Rainbow Electronics LM334 - Manual

LM134/LM234/LM334
3-Terminal Adjustable Current Sources
General Description
The LM134/LM234/LM334 are 3-terminal adjustable current
sources featuring 10,000:1 range in operating current, excel-
lent current regulation and a wide dynamic voltage range of
1V to 40V. Current is established with one external resistor
and no other parts are required. Initial current accuracy is
± 3%. The LM134/LM234/LM334 are true floating current
sources with no separate power supply connections. In ad-
dition, reverse applied voltages of up to 20V will draw only a
few dozen microamperes of current, allowing the devices to
act as both a rectifier and current source in AC applications.
The sense voltage used to establish operating current in the
LM134 is 64mV at 25˚C and is directly proportional to abso-
lute temperature (˚K). The simplest one external resistor
connection, then, generates a current with
≈+0.33%/˚C tem-
perature dependence. Zero drift operation can be obtained
by adding one extra resistor and a diode.
Applications for the current sources include bias networks,
surge protection, low power reference, ramp generation,
LED driver, and temperature sensing. The LM234-3 and
LM234-6 are specified as true temperature sensors with
guaranteed initial accuracy of
± 3˚C and ± 6˚C, respectively.
These devices are ideal in remote sense applications be-
cause series resistance in long wire runs does not affect
accuracy. In addition, only 2 wires are required.
The LM134 is guaranteed over a temperature range of
−55˚C to +125˚C, the LM234 from −25˚C to +100˚C and the
LM334 from 0˚C to +70˚C. These devices are available in
TO-46 hermetic, TO-92 and SO-8 plastic packages.
Features
n Operates from 1V to 40V
n 0.02%/V current regulation
n Programmable from 1µA to 10mA
n True 2-terminal operation
n Available as fully specified temperature sensor
n
± 3% initial accuracy
Connection Diagrams
SO-8
Surface Mount Package
SO-8 Alternative Pinout
Surface Mount Package
00569724
Order Number LM334M or LM334MX
See NS Package Number M08A
00569725
Order Number LM334SM or LM334SMX
See NS Package Number M08A
TO-46
Metal Can Package TO-92 Plastic Package
00569712
V − Pin is electrically connected to case.
Bottom View
Order Number LM134H,
LM234H or LM334H
See NS Package
Number H03H
00569710
Bottom View
Order Number LM334Z, LM234Z-3 or LM234Z-6
See NS Package Number Z03A
March 2000
LM134/LM234/LM334
3-T
erminal
Adjustable
Current
Sources
© 2004 National Semiconductor Corporation DS005697 www.national.com