Nexperia USA Inc. 74HC194DB/DG,118

Overview

74HC194DB/DG,118 from Nexperia is a 4-bit bidirectional universal shift register in SSOP16 package, supporting synchronous parallel load, left/right serial shift, and hold modes via S0/S1 control inputs. It operates from 2.0 V to 6.0 V, features asynchronous master reset (MR), edge-triggered clock (CP), and delivers tpd ≤29 ns at VCC = 4.5 V. Used in digital logic sequencing, data alignment, and bus interface buffering.

For engineers reviewing the 74HC194DB/DG,118 datasheet, 74HC194DB/DG,118 pinout, 74HC194DB/DG,118 application, or 74HC194DB/DG,118 equivalent, this page provides verified functional behavior, timing constraints, mode-select truth table mapping, and real-world implementation context for synchronous shift register integration in industrial control and communication subsystems.

Technical Context

The 74HC194DB/DG,118 implements four independent D-type flip-flops with shared mode control logic, enabling deterministic state transitions on every LOW-to-HIGH CP edge. Its function table defines five distinct operations-reset, hold, parallel load, shift-left (via DSL), and shift-right (via DSR)-all governed by stable S0/S1 levels one setup time before clocking.

Input clamping diodes allow interfacing with voltages exceeding VCC when current-limiting resistors are used. The device supports operation across -40 °C to +125 °C, with VIH/VIL thresholds scaling linearly with VCC and guaranteed VOL ≤0.26 V at IO = 4.0 mA (VCC = 4.5 V).

Key Specifications

Pinout & Package

74HC194DB/DG,118 uses the SOT338-1 (SSOP16) package: plastic shrink small outline, 16 leads, 5.3 mm body width, 0.65 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit bidirectional shift register applications.

Compared with SN74HC194N and 74HCT194DB,118, the 74HC194DB/DG,118 provides optimal balance of industrial temperature range, SSOP footprint efficiency, and CMOS input noise immunity - making it the preferred choice for new surface-mount designs requiring robust 4-bit shift functionality.

Availability

74HC194DB/DG,118 is available at Aetrix Electronics and suitable for industrial PLC data buffering, LED matrix column driving, UART frame alignment, and digital test pattern generation requiring stable component supply across extended temperature ranges.

Supply support for 74HC194DB/DG,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 specializing in high-performance logic, analog, and discrete components, with leadership in automotive-grade and industrial reliability standards.

The 74HC194 belongs to Nexperia's HC-series logic family, designed for low-power, high-noise-immunity digital interfacing in industrial automation, consumer electronics, and communication infrastructure.

FAQ

What is the minimum setup time required for S0/S1 inputs before the CP rising edge?

At VCC = 4.5 V, the minimum setup time (tsu) for S0 and S1 is 18 ns. This ensures reliable mode selection sampling on the clock edge. The value scales with supply voltage: 90 ns at VCC = 2.0 V and 15 ns at VCC = 6.0 V. Violating this window may cause metastable mode decoding or unintended operation.

Can 74HC194DB/DG,118 operate reliably at 3.3 V supply?

Yes - the device is fully specified from 2.0 V to 6.0 V. At 3.3 V, VIH is guaranteed ≥2.31 V and VIL ≤1.09 V, providing >1.2 V noise margin. Propagation delay increases to ~36 ns (vs. 29 ns at 4.5 V), and fmax drops to ~62 MHz, both well within typical 3.3 V system timing budgets.

How does the asynchronous MR pin interact with ongoing shift operations?

MR is asynchronous and dominant: when pulled LOW, it forces Q0–Q3 to LOW immediately, overriding all clock edges, mode settings, and data inputs. The register remains held in reset until MR returns HIGH, after which normal operation resumes on the next CP rising edge - no recovery delay is required.

Is there any restriction on using DSL and DSR simultaneously?

No functional restriction exists - DSL and DSR are electrically isolated inputs. However, only one is active per mode: DSL is sampled during left-shift (S0=LOW, S1=HIGH), DSR during right-shift (S0=HIGH, S1=LOW). In parallel load or hold mode, neither affects outputs, so both may float or be driven without consequence.