Texas Instruments SN74HC652NTG4

Overview

SN74HC652NTG4 from Texas Instruments is an octal bus transceiver and register IC with independent A/B data paths, 3-state outputs, dual clock inputs (CLKAB/CLKBA), and real-time/stored-data select control (SAB/SBA). It operates from 2 V to 6 V, delivers 11 ns typical propagation delay at 5 V, and provides ±6-mA output drive. It is used in bidirectional data buffering and synchronized bus isolation in industrial control backplanes.

For engineers reviewing the SN74HC652NTG4 datasheet, SN74HC652NTG4 pinout, SN74HC652NTG4 application, or SN74HC652NTG4 equivalent, key selection criteria include its dual-register storage capability, simultaneous real-time + stored-data routing, 24-pin PDIP package thermal profile (θ_JA = 67°C/W), and compatibility with LSTTL load driving (up to 15 loads).

Technical Context

The SN74HC652NTG4 integrates eight independent D-type flip-flops per bus (A and B), enabling synchronous latching of data on low-to-high clock transitions at CLKAB or CLKBA-regardless of OEAB/OEBA state. Its dual-select architecture allows real-time transfer (SAB/SBA = L) or stored-data transfer (SAB/SBA = H), with staggered clocking required when both registers are loaded in stored mode.

Output-enable logic is fully independent: OEAB controls A-side 3-state drivers, OEBA controls B-side drivers. The device supports bus hold behavior during power-up/down via external pullup/pulldown resistors on OEBA/OEAB, and all unused inputs must be tied to VCC or GND per TI SCBA004 guidelines.

Key Specifications

Pinout & Package

SN74HC652NTG4 is supplied in a 24-pin plastic dual in-line package (PDIP-NT), with 0.300-inch body width and through-hole mounting. Pin 1 is located at top-left corner (Q1 quadrant), with standard DIP pin numbering (1–12 top row left-to-right, 13–24 bottom row right-to-left).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal registered transceiver applications.

Compared with SN74HC652NTG4, SN74HCT652N offers improved noise immunity in noisy 5 V environments but sacrifices 2–3.3 V operation, while 74ACT652PC delivers higher performance at the cost of increased ICC (40 mA vs. 80 µA) and reduced supply range flexibility.

Availability

SN74HC652NTG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy bus isolation, and redundant data path controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74HC652NTG4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74HC652NTG4 belongs to TI's HC logic family, designed for low-power, wide-voltage-range digital interfacing in space-constrained industrial and instrumentation systems where reliability and long-term availability are critical.

FAQ

What is the maximum clock frequency supported by SN74HC652NTG4 in real-time transfer mode?

The SN74HC652NTG4 supports up to 31 MHz clock frequency at V_CC = 4.5 V and 36 MHz at V_CC = 6 V in real-time transfer mode, as specified in the timing requirements table. This assumes proper PCB layout, 50-pF load, and clean power supply decoupling. The actual achievable frequency in a given design depends on trace length, fanout, and signal integrity margins.

Can SN74HC652NTG4 operate reliably at 3.3 V supply voltage?

Yes, SN74HC652NTG4 is fully specified for operation from 2 V to 6 V, including 3.3 V. At V_CC = 3.3 V, it maintains guaranteed logic thresholds (VIH ≥ 2.0 V, VIL ≤ 0.99 V), 10 ns typical propagation delay, and ±4.2 mA output drive-making it suitable for direct interfacing with 3.3 V microcontrollers and FPGAs without level shifters.

How does SN74HC652NTG4 handle power-up sequencing to avoid bus contention?

To ensure high-impedance outputs during power-up, OEBA should be tied to V_CC via a pullup resistor and OEAB to GND via a pulldown resistor. SN74HC652NTG4 has no internal power-on reset; this external biasing guarantees that both A- and B-side drivers remain disabled until firmware asserts valid OEAB/OEBA states, preventing unintended bus conflicts.

Does SN74HC652NTG4 support simultaneous real-time and stored-data transfer?

No, SN74HC652NTG4 does not support simultaneous real-time and stored-data transfer on the same bus pair. Its function table shows mutually exclusive modes: SAB/SBA = L enables real-time transfer, while SAB/SBA = H enables stored-data transfer. However, one direction (e.g., A→B) can be in real-time mode while the other (B→A) is in stored mode, provided clocks and enables are independently controlled.

What is the thermal resistance (θ_JA) of the SN74HC652NTG4 in its NT package?

The SN74HC652NTG4 in the 24-pin PDIP-NT package has a junction-to-ambient thermal resistance (θ_JA) of 67°C/W, measured per JESD 51-3. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance improves with copper pour, thermal vias, or forced airflow, and must be verified against maximum junction temperature limits (150°C) under worst-case power dissipation.