Product Information:
Category：Discrete Semiconductor Products Transistors - Bipolar (BJT) - Arrays
Series：Automotive, AEC-Q100
Transistor Type：8 NPN Darlington
Current - Collector (Ic) (Max)：500mA
Voltage - Collector Emitter Breakdown (Max)：50V
Vce Saturation (Max) @ Ib, Ic：1.6V @ 500µA, 350mA
Operating Temperature：-40°C ~ 85°C (TA)
Features：500-mA-Rated Collector Current (Single Output) / High-Voltage Outputs: 50 V / Output Clamp Diodes / Inputs Compatible With Various Types of Logic.
Applications：Relay Drivers / Hammer Drivers / Lamp Drivers / Display Drivers (LED and Gas Discharge) / Line Drivers / Logic Buffers / Stepper Motors / IP Camera / HVAC Valve and LED Dot Matrix.
The ULN2803A device is a 50 V, 500 mA Darlington transistor array. The device consists of eight NPN Darlington pairs that feature high-voltage outputs with
common-cathode clamp diodes for switching inductive loads. The
collector-current rating of each Darlington pair is 500 mA. The Darlington pairs may be connected in parallel for higher current capability. Applications include relay drivers, hammer drivers,lamp drivers, display drivers (LED and gas
discharge), line drivers, and logic buffers. The ULN2803A device has a 2.7-kΩ series base resistor for each Darlington pair for operation directly with TTL or 5-V CMOS devices.
Overview：
This standard device has proven ubiquity and versatility across a wide range of applications. This is due to its integration of 8 Darlington transistors that are capable of sinking up to 500 mA and wide GPIO range capability.
The ULN2803A is comprised of eight high voltage, high current NPN Darlington transistor pairs. All units feature a common emitter and open collector outputs. To maximize their effectiveness, these units contain suppression diodes for inductive loads. The ULN2803A has a series base resistor to each Darlington pair, thus allowing operation directly with TTL or CMOS operating at supply voltages of 5 V or 3.3 V. The ULN2803A offers solutions to a great many interface needs, including solenoids, relays, lamps, small motors, and LEDs.
Applications requiring sink currents beyond the capability of a single output may be accommodated by paralleling the outputs.
Feature Description：
Each channel of ULN2803A consists of Darlington connected NPN transistors. This connection creates the effect of a single transistor with a very-high current gain. The very high β allows for high output current drive with a very-low input current, essentially equating to operation with low GPIO voltages.
The GPIO voltage is converted to base current through the 2.7-kΩ resistor connected between the input and base of the predriver Darlington NPN.
The diodes connected between the output and COM pin are used to suppress the kick-back voltage from an inductive load that is excited when the NPN drivers are turned off (stop sinking) and the stored energy in the coils causes a reverse current to flow into the coil supply through the kick-back diode.
In normal operation, the diodes on base and collector pins to emitter will be reverse biased. If these diode are forward biased, internal parasitic NPN transistors will draw (a nearly equal) current from other (nearby) device pins.
Device Functional Modes：
1、Inductive Load Drive
When the COM pin is tied to the coil supply voltage, ULN2803A is able to drive inductive loads and suppress the kick-back voltage through the internal free wheeling diodes.
2、Resistive Load Drive
When driving resistive loads, COM can be left unconnected or connected to the load voltage supply. If multiple supplies are used, connect to the highest voltage supply.
ULN2803ADWR is in stock，if you need this part，we can meet the needs of large quantities.Ships within 2-3 business days.
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