DS1666, DS1666S
DS1666, DS1666S
Audio Digital Resistor
FEATURES
PIN ASSIGNMENT
NC
U/D
INC
CS
GND
NC
NC
1
2
3
4
5
6
7
14
13
12
11
10
9
8
NC
V
CC
V
B
V
W
V
H
V
L
NC
•
128 position, digitally controlled potentiometer
•
Operates from a +5 volts power supply with TTL sig-
nal inputs
•
Wide analog voltage range of
±5
volts
•
Resistive elements are temperature compensated to
±20
percent end to end
•
Low–power CMOS
•
14–pin DIP or 16–pin SOIC for surface mount applica-
tions
14–PIN DIP (300 MIL)
See Mech. Drawings Section
U/D
NC
NC
INC
NC
CS
NC
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
NC
V
B
V
W
V
H
NC
NC
V
L
•
Default position on power up sets wiper position at
10%
•
Operating temperature range
– –40°C to +85°C; industrial
Resolution/Step
Resistance values Low End High End –3dB Point
DS1666–10 10KΩ
24Ω
152Ω
1.1 MHz
DS1666–50 50KΩ
122Ω
759Ω
200 KHz
DS1666–100100KΩ 243Ω
1.519KΩ 100 KHz
16–PIN SOIC (300 MIL)
See Mech. Drawings Section
PIN DESCRIPTION
V
H
V
L
V
W
U/D
INC
CS
NC
V
CC
GND
V
B
–
–
–
–
–
–
–
–
–
–
High Terminal of Resistor
Low Terminal of Resistor
Wiper Terminal of Resistor
Up/Down Control
Wiper Movement Control
Chip Select for Wiper Movement
No Connection
+5 Volts
Ground
0 to –5 Volts
DESCRIPTION
The DS1666 is a solid–state potentiometer which is set
to value by digitally controlled resistive elements. The
potentiometer is composed of 127 resistive sections.
Between each resistive section and both ends of the po-
tentiometer are TAP points accessible to the wiper. The
position of the wiper on the resistance array is controlled
by the CS, U/D and INC inputs. The position of the wiper
defaults to the 10% position on power up. The resolu-
tion of the DS1666 is shown in Figure 1.
The DS1666 Digital Audio Resistor is uniquely designed
to provide a potentiometer that is logarithmic rather than
linear across its entire range. The lower half of the po-
tentiometer advances 1% of total resistance for each
3% of scale advanced, providing for precise amplifica-
tion of low volume signals. The upper half of the poten-
tiometer advances 2% of resistance for every 1% of
scale advanced, providing for the lower resolution gain
required for high volume amplification.
022698 1/7
DS1666, DS1666S
GRAPH OF AUDIO TAPER
Figure 1
100
90
80
70
PERCENT TOTAL RESISTANCE
60
1
50
40
30
20
1
10
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
2
3
LOW TERMINAL
% OF ACTIVE DIGITAL TAPS
HIGH TERMINAL
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
CC
) is lost.
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
CC
is not applied.
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
±20
percent of the stated resistor value over an indus-
trial temperature range of –40°C to +85°C.
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%
±
2% of total resistance.
PIN DESCRIPTIONS
V
H
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.
V
L
V
W
Up/Down
(U/D)
Increment
(INC)
Chip Select The device is selected when CS input is
(CS)
low. The current counter value is stored
when CS is returned high.
022698 2/7
DS1666, DS1666S
BLOCK DIAGRAM
Figure 2
TRANSFER LOGIC
ARRAY
V
H
U/D
INC
CS
7 BIT
COUNTER
WIPER
POSITION
DECODE
1 OF 128
V
L
V
W
MODE SELECTION
Figure 3
CS
L
L
H
INC
U/D
H
L
X
MODE
WIPER UP
WIPER DOWN
STORE WIPER POSITION
022698 3/7
DS1666, DS1666S
ABSOLUTE MAXIMUM RATINGS*
Voltage on CS, INC, U/D, and V
CC
Relative to Ground
Voltage on V
H
, V
L
, and V
W
Relative to Ground
Voltage on V
B
Operating Temperature
Storage Temperature
Soldering Temperature
–0.5V to +7.0V
–6.5V to +6.5V
–6.5V to Ground
–40°C to +85°C
–55°C to +125°C
260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions above those
indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
PARAMETER
Supply Voltage
Input Logic 1
Input Logic 0
V
H
, V
L
, V
W
Voltage
V
B
Voltage
SYMBOL
V
CC
V
IH
V
IL
V
R
V
B
MIN
+4.5
2.0
–0.5
V
B
–0.3
–5.5
TYP
5.0
MAX
5.5
V
CC
+0.5
+0.8
V
CC
+0.3
GND
(–40
°
C to +85
°
C)
UNITS
V
V
V
V
V
NOTES
1
1
1
1
1
DC ELECTRICAL CHARACTERISTICS
PARAMETER
Supply Current
Input Leakage
Wiper Resistance
Wiper Current
SYMBOL
I
CC
I
LI
R
W
I
W
–1
350
MIN
TYP
0.1
(–40
°
C to +85
°
C; V
CC
= 5.0V
±
10%)
MAX
5
+1
650
1
UNITS
mA
µA
Ω
mA
3
NOTES
3
2
CAPACITANCE
PARAMETER
Capacitance
SYMBOL
C
IN
CONDITION
t
A
=25°C
TYP
6
MAX
10
UNITS
pF
(t
A
= 25
°
C)
NOTES
2
022698 4/7
DS1666, DS1666S
AC ELECTRICAL CHARACTERISTICS
PARAMETER
CS to INC Setup
INC High to U/D Change
U/D to INC Setup
INC Low Period
INC High Period
INC Inactive to CS Inactive
CS Deselect Time
SYMBOL
t
CI
t
ID
t
DI
t
IL
t
IH
t
IC
t
CPH
MIN
100
100
1
500
1
500
100
(t
A
=–40
°
C to +85
°
C; V
CC
=+5V
±
10%)
TYP
MAX
UNITS
ns
ns
µs
ns
µs
ns
ns
NOTES
AC TIMING
Figure 4
CS
t
CI
t
IL
t
IH
INC
t
IC
t
CPH
t
ID
t
DI
U/D
t
IW
V
W
V
VH
V
VL
NOTES:
1. All voltages are referenced to ground.
2. This parameter is periodically sampled and not 100% tested.
3. Typical values are for t
A
= 25°C and nominal supply voltages.
4. Wiper output open circuited.
AC TEST CONDITIONS
Input Pulse Levels
Input Rise and Fall Times
Input Level
0V to 3V
10 ns
1.5V
022698 5/7
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