ISL23325 Datasheet, PDF (1/20 Pages) Intersil Corporation – Dual, 256-Tap, Low Voltage Digitally Controlled Potentiometer (XDCP™)

Dual, 256-Tap, Low Voltage Digitally Controlled
Potentiometer (XDCP™)
ISL23325
The ISL23325 is a volatile, low voltage, low noise, low power,
256-Tap, dual digitally controlled potentiometer (DCP) with an
I²C Bus™ interface. It integrates two DCP cores, wiper switches
and control logic on a monolithic CMOS integrated circuit.
Each 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 I²C
bus interface. Each potentiometer has an associated volatile
Wiper Register (WRi, i = 0, 1) that can be directly written to and
read by the user. The contents of the WRi controls the position
of the wiper. When powered on, the wiper of each DCP will
always commence at mid-scale (128 tap position).
The low voltage, low power consumption, and small package
of the ISL23325 make it an ideal choice for use in battery
operated equipment. In addition, the ISL23325 has a V_LOGIC
pin allowing down to 1.2V bus operation, independent from the
V_CC value. This allows for low logic levels to be connected
directly to the ISL23325 without passing through a voltage
level shifter.
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
• Power supply margining
• Trimming sensor circuits
• Gain adjustment in battery powered instruments
• RF power amplifier bias compensation
Features
• Two potentiometers per package
• 256 resistor taps
• 10kΩ 50kΩ or 100kΩ total resistance
• I²C serial interface
- No additional level translator for low bus supply
- Three address pins allow up to eight devices per bus
• Maximum supply current without serial bus activity
(standby)
- 3µA @ V_CC and V_LOGIC = 5V
- 1.7µA @ V_CCand V_LOGIC = 1.7V
• Shutdown Mode
- Forces the DCP into an end-to-end open circuit and RWi is
connected to RLi internally
- Reduces power consumption by disconnecting the DCP
resistor from the circuit
• Power supply
- V_CC = 1.7V to 5.5V analog power supply
- V_LOGIC = 1.2V to 5.5V I²C bus/logic power supply
• Wiper resistance: 70Ω typical @ V_CC = 3.3V
• Power-on preset to mid-scale (128 tap position)
• Extended industrial temperature range: -40°C to +125°C
• 14 Ld TSSOP or 16 Ld µTQFN packages
• Pb-free (RoHS Compliant)
10000
8000
6000
4000
2000
0
0
64
128
192
256
TAP POSITION (DECIMAL)
FIGURE 1. FORWARD AND BACKWARD RESISTANCE vs TAP
POSITION, 10kΩ DCP
VREF
RH1
1 DCP
OF
ISL23325
RW1
RL1
-
+
ISL28114
VREF_M
FIGURE 2. V_REF ADJUSTMENT
June 21, 2011
1
FN7870.0
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Intersil (and design) and XDCP are trademarks owned by Intersil Corporation or one of its subsidiaries.
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