NXP Semiconductors 74HC652D,112

Overview

74HC652D,112 from NXP Semiconductors (formerly Philips) is an octal bus transceiver/register with independent A/B register storage, dual 3-state output enables (OEAB/OEBA), and real-time or clocked data routing between two 8-bit buses. It operates at VCC = 2.0–6.0 V, supports up to 92 MHz clock frequency (typ.), delivers bus-driver output capability, and uses CMOS technology for low static power consumption. It is used in bidirectional data bus isolation and synchronized inter-bus transfer in industrial control backplanes.

For engineers reviewing the 74HC652D,112 datasheet, 74HC652D,112 pinout, 74HC652D,112 application, or 74HC652D,112 equivalent, key selection criteria include independent A/B clocking (CPAB/CPBA), simultaneous stored-A-to-B and stored-B-to-A transfer capability, Schmitt-trigger clock inputs for noise immunity, and SO-24 package compatibility with legacy 74LS/LSTTL board layouts.

Technical Context

The 74HC652D,112 integrates eight non-inverting transceiver channels, dual D-type flip-flop banks (A and B), and multiplexed control logic enabling three operational modes: real-time pass-through (via SAB/SBA), registered storage (on CPAB/CPBA rising edge), and concurrent bidirectional register-to-bus transfer. Its Schmitt-trigger clock inputs tolerate slow rise/fall times, and all data inputs are always enabled-storage occurs on every LOW-to-HIGH clock transition regardless of select or enable states.

Output enable pins OEAB and OEBA independently gate A→B and B→A paths, while SAB/SBA determine whether data flows directly or via internal registers. The device supports isolation (both OEs inactive), real-time transfer, stored-data transfer, and dual-register update-all confirmed in the function table and functional diagram. It belongs to the MSI-level HC logic family and is JEDEC 7A-compliant.

Key Specifications

Pinout & Package

74HC652D,112 is housed in a 24-pin Small Outline (SO) plastic package (SOT137A), with 1.27 mm pitch, gull-wing leads, and standard JEDEC MS-013 footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver/register applications.

Compared with 74HC652D,112, the 74HCT652D,112 offers identical functionality with improved noise immunity in mixed-logic systems, while the SN74LVTH16652DGGR provides greater bandwidth and voltage flexibility at the cost of layout redesign and increased complexity.

Availability

74HC652D,112 is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller peripheral expansion, and legacy TTL-to-CMOS bus bridging requiring stable component supply and long-term obsolescence management.

Supply support for 74HC652D,112 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' pioneering logic IC development.

The 74HC652D,112 belongs to NXP's legacy 74HC logic family, designed specifically for robust, low-power, pin-compatible upgrades of LSTTL bus interface circuits in industrial control and instrumentation systems.

FAQ

What is the maximum operating frequency of the 74HC652D,112?

The 74HC652D,112 supports a maximum clock frequency of 92 MHz (typical) at VCC = 5 V and CL = 15 pF. At VCC = 4.5 V, the guaranteed minimum fmax is 83 MHz over the −40 °C to +85 °C range. This allows reliable use in high-speed synchronous bus architectures where timing margin is critical, and the 74HC652D,112 maintains consistent performance across its full supply and temperature range.

Does the 74HC652D,112 support simultaneous bidirectional registered data transfer?

Yes-the 74HC652D,112 uniquely supports concurrent transfer of stored A-bus data to the B-bus and stored B-bus data to the A-bus in a single operation, as confirmed in the function table (last row: "Stored A Data to B Bus and Stored B Data to A Bus"). This capability distinguishes it from the 74HC646 and enables full-duplex register-to-bus communication without additional control logic, making the 74HC652D,112 ideal for tightly coupled dual-bus systems.

What is the purpose of the Schmitt-trigger inputs on CPAB and CPBA in the 74HC652D,112?

The Schmitt-trigger action on CPAB and CPBA inputs provides hysteresis (≈0.8 V typical at VCC = 5 V), allowing the 74HC652D,112 to reliably accept slow-rising or noisy clock signals-such as those from RC oscillators, microcontroller GPIO toggles, or long PCB traces-without unintended multiple clocking or metastability. This feature eliminates external conditioning circuitry and improves system robustness, especially in electrically noisy industrial environments where the 74HC652D,112 is commonly deployed.

How does the 74HC652D,112 handle bus isolation when both OEAB and OEBA are HIGH?

When both OEAB and OEBA are HIGH, all B0–B7 and A0–A7 outputs enter high-impedance (3-state) mode, effectively isolating the A and B buses from each other. In this state, no data transmission occurs in either direction, and the internal registers retain their last-stored values. This isolation mode is essential for bus arbitration, hot-plug scenarios, and preventing contention during system reset-ensuring the 74HC652D,112 maintains safe, predictable behavior under all control combinations.

Is the 74HC652D,112 pin-compatible with older 74LS652 devices?

Yes-the 74HC652D,112 is explicitly designed as a pin-compatible, functionally equivalent CMOS upgrade for Low-Power Schottky TTL (LSTTL) devices like the 74LS652. It matches the same 24-pin SO package (SOT137A), identical pin numbering, and logic behavior, while offering lower power consumption, wider supply range (2.0–6.0 V), and improved noise immunity. Engineers can replace 74LS652 with 74HC652D,112 without PCB changes, provided timing margins accommodate HC propagation delays.