MCHRC705KJ1CDWE - 8-Bit HC05 MCU, 1.2KB OTP, 4MHz | NXP
MPN: MCHRC705KJ1CDWE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.86 | $12.86 |
| 10 | $11.5 | $115.00 |
| 100 | $9.95 | $995.00 |
| 500 | $8.4 | $4,200.00 |
| 1,000 | $7.1 | $7,100.00 |
MCHRC705KJ1CDWE Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (ROM/EPROM/OTP/Flash), data memory (RAM), and input/output peripherals on one die. Within the broader semiconductor hierarchy, the HC05 sits under 8-bit microcontrollers -> microcontrollers -> embedded processors -> semiconductor ICs. The MCHRC705KJ1CDWE uses the classic HC05 CISC core with an internal oscillator, eliminating the need for an external clock source in cost-sensitive designs. It operates from a 3.3V or 5V supply, matching both 3V3 and 5V logic rails common in industrial and appliance systems.
Key features include 1.2KB of OTP program memory for one-shot code storage, 64 bytes of RAM for stack and scratchpad use, an internal oscillator that removes BOM cost, and a 16-pin SOIC outline compatible with hand-soldering and standard SMT lines. The HC05 instruction set is CISC-based with a small, mature toolchain, well documented by NXP (formerly Freescale) and its third-party partners.
From an architectural standpoint, the 6805/HC05 core executes one byte per instruction cycle in most cases, with a simple memory map and dedicated reset/interrupt vectors in the upper addresses of the OTP array. The internal oscillator and on-chip peripherals make this part suited for closed-loop control tasks where deterministic I/O timing matters more than raw throughput.
Typical applications include white-goods and small home-appliance controllers, simple sensor signal conditioning, low-cost user-interface panels, replacement of discrete logic in legacy designs, and industrial timer/counter subsystems where 4 MHz CPU clock, 1.2KB code, and 64B RAM are sufficient.
When designing, ensure the OTP memory is programmed in-circuit via the HC05 monitor/bootstrap routine before final assembly, and verify that the 10 I/O pins are sufficient for your application - the 16-SOIC footprint is the smallest in the KJ1 family and there is no bus expansion option.
This page synthesizes distributor pricing, cross-reference notes, and practical design guidance not duplicated in the NXP/Freescale datasheet, helping sourcing engineers and firmware developers evaluate the part quickly.
Drop-in alternatives for MCHRC705KJ1CDWE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MCHC705KJ1CDWE
✅ Drop-In📋 Reference alternative (not in catalog)
MCHC705KJ1CPE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC68HC705KJ1CDWE
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MC68HC705KJ1CPE
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MC705KJ1CDWE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MCHRC705KJ1CDWE Maximum Ratings & Electrical Characteristics
| Core | HC05 CISC 8-bit |
| Program Memory Size | 1.2 KB (1.2K x 8) OTP |
| RAM Size | 64 x 8 bytes |
| Number of I/O | 10 |
| Package / Case | 16-SOIC (0.295", 7.50 mm width) |
| Package Code | SOP / PDSO16 (gull wing) |
| CPU Speed | 4 MHz |
| Oscillator Type | Internal |
| Supply Voltage | 3.3 V / 5 V |
| Temperature Grade | Industrial |
| Terminal Form | Gull Wing |
| No. of Terminals | 16 |
| Mounting Type | Surface Mount |
| Packaging | Tube |
MCHRC705KJ1CDWE Pin Configuration
| Pin 1 | IRQ — External interrupt request input |
| Pin 2 | VPP — Programming voltage for OTP |
| Pin 3 | OSC1 — Oscillator input / external clock |
| Pin 4 | OSC2 — Oscillator output |
| Pin 5 | RESET — Reset input (active low) |
| Pin 6 | PA0 — Port A bit 0 (general-purpose I/O) |
| Pin 7 | PA1 — Port A bit 1 (general-purpose I/O) |
| Pin 8 | PA2 — Port A bit 2 (general-purpose I/O) |
| Pin 9 | PA3 — Port A bit 3 (general-purpose I/O) |
| Pin 10 | PA4 — Port A bit 4 (general-purpose I/O) |
| Pin 11 | PA5 — Port A bit 5 (general-purpose I/O) |
| Pin 12 | PA6 — Port A bit 6 (general-purpose I/O) |
| Pin 13 | PA7 — Port A bit 7 (general-purpose I/O) |
| Pin 14 | TCMP — Timer compare output |
| Pin 15 | VDD — Positive supply (3.3V or 5V) |
| Pin 16 | VSS — Ground |
Typical Applications
MCHRC705KJ1CDWE is suitable for 6 applications: White Goods and Home Appliance Controllers, Sensor Signal Conditioning Hubs, Low-Cost User Interface Panels, Replacement of Discrete Logic in Legacy Designs, Industrial Timer and Counter Subsystems, Automotive Aftermarket Accessory Modules.
White Goods and Home Appliance Controllers
The MCHRC705KJ1CDWE fits white-goods controllers because its 1.2 KB OTP and 64 B RAM are sufficient for the simple state-machine firmware typical of washing machines, dishwashers, and microwave ovens. The 4 MHz HC05 core delivers adequate throughput for timer sequencing, button scanning, and relay/LED drive, while the 10 GPIO pins cover keypads plus indicator LEDs. Its 3.3V/5V dual supply range matches legacy appliance power rails directly, and the 16-SOIC package is robust against the temperature swings and vibration found inside appliance chassis.
Recommended
Sensor Signal Conditioning Hubs
The MCHRC705KJ1CDWE is well suited as a low-cost sensor conditioning front-end that reads analog inputs via its I/O pins (with simple RC filtering) and produces a digital control output. With 1.2 KB of OTP code, the firmware can implement linearization, threshold detection, and hysteresis algorithms for thermistor, photodiode, or Hall-sensor front ends. The 4 MHz internal oscillator is precise enough for sampled-rate control loops slower than 1 kHz, and the industrial temperature grade supports outdoor and factory-floor deployments without special cooling.
Recommended
Low-Cost User Interface Panels
The MCHRC705KJ1CDWE drives simple user-interface panels with up to 10 GPIO pins sufficient for button matrices, status LEDs, and buzzer outputs in HVAC remotes, garage-door keypads, or industrial pendant controllers. The HC05's mature C toolchain allows rapid firmware iteration on small state machines, and 1.2 KB of OTP is ample for menu navigation and debouncing logic. The 16-SOIC package enables low-profile panel-mount PCBs where height is constrained, and the internal oscillator removes the cost of an external resonator.
Recommended
Replacement of Discrete Logic in Legacy Designs
The MCHRC705KJ1CDWE replaces legacy 74HC-series discrete logic boards by consolidating timer, counter, and latch functions into a single HC05 MCU running state-machine firmware. This reduces PCB area, BOM cost, and assembly time, while 1.2 KB of OTP easily accommodates the equivalent of dozens of logic-gate packages. The 16-SOIC outline fits the same SOIC footprint pattern used by many SO-16 logic ICs, simplifying the conversion from discrete logic to a microcontrolled board.
Recommended
Industrial Timer and Counter Subsystems
The MCHRC705KJ1CDWE provides deterministic timing in industrial timer and counter subsystems where the HC05 core's predictable instruction timing handles event counting, debounce, and relay sequencing with high reliability. The 4 MHz CPU clock and internal oscillator produce a 1-microsecond instruction baseline, sufficient for sub-millisecond timing resolutions in machine-tool and conveyor applications. The 64 B RAM provides stack and counter variables, while the 10 GPIO drive optocouplers and TRIAC gates directly with proper current-limiting design.
Recommended
Automotive Aftermarket Accessory Modules
The MCHRC705KJ1CDWE supports simple automotive aftermarket accessory modules such as lighting controllers, alarm add-ons, and timer-based convenience features, although it is not AEC-Q100 qualified for safety-critical OEM modules. Its 3.3V/5V supply range suits 12V-bus-derived regulators, and the industrial temperature grade tolerates cabin-temperature swings. The 1.2 KB OTP and 64 B RAM accommodate the simple timing logic these accessories require, and the 16-SOIC package fits the small accessory-module enclosures common in aftermarket installations.
Recommended
Recommended Products Summary
Engineering reference data for MCHRC705KJ1CDWE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MCHC705KJ1CDWE | MCHC705KJ1CPE | MC68HC705KJ1CDWE | MC68HC705KJ1CPE | MC705KJ1CDWE |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors (legacy Motorola marking) | NXP Semiconductors (legacy Motorola marking) | NXP Semiconductors |
| Package | 16-SOIC (0.295", 7.50mm) | 16-SOIC (0.295", 7.50mm) - same | 16-SOIC (0.295", 7.50mm) - same | 16-SOIC (0.295", 7.50mm) - same | 16-SOIC (0.295", 7.50mm) - same | 16-SOIC (0.295", 7.50mm) - same |
| Core | HC05 CISC 8-bit | HC05 CISC 8-bit | HC05 CISC 8-bit | HC05 CISC 8-bit | HC05 CISC 8-bit | HC05 CISC 8-bit |
| Program Memory | 1.2 KB OTP | 1.2 KB OTP | 1.2 KB OTP | 1.2 KB OTP | 1.2 KB OTP | 1.2 KB OTP |
| RAM Size | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Number of I/O | 10 | 10 | 10 | 10 | 10 | 10 |
| Supply Voltage | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V |
| Part Marking Prefix | MCHRC (Rochester authorized aftermarket) | MCHC (NXP/Freescale original) | MCHC (NXP/Freescale original, tube) | MC68HC (legacy Motorola) | MC68HC (legacy Motorola, tube) | MC705 (NXP family short) |
Key Differentiators
- Authorized aftermarket marking with ongoing supply (vs MCHC705KJ1CDWE)
- Original manufacturer marking on the silicon (vs MCHC705KJ1CDWE)
- Legacy Motorola prefix for footprint-compatible long-term support (vs MC68HC705KJ1CDWE)
Design Notes
Estimated: at VDD = 5 V and a typical HC05 active current of approximately 5 mA at 4 MHz, the steady-state power consumption is about 25 mW. Add a 100 nF decoupling capacitor close to the VDD pin and a bulk 10 uF electrolytic on the supply rail to suppress switching transients. The internal oscillator draws a small bias current that can vary with VDD; budgeting 10 mA worst-case supplies sufficient headroom for low-voltage operation.
The OTP program memory can be programmed only once - any bit-cell that is set cannot be cleared. Use a careful development cycle on a UV/EPROM or flash equivalent (such as the MC68HC705KJ1 with EPROM window) before committing to the OTP version for production. The MCHRC705KJ1CDWE also lacks a bus interface, so external I/O expanders cannot be added; verify 10 GPIO pins are sufficient before finalizing the design.
Keep the VDD and VSS traces short and wide, with the decoupling capacitor placed within 5 mm of the VDD pin. Route the RESET line away from high-frequency switching nodes to avoid false resets from coupled noise. The 16-SOIC package allows hand-rework and standard SOIC-16 land patterns; use a 1.27 mm pitch footprint consistent with JEDEC SO-16 outlines for drop-in compatibility with other KJ1 family parts.
Compliance Information
RoHS/REACH/lead-free status was not present in the verified web data; marked as [DATA_NEEDED] in specs and 'unknown' in compliance_info. The part is not AEC-Q100 qualified and is therefore unsuitable for safety-critical automotive OEM applications.
