![ULN2003A Pin Connection](https://upload.wikimedia.org/wikipedia/commons/a/a2/ULN2003A_Pin_Connection.PNG)
The ULN2003A is an integrated circuit produced by
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
. It consists of an
array of seven NPN
Darlington transistor
In electronics, a multi-transistor configuration called the Darlington configuration (commonly called a Darlington pair) is a circuit consisting of two bipolar transistors with the emitter of one transistor connected to the base of the other, su ...
s capable of 500 mA, 50 V output. It features common-cathode
flyback diode
A flyback diode is any diode connected across an inductor used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted. It is used in circuits in which indu ...
s for switching inductive loads (such as
servomotors). It can come in
PDIP
In microelectronics, a dual in-line package (DIP or DIL), is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board ( ...
,
SOIC,
SOP
A sop is a piece of bread or toast that is drenched in liquid and then eaten. In medieval cuisine, sops were very common; they were served with broth, soup, or wine and then picked apart into smaller pieces to soak in the liquid. At elaborate f ...
or
TSSOP packaging. In the same family are ULN2002A, ULN2004A, as well as ULQ2003A and ULQ2004A, designed for different logic input levels.
The ULN2003A is also similar to the ULN2001A (4 inputs) and the ULN2801A, ULN2802A, ULN2803A, ULN2804A and ULN2805A, only differing in logic input levels (
TTL,
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
,
PMOS) and number of in/outputs (4/7/8).
Darlington Transistor
A Darlington transistor (also known as Darlington pair) achieves very high current amplification by connecting two bipolar transistors in direct DC coupling so the current amplified by the first transistor is amplified further by the second one. The resultant current gain is the product of those of the two component transistors:
The seven Darlington pairs in ULN2003 can operate independently except the common cathode diodes that connect to their respective collectors.
Features
![ULN2003 Darlington Transistor Array Micrograph](https://upload.wikimedia.org/wikipedia/commons/c/c0/ULN2003_Darlington_Transistor_Array_Micrograph.jpg)
The ULN2003 is known for its high-current, high-voltage capacity. The drivers can be paralleled for even higher current output. Even further, stacking one chip on top of another, both electrically and physically, has been done. Generally it can also be used for interfacing with a
stepper motor, where the motor requires high ratings which cannot be provided by other interfacing devices.
Main specifications:
* 500 mA rated collector current (single output)
* 50 V output (there is a version that supports 100 V output)
* Includes output flyback diodes
* Inputs compatible with
TTL and 5-V
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
logic
Applications
Typical usage of the ULN2003A is in
driver circuit
In electronics, a driver is a circuit or component used to control another circuit or component, such as a high-power transistor, liquid crystal display (LCD), stepper motors, SRAM memory, and numerous others.
They are usually used to regula ...
s for
relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
s, lamp and
LED displays,
stepper motors, logic buffers and line drivers.
See also
*
Solid state relay
Solid state contactor
PCB mount solid-state DIL relay
A solid state relay (SSR) is an electronic switching device that switches on or off when an external voltage (AC or DC) is applied across its control terminals. They serve the same function ...
References
{{Reflist
Integrated circuits