DS1666-050 DALLAS [Dallas Semiconductor], DS1666-050 Datasheet - Page 2

• Manufacturer Part Number: DS1666-050
• Description: Audio Digital Resistor
• Manufacturer: DALLAS [Dallas Semiconductor]

GRAPH OF AUDIO TAPER Figure 1
OPERATION
The CS, U/D and INC inputs control the position of the
wiper along the resistor array (Figure 1). When CS is ac-
tive (low), a high to low transition on the INC will incre-
ment or decrement an internal counter depending on the
level of the U/D pin. When the U/D pin is low, the counter
will decrement. When the U/D pin is high, the counter will
increment. The state of the U/D pin can be changed while
CS is active allowing for precise adjustment during cali-
bration. The output of the counter is decoded to set the
position of the wiper. When the CS input transitions to the
high (inactive) level, the value of the counter is stored and
the wiper position is maintained until power (V
When power is restored, the DS1666 returns to the de-
fault setting and positions the wiper to 10 percent. The
value of the end–to–end and end–to–wiper position is in-
determinate while V
The DS1666 has a resistor array that resembles an au-
dio taper potentiometer as shown in Figure 1 1. Since
the taper is not linear, exact resistance values for each
of the 128 positions of the resistor is not specified. How-
ever, the end-to-end resistance is specified to be within
trial temperature range of –40 C to +85 C.
DS1666, DS1666S
022698 2/7
20 percent of the stated resistor value over an indus-
100
90
80
70
60
50
40
30
20
10
0
0
LOW TERMINAL
5
10
CC
is not applied.
15
20
25
30
1
3
35
CC
) is lost.
40
% OF ACTIVE DIGITAL TAPS
45
50
ANALOG CHARACTERISTICS
End–to–End Resistance Tolerance = 20 percent
Typical Noise = <120 dB/Hz REF:IV
Temperature Coefficient = 800 PPM/ C typical
Resistance at tap #74=18%
PIN DESCRIPTIONS
V
V
V
Up/Down
(U/D)
Increment
(INC)
Chip Select The device is selected when CS input is
(CS)
H
L
W
55
60
The high end of the potentiometer. This
terminal is capable of handling input volt-
ages between 5 volts.
The Low end of the potentiometer. This
terminal is capable of handling input volt-
ages between 5 volts.
The wiper terminal of the potentiometer.
The value of the wiper is controlled by the
U/D and the INC pins.
The U/D input controls the direc-
tion of the wiper movement when setting
the potentiometer.
Toggling INC will move the potentiome-
ter wiper by either incrementing or decre-
menting the counter.
low. The current counter value is stored
when CS is returned high.
65
70
2
1
75
80
HIGH TERMINAL
2% of total resistance.
85
90
95
100