The ULN2803ADW from onsemi is an 8-channel Darlington transistor array with 500mA per channel, integrated flyback diodes, and 2.7kOhm input resistors for direct 5V TTL\/CMOS interface in an 18-pin SOIC package.<\/p>\n
| \u0627\u0644\u0642\u0646\u0648\u0627\u062a<\/td>\n | 8 (Darlington pairs)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Output Current per Channel<\/td>\n | 500 mA (max)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Collector-Emitter Voltage<\/td>\n | 50V<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Input Resistor<\/td>\n | 2.7 kOhm (built-in, for 5V logic)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Saturation Voltage<\/td>\n | 1.1V @ 100mA, 1.3V @ 350mA<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Current Gain (hFE)<\/td>\n | >1000 (Darlington)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Flyback Diodes<\/td>\n | Yes (integrated, common cathode)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| Input Compatibility<\/td>\n | 5V TTL, CMOS directly<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| \u0627\u0644\u062d\u0632\u0645\u0629<\/td>\n | SOIC-18 (wide, 7.5mm)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||
| \u062f\u0631\u062c\u0629 \u062d\u0631\u0627\u0631\u0629 \u0627\u0644\u062a\u0634\u063a\u064a\u0644<\/td>\n | -40 to +85 C<\/td>\n<\/tr>\n<\/table>\n\u0627\u0644\u0645\u064a\u0632\u0627\u062a<\/h2>\n\u0627\u0644\u062a\u0637\u0628\u064a\u0642\u0627\u062a<\/h2>\nProduct Overview The ULN2803ADW from onsemi is an 8-channel Darlington transistor array with 500mA per channel, integrated flyback diodes, and 2.7kOhm input resistors for direct 5V TTL\/CMOS interface in an 18-pin SOIC package. Key Specifications Channels 8 (Darlington pairs) Output Current per Channel 500 mA (max) Collector-Emitter Voltage 50V Input Resistor 2.7 kOhm (built-in, for […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[57,13],"tags":[],"chip_brand":[144],"class_list":["post-3767","post","type-post","status-publish","format-standard","hentry","category-insulated-gate-bipolar-transistors-igbt","category-integrated-circuits-ics","chip_brand-on"],"acf":{"brief_explanation":"8-ch Darlington driver, 500mA\/ch, 50V, built-in diodes + 2.7k input R, SOIC-18","date_code":"","package_case":"SOIC-18 (11.4 x 7.5 x 2.65 mm, DW package, wide body)","in_stock":8340,"datasheet":"https:\/\/www.onsemi.com\/pub\/Collateral\/ULN2803A-D.PDF","price":"$0.65 @ 1ku","product_introduction":"The ULN2803ADW from onsemi is an 8-channel Darlington transistor array designed for interfacing low-level logic signals to high-current loads such as relays, solenoids, stepper motors, and LED displays. Each of the 8 channels consists of a Darlington-connected NPN transistor pair with integrated 2.7kOhm base resistors, allowing direct connection to 5V TTL or CMOS logic outputs without additional interface components. The Darlington configuration provides a current gain exceeding 1000, enabling 500mA output current from just 0.5mA of input drive current. The 50V collector-emitter voltage rating supports common relay and solenoid supply voltages. Integrated flyback (clamp) diodes on each output suppress the inductive kickback voltage generated when driving inductive loads such as relay coils and stepper motor windings, protecting both the driver transistors and the driving logic. The common cathode connection of all flyback diodes (COM pin) is typically connected to the load supply voltage. The ULN2803 is the 5V logic version of the ULN2800 family; the ULN2804 variant has 10.5kOhm input resistors for 6-15V CMOS\/P-MOS logic, and the ULN2801\/2802 have no input resistors for custom interface circuits. The SOIC-18 wide-body package (DW suffix) provides adequate thermal performance for moderate current applications. The device is commonly used in PLC output modules, relay boards, and Arduino-compatible motor shields.","working_principle":"The ULN2803ADW operates as 8 independent Darlington-pair open-collector sinking drivers. Key subsystems include: (1) Darlington Pair - each channel consists of two NPN transistors connected in a Darlington configuration; the collector of the first transistor feeds the base of the second; this multiplies the current gains (hFE1 x hFE2 > 1000), so a 0.5mA input current can drive 500mA output; the tradeoff is a higher saturation voltage (1.1V at 100mA, 1.3V at 350mA) compared to a single transistor; (2) Input Resistor - a 2.7kOhm series resistor is integrated between the input pin and the first transistor base; at 5V logic HIGH, this provides approximately (5V - 2xVBE) \/ 2.7k = 1.35mA base drive, sufficient to saturate the Darlington at up to 500mA load; (3) Flyback Diode - each output has an integrated diode from the collector to the COM pin; when an inductive load (relay, motor) is turned off, the collapsing magnetic field generates a reverse voltage spike; the flyback diode provides a path for the inductive current, clamping the collector voltage to Vsupply + 0.7V; the COM pin connects all diode cathodes together and should be tied to the load supply; (4) Open-Collector Output - the output can only sink current (pull to GND); it cannot source current; the load connects between the supply and the output pin; when the input is HIGH, the Darlington saturates and the output pulls toward GND; when the input is LOW, the Darlington is off and the output floats (the load sees the supply voltage through its own connection).","pin_description":"
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