“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).
Read Wiper Counter Register (WCR)
S device type
device
T
identifier
addresses
A
R 0 1 0 1 A A 0 A
3 2
0
T
instruction
wiper position
S
S
opcode
(sent by slave on SDA)
A
A
W W W W W W
C
C
1 0 0 1 0 0 0 0
0 0 P P P P P P
K
K
5 4 3 2 1 0
M
A
C
K
S
T
O
P
instruction
wiper position
S
S
opcode
(sent by master on SDA)
A
A
W W W W W W
C
C
1
0
1
0
0
0
0
0
0
0
P P P P P P
K
K
5 4 3 2 1 0
S
A
C
K
S
T
O
P
instruction
register
S
opcode
addresses
A
C
R R
K 1 0 1 1 1 0 0 0
M
A
C
K
S
T
O
P
Write Wiper Counter Register (WCR)
S device type
device
T
identifier
addresses
A
R 0 1 0 1 A A 0 A
3 2
0
T
Read Data Register (DR)
S device type
device
T
identifier
addresses
A
R 0 1 0 1 A A 0 A
3 2
0
T
wiper position/data
S
(sent by slave on SDA)
A
W W W W W W
C
0
0
P P P P P P
K
5 4 3 2 1 0
Write Data Register (DR)
S device type
device
instruction
register
S
T identifier
addresses
opcode
addresses
A
A
C
R R
R 0 1 0 1 A A 0 A
1 1 0 0
0 0
3 2
0 K
1 0
T
wiper position/data
S
(sent by master on SDA)
A
W W W W W W
C
0 0 P P P P P P
K
5 4 3 2 1 0
S
A
C
K
S
T HIGH-VOLTAGE
O WRITE CYCLE
P
XFR Data Register (DR) to Wiper Counter Register (WCR)
S device type
device
instruction
register
S
T identifier
addresses
opcode
addresses
A
A
C
A
A
A
R R
R 0 1 0 1
0
1 1 0 1
0 0
3 2
0 K
1 0
T
FN8197 Rev 1.00
April 26, 2006
S
A
C
K
S
T
O
P
Page 11 of 21
X9428 Low Noise/Low Power/2-Wire Bus
XFR Wiper Counter Register (WCR) to Data Register (DR)
S device type
device
T
identifier
addresses
A
R 0 1 0 1 A A 0 A
3 2
0
T
instruction
register
S
opcode
addresses
A
C
R R
1 1 1 0
0 0
K
1 0
S
A
C
K
S
T
O
P
HIGH-VOLTAGE
WRITE CYCLE
Increment/Decrement Wiper Counter Register (WCR)
S device type
device
T
identifier
addresses
A
R 0 1 0 1 A A 0 A
3 2
0
T
instruction
increment/decrement
S
S
opcode
(sent by master on SDA)
A
A
C
C I/ I/
I/ I/
K 0 0 1 0 0 0 0 0 K D D . . . . D D
SYMBOL TABLE
FN8197 Rev 1.00
April 26, 2006
Guidelines for Calculating Typical Values of Bus
Pull-Up Resistors
INPUTS
OUTPUTS
120
Must be
steady
Will be
steady
100
May change
from Low to
High
Will change
from Low to
High
May change
from High to
Low
Will change
from High to
Low
Don’t Care:
Changes
Allowed
Changing:
State Not
Known
N/A
Center Line
is High
Impedance
Resistance (K)
WAVEFORM
S
T
O
P
80
60
V
RMIN = CC MAX=1.8k
IOL MIN
RMAX =
tR
CBUS
Max.
Resistance
40
20 Min.
Resistance
0
0 20 40 60
80 100 120
Bus Capacitance (pF)
Page 12 of 21
X9428 Low Noise/Low Power/2-Wire Bus
ABSOLUTE MAXIMUM RATINGS
COMMENT
Temperature under bias .................... -65C to +135C
Storage temperature ......................... -65C to +150C
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) ........ 300C
IW (10 seconds)................................................±12mA
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; 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.
0C
-40C
Max.
Device
X9428
X9428-2.7
+70C
+85C
Supply Voltage (VCC) Limits
5V 10%
2.7V to 5.5V
ANALOG CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
Max.
Unit
End to end resistance tolerance
±20
%
Power rating
50
mW
IW
Wiper current
±6
mA
RW
Wiper resistance
V+
VVTERM
Parameter
Voltage on V+ pin
Voltage on V- pin
Min.
Typ.
250
Wiper current = 1mA, VCC = 3V
40
100
Wiper current = 1mA, VCC = 5V
V
+4.5
+5.5
X9428-2.7
+2.7
+5.5
X9428
-5.5
-4.5
X9428-2.7
-5.5
-2.7
V-
V+
Noise
Resolution (4)
-140
Relative linearity (2)
CH/CL/C
Potentiometer Capacitances
W
FN8197 Rev 1.00
April 26, 2006
Ref: 1kHz
%
MI(3)
±0.2
MI(3)
Vw(n)(actual) - Vw(n)(expected)
Vw(n + 1 )- [Vw(n) + MI]
ppm/C
±20
10/10/25
V
±1
300
Ratiometric Temperature Coefficient
V
dBV
1.6
Absolute linearity (1)
Temperature Coefficient of RTOTAL
25°C, each pot
150
X9428
Voltage on any VH/RH or VL/RL pin
Test Conditions
ppm/°C
pF
See Circuit #3,
Spice Macromodel
Page 13 of 21
X9428 Low Noise/Low Power/2-Wire Bus
D.C. OPERATING CHARACTERISTICS (Over the recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
Min.
Typ.
Max.
Unit
Test Conditions
1
mA
fSCL = 400kHz, SDA = Open,
Other Inputs = VSS
100
µA
fSCL = 400kHz, SDA = Open,
Other Inputs = VSS
ICC1
VCC supply current
(nonvolatile write)
ICC2
VCC supply current
(move wiper, write, read)
ISB
VCC current (standby)
1
µA
SCL = SDA = VCC, Addr. = VSS
ILI
Input leakage current
10
µA
VIN = VSS to VCC
VOUT = VSS to VCC
ILO
Output leakage current
10
µA
VIH
Input HIGH voltage
VCC x 0.7
VCC x 0.5
V
VIL
Input LOW voltage
-0.5
VCC x 0.1
V
VOL
Output LOW voltage
0.4
V
IOL = 3mA
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/63 or (RH - RL)/63, single pot
(4) Max. = all four arrays cascaded together, Typical = individual array resolutions.
ENDURANCE AND DATA RETENTION
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit per register
Data retention
100
Years
CAPACITANCE
Symbol
CI/O
(5)
CIN(5)
Test
Max.
Unit
Test Conditions
Input/output capacitance (SDA)
8
pF
VI/O = 0V
Input capacitance (A0, A1, A2, A3, and SCL)
6
pF
VIN = 0V
POWER-UP TIMING
Symbol
tPUR
Parameter
Max.
Unit
Power-up to initiation of read operation
1
ms
Power-up to initiation of write operation
5
ms
50
V/msec
(6)
(6)
(7)
VCC Power-up ramp rate
tPUW
tRVCC
Min.
0.2
Typ.
POWER-UP AND POWER-DOWN
There are no restrictions on the power-up or power-down sequencing of the bias supplies VCC, V+, and V- provided
that all three supplies reach their final values within 1msec of each other. However, 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.
Notes: (5) This parameter is periodically sampled and not 100% tested
(6) tPUR and tPUW are the delays required from the time the third (last) power supply (VCC, V+ or V-) is stable until the specific
instruction can be issued. These parameters are periodically sampled and not 100% tested.
(7) Sample tested only.
FN8197 Rev 1.00
April 26, 2006
Page 14 of 21
X9428 Low Noise/Low Power/2-Wire Bus
A.C. TEST CONDITIONS
Circuit #3 SPICE Macro Model
Input pulse levels
VCC x 0.1 to VCC x 0.9
Input rise and fall times
10ns
Input and output timing level
VCC x 0.5
RTOTAL
RH
CH
CW
EQUIVALENT A.C. LOAD CIRCUIT
10pF
5V
2.7V
RL
CL
10pF
25pF
RW
1533
SDA Output
100pF
100pF
AC TIMING (over recommended operating conditions)
Symbol
Min.
Max.
Unit
fSCL
Clock frequency
Parameter
100
400
kHz
tCYC
Clock cycle time
2500
ns
tHIGH
Clock high time
600
ns
tLOW
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
ns
tF
SCL and SDA fall time
300
ns
tAA
SCL low to SDA data output valid time
900
ns
tDH
SDA data output hold time
50
ns
Noise suppression time constant at SCL and SDA inputs
50
ns
1300
ns
TI
tBUF
Bus free time (prior to any transmission)
tSU:WPA
WP, A0, A1, A2 and A3 setup time
0
ns
tHD:WPA
WP, A0, A1, A2 and A3 hold time
0
ns
FN8197 Rev 1.00
April 26, 2006
Page 15 of 21
X9428 Low Noise/Low Power/2-Wire Bus
HIGH-VOLTAGE WRITE CYCLE TIMING
Symbol
Parameter
tWR
Typ.
Max.
Unit
5
10
ms
High-voltage write cycle time (store instructions)
XDCP TIMING
Symbol
Max.
Unit
Wiper response time after the third (last) power supply is stable
10
µs
tWRL
Wiper response time after instruction issued (all load instructions)
10
µs
tWRID
Wiper response time from an active SCL/SCK edge (increment/decrement instruction)
10
µs
tWRPO
Note:
Parameter
Min.
(8) A device must internally provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of the falling
edge of SCL.
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
FN8197 Rev 1.00
April 26, 2006
tDH
Page 16 of 21
X9428 Low Noise/Low Power/2-Wire Bus
XDCP Timing (for All Load Instructions)
(STOP)
SCL
LSB
SDA
tWRL
VW/RW
XDCP Timing (for Increment/Decrement Instruction)
SCL
SDA
Wiper Register Address
Inc/Dec
Inc/Dec
tWRID
VW/RW
Write Protect and Device Address Pins Timing
(START)
SCL
(STOP)
...
(Any Instruction)
...
SDA
...
tSU:WPA
tHD:WPA
WP
A0, A2, A3
FN8197 Rev 1.00
April 26, 2006
Page 17 of 21
X9428 Low Noise/Low Power/2-Wire Bus
APPLICATIONS INFORMATION
Basic Configurations of Electronic Potentiometers
+VR
VR
VW/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 Hysteresis
R2
VS
VS
–
+
100k
–
VO
+
+12V
FN8197 Rev 1.00
April 26, 2006
10k
R1
}
10k
}
TL072
10k
VO
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
-12V
Page 18 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Application Circuits (continued)
Attenuator
Filter
C
VS
R2
R1
VO
–
–
VS
+
R
VO
+
R3
R4
R2
All RS = 10k
R1
GO = 1 + R2/R1
fc = 1/(2RC)
V O = G VS
-1/2 G +1/2
R2
}
VS
R1
}
Inverting Amplifier
Equivalent L-R Circuit
R2
C1
–
VS
VO
+
+
–
R1
ZIN
VO = 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
FN8197 Rev 1.00
April 26, 2006
Page 19 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Thin Shrink Small Outline Plastic Packages (TSSOP)
M14.173
N
INDEX
AREA
E
0.25(0.010) M
E1
2
SYMBOL
3
0.05(0.002)
-A-
INCHES
GAUGE
PLANE
-B1
14 LEAD THIN SHRINK SMALL OUTLINE PLASTIC
PACKAGE
B M
L
A
D
-C-
e
A1
b
0.10(0.004) M
0.25
0.010
SEATING PLANE
A2
c
0.10(0.004)
C A M
B S
MIN
1. These package dimensions are within allowable dimensions of
JEDEC MO-153-AC, Issue E.
MILLIMETERS
MIN
MAX
NOTES
A
-
0.047
-
1.20
-
A1
0.002
0.006
0.05
0.15
-
A2
0.031
0.041
0.80
1.05
-
b
0.0075
0.0118
0.19
0.30
9
c
0.0035
0.0079
0.09
0.20
-
D
0.195
0.199
4.95
5.05
3
E1
0.169
0.177
4.30
4.50
4
e
0.026 BSC
0.65 BSC
-
E
0.246
0.256
6.25
6.50
-
L
0.0177
0.0295
0.45
0.75
6
8o
0o
N
NOTES:
MAX
14
0o
14
7
8o
Rev. 2 4/06
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm
(0.006 inch) per side.
4. Dimension “E1” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.15mm (0.006 inch) per
side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. Dimension “b” does not include dambar protrusion. Allowable dambar
protrusion shall be 0.08mm (0.003 inch) total in excess of “b” dimension at maximum material condition. Minimum space between protrusion and adjacent lead is 0.07mm (0.0027 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact. (Angles in degrees)
FN8197 Rev 1.00
April 26, 2006
Page 20 of 21
X9428 Low Noise/Low Power/2-Wire Bus
Small Outline Plastic Packages (SOIC)
M16.3 (JEDEC MS-013-AA ISSUE C)
N
16 LEAD WIDE BODY SMALL OUTLINE PLASTIC PACKAGE
INDEX
AREA
H
0.25(0.010) M
B M
INCHES
E
-B-
1
2
3
L
SEATING PLANE
-A-
A
D
h x 45°
-C-
e
A1
B
0.25(0.010) M
C
0.10(0.004)
C A M
SYMBOL
MIN
MAX
MIN
MAX
NOTES
A
0.0926
0.1043
2.35
2.65
-
A1
0.0040
0.0118
0.10
0.30
-
B
0.013
0.0200
0.33
0.51
9
C
0.0091
0.0125
0.23
0.32
-
D
0.3977
0.4133
10.10
10.50
3
E
0.2914
0.2992
7.40
7.60
4
e
B S
0.050 BSC
1.27 BSC
-
H
0.394
0.419
10.00
10.65
-
h
0.010
0.029
0.25
0.75
5
L
0.016
0.050
0.40
1.27
6
N
NOTES:
MILLIMETERS
16
0°
16
8°
0°
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.
7
8°
Rev. 1 6/05
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Interlead
flash and protrusions shall not exceed 0.25mm (0.010 inch) per side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater above
the seating plane, shall not exceed a maximum value of 0.61mm (0.024
inch)
10. Controlling dimension: MILLIMETER. Converted inch dimensions are
not necessarily exact.
© Copyright Intersil Americas LLC 2005-2006. All Rights Reserved.
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For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such
modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets 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.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN8197 Rev 1.00
April 26, 2006
Page 21 of 21