Renesas 74HC670P-E

Overview

74HC670P-E from Renesas Electronics is a 4×4 register file IC with 3-state outputs, functioning as a synchronous dual-port RAM block for data buffering and temporary storage in digital logic systems. It supports simultaneous read and write operations on independent word addresses, operates across 2–6 V supply, delivers 21 ns typical read-access time (CL = 50 pF), and features high-impedance outputs controlled by GR and GW enables - used in addressable latch-based control logic and microcontroller peripheral interfaces.

For engineers reviewing the 74HC670P-E datasheet, 74HC670P-E pinout, 74HC670P-E application, or 74HC670P-E equivalent, this page provides verified functional specifications, validated pin roles, confirmed operating conditions (–40°C to +85°C), package-mapped terminal definitions, and two technically documented alternative register files for logic design reuse.

Technical Context

The 74HC670P-E implements four independent D-type latches with dedicated write-address decoding (WA/WB) and read-address decoding (RA/RB), enabling concurrent access to separate 4-bit words. Its dual-enable architecture isolates write path (GW) and read path (GR), ensuring output high-impedance during read disable and latch hold during write disable.

Internal logic uses standard HC-series CMOS gates with rail-to-rail input thresholds (VIH = 3.15 V min at VCC = 4.5 V; VIL = 1.35 V max), supports fanout of 15 LSTTL loads, and maintains static ICC ≤ 4 µA at 25°C - confirming suitability for low-power combinational control subsystems requiring deterministic timing and bus isolation.

Key Specifications

Pinout & Package

DIP-16 plastic package (PRDP0016AE-B, DP-16FV), 19.2 mm × 6.3 mm body, 2.54 mm pitch, through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4×4 register file applications.

Compared with 74HC670P-E, SN74HC670N offers identical timing and interface behavior with alternate supply-chain availability, while 74HCT670N trades CMOS input thresholds for TTL compatibility - making it essential for direct connection to older logic families but unsuitable for pure 3.3 V HC-systems.

Availability

74HC670P-E is available at Aetrix Electronics and suitable for microcontroller I/O expansion, digital signal routing, programmable logic control, legacy bus interface, and industrial data acquisition requiring stable component supply and long-term obsolescence management.

Supply support for 74HC670P-E 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

Renesas Electronics Corporation is a global semiconductor manufacturer headquartered in Tokyo, Japan, specializing in microcontrollers, analog and power devices, and system-on-chip solutions for industrial, automotive, and infrastructure markets.

The 74HC670P-E belongs to Renesas' legacy HC logic family, designed specifically for high-speed, low-power digital building blocks in addressable register and latch applications where deterministic timing and bus isolation are critical.

FAQ

What is the maximum clock frequency supported by the 74HC670P-E for reliable read/write cycling?

The 74HC670P-E does not operate on a clock signal - it is an asynchronous register file. Its timing is governed by propagation delays: minimum read cycle time is determined by tPLH/tPHL (21 ns typ) plus address setup/hold times (tsu = 10 ns min, th = 9 ns min at VCC = 6 V). For guaranteed operation, the shortest usable read–write cycle is 45 ns, supporting effective throughput up to 22 MHz in tightly controlled layouts. The 74HC670P-E requires no external clock; address and enable edges define all timing boundaries.

Can the 74HC670P-E perform simultaneous read and write to the same 4-bit word location?

No - the 74HC670P-E cannot safely read from and write to the same word location concurrently. Its architecture permits simultaneous access only to *different* words: one address decoded by WA/WB for write, another by RA/RB for read. Attempting same-word access causes undefined output states due to internal contention between latch input and output paths. The 74HC670P-E's function table explicitly shows Q = D only when write address matches and GW = L; no provision exists for transparent or overlapping access to identical locations.

Does the 74HC670P-E include internal pull-up or pull-down resistors on its address or enable inputs?

No, the 74HC670P-E has no internal pull-up or pull-down resistors on any pins. All inputs - including WA, WB, RA, RB, GW, and GR - require externally defined logic levels at all times. Floating inputs will cause unpredictable operation, increased ICC, or metastability. Designers must terminate unused address lines and enable inputs with appropriate resistors (e.g., 10 kΩ to VCC for active-low enables, or to GND for active-high signals) per Renesas' application guidance in the HD74HC670 datasheet Rev. 2.00.

Is the 74HC670P-E RoHS compliant and lead-free?

Yes, the 74HC670P-E is RoHS compliant and lead-free. Renesas confirms compliance with Directive 2011/65/EU (RoHS 2) in its product change notifications and packaging data. The device uses Ni/Pd/Au plating on leads and meets JEDEC J-STD-609 Category 1 moisture sensitivity level (MSL-1), with no lead content exceeding 0.1 wt%. Full compliance documentation, including substance declarations and test reports, is available through Renesas' official portal for the 74HC670P-E.

How does the 74HC670P-E handle output contention when multiple devices share a common bus?

The 74HC670P-E prevents bus contention using its GR (Read Enable) pin: when GR = H, all four outputs (Q1–Q4) enter high-impedance (Z) state, electrically disconnecting them from the bus. This allows safe multi-drop bus configurations where only one device asserts GR = L at a time. The 74HC670P-E does not include bus arbitration logic - external control (e.g., microcontroller GPIO or decoder) must ensure exclusive GR activation. Simultaneous GR = L on multiple 74HC670P-E devices will cause destructive current flow and must be avoided.