Rainbow Electronics DS1669S User Manual
Dallastat
DS1668, DS1669, DS1669S
DS1668, DS1669, DS1669S
TM
Electronic Digital Rheostat
FEATURES
• Replaces mechanical variable resistors
• Available as the DS1668 with manual interface or the
DS1669 integrated circuit
• Human engineered interface provides easy control
with DS1668
• Electronic interface provided for digital as well as
manual control
• Wide differential input voltage range between 4.5 and
8 volts
• Wiper position is maintained in the absence of power
• Low cost alternative to mechanical controls
• Applications include volume, tone, contrast, bright-
ness, and dimmer control
• 8–pin SOIC and 8–pin DIP packages for DS1669
• Standard resistance values for Dallastat
– DS1668/DS1669–10
– DS1668/DS1669–50
– DS1668/DS1669–100
10KΩ
~
50KΩ
~
100KΩ
~
• Operating Temperature Range
– Commercial: 0°C to 70°C; DS1668, DS1669
– Industrial: –40°C to +85°C; DS1669
PIN ASSIGNMENT DS1668
NC DR
PIN 1
INDICATO R
H
654
123
-VRW+V
TOP VIEW
INTEGRATED
PUSHBUTTON
PIN ASSIGNMENT DS1669
1
(R
)
H
2
UC
3
D
4
(RL)
8-Pin DIP (300 Mil)
(R
)
H
UC
D
(RL)
8-Pin SOIC (208 Mil)
8
+V
7
DC
6
R
W
5
–V
1
2
3
4
+V
8
7
DC
6
R
W
5
V-
PIN DESCRIPTION DS1669
R
H
R
W
R
L
-V, +V - Voltage Inputs
UC - Up Contact Input
D - Digital Input
DC - Down Contact Input
- Resistor High End
- Resistor Wiper
- Resistor Low End
PIN DESCRIPTION DS1668
+V - Positive Voltage Input
-V - Negative Voltage
R
W
D - Digital Input
R
H
NC - No Connection - Pin Missing
- Resistor Wiper
- Resistor High End
Copyright 1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
081895 1/10
DS1668, DS1669, DS1669S
DESCRIPTION
The DS1668 and DS1669 Dallastats are digital rheostats or potentiometers. These units provide 64 possible uniform tap points over the resistive range and are
available in standard versions of 10K, 50K, and 100K
ohms. The Dallastats can be controlled by either a
mechanical–type contact closure input or a digital
source input such as a CPU. Wiper position is maintained in the absence of power which is accomplished
through the use of a EEPROM memory cell array . The
EEPROM cell array is specified to accept greater than
80,000 writes.
The DS1668 and DS1669 differ in the type packages in
which they are offered. The DS1668 is only available in
a custom 6–pin package with a single integrated pushbutton as shown in the package drawing. The single
integrated pushbutton provides the mechanical control
input of the wiper position. In addition, a digital source
input, D, allows the potentiometer to be controlled by a
microcontroller or processor. Other package pins
include the positive voltage input, +V , the negative voltage input, –V , the resistor wiper terminal, RW, and the
high resistor terminal, R
mercial temperature usage only (0°C to 70°C).
The DS1669 is offered in two standard IC packages
which include an 8–pin 300 mil DIP and an 8–pin 200 mil
SOIC. Like the DS1668, the DS1669 can be configured
to operate using a single pushbutton or digital source
input. This is illustrated in Figure 1. Additionally, the
DS1669 can be configured to operate in a dual pushbutton configuration which is shown in Figure 2. The
DS1669 pinouts allow access to both ends of the potentiometer R
, RH, and the wiper, RW. Control inputs
L
include the digital source input, D, the up contact input,
UC, and the down contact input, DC. Other package
pinouts include the positive,+V , and negative, –V , supply inputs. The DS1669 is available in commercial or
industrial temperature versions.
. The DS1668 is rated for com-
H
Figure 3 illustrates the single pushbutton configuration
of the DS1668. Internally, the low end resistor terminal
is connected to the negative supply input terminal. The
integrated pushbutton has one side connected to the
negative supply input while the other side is connected
to the up contact terminal (UC). The digital source input
(D) is accessible through pin 4 of the package. The (D)
input has an internal pull–up resistor and can be allowed
to float when not in use. The down contact input (DC) is
not accessible externally. However , this control input is
internally connected to the positive input supply .
When powered, the DS1668 assumes a single pushbutton mode of operation. Pressure applied to the integrated pushbutton will cause contact closure which in
turn will move the wiper position upward or downward
depending on the previous wiper direction. Single pushbutton mode is accomplished in the same manner for
the DS1669. However, for the DS1669, all connections
must be made by the user since no internal connections
exist (see Figure 1). Note that single pushbutton control
is accomplished when 1) the (DC) input is connected to
the positive supply input and 2) the (D) input is allowed
to float. These two conditions must exist from the time of
device power–up. The UC input controls both upward
and downward movement of the device wiper position in
single pushbutton mode of operation.
Dual pushbutton operation is only available when using
the DS1669. The DS1668, by design, only supports the
single pushbutton mode of operation and digital source
input control. Figure 2 provides a typical application
example of the dual pushbutton configuration for the
DS1669. In dual–pushbutton mode, the up–contact
input (UC) is used solely to provide upward movement
of the wiper position and the down–contact input (DC) is
used to provide downward movement of the wiper position. For dual pushbutton configuration, all control
inputs (UC, DC, and D) must remain open on device
power–up.
OPERATION
The DS1668/DS1669 Dallastats are controlled through
a contact closure input or by a digital source input. The
DS1668 is configured to operate from a single contact
closure (pushbutton) input which is integrated in the
custom 6–pin package or the device can be driven from
the digital source input (D). The DS1669 can be controlled using a single pushbutton input, dual pushbutton,
or using the digital source input.
081895 2/10
The digital source input, D, was designed for microprocessor or controller applications. This control input
manipulates the device in the same manner as the
single pushbutton configuration; controlling movement
of the wiper position in both upward and downward
directions. One added feature over the single pushbutton configuration is the ability to increment or decrement
wiper position at a faster rate. Digital source input control is available regardless of the type of pushbutton
configuration.
DS1668, DS1669, DS1669S
DS1669 SINGLE PUSHBUTTON CONFIGURATION (TYPICAL EXAMPLE) Figure 1
DS1669
R
UC
D
R
H
L
DC
R
V+
W
V–
DS1669 DUAL PUSHBUTTON CONFIGURATION (TYPICAL APPLICATION) Figure 2
DS1669
R
UC
D
R
H
L
DC
R
V+
W
V–
081895 3/10
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