DS1667
Digital Resistor with OP AMP
www.dalsemi.com
FEATURES
Two digitally controlled 256-position
potentiometers
Serial port provides means for setting and
reading both potentiometers
Resistors can be connected in series to
provide additional resolution
Default wiper position on power up is 50%
Resistive elements are temperature-
compensated to +20% end to end
Two high-gain, wide bandwidth operational
amplifiers
Low power CMOS design
Applications include analog-to-digital and
digital-to-analog converters, variable
oscillators, and variable gain amplifiers
20-pin DIP package or optional 20-pin SOIC
surface mount package
Operating temperature range
- Commercial: 0掳C to 70掳C
Resistance values:
RESOLUTION -3 dB POINT
DS1667-10: 10k 39 ohms
1.1 MHz
DS1667-50: 50k 195 ohms
200 kHz
DS1667-100: 100k 390 ohms 100 kHz
PIN ASSIGNMENT
NINV0
INV0
V
B
W1
H1
L1
RST
CLK
OUT1
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
CC
OUT0
SOUT
W0
H0
L0
COUT
DQ
INVI
NINVI
20-Pin DIP (300-mil) and 20-Pin SOIC
See Mech. Drawings Section
PIN DESCRIPTION
V
CC
GND
L0, L1
H0, H1
W0, W1
V
B
SOUT
RST
DQ
CLK
COUT
NINV0, NINVI
INV0, INVI
OUT0, OUT1
- +5-Volt Supply
- Ground
- Low End of Resistor
- High End of Resistor
- Wiper End of Resistor
- Substrate Bias and OP
AMP Negative Supply
- Wiper for Stacked
Configuration
- Serial Port Reset Input
- Serial Port Input/Output
- Serial Port Clock Input
- Cascade Serial Port
Output
- Noninverting OP AMP
Input
- Inverting OP AMP Input
- OP AMP Outputs
DESCRIPTION
The DS1667 is a dual-solid state potentiometer that is adjustable by digitally selected resistive elements.
Each potentiometer is composed of 256 resistive elements. Between each resistive section of each
potentiometer are tap points accessible to the wiper. The position of the wiper on the resistive array is set
by an 8-bit register that controls which tap point is connected to the wiper output. Each 8-bit register can
be read or written by sending or receiving data bits over a 3-wire serial port. In addition, the resistors can
be stacked such that a single potentiometer of 512 sections results. When two separate potentiometers are
used, the resolution of the DS1667 is equal to the resistance value divided by 256. When the
potentiometers are stacked end to end, the resistance value is doubled while the resolution remains the
1 of 10
032000
1
2
3
4
5
6
7
8
9
10
