74145 BCD to Decimal Decoder 5V 7mA IC PDIP-16

Description

74145 BCD to Decimal Decoder/driver IC PDIP-16 The 74145 is a 4-to-10 (BCD-to-decimal) decoder/driver implemented in Low-Power Schottky (LS) TTL. It decodes a 4-bit BCD input (A, B, C, D) into one active low output among ten (Y0–Y9); all outputs are held off for invalid BCD codes. The device integrates pairs of inverters and four-input NAND gates to implement full BCD decoding and uses high-breakdown N-PN output transistors (open-collector) so the outputs can be pulled up to external voltages (the HD74LS145 supports up to 15 V on the off-state outputs), making it suitable to interface directly to indicators, lamp loads or relays when used with appropriate pull-ups. Because the outputs are open-collector, the HD74LS145 sinks current rather than sourcing; each output is designed for high low-side drive (sink capability up to 80 mA for heavy indicator/relay drive). Inputs are TTL-level compatible and include clamp diodes for termination/speed control. The device comes in common 16-pin packages (DIP and SOP) and is a drop-in LS replacement for classic 74LS145 parts used in numeric display and driver applications. Features: Decodes 4-bit BCD to one-of-ten active-LOW outputs. Open-collector outputs for high-voltage pull-ups (off-state up to 15 V). High-breakdown N-PN output transistors designed for indicator/relay driving. All outputs remain off for invalid BCD inputs (prevents false outputs). Low-Power Schottky TTL process (TTL input compatibility, faster switching). Specifications: Parameter Symbol Min Typ Max Unit Supply voltage (recommended operating): VCC — 5.0 — V Off-state output voltage (allowed pull-up): VO(off) — — 15 V Output low sink current (per output, max): IOL (max) — — 80 mA Output low voltage @ IOL = 12 mA: VOL — — 0.4 V Output low voltage @ IOL = 24 mA: VOL — — 0.5 V Output low voltage @ IOL = 80 mA: VOL — — 3.0 V Off-state output current @ 15 V: IO(off) — — 250 µA Input VIH / VIL (TTL levels): — 2.0 — 0.8 V Supply current (outputs open): ICC — 7 13 mA propagation delay: — — — ~50 ns Pinout: Pin Name Description 1 Y0 Decimal output 0 (active LOW, open-collector) 2 Y1 Decimal output 1 3 Y2 Decimal output 2 4 Y3 Decimal output 3 5 Y4 Decimal output 4 6 Y5 Decimal output 5 7 Y6 Decimal output 6 8 GND Ground 9 Y7 Decimal output 7 10 Y8 Decimal output 8 11 Y9 Decimal output 9 12 D BCD input D (MSB) 13 C BCD input C 14 B BCD input B 15 A BCD input A (LSB) 16 VCC +5V supply Applications: Driving 10-digit indicator lamps or vacuum/filament indicators. Driving relay coils or other loads that require a low-side switch (with appropriate pull-ups and flyback protection). Numerical display multiplexing and legacy display drivers. Open-collector logic interfacing where one-of-ten decoding is required (industrial counters, scoreboards, selectors). Packages: 1x 74145 BCD to Decimal Decoder 5V 7mA IC PDIP-16. Documents: 74145 Datasheet.

From the supplier's page.