NXP Semiconductors 74HC597DB,118

Overview

74HC597DB,118 from Nexperia is an 8-bit parallel-in/serial-out shift register with integrated input flip-flops and dual edge-triggered clocks (STCP for storage, SHCP for shifting). It features asynchronous master reset (MR), parallel load (PL), and serial data input (DS), operating across 2.0 V–6.0 V supply with CMOS-level inputs. Used in industrial I/O expansion and LED matrix controllers where synchronized parallel capture and serial streaming are required.

For engineers reviewing the 74HC597DB,118 datasheet, 74HC597DB,118 pinout, 74HC597DB,118 application, or 74HC597DB,118 equivalent, this device supports precise timing-critical data latching and shift operations in microcontroller peripheral interfaces, requiring attention to STCP/SHCP setup/hold times, MR deassertion sequencing, and VCC-dependent propagation delays.

Technical Context

The device implements two cascaded synchronous registers: an 8-bit parallel-access storage register (clocked by STCP) feeding a serial-shift register (clocked by SHCP), both triggered on positive edges. Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors.

Its logic supports three distinct operational modes: parallel loading of D0–D7 into storage (PL active low), transfer from storage to shift register (STCP edge), and serial shifting (SHCP edge with DS input). MR asynchronously clears the shift register while preserving storage register contents until next STCP.

Key Specifications

Pinout & Package

74HC597DB,118 is supplied in SO16 (SOT109-1) package: plastic small outline, 16 leads, 3.9 mm body width, gull-wing leads, JEDEC MS-012 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit parallel-in/serial-out shift register applications.

Compared with 74HC597DB,118, the 74HC165PW,118 simplifies timing but sacrifices independent register control, while the SN74LV595AQPWRQ1 adds automotive qualification and output enable at the cost of higher static current and lack of true storage register isolation.

Availability

74HC597DB,118 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, LED matrix column driving, automotive body control modules, and legacy parallel-to-serial interface adaptation requiring stable component supply across extended temperature ranges.

Supply support for 74HC597DB,118 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions optimized for efficiency, reliability, and manufacturability in high-volume applications.

The 74HC597 belongs to Nexperia's HC logic family, designed for low-power, high-noise-immunity digital interfacing in industrial, consumer, and automotive subsystems where precise timing and wide VCC tolerance are critical.

FAQ

What is the function of the PL (Parallel Load) pin?

The PL pin is an active-low control that enables transfer of data from the D0–D7 inputs into the internal storage register on the next STCP rising edge. When PL is HIGH, Dn inputs are ignored regardless of STCP activity; when PL is LOW, STCP edges capture parallel data. This allows precise synchronization of input sampling independent of shift operations.

Can MR (Master Reset) clear the storage register?

No. MR asynchronously clears only the shift register (Q output and internal shift stages), leaving the storage register (D0–D7 latch) unchanged. The storage register retains its last loaded value until overwritten by a subsequent STCP edge with PL = LOW. This separation enables safe reset of serial output state without losing captured parallel data.

How does the input clamping diode affect external interface design?

The integrated input clamp diodes allow safe connection to signal sources exceeding VCC (up to VCC + 0.5 V) when used with series current-limiting resistors. For example, a 12 V sensor output can drive D0 through a 10 kΩ resistor without damaging the IC, provided IIK remains within ±20 mA. This eliminates need for external Schottky clamps in mixed-voltage systems.

What is the minimum pulse width required on SHCP for reliable operation at 6.0 V?

At VCC = 6.0 V, the minimum SHCP pulse width (tW) is 14 ns for both HIGH and LOW states per datasheet Table 7. This corresponds to a maximum clock frequency of 104 MHz. To ensure margin, designs should maintain ≥20 ns pulse width and verify signal integrity (rise/fall time < 13 ns) at the pin using appropriate PCB layout and termination.