MCHSC705C8ACFNE - 8-bit HC05 MCU, 8KB OTP, 4MHz, 44-PLCC | NXP
MPN: MCHSC705C8ACFNE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.75 | $1,375.00 |
| 500 | $11.4 | $5,700.00 |
| 1,000 | $9.85 | $9,850.00 |
MCHSC705C8ACFNE Overview
What is a microcontroller in the HC05 family? The HC05 is Freescale/NXP's classic 8-bit CISC microcontroller architecture derived from the Motorola 6800, designed for cost-sensitive embedded control applications. Within the broader taxonomy, HC05 sits as an 8-bit MCU -> microcontroller -> embedded processor -> semiconductor IC, offering on-chip peripherals and a simple memory model that has kept the family in production (and in long service) for industrial, automotive, and appliance designs spanning multiple decades. The MCHSC705C8ACFNE belongs to the HC705 sub-family, which adds user-OTP EPROM in place of mask-ROM for flexible prototyping and low-volume production.
The MCHSC705C8ACFNE integrates a 4 MHz internal bus clock, an 8-channel 8-bit ADC, a serial communications interface (SCI), a serial peripheral interface (SPI), a 16-bit timer with one capture input and one compare output, plus a COP watchdog for fail-safe operation. It supports dual voltage operation at 3.0V and 5.0V, simplifying designs that must bridge battery-backed and regulated domains. Programmable in HC05 assembly with the ICC05, Cosmic, or Metrowerks toolchains, the part exposes 24 general-purpose I/O pins grouped into ports A, B, C, and D.
Architecturally, the HC05 core combines an accumulator-based CISC instruction set with on-chip oscillator, brown-out reset, and low-power STOP/WAIT modes that drop quiescent current to microampere levels for battery-friendly designs. The internal oscillator and the 8KB OTP are accessed through a Bootstrap or Monitor mode that uses the SCI to load user code, enabling field reprogrammability equivalent to flash-based parts.
Typical applications include appliance control boards, automotive sub-system controllers, industrial sensor interfaces, low-cost user-interface panels, and legacy retrofit designs where the HC05 code base must be preserved on modern PCB assemblies. NXP's continued support of the family has kept the MCHSC705C8ACFNE in long-term service even as flash-based successors have been introduced.
When designing with this device, ensure VDD decoupling uses a 100 nF ceramic capacitor placed within 5 mm of the VDD pin and a bulk tantalum or electrolytic capacitor of at least 10 uF on the VDD rail. The IRQ/reset pin should be pulled up with a 4.7 kohm resistor and have a 100 nF capacitor to ground for noise immunity in electrically noisy environments such as motor-control or automotive body modules.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MCHSC705C8ACFNE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MCHSC705C8ACFNE (same form factor and footprint) — differing in Mounting Type, Package, Architecture, Core, Number of I/O.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68HC705C8ACFNE
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HC705C8AFNE
✅ Drop-In✓ In Stock
$8.6 / Unit
View Datasheet →SC705C8AE0VFNE
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →SC705C8AE0VFBE
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MC908AZ60ACFUE
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View Datasheet →MC908AP16CFBE
✅ Drop-In✓ In Stock
$13.6 / Unit
View Datasheet →MCHSC705C8ACFNE Maximum Ratings & Electrical Characteristics
| Manufacturer | NXP Semiconductors |
| Product Type | 8-bit Microcontroller (MCU) |
| Core Architecture | HC05 / HC705 CISC |
| Program Memory Size | 8 KB (8K x 8) OTP EPROM |
| RAM Size | 304 x 8 (304 bytes) |
| Number of I/O | 24 |
| CPU Speed (Bus Clock) | 4 MHz |
| Operating Voltage | 3.0 V / 5.0 V |
| Package / Case | 44-LCC (J-Lead), PLCC-44 16.59 x 16.59 mm |
| Terminal Form | J-BEND (J-lead) |
| Mounting Type | Surface Mount |
| Number of Terminals | 44 |
| Package Code | QCCJ |
| Temperature Grade | Industrial |
| Supplier Packing | TUBE (also REEL-Reel 13" Q1 DP available) |
| Min. Package Quantity | 450 |
| Lifecycle | No Longer Manufactured (NRND per NXP product page) |
MCHSC705C8ACFNE Pin Configuration
| Pin 1 | PA0 — Port A bit 0 (digital I/O, ADC input channel 0) |
| Pin 2 | PA1 — Port A bit 1 (digital I/O, ADC input channel 1) |
| Pin 3 | PA2 — Port A bit 2 (digital I/O, ADC input channel 2) |
| Pin 4 | PA3 — Port A bit 3 (digital I/O, ADC input channel 3) |
| Pin 5 | PA4 — Port A bit 4 (digital I/O, ADC input channel 4) |
| Pin 6 | PA5 — Port A bit 5 (digital I/O, ADC input channel 5) |
| Pin 7 | PA6 — Port A bit 6 (digital I/O, ADC input channel 6) |
| Pin 8 | PA7 — Port A bit 7 (digital I/O, ADC input channel 7) |
| Pin 9 | VSS — Ground (digital GND) |
| Pin 10 | VDD — Positive supply (3.0 V or 5.0 V) |
| Pin 11 | PB0 — Port B bit 0 (digital I/O, OC1 timer output) |
| Pin 12 | PB1 — Port B bit 1 (digital I/O, IC1 timer input) |
| Pin 13 | PB2 — Port B bit 2 (digital I/O) |
| Pin 14 | PB3 — Port B bit 3 (digital I/O) |
| Pin 15 | PB4 — Port B bit 4 (digital I/O) |
| Pin 16 | PB5 — Port B bit 5 (digital I/O, MOSI SPI) |
| Pin 17 | PB6 — Port B bit 6 (digital I/O, MISO SPI) |
| Pin 18 | PB7 — Port B bit 7 (digital I/O, SCLK SPI) |
| Pin 19 | PC0 — Port C bit 0 (digital I/O) |
| Pin 20 | PC1 — Port C bit 1 (digital I/O) |
| Pin 21 | PC2 — Port C bit 2 (digital I/O) |
| Pin 22 | PC3 — Port C bit 3 (digital I/O) |
| Pin 23 | PC4 — Port C bit 4 (digital I/O) |
| Pin 24 | PC5 — Port C bit 5 (digital I/O) |
| Pin 25 | PC6 — Port C bit 6 (digital I/O) |
| Pin 26 | PC7 — Port C bit 7 (digital I/O) |
| Pin 27 | PD0 — Port D bit 0 (digital I/O, RxD SCI) |
| Pin 28 | PD1 — Port D bit 1 (digital I/O, TxD SCI) |
| Pin 29 | PD2 — Port D bit 2 (digital I/O) |
| Pin 30 | PD3 — Port D bit 3 (digital I/O) |
| Pin 31 | PD4 — Port D bit 4 (digital I/O) |
| Pin 32 | PD5 — Port D bit 5 (digital I/O) |
| Pin 33 | TCAP — Timer capture (alternate function) |
| Pin 34 | TCMP — Timer compare (alternate function) |
| Pin 35 | OSC1 — Crystal/oscillator input (or external clock) |
| Pin 36 | OSC2 — Crystal/oscillator output |
| Pin 37 | VSS — Ground (digital GND) |
| Pin 38 | VDD — Positive supply (3.0 V or 5.0 V) |
| Pin 39 | IRQ — External interrupt request (active low) |
| Pin 40 | RESET — Reset (active low) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
MCHSC705C8ACFNE is suitable for 6 applications: Appliance Control Boards (Washing Machines, Dishwashers), Automotive Body Electronics and Sub-System Controllers, Industrial Sensor Interface and Process Modules, User-Interface Keypad Panels and Keypad Decoders, Legacy Industrial Retrofit and Replacement Designs, Building Automation and HVAC Zone Controllers.
Appliance Control Boards (Washing Machines, Dishwashers)
The NXP MCHSC705C8ACFNE targets appliance control boards because its 4 MHz HC05 core, 24 GPIO, and 8 KB OTP provide enough cycles and code space to drive user-interface keypads, drive LED indicators, and orchestrate TRIAC-controlled motor stages. The 304 bytes of on-chip RAM suffice for state-machine scheduling of wash cycles, while the SCI peripheral offers diagnostic data logging via UART link to factory testers. Industrial temperature grade with 3.0 V/5.0 V dual-voltage operation aligns directly with the rectifier-fed, unfiltered supply rails typical in white goods. The 44-PLCC footprint drops onto socketed modules for serviceability, and the HC05 assembly base allows reuse of legacy code libraries. Compared to flash-only successors, OTP keeps unit cost low enough for sub-30 USD BOM targets in appliance SKUs.
Recommended
Automotive Body Electronics and Sub-System Controllers
The MCHSC705C8ACFNE is well suited to automotive body sub-systems such as HVAC blend-door actuators, seat-position memory, or interior lighting controllers, where its industrial temperature grade and robust PLCC package survive under-hood thermal stress. The on-chip 8-channel ADC reads sensor inputs such as NTC thermistors and potentiometers, while the 16-bit timer with capture/compare drives MOSFET or relay driver stages. The COP watchdog and brown-out reset cover the ISO 7637 transient environment on automotive 12 V battery rails, and the 3.0 V-5.0 V dual-rail tolerance eases supply supervision. Compared with AEC-Q100 qualified parts, the HC05 offers lower unit cost for non-safety sub-systems such as trim-level lighting and convenience modules. The 44-PLCC footprint eases procurement and is supported across multiple automotive aftermarket distributors.
Recommended
Industrial Sensor Interface and Process Modules
Sensor-interface modules in industrial plants use the MCHSC705C8ACFNE to convert analog sensor outputs into digital readings via the on-chip 8-channel 8-bit ADC, then forward structured process values over the SCI UART to a PLC or SCADA master. With 4 MHz bus clock and HC05 CISC instructions, the part executes scaling loops, linearization routines, and MODBUS-RTU frame composition within tight cycle budgets. The 3.0 V/5.0 V operation lets the same part work on legacy 5 V field wiring as well as modern 3.3 V sensor boards. The 304-byte RAM is plenty for holding calibration tables and rolling averages, and the COP watchdog guards against firmware lockup in unattended cabinet installations. The PLCC-44 package is socketable, easing field replacement without de-soldering.
Recommended
User-Interface Keypad Panels and Keypad Decoders
User-interface panels for access control, industrial machinery HMI, and consumer electronics use the MCHSC705C8ACFNE to scan 4x4 or larger matrix keypads using a port-mapped I/O expansion scheme. The 24 GPIO lines multiplex with the SPI peripheral to drive LED status indicators, character LCDs, or dot-matrix displays. At 4 MHz, the HC05 core delivers sub-50 ms debounce cycles for tactile switches, sufficient to mask contact bounce without perceived lag. STOP and WAIT low-power modes enable battery-backed keypad locks that draw microamps in standby. The HC05 tool chain is well established with Cosmic and ICC05 C compilers, simplifying firmware reuse from existing keypad product families.
Recommended
Legacy Industrial Retrofit and Replacement Designs
Equipment manufacturers maintaining installed fleets of industrial controllers (textile machinery, packaging lines, hydraulic test stands) frequently need drop-in replacements for obsolete HC05 mask-ROM parts, and the MCHSC705C8ACFNE fills that role with OTP for last-buy flexibility. Because the 44-PLCC QCCJ footprint is identical to the original MC68HC05C8 and to the MC68HC705C8 variants, board retrofits require no PCB rework - the new part drops into the same socket or land pattern. HC05 assembly source is binary-compatible with the original tool chain, so legacy code modules can be recompiled and reloaded through Bootstrap mode. Stocking MCHSC705C8ACFNE as a service spare avoids multi-month obsolescence risk for installed bases.
Recommended
Building Automation and HVAC Zone Controllers
Building-automation zone controllers for fan-coil units, VAV boxes, and underfloor heating manifolds use the MCHSC705C8ACFNE to read NTC thermistors and 0-10 V actuators through the on-chip ADC, then drive TRIAC or relay outputs to modulate HVAC loads. The 24 GPIO count handles multi-stage fan control plus a serial link to a centralized BMS gateway. Operating directly from 24 VAC rectified rails via a small linear regulator keeps the BOM cost low; the 3.0 V/5.0 V tolerance simplifies that supply. The 304-byte RAM holds ramp/soak setpoint tables, while the 8 KB OTP carries the zone scheduling logic. Industrial temperature grade plus the well-characterized HC05 silicon process suits unattended plant-room installations.
Recommended
Recommended Products Summary
Engineering reference data for MCHSC705C8ACFNE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68HC705C8ACFNE | MC68HC705C8AFNE | SC705C8AE0VFNE | SC705C8AE0VFBE | MC908AZ60ACFUE | MC908AP16CFBE |
|---|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors (legacy Freescale marking) | NXP Semiconductors (legacy Freescale marking) | NXP Semiconductors (SC prefix) | NXP Semiconductors (SC prefix) | NXP Semiconductors | NXP Semiconductors |
| Package | PLCC-44 (QCCJ, J-bend) | PLCC-44 (QCCJ, J-bend) - identical | PLCC-44 (QCCJ, J-bend) - identical | PLCC-44 (QCCJ, J-bend) - identical | PLCC-44 (QCCJ, J-bend) - identical | PLCC-44 (QCCJ, J-bend) - identical | PLCC-44 (QCCJ, J-bend) - identical |
| Core | HC05 CISC | HC05 CISC - identical | HC05 CISC - identical | HC05 CISC - identical | HC05 CISC - identical | HC08 CISC (4-5x faster) | HC08 CISC (4-5x faster) |
| Program Memory | 8 KB OTP EPROM | 8 KB OTP EPROM - identical | 8 KB OTP EPROM - identical | 8 KB OTP EPROM - identical | 8 KB OTP EPROM - identical | 60 KB Flash (+650%) | 16 KB Flash (+100%) |
| CPU Speed | 4 MHz | 4 MHz - identical | 4 MHz - identical | 4 MHz - identical | 4 MHz - identical | Up to 8 MHz HC08 (2x) | Up to 8 MHz HC08 (2x) |
| Operating Voltage | 3.0 V / 5.0 V | 3.0 V / 5.0 V - identical | 3.0 V / 5.0 V - identical | 3.0 V / 5.0 V - identical | 3.0 V / 5.0 V - identical | 3.0 V / 5.0 V - identical | 3.0 V / 5.0 V - identical |
| GPIO Count | 24 | 24 - identical | 24 - identical | 24 - identical | 24 - identical | 26-32 (HC08 specific) | 24-26 (HC08 specific) |
| Lifecycle Status | NRND | NRND (last-buy available) | NRND (last-buy available) | Active (SC long-life supply program) | Active (SC long-life supply program) | Active | Active |
Key Differentiators
- Active long-life supply program for industrial continuity (vs MC68HC705C8ACFNE)
- Same-footprint HC08 upgrade path with flash (vs MC908AP16CFBE)
- Industrial temperature grade with 3.0 V / 5.0 V dual-rail (vs SC705C8AE0VFNE)
- Native 8 KB OTP for low-BOM-cost designs (vs MC908AZ60ACFUE)
Design Notes
Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD pin and a 10 uF bulk (tantalum or low-ESR aluminum) capacitor on the main VDD rail. The HC05 is sensitive to VDD droop during A/D conversions; inadequate decoupling causes ADC code spread of 2-3 LSBs above the rated 8-bit noise floor. Pin 10 and pin 38 are both VDD - tying them together on the PCB with a wide trace or via-stitched pour avoids ground bounce between the core and the I/O pads during high-current source/sink transitions.
The PLCC-44 package dissipates well under 100 mA of internal current at 4 MHz, so no heatsink is required and the part does not need thermal vias. However, in enclosed housings above 70 C ambient, ensure airflow path across the package. For industrial temperature grade designs in sealed enclosures, measure case temperature rise - the HC05 silicon is rated -40 C to +85 C (industrial) and any prolonged exposure above +70 C internal ambient shortens OTP data retention.
Route the 4 MHz oscillator traces (OSC1, OSC2) shorter than 25 mm and keep them away from switching regulator or relay-driver traces to avoid EMI coupling into the clock. Place the 10-22 pF load caps within 1 cm of the crystal or resonator pins, with a ground guard trace between OSC traces and adjacent signal lines. The PLCC footprint should accept standard 44-pin PLCC sockets (e.g., Yamaichi IC120-44) for prototype bring-up, then reflow-soldered sockets or direct solder for production.
Do not confuse the MCHSC705C8ACFNE (44-PLCC) with the 40-PDIP version (MCHSC705C8ACP) - they have different pinouts and cannot be dropped into each other's socket. For OTP programming, ensure the Bootstrap entry sequence (5 V on IRQ, TxD low during reset) is glitch-free - a slow-rising TxD line prevents successful mode entry. Always validate the brown-out reset threshold against your supply voltage; at 3.0 V operation, ensure the regulator stays above the BORMIN spec otherwise the part can enter unintended reset cycles.
The HC05's SCI (UART) and SPI peripherals share port pins and require careful assignment to avoid contention with keypad scanning routines. Use a pull-up on the IRQ pin (4.7 kohm to VDD) for noise immunity in motor-control enclosures. When chained on a multi-drop UART bus, terminate the line at both ends with 120 ohm if cable length exceeds 30 cm - the HC05's output drive is weak compared to modern RS-485 transceivers.
Compliance Information
RoHS and REACH compliant per NXP product page; industrial temperature grade -40 C to +85 C. Not AEC-Q100 qualified - the automotive body-electronics use cases are non-safety sub-systems; AEC-Q100 variants fall under other NXP part numbers.
