APPLICATIONS
GENERAL DESCRIPTION
ALD1108E/ALD1110E are monolithic quad/dual EPADs (Electrically
Programmable Analog Device) that utilize CMOS MOSFET with elec-
trically programmable threshold voltage. For a given input voltage,
changing the threshold turn-on voltage of a MOSFET device precisely
changes its drain on-current, resulting in an on-resistance characteris-
tic that can be precisely set and controlled. Used as an in-circuit element
for trimming or setting a combination of voltage and/or current charac-
teristics, it can be programmed via a Personal Computer remotely and
automatically via software control. Once programmed and set, the set
voltage and current levels are stored indefinitely inside the device as a
precisely controlled nonvolatile stored charge, which is not affected
during normal operation of the device, even after power has been turned
off.
The ALD1108E/ALD1110E are devices built with ALD's EPAD technol-
ogy, an electrically programmable device technology refined for analog
applications. The ALD1108E/ALD1110E functions like a regular MOSFET
transistor except with precise user preset threshold voltage. Using the
ALD1108E/ALD1110E is simple and straight forward. The device is
extremely versatile as a circuit element and design component. It
presents the user with a wealth of possible applications, limited only by
the imagination of the user and the many ways an analog MOSFET
device can be used as a circuit design element. The ALD1108E/
ALD1110E do not need other active circuitry for functionality.
The basic device is a monotonically adjustable device which means the
device can normally be programmed to increase in threshold voltage
and to decrease in drain-on current as a function of a given input bias
voltage. Once adjusted, the voltage and current conditions are perma-
nent and not reversible. However, a given EPAD device can be adjusted
many times to continually increase the threshold voltage. A pair of EPAD
devices can also be connected such that one device is used to adjust a
parameter in one direction and the other device is used to adjust the
same parameter in the other direction.
The ALD1108E/ALD1110E can be pre-programmed with the ALD
EPAD programmer to obtain the desired voltage and current levels. Or,
they can be programmed as an active in-system element in a user
system, via user designed interface circuitry. For more information, see
Application Note AN1108.
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Precision PC-based electronic calibration
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Automated voltage trimming or setting
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Remote voltage or current adjustment of
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inaccessible nodes
PCMCIA based instrumentation trimming
Electrically adjusted resistive load
Temperature compensated current sources
and current mirrors
Electrically trimmed/calibrated current
sources
Permanent precision preset voltage level
shifter
Low temperature coefficient voltage and/or
current bias circuits
Multiple preset voltage bias circuits
Multiple channel resistor pull-up or pull-down
circuits
Microprocessor based process control systems
Portable data acquisition systems
Battery operated terminals and instruments
Remote telemetry systems
Programmable gain amplifiers
Low level signal conditioning
Sensor and transducer bias currents
Neural networks
BLOCK DIAGRAM
ALD1110E
V+(5)
P
N1
(1)
D
N1
(3)
D
N2
(6)
P
N2
(8)
~
G
N1
(2)
G
N2
(7)
EPAD 1
EPAD 2
S
12
(4)
BLOCK DIAGRAM
ALD1108E
V+(13)
P
N
(1)
D
N1
(3)
D
N2
(14)
P
N2
(16)
P
N3
(9)
D
N3
(11)
D
N4
(6)
P
N4
(8)
G
N1
(2)
S
12
(4)
ALD1108E/ALD1110E
Advanced Linear Devices
~
EPAD 1
~
V- (4)
~
G
N2
(15) G
N3
(10)
G
N4
(7)
EPAD 2
EPAD 3
EPAD 4
V- (5)
S
34
(12)
2
ALD [ ADVANCED LINEAR DEVICES ]
