Part of the Day · SN74HC595 — SOIC-16 8-bit shift register (marking HC595)

Part of the Day · 2026-10-23

A serial-in → parallel-out shift register that gives you 8 outputs from 3 wires (data, clock, latch). Several can be daisy-chained to drive many LEDs or 7-segment displays. The TI SOIC-16 (D) part is marked HC595.

Actual size

↓ Actual size, left edge aligned to 0 on the ruler

One ruler tick = 1mm. On PC this is actual size on a 24-inch FHD monitor at 100% zoom; on iPhone it adjusts automatically. For other screens, use “Calibrate ruler” below.

Enlarged (SOIC-16 · top view · approx. 10×)

Pins 1 QB · 2 QC · 3 QD · 4 QE · 5 QF · 6 QG · 7 QH · 8 GND · 9 QH′ (serial output, to the next chip) · 10 SRCLR (shift register clear, Low) · 11 SRCLK (shift clock) · 12 RCLK (storage clock / latch) · 13 OE (output enable, Low) · 14 SER (serial data input) · 15 QA · 16 VCC

Package SOIC-16 · Marking HC595

Key specifications

Values are from the Texas Instruments datasheet.

Marking and pins

Marking code HC595 · Pins 1 QB · 2 QC · 3 QD · 4 QE · 5 QF · 6 QG · 7 QH · 8 GND · 9 QH′ (serial output, to the next chip) · 10 SRCLR (shift register clear, Low) · 11 SRCLK (shift clock) · 12 RCLK (storage clock / latch) · 13 OE (output enable, Low) · 14 SER (serial data input) · 15 QA · 16 VCC

Typical uses

• Adding outputs when MCU pins run short
• Driving many LEDs, 7-segment displays and dot matrices
• Chaining several via QH′→SER for 16- or 24-bit outputs

Companion & similar parts

• SN74HC595DW — Same chip in a wide SOIC-16 (10.30 × 7.50mm)
• SN74HC595PW — Same chip in a small TSSOP-16 (5.00 × 4.40mm)
• SN54HC595 — -55 ~ 125℃ version from the same datasheet (ceramic package)

When OE (pin 13) is High, all 8 outputs are disconnected (high impedance). To keep them always enabled, connect it to GND. The datasheet says unused inputs must be tied to VCC or GND (SRCLR, pin 10, clears on Low, so tie it to VCC).