Rainbow Electronics DS1866 User Manual
www.dalsemi.com
DS1866
Log Trimmer Potentiometer
FEATURES
Single 8-position Log Trimmer Potentiometer
5-dB/step
Operates from 2.7V to 5.5V supplies
Parallel interface control: P0, P1, P2
Standard Resistance Value: 10 kΩ
8-pin DIPs; 8-pin (150) SOICs
Operating Temperature Range:
- Industrial: -40°C to +85°C
PIN ASSIGNMENT
1
P0
P1
2
H
3
GND
See Mech. Drawings Section
GND
See Mech. Drawings Section
4
8-Pin DIP (300-mil)
1
P0
2
P1
3
H
4
8-Pin SOIC (150-mil)
8
V
CC
7
P2
6
L
5
W
V
8
CC
P2
7
L
6
W
5
PIN DESCRIPTION
H - High End of Resistor
L - Low End of Resistor
W - Wiper Terminal
V
CC
P0 - Position Select - Bit 0
P1 - Position Select - Bit 1
P2 - Position Select - Bit 2
GND - Ground
- 3V or 5V Power Supply Input
DESCRIPTION
The DS1866 Log Trimmer Potentiometer is a single volatile digital potentiometer having eight positions
with a 5-dB resolution per st ep. The device provides an ideal method for low-cost trimming or volume
control using a CPU or manual control input. The device’s wiper position is set to one of eight positions
by a 3-terminal parallel port. The value of the wiper position is determined by the P0, P1, and P2 port
pins.
The DS1866 is available as a 10k potentiometer and is available in an industrial temperature grade.
Additionally, the DS1866 will operate from 3V or 5V supplies and is ideal for portable applications
requiring low standby current. Two packaging options are available and include the 8-pin (300-mil) DIP,
8-pin (150-mil) SOIC.
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DS1866
OPERATION
The DS1866 is a single volatile potentiometer. The device has a total of eight positions providing a
resolution of 5 dB per step and giving a total attenuation range of 0 dB to -35 dB. These tap points are
accessible to the W-terminal whose position is controlled via a 3-terminal parallel port consisting of input
signals P0, P1, and P2. A block diagram of the DS1866 is shown in Figure 1.
Wiper position setting of the DS1866 is determined by the states of the P0, P1, and P2 input terminals.
Table 1 below outlines position setting versus value of the parallel port inputs. A Position-0 setting places
the wiper position at the L-terminal of the potentiometer and provides 35 dB of attenuation. As wiper
position increases, attenuation decreases with Position-7 giving 0 dB of attenuation.
On power-up, the wiper position of the DS1866 will be set to the P0, P1, and P2 values.
P2 P1 P0
(binary)
000 0 35 dB
001 1 30 dB
010 2 25 dB
011 3 20 dB
100 4 15 dB
101 5 10 dB
110 6 5 dB
111 7 0 dB
Wiper
Position
Attenuation
(dB)
PIN DESCRIPTIONS
VCC - Power Supply Terminal. The DS1866 will support supply voltages ranging from +2.7 to +5.5
volts.
GND - Ground Terminal.
H - High-end Resistor. This is the high-end terminal of the potentiometer. It is not required that this
terminal be connected to a potential greater than the L-terminal. Maximum voltage on the H-terminal can
not exceed the power supply voltage, VCC, or go below ground.
L - Low-end Resistor. This is the low-end terminal of the potentiometer. It is not required that this
terminal be connected to a potential less than the H-terminal. Maximum voltage on the L-terminal can not
exceed the power-supply voltage, VCC, or go below ground.
W - Wiper of the Potentiometer. This pin is the wiper terminal of the potentiometer. Its position on the
resistor array is controlled by the 3-terminal parallel port. Maximum voltage on the W-terminal can not
exceed the power supply voltage, VCC, or go below ground.
P0 - Bit 0. P0 is the bit 0 data input to the parallel port.
P1 - Bit 1. P1 is the bit 1 data input to the parallel port.
P2 - Bit 2. P2 is the bit 2 data input to the parallel port.
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