DATASHEET
OBSOLETE PRODUCT
POSSIBLE SUBSTITUTE PRODUCT
ISL22346
ISL22349
Quad Digitally Controlled Potentiometers (XDCP™) Low Noise, Low Power, I2C™
Bus, 128 Taps, Wiper Only
The ISL22349 integrates four digitally controlled
potentiometers (DCP) and non-volatile memory on a
monolithic CMOS integrated circuit.
FN6331
Rev 3.00
May 28, 2009
Features
• Four potentiometers in one package
The digitally controlled potentiometers are implemented with
a combination of resistor elements and CMOS switches. The
position of the wipers are controlled by the user through the
I2C bus interface. Each potentiometer has an associated
volatile Wiper Register (WR) and a non-volatile Initial Value
Register (IVR) that can be directly written to and read by the
user. The contents of the WR controls the position of the
wiper. At power up the device recalls the contents of the two
DCP’s IVR to the corresponding WRs.
The DCPs can be used as a voltage divider in a wide variety
of applications including control, parameter adjustments, AC
measurement and signal processing.
Pinout
ISL22349
(14 LD TSSOP)
TOP VIEW
• 128 resistor taps
• I2C serial interface
- Three address pins, up to eight devices/bus
• Non-volatile storage of wiper position
• Wiper resistance: 70 typical
• Shutdown mode
• Shutdown current 6.5µA max
• Power supply: 2.7V to 5.5V
• 50kor 10k total resistance
• High reliability
- Endurance: 1,000,000 data changes per bit per register
- Register data retention: 50 years @ T < +55°C
• 14 Ld TSSOP
• Pb-free (RoHS compliant)
RW3
1
14
RW0
A2
2
13
SHDN
SCL
3
12
VCC
SDA
4
11
NC
GND
5
10
A1
RW2
6
9
A0
RW1
7
8
NC
Ordering Information
PART NUMBER
(Note)
PART
MARKING
RESISTANCE OPTION
(k)
TEMP. RANGE
(°C)
PACKAGE
(Pb-free)
PKG.
DWG. #
ISL22349UFV14Z*
22349 UFVZ
50
-40 to +125
14 Ld TSSOP
M14.173
ISL22349WFV14Z*
22349 WFVZ
10
-40 to +125
14 Ld TSSOP
M14.173
*Add “-TK” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100%
matte tin plate plus anneal (e3 termination finish, which is 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.
FN6331 Rev 3.00
May 28, 2009
Page 1 of 13
ISL22349
Block Diagram
VCC
VCC
WR3
SCL
SDA
A0
I2C
INTERFACE
A1
POWER-UP
INTERFACE,
CONTROL
AND STATUS
LOGIC
RW3
VCC
WR2
RW2
A2
VCC
WR1
NONVOLATILE
REGISTERS
SHDN
RW1
VCC
WR0
RW0
GND
Pin Descriptions
TSSOP PIN
SYMBOL
1
RW3
2
A2
3
SCL
Open drain I2C interface clock input
4
SDA
Open drain serial data I/O for the I2C interface
5
GND
Device ground pin and the RL connection for each DCP
6
RW2
“Wiper” terminal of DCP2
7
RW1
“Wiper” terminal of DCP1
8
NC
9
A0
Device address input for the I2C interface
10
A1
Device address input for the I2C interface
11
NC
12
VCC
13
SHDN
Shutdown active low input
14
RW0
“Wiper” terminal of DCP0
FN6331 Rev 3.00
May 28, 2009
DESCRIPTION
“Wiper” terminal of DCP3
Device address input for the I2C interface
Power supply pin and the RH connection for each DCP
Page 2 of 13
ISL22349
Absolute Maximum Ratings
Thermal Information
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Voltage at any Digital Interface Pin
with Respect to GND . . . . . . . . . . . . . . . . . . . . -0.3V to VCC + 0.3
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6V
Voltage at any DCP Pin with Respect to GND. . . . . . . -0.3V to VCC
IW (10s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±6mA
Latchup (Note 2) . . . . . . . . . . . . . . . . . . Class II, Level B @ +125°C
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5kV
Charged Device Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1kV
Thermal Resistance (Typical, Note 1)
JA (°C/W)
14 Ld TSSOP package . . . . . . . . . . . . . . . . . . . . . .
+100
Max Junction Temperature (Plastic Package) . .
+50°C to +150°C
Pb-Free Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
Ambient Temperature . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C
VCC Voltage for DCP Operation . . . . . . . . . . . . . . . . . . 2.7V to 5.5V
Wiper Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -3mA to 3mA
Power Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5mW
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTES:
1. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
2. Jedec Class II pulse conditions and failure criterion used. Level B exceptions are: using a max positive pulse of 6.5V on the SHDN pin, and using
a max negative pulse of -0.8V for all pins.
Analog Specifications
SYMBOL
RTOTAL
Over recommended operating conditions unless otherwise stated.
PARAMETER
End-to-End Resistance
TEST CONDITIONS
MIN
(Note 13)
TYP
(Note 3)
MAX
(Note 13)
UNIT
W option
10
k
U option
50
k
End-to-End Resistance Tolerance
W and U option
End-to-End Temperature Coefficient
W option
±50
ppm/°C
(Note 11)
U option
±80
ppm/°C
(Note 11)
VCC = 3.3V @ +25°C,
wiper current = VCC/RTOTAL
70
25
pF
RW
(Note 13)
Wiper Resistance
CW
(Note 11)
Wiper Capacitance
-20
+20
%
VOLTAGE DIVIDER MODE (measured at RWi, unloaded; i = 0, 1, 2, or 3)
INL
(Note 8)
Integral Non-linearity
Monotonic over all tap positions
-1
1
LSB
(Note 4)
DNL
(Note 7)
Differential Non-linearity
Monotonic over all tap positions
-0.5
0.5
LSB
(Note 4)
ZSerror
(Note 5)
Zero-scale Error
W option
0
1
5
U option
0
0.5
2
LSB
(Note 4)
FSerror
(Note 6)
Full-scale Error
W option
-5
-1
0
U option
-2
-1
0
VMATCH
(Note 9)
DCP to DCP Matching
Any two DCPs at the same tap position
-2
TCV
(Note 10)
Ratiometric Temperature Coefficient
DCP register set to 40 hex
FN6331 Rev 3.00
May 28, 2009
2
±4
LSB
(Note 4)
LSB
(Note 4)
ppm/°C
Page 3 of 13
ISL22349
Operating Specifications Over the recommended operating conditions unless otherwise specified.
SYMBOL
ICC1
ICC2
ISB
ISD
PARAMETER
TEST CONDITIONS
MIN
(Note 13)
TYP
(Note 3)
MAX
(Note 13)
UNIT
VCC Supply Current (volatile
write/read)
VCC = +3.6V, 10k DCP, fSCL = 400kHz; (for
I2C active, read and write states)
2.5
mA
VCC Supply Current (volatile
write/read, non-volatile read)
VCC = +3.6V, 50k DCP, fSCL = 400kHz; (for
I2C active, read and write states)
0.65
mA
VCC Supply Current (non-volatile
write/read)
VCC = +5.5V, 10k DCP, fSCL = 400kHz; (for
I2C active, read and write states)
4.0
mA
VCC Supply Current (non-volatile
write/read)
VCC = +5.5V, 50k DCP, fSCL = 400kHz; (for
I2C active, read and write states)
3.0
mA
VCC Current (standby)
VCC = +5.5V, 10k DCP, I2C interface in
standby state
2.4
mA
VCC = +3.6V, 10k DCP, I2C interface in
standby state
525
µA
VCC = +5.5V, 50k DCP, I2C interface in
standby state
1.6
mA
VCC = +3.6V, 50k DCP, I2C interface in
standby state
350
µA
VCC = +5.5V @ +85°C, I2C interface in
standby state
5
µA
VCC = +5.5V @ +125°C, I2C interface in
standby state
6.5
µA
VCC = +3.6V @ +85°C, I2C interface in
standby state
4
µA
VCC = +3.6V @ +125°C, I2C interface in
standby state
5.5
µA
1
µA
VCC Current (shutdown)
Leakage Current, at Pins A0, A1, A2,
SHDN, SDA, and SCL
Voltage at pin from GND to VCC
tWRT
(Note 11)
DCP Wiper Response Time
SCL falling edge of last bit of DCP data byte
to wiper new position
1.5
µs
tShdnRec
(Note 11)
DCP Recall Time from Shutdown
Mode
From rising edge of SHDN signal to wiper
stored position and RH connection
1.5
µs
SCL falling edge of last bit of ACR data byte
to wiper stored position and RH connection
1.5
µs
ILkgDig
Vpor
Power-on Recall Voltage
VccRamp
VCC Ramp Rate
tD
Power-up Delay
Minimum VCC at which memory recall occurs
-1
2.0
2.6
0.2
V
V/ms
3
Vcc above Vpor, to DCP Initial Value
Register recall completed, and I2C Interface
in standby state
ms
EEPROM SPECIFICATION
EEPROM Endurance
EEPROM Retention
tWC
(Note 12)
Non-volatile Write Cycle Time
FN6331 Rev 3.00
May 28, 2009
Temperature T < +55°C
1,000,000
Cycles
50
Years
12
20
ms
Page 4 of 13
ISL22349
Operating Specifications Over the recommended operating conditions unless otherwise specified. (Continued)
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
(Note 13)
TYP
(Note 3)
MAX
(Note 13)
UNIT
SERIAL INTERFACE SPECS
VIL
A2, A1, A0, SHDN, SDA, and SCL
Input Buffer LOW Voltage
-0.3
0.3*VCC
V
VIH
A2, A1, A0, SHDN, SDA, and SCL
Input Buffer HIGH Voltage
0.7*VCC
VCC + 0.3
V
Hysteresis
VOL
Cpin
(Note 11)
SDA and SCL Input Buffer Hysteresis
0.05*
VCC
SDA Output Buffer LOW Voltage,
Sinking 4mA
V
0
A2, A1, A0, SHDN, SDA, and SCL Pin
Capacitance
0.4
10
V
pF
SCL Frequency
400
kHz
tsp
Pulse Width Suppression Time at SDA Any pulse narrower than the max spec is
and SCL Inputs
suppressed
50
ns
tAA
SCL Falling Edge to SDA Output Data SCL falling edge crossing 30% of VCC, until
Valid
SDA exits the 30% to 70% of VCC window
900
ns
fSCL
tBUF
Time the Bus Must be Free Before the SDA crossing 70% of VCC during a STOP
Start of a New Transmission
condition, to SDA crossing 70% of VCC
during the following START condition
1300
ns
tLOW
Clock LOW Time
Measured at the 30% of VCC crossing
1300
ns
tHIGH
Clock HIGH Time
Measured at the 70% of VCC crossing
600
ns
tSU:STA
START Condition Setup Time
SCL rising edge to SDA falling edge; both
crossing 70% of VCC
600
ns
tHD:STA
START Condition Hold Time
From SDA falling edge crossing 30% of VCC
to SCL falling edge crossing 70% of VCC
600
ns
tSU:DAT
Input Data Setup Time
From SDA exiting the 30% to 70% of VCC
window, to SCL rising edge crossing 30% of
VCC
100
ns
tHD:DAT
Input Data Hold Time
From SCL rising edge crossing 70% of VCC
to SDA entering the 30% to 70% of VCC
window
0
ns
tSU:STO
STOP Condition Setup Time
From SCL rising edge crossing 70% of VCC,
to SDA rising edge crossing 30% of VCC
600
ns
tHD:STO
STOP Condition Hold Time for Read,
or Volatile Only Write
From SDA rising edge to SCL falling edge;
both crossing 70% of VCC
1300
ns
Output Data Hold Time
From SCL falling edge crossing 30% of VCC,
until SDA enters the 30% to 70% of VCC
window
0
ns
tR
SDA and SCL Rise Time
From 30% to 70% of VCC
20 +
0.1*Cb
250
ns
tF
SDA and SCL Fall Time
From 70% to 30% of VCC
20 +
0.1*Cb
250
ns
Cb
Capacitive Loading of SDA or SCL
Total on-chip and off-chip
10
400
pF
Rpu
SDA and SCL Bus Pull-up Resistor
Off-chip
Maximum is determined by tR and tF
For Cb = 400pF, max is about 2~2.5k
For Cb = 40pF, max is about 15~20k
1
tDH
FN6331 Rev 3.00
May 28, 2009
k
Page 5 of 13
ISL22349
Operating Specifications Over the recommended operating conditions unless otherwise specified. (Continued)
SYMBOL
PARAMETER
MIN
(Note 13)
TEST CONDITIONS
TYP
(Note 3)
MAX
(Note 13)
UNIT
tSU:A
A2, A1 and A0 Setup Time
Before START condition
600
ns
tHD:A
A2, A1 and A0 Hold Time
After STOP condition
600
ns
NOTES:
3. Typical values are for TA = +25°C and 3.3V supply voltage.
4. LSB: [V(RW)127 – V(RW)0]/127. V(RW)127 and V(RW)0 are V(RW) for the DCP register set to 7F hex and 00 hex respectively. LSB is the
incremental voltage when changing from one tap to an adjacent tap.
5. ZS error = V(RW)0/LSB.
6. FS error = [V(RW)127 – VCC]/LSB.
7. DNL = [V(RW)i – V(RW)i-1]/LSB-1, for i = 1 to 127. i is the DCP register setting.
8. INL = [V(RW)i – i • LSB – V(RW)0]/LSB for i = 1 to 127.
9. VMATCH = [V(RWx)i – V(RWy)i]/LSB, for i = 1 to 127, x = 0 to 3 and y = 0 to 3.
Max V RW i – Min V RW i
10 6
10. TC V = ---------------------------------------------------------------------------------------------- ----------------- for i = 16 to 112 decimal, T = -40°C to +125°C. Max( ) is the maximum value of the wiper
Max V RW i + Min V RW i 2 165°C minimum value of the resistance over the temperature range.
11. This parameter is not 100% tested.
12. tWC is the time from a valid STOP condition at the end of a Write sequence of I2C serial interface, to the end of the self-timed internal non-volatile
write cycle.
13. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization
and are not production tested.
SDA vs SCL Timing
tHIGH
tF
SCL
tLOW
tsp
tR
tSU:DAT
tSU:STA
SDA
(INPUT TIMING)
tHD:DAT
tHD:STA
tSU:STO
tAA
tDH
tBUF
SDA
(OUTPUT TIMING)
A0, A1, and A2 Pin Timing
STOP
START
SCL
CLK 1
SDA
tSU:A
tHD:A
A0, A1, OR A2
FN6331 Rev 3.00
May 28, 2009
Page 6 of 13
ISL22349
Typical Performance Curves
100
90
1.2
80
60
50
40
30
0.8
0.6
0.4
VCC = 3.3V, T = -40°C
VCC = 3.3V, T = +20°C
20
0.2
10
0
T = +125°C
1.0
70
Isb (µA)
WIPER RESISITANCE ()
1.4
VCC = 3.3V, T = +125°C
0
20
40
60
80
100
T = +25°C
0
2.7
120
3.2
3.7
TAP POSITION (DECIMAL)
0.2
T = +25°C
0.1
0.1
INL (LSB)
DNL (LSB)
5.2
0.2
T = +25°C
VCC = 2.7V
0
-0.1
VCC = 2.7V
0
-0.1
VCC = 5.5V
VCC = 5.5V
0
20
40
60
80
100
TAP POSITION (DECIMAL)
-0.2
120
FIGURE 3. DNL vs TAP POSITION IN VOLTAGE DIVIDER
MODE FOR 10k (W)
1.1
40
60
80
100
TAP POSITION (DECIMAL)
120
0.0
-0.3
FSerror (LSB)
0.7
VCC = 2.7V
VCC = 5.5V
0.3
VCC = 2.7V
50k
VCC = 5.5V
-0.6
-0.9
10k
0.1
-1.2
50k
-0.1
-0.3
-40
20
10k
0.9
0.5
0
FIGURE 4. INL vs TAP POSITION IN VOLTAGE DIVIDER
MODE FOR 10k (W)
1.3
ZSerror (LSB)
4.7
FIGURE 2. STANDBY ICC vs VCC
FIGURE 1. WIPER RESISTANCE vs TAP POSITION
[ I(RW) = VCC/RTOTAL ] FOR 10k (W)
-0.2
4.2
VCC (V)
-20
0
20
40
60
TEMPERATURE (ºC)
80
FIGURE 5. ZSerror vs TEMPERATURE
FN6331 Rev 3.00
May 28, 2009
100
120
-1.5
-40
-20
0
20
40
60
TEMPERATURE (ºC)
80
100
120
FIGURE 6. FSerror vs TEMPERATURE
Page 7 of 13
ISL22349
Typical Performance Curves
(Continued)
105
VCC = 2.7V
90
0.5
50k
0.0
60
45
30
-0.5
50
10k
15
VCC = 5.5V
-1.0
-40
10
75
TCv (ppm/°C)
END-TO-END RTOTAL CHANGE (%)
1.0
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 7. END-TO-END RTOTAL % CHANGE vs
TEMPERATURE
0
16
36
56
76
TAP POSITION (DECIMAL)
96
FIGURE 8. TC FOR VOLTAGE DIVIDER MODE IN ppm
SCL
SIGNAL AT WIPER
(WIPER UNLOADED)
SIGNAL AT WIPER
(WIPER UNLOADED) MOVEMENT
FROM 7Fh TO 00h
FIGURE 9. MIDSCALE GLITCH, CODE 3Fh TO 40h
FIGURE 10. LARGE SIGNAL SETTLING TIME
Pin Descriptions
Potentiometers Pins
RWI (I = 0, 1, 2 OR 3)
RWi is the wiper terminal and is equivalent to the movable
terminal of a mechanical potentiometer. The position of the
wiper within the array is determined by the WRi register.
RW
SHDN
The SHDN pin forces the resistor to end-to-end open circuit
condition and shorts all RWi to GND. When SHDN is
returned to logic high, the previous latch settings put RWi at
the same resistance setting prior to shutdown. This pin is
logically AND with SHDN bit in ACR register. I2C interface is
still available in shutdown mode and all registers are
accessible. This pin must remain HIGH for normal operation.
FIGURE 11. DCP CONNECTION IN SHUTDOWN MODE
Bus Interface Pins
SERIAL DATA INPUT/OUTPUT (SDA)
The SDA is a bidirectional serial data input/output pin for I2C
interface. It receives device address, operation code, wiper
address and data from an I2C external master device at the
rising edge of the serial clock SCL, and it shifts out data after
each falling edge of the serial clock.
SDA requires an external pull-up resistor, since it is an open
drain input/output.
FN6331 Rev 3.00
May 28, 2009
Page 8 of 13
ISL22349
SERIAL CLOCK (SCL)
Memory Description
This is the serial clock input of the I2C serial interface. SCL
The ISL22349 contains seven non-volatile and five volatile 8bit registers. The memory map of ISL22349 is on Table 1. The
four non-volatile registers (IVRi) at address 0, 1, 2 and 3,
contain initial wiper value and volatile registers (WRi) contain
current wiper position. In addition, three non-volatile General
Purpose registers from address 4 to address 6 are available.
requires an external pull-up resistor, since it is an open drain
input.
DEVICE ADDRESS (A2 - A0)
The address inputs are used to set the least significant 3 bits of
the 7-bit I2C interface slave address. A match in the slave
address serial data stream must match with the Address input
pins in order to initiate communication with the ISL22349. A
maximum of 8 ISL22349 devices may occupy the I2C serial
bus.
Principles of Operation
The ISL22349 is an integrated circuit incorporating four DCPs
with their associated registers, non-volatile memory and an I2C
serial interface providing direct communication between a host
and the potentiometers and memory. The resistor arrays are
comprised of individual resistors connected in series. At either
end of the array and between each resistor is an electronic
switch that transfers the potential at that point to the wiper.
The electronic switches on the device operate in a “make
before break” mode when the wiper changes tap positions.
When the device is powered down, the last value stored in IVRi
will be maintained in the non-volatile memory. When power is
restored, the contents of the IVRi are recalled and loaded into
the corresponding WRi to set the wipers to the initial value.
DCP Description
Each DCP is implemented with a combination of resistor
elements and CMOS switches. The physical ends of each DCP
are equivalent to the fixed terminals of a mechanical
potentiometer and internally connected to Vcc and GND. The
RW pin of each DCP is connected to intermediate nodes, and
is equivalent to the wiper terminal of a mechanical
potentiometer. The position of the wiper terminal within the
DCP is controlled by volatile Wiper Register (WR). Each DCP
has its own WR. When the WR of a DCP contains all zeroes
(WR[6:0] = 00h), its wiper terminal (RW) is closest to GND.
When the WR register of a DCP contains all ones (WR[6:0] =
7Fh), its wiper terminal (RW) is closest to VCC. As the value of
the WR increases from all zeroes (0) to all ones (127 decimal),
the wiper moves monotonically from the position closest to
GND to the closest to VCC.
While the ISL22349 is being powered up, all four WRs are
reset to 40h (64 decimal), which locates RW roughly at the
center between GND and VCC. After the power supply voltage
becomes large enough for reliable non-volatile memory
reading, all WRs will be reload with the value stored in
corresponding non-volatile Initial Value Registers (IVRs).
The WRs can be read or written to directly using the I2C serial
interface as described in the following sections. The I2C
interface Address Byte has to be set to 00h, 01h, 02h or 03h to
access the WR of DCP0, DCP1, DCP2 or DCP3 respectively.
FN6331 Rev 3.00
May 28, 2009
TABLE 1. MEMORY MAP
ADDRESS
NON-VOLATILE
VOLATILE
8
—
ACR
7
Reserved
6
5
4
General Purpose
General Purpose
General Purpose
Not Available
Not Available
Not Available
3
2
1
0
IVR3
IVR2
IVR1
IVR0
WR3
WR2
WR1
WR0
The non-volatile IVRi and volatile WRi registers are accessible
with the same address.
The Access Control Register (ACR) contains information and
control bits described below in Table 2. The VOL bit at access
control register (ACR[7]) determines whether the access is to
wiper registers WRi or initial value registers IVRi.
TABLE 2. ACCESS CONTROL REGISTER (ACR)
VOL
SHDN
0
WIP
0
0
0
0
If VOL bit is 0, the non-volatile IVRi registers are accessible. If
VOL bit is 1, only the volatile WRi are accessible. Note, value
is written to IVRi register also is written to the corresponding
WRi. The default value of this bit is 0.
The SHDN bit (ACR[6]) disables or enables Shutdown mode.
This bit is logically AND with SHDN pin. When this bit is 0,
DCPs are in Shutdown mode. Default value of SHDN bit is 1.
The WIP bit (ACR[5]) is read only bit. It indicates that
non-volatile write operation is in progress. It is impossible to
write to the WRi or ACR while WIP bit is 1.
Shutdown Mode
The device can be put in Shutdown mode either by pulling the
SHDN pin to GND or setting the SHDN bit in the ACR register to
0. The truth table for Shutdown mode is in Table 3.
TABLE 3.
SHDN pin
SHDN bit
Mode
High
1
Normal operation
Low
1
Shutdown
High
0
Shutdown
Low
0
Shutdown
Page 9 of 13
ISL22349
I2C Serial Interface
The ISL22349 supports an I2C 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 always
initiates data transfers and provides the clock for both transmit
and receive operations. Therefore, the ISL22349 operates as a
slave device in all applications.
All communication over the I2C interface is conducted by
sending the MSB of each byte of data first.
Protocol Conventions
Data states on the SDA line must change only during SCL
LOW periods. SDA state changes during SCL HIGH are
reserved for indicating START and STOP conditions
(see Figure 12). On power-up of the ISL22349 the SDA pin is
in the input mode.
All I2C interface operations must begin with a START
condition, which is a HIGH to LOW transition of SDA while SCL
is HIGH. The ISL22349 continuously monitors the SDA and
SCL lines for the START condition and does not respond to
any command until this condition is met. A START condition is
ignored during the power-up of the device.
All I2C interface operations must be terminated by a STOP
condition, which is a LOW to HIGH transition of SDA while SCL
is HIGH (see Figure 12). A STOP condition at the end of a read
operation, or at the end of a write operation places the device
in its standby mode.
An ACK, Acknowledge, is a software convention used to
indicate a successful data transfer. The transmitting device,
either master or slave, releases the SDA bus after transmitting
eight bits. During the ninth clock cycle, the receiver pulls the
SDA line LOW to acknowledge the reception of the eight bits of
data (See Figure 13).
The ISL22349 responds with an ACK after recognition of a
START condition followed by a valid Identification Byte, and
once again after successful receipt of an Address Byte. The
ISL22349 also responds with an ACK after receiving a Data
Byte of a write operation. The master must respond with an
ACK after receiving a Data Byte of a read operation.
A valid Identification Byte contains 1010b as the four MSBs,
and the following three bits matching the logic values present
at pins A2, A1, and A0. The LSB is the Read/Write bit. Its value
is “1” for a Read operation, and “0” for a Write operation (see
Table 4).
TABLE 4. IDENTIFICATION BYTE FORMAT
Logic values at pins A2, A1, and A0 respectively
1
0
1
0
A2
A1
(MSB)
A0
R/W
(LSB)
SCL
SDA
START
DATA
STABLE
DATA
CHANGE
DATA
STABLE
STOP
FIGURE 12. VALID DATA CHANGES, START AND STOP CONDITIONS
SCL FROM
MASTER
1
8
SDA OUTPUT FROM
TRANSMITTER
9
HIGH IMPEDANCE
HIGH IMPEDANCE
SDA OUTPUT FROM
RECEIVER
START
ACK
FIGURE 13. ACKNOWLEDGE RESPONSE FROM RECEIVER
FN6331 Rev 3.00
May 28, 2009
Page 10 of 13
ISL22349
WRITE
S
T
A
R
T
SIGNALS FROM
THE MASTER
SIGNAL AT SDA
IDENTIFICATION
BYTE
ADDRESS
BYTE
1 0 1 0 A2 A1 A0 0
SIGNALS FROM
THE SLAVE
S
T
O
P
DATA
BYTE
0 0 0 0
A
C
K
A
C
K
A
C
K
FIGURE 14. BYTE WRITE SEQUENCE
SIGNALS
FROM THE
MASTER
S
T
A
R
T
SIGNAL AT SDA
SIGNALS FROM
THE SLAVE
IDENTIFICATION
BYTE WITH
R/W = 0
S
T
A IDENTIFICATION
R
BYTE WITH
T
R/W = 1
ADDRESS
BYTE
1 0 1 0 A2 A1 A0 0
S
A T
C O
K P
A
C
K
1 0 1 0 A2 A1 A0 1
0 0 0 0
A
C
K
A
C
K
A
C
K
A
C
K
FIRST READ
DATA BYTE
LAST READ
DATA BYTE
FIGURE 15. READ SEQUENCE
FN6331 Rev 3.00
May 28, 2009
Page 11 of 13
ISL22349
Write Operation
Read Operation
A Write operation requires a START condition, followed by a
valid Identification Byte, a valid Address Byte, a Data Byte, and
a STOP condition. After each of the three bytes, the ISL22349
responds with an ACK. At this time, the device enters its
standby state (see Figure 14). Device can receive more than
one byte of data by auto incrementing the address after each
received byte. Note after reaching the address 08h, the internal
pointer “rolls over” to address 00h.
A Read operation consist of a three byte instruction followed by
one or more Data Bytes (See Figure 15). The master initiates
the operation issuing the following sequence: a START, the
Identification byte with the R/W bit set to “0”, an Address Byte,
a second START, and a second Identification byte with the R/W
bit set to “1”. After each of the three bytes, the ISL22349
responds with an ACK. Then the ISL22349 transmits Data
Bytes as long as the master responds with an ACK during the
SCL cycle following the eighth bit of each byte. The master
terminates the read operation (issuing a ACK and a STOP
condition) following the last bit of the last Data Byte (see Figure
15).
The non-volatile write cycle starts after STOP condition is
determined and it requires up to 20ms delay for the next nonvolatile write. Thus, non-volatile registers must be written
individually.
The Data Bytes are from the registers indicated by an internal
pointer. This pointer initial value is determined by the Address
Byte in the Read operation instruction, and increments by one
during transmission of each Data Byte. After reaching the
memory location 08h, the pointer “rolls over” to 00h, and the
device continues to output data for each ACK received.
In order to read back the non-volatile IVR, it is recommended
that the application reads the ACR first to verify the WIP bit is
0. If the WIP bit (ACR[5]) is not 0, the host should repeat its
reading sequence again.
FN6331 Rev 3.00
May 28, 2009
Page 12 of 13
ISL22349
Thin Shrink Small Outline Plastic Packages (TSSOP)
N
INDEX
AREA
E
0.25(0.010) M
E1
2
INCHES
SYMBOL
3
0.05(0.002)
-A-
14 LEAD THIN SHRINK SMALL OUTLINE PLASTIC
PACKAGE
GAUGE
PLANE
-B1
M14.173
B M
SEATING PLANE
L
A
D
-C-
e
A2
A1
b
0.10(0.004) M
0.25
0.010
c
0.10(0.004)
C A M
B S
NOTES:
1. These package dimensions are within allowable dimensions of
JEDEC MO-153-AC, Issue E.
MIN
MAX
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
14
0o
14
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
7
8o
Rev. 2 4/06
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)
© Copyright Intersil Americas LLC 2006-2009. All Rights Reserved.
All trademarks and registered trademarks are the property of their respective owners.
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
FN6331 Rev 3.00
May 28, 2009
Page 13 of 13
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