Renesas HD4074344FT

Overview

HD4074344FT from Renesas Electronics is a 4-bit ZTAT™ PROM-based microcontroller featuring 4,096-word on-chip PROM, 256-digit × 4-bit RAM, 8-bit × 4-channel A/D converter, two timer/counters, and an 8-bit clock-synchronous serial interface. It operates from 2.7 V to 5.5 V with 1 µs instruction cycle at 4 MHz and supports ceramic oscillator or external clock drive. It targets embedded control in industrial instrumentation and sensor interface systems.

For engineers reviewing the HD4074344FT datasheet, HD4074344FT pinout, HD4074344FT application, or HD4074344FT equivalent, key selection criteria include its 22 I/O pins (10 high-current sink), FP-30D 30-pin plastic flat package, PROM programmability for rapid prototyping, and guaranteed operation from –20 °C to +75 °C.

Technical Context

The HD4074344FT implements a Harvard architecture with separate ROM and RAM address spaces, including vector-addressed interrupt handling ($0000–$000F), zero-page subroutines ($0000–$003F), and a 4-kword program area ($0000–$0FFF). Its ALU supports 4-bit arithmetic/logic operations with 14-bit PC and 10-bit SP.

It integrates system-level peripherals: dual timer modules (free-running and reload), event counter with edge-selectable input (EVNB), watchdog timer, and serial interface with dedicated SCK/SI/SO pins. The A/D converter uses internal ladder resistors and accepts analog inputs on AN0–AN3 without external reference-unlike the HD404394 series which requires Vref.

Key Specifications

Pinout & Package

HD4074344FT is housed in a 30-pin plastic flat package (FP-30D), 13.2 mm × 5.3 mm body size, 0.8 mm pitch, with gull-wing leads. Pin 1 marked by notch or dot; top view shown in datasheet Rev. 7.0, page 7.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit microcontroller applications.

Compared with HD404344RFT, HD4074344FT provides field-programmable firmware and identical analog/peripheral integration; compared with HD4074394FT, it retains AN0 and eliminates Vref dependency - making it the most self-contained option for general-purpose 4-bit sensor control.

Availability

HD4074344FT is available at Aetrix Electronics and suitable for industrial sensor nodes, portable test instruments, motor control interfaces, and home appliance subsystems requiring stable component supply across extended product lifecycles.

Supply support for HD4074344FT 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 leader specializing in microcontrollers, analog, and power solutions for industrial, automotive, and infrastructure markets.

The HD4074344FT belongs to the HMCS400 family of 4-bit microcomputers designed for compact, cost-sensitive embedded control - emphasizing integrated A/D, low-power operation, and rapid development via PROM programmability.

FAQ

What is the maximum clock frequency supported by HD4074344FT?

The HD4074344FT achieves a 1 µs instruction cycle time at 4 MHz oscillator frequency, as specified in the Rev. 7.0 datasheet. It supports ceramic resonators up to 4 MHz or external CMOS clock signals within the same frequency range. Operation beyond 4 MHz is not characterized or guaranteed, and higher frequencies may cause timing violations in internal peripherals like the A/D converter or serial interface.

Does HD4074344FT require an external voltage reference for its A/D converter?

No, HD4074344FT does not require an external voltage reference. Its 8-bit × 4-channel A/D converter uses an internal ladder resistor network referenced to VCC, with AN0–AN3 accepting single-ended analog inputs directly. This differs from the HD404394 series, which mandates an external Vref connection - confirming HD4074344FT's self-contained analog capability.

How many I/O pins on HD4074344FT support 15 mA sink current?

HD4074344FT provides 10 I/O pins rated for 15 mA sink current: R10 through R23. These are explicitly designated as "large-current I/O pins" in the Rev. 7.0 datasheet (page 2). Pins D1 and D2 also support 15 mA sink, but the primary high-drive group remains the R-port subset - enabling direct LED or relay coil drive without external buffers.

What package type and dimensions does HD4074344FT use?

HD4074344FT is supplied in the FP-30D package: a 30-pin plastic flat package with 0.8 mm lead pitch, 13.2 mm × 5.3 mm body size, and gull-wing leads. Pin 1 is identified by a notch or dot on the package top surface. This footprint is distinct from DP-28S and FP-28DA variants and is documented in the pin arrangement diagram on page 7 of Rev. 7.0.

Can HD4074344FT be programmed in-circuit after soldering to the PCB?

No, HD4074344FT cannot be programmed in-circuit. As a ZTAT™ PROM device, it requires programming prior to mounting using a standard 27256-compatible PROM writer applying VPP voltage to the TEST/VPP pin (Pin 19). Once programmed, the device is read-only; reprogramming necessitates removal and erasure via UV exposure - which HD4074344FT does not support, as it is PROM, not EPROM.