DATASHEET
ISL23318
FN7887
Rev 0.00
July 26, 2011
Single, 128-taps Low Voltage Digitally Controlled Potentiometer (XDCP™)
The ISL23318 is a volatile, low voltage, low noise, low power,
I C Bus™, 128 Taps, single digitally controlled potentiometer
(DCP), which integrates DCP core, wiper switches and control
logic on a monolithic CMOS integrated circuit.
Features
2
• 128 resistor taps
2
• I C serial interface
- No additional level translator for low bus supply
- Two address pins allow up to four devices per bus
The digitally controlled potentiometer is implemented with a
combination of resistor elements and CMOS switches. The
position of the wipers are controlled by the user through the
• Power supply
2
I C bus interface. The potentiometer has an associated
- V = 1.7V to 5.5V analog power supply
CC
volatile Wiper Register (WR) that can be directly written to and
read by the user. The contents of the WR controls the position
of the wiper. When powered on, the ISL23318’s wiper will
always commence at mid-scale (64 tap position).
2
- V
LOGIC
= 1.2V to 5.5V I C bus/logic power supply
• Wiper resistance: 70Ω typical @ V = 3.3V
CC
• Shutdown Mode - forces the DCP into an end-to-end open
The low voltage, low power consumption, and small package
of the ISL23318 make it an ideal choice for use in battery
circuit and R is shorted to R internally
W
L
• Power-on preset to mid-scale (64 tap position)
• Shutdown and standby current <2.8µA max
operated equipment. In addition, the ISL23318 has a V
LOGIC
pin allowing down to 1.2V bus operation, independent from the
value. This allows for low logic levels to be connected
V
CC
• DCP terminal voltage from 0V to V
CC
directly to the ISL23318 without passing through a voltage
level shifter.
• 10kΩ 50kΩor 100kΩ total resistance
• Extended industrial temperature range: -40°C to +125°C
• 10 Ld MSOP or 10 Ld UTQFN packages
• Pb-free (RoHS compliant)
The DCP 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.
Applications
• Gain adjustment in battery powered instruments
• Trimming sensor circuits
• Power supply margining
• RF power amplifier bias compensation
10000
8000
6000
4000
VREF
RH
-
VREF_M
RW
ISL23318
+
ISL28114
2000
0
RL
0
32
64
96
128
TAP POSITION (DECIMAL)
FIGURE 1. FORWARD AND BACKWARD RESISTANCE vs TAP
POSITION, 10k DCP
FIGURE 2. V
ADJUSTMENT
REF
FN7887 Rev 0.00
July 26, 2011
Page 1 of 19