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
duringnormaloperationofthedevice, evenafterpowerhasbeenturned
off.
• Precision PC-based electronic calibration
• Automated voltage trimming or setting
• Remote voltage or current adjustment of
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
The ALD1108E/ALD1110E are devices built with ALD's EPAD technol-
ogy, an electrically programmable device technology refined for analog
applications.TheALD1108E/ALD1110EfunctionslikearegularMOSFET
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.
BLOCK DIAGRAM
ALD1110E
V+(5)
D
N2
(6)
P
(8)
N2
P
N1
(1)
D
N1
(3)
N2
~
G
(7)
G
(2)
N1
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.
EPAD 1
EPAD 2
~
S
(4)
V- (4)
12
BLOCK DIAGRAM
ALD1108E
V+(13)
P
(16)
D
(11)
N3
P
N
(1)
D
(3)
P
(9)
D
(6)
P
(8)
N4
D
(14)
N2
N1
N3
N4
N4
G
N2
~
G
G
(2)
N1
(10)
N3
(7)
G
(15)
N2
EPAD 2
EPAD 3
EPAD 4
EPAD 1
~
S
12
(4)
V- (5)
S
(12)
34
ALD1108E/ALD1110E
Advanced Linear Devices
2
ALD [ ADVANCED LINEAR DEVICES ]
