PIC16C662-04/PQ - 8-bit OTP MCU, 7KB, 33 I/O | Microchip | MQFP-44
MPN: PIC16C662-04/PQ β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.95 | $9.95 |
| 10 | $8.75 | $87.50 |
| 100 | $7.4 | $740.00 |
| 500 | $6.2 | $3,100.00 |
| 1,000 | $5.35 | $5,350.00 |
PIC16C662-04/PQ Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory (here OTP EPROM), working RAM, and a set of on-chip peripherals such as timers, capture/compare/PWM modules, a watchdog timer, and analog comparators. Within the broader semiconductor hierarchy, an MCU belongs to the embedded processor family, sitting between simple microcontrollers and 16/32-bit MPUs in compute capability. The PIC16C66x series targets cost-sensitive, deterministic real-time control tasks where its 35 single-word instruction set and 14-bit instruction word keep code density high and interrupt latency predictable.
Key features of the PIC16C662-04/PQ include 7 KB EPROM program memory, 176 bytes of data RAM, 33 I/O pins, two 8-bit and one 16-bit timer/counter modules, a watchdog timer with its own on-chip RC oscillator, two analog comparators, and a programmable code-protection mechanism. Operating voltage spans 3.0 V to 6.0 V over commercial, industrial, and extended temperature grades, with typical active current around 2 mA at 5 V / 4 MHz and standby currents in the microamp range at low clock rates.
The architecture is a RISC-like design with a two-stage pipeline, separate program and data buses (modified Harvard), and a 14-bit program word that carries both opcode and literal data. OTP EPROM programming is performed via Microchip's standard in-circuit serial programming interface, allowing field programming of unprogrammed parts before conformal coating or final test.
Typical applications include white-good and small-appliance control boards, HVAC blower and thermostat controls, automotive interior accessories (non-safety-critical), industrial sensor interfaces, simple remote keyless entry transmitters, and low-cost remote sensor nodes. The combination of on-chip comparators and PWM makes it well suited to closed-loop fan, pump, and solenoid control.
A key design tip: because the part uses OTP EPROM, firmware must be fully validated before programming the production lot - there is no field re-programmability. Place decoupling capacitors (100 nF ceramic plus 10 uF bulk) within 5 mm of VDD/VSS, and route the OSC1/OSC2 traces over a continuous ground pour to limit EMI coupling into the analog comparator inputs.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives, and practical design guidance not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C662-04/PQ β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C66-04/PQ
β Drop-Inπ Reference alternative (not in catalog)
PIC16F877A-I/PQ
β Drop-Inπ Reference alternative (not in catalog)
PIC16F874A-I/PQ
β Drop-Inπ Reference alternative (not in catalog)
PIC16C662-04/PQ Maximum Ratings & Electrical Characteristics
| Architecture | PIC16C66 (modified Harvard, 14-bit instruction word) |
| Core | 8-bit RISC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 7 KB |
| Data RAM | 176 bytes |
| I/O Pins | 33 |
| Instruction Set Size | 35 single-word instructions |
| Instruction Cycle Time | 200 ns at 4 MHz oscillator |
| Maximum Oscillator Frequency (04 grade) | 4 MHz |
| Timers | Timer0 (8-bit), Timer1 (16-bit), Timer2 (8-bit with PWM) |
| Analog Comparators | 2 on-chip |
| Watchdog Timer | Yes, with dedicated on-chip RC oscillator |
| Operating Voltage Range | 3.0 V to 6.0 V |
| Typical Active Current | approx. 2 mA at 5 V / 4 MHz |
| Package | 44-lead MQFP (PQ) |
| Mounting Type | Surface Mount |
| Programming Method | In-circuit serial programming (ICSP) |
| Operating Temperature | Commercial 0C to +70C / Industrial -40C to +85C (suffix dependent) |
PIC16C662-04/PQ Pin Configuration
| Pin 1 | MCLR/VPP β Master clear (reset) input / programming voltage |
| Pin 2 | OSC1/CLKIN β Oscillator input or external clock input |
| Pin 3 | OSC2/CLKOUT β Oscillator output (Fosc/4 for external clock mode) |
| Pin 4 | RA0 β Port A bit 0 (digital I/O, analog input) |
| Pin 5 | RA1 β Port A bit 1 (digital I/O, analog input) |
| Pin 6 | RA2 β Port A bit 2 (digital I/O, analog input) |
| Pin 7 | RA3 β Port A bit 3 (digital I/O, analog input) |
| Pin 8 | RA4 β Port A bit 4 (digital I/O, T0CKI) |
| Pin 9 | RA5 β Port A bit 5 (digital I/O, analog input) |
| Pin 10 | VSS β Ground reference |
| Pin 11 | VDD β Positive supply (3.0 V to 6.0 V) |
| Pin 12 | RB0 β Port B bit 0 (digital I/O, external interrupt) |
| Pin 13 | RB1 β Port B bit 1 (digital I/O) |
| Pin 14 | RB2 β Port B bit 2 (digital I/O) |
| Pin 15 | RB3 β Port B bit 3 (digital I/O) |
| Pin 16 | RB4 β Port B bit 4 (digital I/O, interrupt-on-change) |
| Pin 17 | RB5 β Port B bit 5 (digital I/O, interrupt-on-change) |
| Pin 18 | RB6 β Port B bit 6 (digital I/O, PGC programming clock) |
| Pin 19 | RB7 β Port B bit 7 (digital I/O, PGD programming data) |
| Pin 20 | VSS β Ground reference |
| Pin 21 | RC0 β Port C bit 0 (digital I/O, T1OSO/T1CKI) |
| Pin 22 | RC1 β Port C bit 1 (digital I/O, T1OSI) |
| Pin 23 | RC2 β Port C bit 2 (digital I/O, CCP1) |
| Pin 24 | RC3 β Port C bit 3 (digital I/O) |
| Pin 25 | RC4 β Port C bit 4 (digital I/O) |
| Pin 26 | RC5 β Port C bit 5 (digital I/O) |
| Pin 27 | RC6 β Port C bit 6 (digital I/O) |
| Pin 28 | RC7 β Port C bit 7 (digital I/O) |
| Pin 29 | VSS β Ground reference |
| Pin 30 | VDD β Positive supply |
| Pin 31 | RD0 β Port D bit 0 (digital I/O) |
| Pin 32 | RD1 β Port D bit 1 (digital I/O) |
| Pin 33 | RD2 β Port D bit 2 (digital I/O) |
| Pin 34 | RD3 β Port D bit 3 (digital I/O) |
| Pin 35 | RD4 β Port D bit 4 (digital I/O) |
| Pin 36 | RD5 β Port D bit 5 (digital I/O) |
| Pin 37 | RD6 β Port D bit 6 (digital I/O) |
| Pin 38 | RD7 β Port D bit 7 (digital I/O) |
| Pin 39 | VSS β Ground reference |
| Pin 40 | VDD β Positive supply |
| Pin 41 | RE0 β Port E bit 0 (digital I/O, analog comparator reference) |
| Pin 42 | RE1 β Port E bit 1 (digital I/O, analog comparator reference) |
| Pin 43 | RE2 β Port E bit 2 (digital I/O) |
| Pin 44 | NC β Not connected (per datasheet) |
Typical Applications
PIC16C662-04/PQ is suitable for 6 applications: White-Good Appliance Control, HVAC Thermostat and Blower Control, Automotive Interior Accessories, Industrial Sensor Interface Module, Remote Keyless Entry (RKE) Transmitter, Low-Cost Remote Sensor Node.
White-Good Appliance Control
The PIC16C662-04/PQ is a strong fit for white-good control boards such as washing machines, dishwashers, and microwave ovens. Its 33 I/O pins can drive seven-segment displays, keypad matrices, and triac-based load switches directly. The on-chip analog comparators allow zero-crossing detection of the AC line for synchronous load firing, while PWM-driven Timer2 enables precise heating-element control. The 3.0 V to 6.0 V supply range matches rectified 5 V rails from small transformer supplies. Designers benefit from the deterministic 200 ns instruction cycle, which simplifies time-critical triac-latch and relay-debounce routines. Note that OTP EPROM requires final firmware before production programming, so engineering builds must use a flash equivalent.
Recommended
HVAC Thermostat and Blower Control
The PIC16C662-04/PQ suits wall-thermostat and HVAC-blower controllers that demand reliable real-time response. Its three timers cover fan speed measurement (Timer0), brown-out timing (Timer1), and PWM blower drive (Timer2). The two analog comparators can be configured for thermistor bridge sensing, giving a 1.5C resolution without an external ADC. Operating current around 2 mA at 5 V / 4 MHz is acceptable for a transformer-supplied thermostat that does not need battery backup. The 200 ns instruction cycle keeps control-loop latency under 10 us, fast enough for a 1 ms HVAC scan rate. For battery-backed thermostats, consider the PIC16F88x family to retain time-of-day across power cycles via internal EEPROM.
Recommended
Automotive Interior Accessories
Non-safety automotive interior accessories such as seat-position controllers, mirror-position modules, and HVAC blend-door actuators benefit from the PIC16C662-04/PQ's 33 I/O count and PWM timers. The PIC16C662 -04 grade operates across industrial temperature ranges suitable for cabin environments. The 5 V supply rail typical in body-control modules directly powers the MCU. Designers should add external watchdog supervision and load-dump protection because OTP parts cannot accept late-stage firmware changes; field failures require mechanical recall. The on-chip comparators provide Hall-effect sensor interfaces for seat-track motors. For safety-relevant ECUs, use a flash-based PIC16F or PIC18 part with CAN or LIN support.
Recommended
Industrial Sensor Interface Module
The PIC16C662-04/PQ can serve as a small industrial sensor-interface module converting 4-20 mA loop signals or thermistor inputs into a UART-style bit-banged output. The two analog comparators threshold-detect against a precision reference, and the timers measure pulse widths. Its 3.0 V to 6.0 V operating range handles 24 V loop-powered designs through a small regulator. The deterministic instruction cycle simplifies IEC 61131-3-style ladder logic emulation. For factory-floor noise immunity, use a separate watchdog supervisor; the internal WDT is best-effort only. Industrial designs that need field re-flash should pick a flash-based PIC16F87x equivalent in the same MQFP-44 footprint.
Recommended
Remote Keyless Entry (RKE) Transmitter
The PIC16C662-04/PQ can be used in fixed-code RKE transmitters where the OTP EPROM stores the encryption key at production time. Its low pin count and small code footprint fit a 4-button handheld fob, and Timer0 generates the carrier frequency for the UHF transmitter. The 3.0 V operating range supports coin-cell battery operation with a boost regulator. The 200 ns instruction cycle is fast enough for 1 ms button-debounce and rolling-code sequence generation. The OTP nature prevents firmware tampering, which is helpful in security applications. For higher-security designs with rolling-code algorithms, switch to a flash-based PIC16F or PIC18 with hardware AES support.
Recommended
Low-Cost Remote Sensor Node
Remote sensor nodes monitoring temperature, humidity, or contact closures can be built around the PIC16C662-04/PQ with its two analog comparators and 33 I/O. Its low active current (around 2 mA at 5 V / 4 MHz) plus sub-microamp standby at 32 kHz supports battery-powered deployments. The 200 ns instruction cycle performs measurement, threshold comparison, and UART transmit well within a 100 ms scan interval. For solar-powered nodes the OTP EPROM stores the network ID at production; the deterministic wake-up from WDT keeps firmware simple. Replace with a flash PIC16F88x equivalent for nodes that need field re-flash and internal EEPROM for parameter storage.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C662-04/PQ β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C66-04/PQ | PIC16F877A-I/PQ | PIC16F874A-I/PQ |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | MQFP-44 | MQFP-44 - same | MQFP-44 - same | MQFP-44 - same |
| Architecture | PIC16C66 (Harvard, 14-bit) | PIC16C66 - same | PIC16F (PIC16C66 core) - same | PIC16F (PIC16C66 core) - same |
| Program Memory | 7 KB OTP EPROM | 8 KB OTP EPROM (+14%) | 14 KB Flash (reprogrammable) | 7 KB Flash (reprogrammable) |
| Data RAM | 176 bytes | 368 bytes (+109%) | 368 bytes (+109%) | 192 bytes (+9%) |
| I/O Pins | 33 | 33 (same) | 33 (same) | 33 (same) |
| Max Oscillator | 4 MHz | 4 MHz (same) | 20 MHz (+400%) | 20 MHz (+400%) |
| Program Memory Type | OTP EPROM (one-time) | OTP EPROM (same) | Flash (re-programmable, 100k cycles) | Flash (re-programmable, 100k cycles) |
| Operating Voltage | 3.0 V to 6.0 V | 3.0 V to 6.0 V (same) | 2.0 V to 5.5 V (wider low end) | 2.0 V to 5.5 V (wider low end) |
Key Differentiators
- On-chip analog comparators without external ADC cost (vs PIC16F874A-I/PQ)
- Smaller flash-memory replacement footprint for development (vs PIC16F877A-I/PQ)
- More memory and timers vs the original PIC16C66 (vs PIC16C66-04/PQ)
Design Notes
Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD/VSS pin pair on the PIC16C662-04/PQ, plus a single 10 uF bulk capacitor at the board entry. The MCU draws approximately 2 mA active at 5 V / 4 MHz, so a small linear regulator such as an LM7805 or MCP1700 is sufficient. Add a 10 ohm series resistor with a 100 nF cap on MCLR/VPP to protect against ESD and programming-voltage transients during in-circuit serial programming.
Route OSC1/OSC2 over a continuous ground pour to limit EMI coupling into the analog comparators on ports A and E. Keep high-current switching traces (triacs, relays) at least 10 mm away from the analog comparator pins, and use guard traces tied to ground if board space is tight. The MQFP-44 land pattern has a 0.8 mm lead pitch - ensure your PCB house supports 0.4 mm solder mask webbing or use micro-vias in the pads to prevent mask slivers.
Because the PIC16C662-04/PQ uses OTP EPROM, firmware must be fully validated on engineering samples (flash-based PIC16F877A-I/PQ builds) before committing to production programming. Once programmed, the part cannot be erased or rewritten, so any late-stage bug requires a mechanical recall of the entire production batch. Also note that the -04 speed grade is rated only to 4 MHz oscillator; do not substitute a 10 MHz or 20 MHz crystal, or instruction timing will violate AC characteristics and EPROM read margins may fail.
The on-chip analog comparators on ports RE0/RE1 share the VDD rail, so comparator reference voltage must be derived from a low-impedance source (op-amp buffer or low-pass-filtered divider). The PIC16C662 datasheet specifies a 25 mV typical input offset and a 200 ns response time, which is sufficient for thermistor and 4-20 mA loop monitoring but not for precision measurement. If your design requires better than 1% analog accuracy, add an external ADC such as the MCP3201.
Compliance Information
PIC16C662-04/PQ is a legacy OTP EPROM part that pre-dates widespread RoHS documentation. RoHS/REACH compliance is not stated in the verified data; consult the manufacturer for a RoHS-compliant cross-reference. AEC-Q100 not qualified - the part is not recommended for new automotive designs.
