PIC16C64A-20I/PQ - 8-bit MCU 3.5KB EPROM 33 I/O | Microchip
MPN: PIC16C64A-20I/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $17.1 | $171.00 |
| 100 | $15.4 | $1,540.00 |
| 500 | $13.85 | $6,925.00 |
| 1,000 | $12.2 | $12,200.00 |
PIC16C64A-20I/PQ Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, RAM, and peripherals such as timers, communication ports, and I/O. The PIC16C6X family is built on Microchip's enhanced Harvard RISC architecture, which separates program and data buses for higher throughput than traditional von Neumann designs. In the broader taxonomy: PIC16C6X -> PIC16 family -> 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. EPROM-based OTP parts like the PIC16C64A are suited for low-to-medium volume production where firmware is finalized and in-system flash updates are not required.
Key differentiating features of the PIC16C64A-20I/PQ include three hardware timers (Timer0, Timer1, Timer2), a synchronous serial port (SSP) supporting SPI and I2C, a USART for asynchronous serial communication, an 8-bit parallel slave port, and a 5-channel 8-bit ADC. Capture/Compare/PWM (CCP) module supports pulse-width modulation and signal measurement. The 33 I/O pins are 5V-tolerant within the supply range, and a programmable brown-out reset (BOR) and watchdog timer (WDT) improve robustness in industrial environments.
Architecturally, the PIC16C64A-20I/PQ uses a 14-bit instruction word and an 8-bit data path, with a two-stage pipeline and 35 single-word instructions, only one of which (program branch) takes two cycles. The fully static design allows the clock to be stopped without losing state, enabling sleep currents of a few microamps for battery-friendly operation. The MQFP-44 (PQ) package provides 33 I/O plus supply, ground, MCLR, oscillator, and reference pins, surefire drop-in for designs already using PIC16C64A on 44-pin MQFP footprints.
Typical applications include industrial control front-ends, sensor signal conditioning with ADC, motor control via CCP/PWM, embedded serial-connected peripherals, and legacy factory automation controllers. Because the part is windowless and EPROM-based, it is most appropriate for products shipping into stable, long-life programs rather than iterative development. A newer revision (PIC16C65B) is recommended for new designs per Microchip's own product page, but the PIC16C64A-20I/PQ remains in active use for maintenance, repair, and legacy board replacements.
When designing with this part, place a 100 nF decoupling capacitor close to VDD, route MCLR through a 10 kohm pull-up to VDD, and select a crystal or resonator that meets the 20 MHz limit. Watch the EPROM/OTP limitation carefully: code must be fully validated before programming, since UV-erase windowing is not present on the PQ package. Cross-check the 33 I/O allocation against any 5V analog input requirements, since the ADC reference and digital thresholds share pin pairs.
This page synthesizes distributor pricing, drop-in alternatives within the PIC16C6X family, lifecycle guidance, and practical design notes not collected in any single manufacturer datasheet - aimed at engineers who need to qualify, source, or substitute the PIC16C64A-20I/PQ in existing or near-clone designs.
Drop-in alternatives for PIC16C64A-20I/PQ — 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 PIC16C64A-20I/PQ (same form factor and footprint) — differing in Package, RoHS Status, Timers, Operating Temperature, Instruction Cycle Time.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C64A-04I/PQ
✅ Drop-In✓ In Stock
$6.4 / Unit
View Datasheet →PIC16C64A-10I/PT
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC16C64A-20E/PT
✅ Drop-In✓ In Stock
$12.4 / Unit
View Datasheet →PIC16C64A-04E/PT
✅ Drop-In✓ In Stock
$7.35 / Unit
View Datasheet →PIC16C64A-04I/PT
✅ Drop-In✓ In Stock
$4.61 / Unit
View Datasheet →PIC16C64A-04I/L
✅ Drop-In✓ In Stock
$4.5 / Unit
View Datasheet →PIC16C64A-20I/PQ Maximum Ratings & Electrical Characteristics
| Architecture | 8-bit RISC (Harvard) |
| Instruction Set | PIC16C6X (35 instructions, 14-bit word) |
| Program Memory (EPROM) | 3.5 KB |
| Data RAM | 128 bytes |
| I/O Pins | 33 |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Supply Voltage (VDD) | 2.5 V to 6.0 V |
| ADC | 8-bit, 5 channels |
| Timers | 3 (Timer0, Timer1, Timer2) |
| CCP Modules | 1 (Capture/Compare/PWM) |
| Serial Interfaces | USART + SSP (SPI / I2C) |
| Parallel Slave Port | Yes (8-bit) |
| Watchdog Timer | Yes |
| Brown-out Reset | Yes (programmable) |
| Package | 44-pin MQFP (PQ), surface mount |
| Operating Temperature | -40 C to +85 C (Industrial, I suffix) |
| RoHS Status | Compliant |
PIC16C64A-20I/PQ Pin Configuration
| Pin 1 | MCLR/VPP — Master clear (reset, active low) / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3/VREF — PORTA bit 3 / analog input 3 / ADC reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4 — PORTA bit 5 / analog input 4 |
| Pin 8 | RE0/RD — PORTE bit 0 / parallel slave port read strobe |
| Pin 9 | RE1/WR — PORTE bit 1 / parallel slave port write strobe |
| Pin 10 | RE2/CS — PORTE bit 2 / parallel slave port chip select |
| Pin 11 | VSS — Ground reference |
| Pin 12 | OSC1/CLKIN — Crystal oscillator input / external clock input |
| Pin 13 | OSC2/CLKOUT — Crystal oscillator output / clock output (Fosc/4) |
| Pin 14 | RC0/T1OSO — PORTC bit 0 / Timer1 oscillator output |
| Pin 15 | RC1/T1OSI — PORTC bit 1 / Timer1 oscillator input |
| Pin 16 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM output |
| Pin 17 | RC3 — PORTC bit 3 |
| Pin 18 | RD0 — PORTD bit 0 |
| Pin 19 | RD1 — PORTD bit 1 |
| Pin 20 | RD2 — PORTD bit 2 |
| Pin 21 | RD3 — PORTD bit 3 |
| Pin 22 | RD4 — PORTD bit 4 |
| Pin 23 | RD5 — PORTD bit 5 |
| Pin 24 | RD6 — PORTD bit 6 |
| Pin 25 | RD7 — PORTD bit 7 |
| Pin 26 | VSS — Ground reference (second VSS) |
| Pin 27 | VDD — Positive supply (5V typical) |
| Pin 28 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 29 | RB1 — PORTB bit 1 |
| Pin 30 | RB2 — PORTB bit 2 |
| Pin 31 | RB3 — PORTB bit 3 |
| Pin 32 | RB4 — PORTB bit 4 |
| Pin 33 | RB5 — PORTB bit 5 |
| Pin 34 | RB6 — PORTB bit 6 |
| Pin 35 | RB7 — PORTB bit 7 |
| Pin 36 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 37 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 38 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 39 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 40 | NC — Not connected (per datasheet) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | VDD — Positive supply (5V typical, second VDD) |
Typical Applications
PIC16C64A-20I/PQ is suitable for 6 applications: Industrial Control Front-End, Sensor Signal Conditioning with ADC, Motor Control via CCP/PWM, Embedded Serial-Connected Peripheral, Legacy Factory Automation Controller, Benchtop Test and Measurement Equipment.
Industrial Control Front-End
The PIC16C64A-20I/PQ fits industrial control front-ends where 33 I/O lines, a 5-channel 8-bit ADC, and a USART are needed at 20 MHz of deterministic throughput. The Industrial -40C to +85C grade tolerates factory-floor ambient swings, while the brown-out reset and watchdog timer protect against brown-out lock-ups common in motor-driven cabinets. Its 3.5KB EPROM stores fixed ladder-logic-equivalent firmware for sensor multiplexing, actuator driving, and CAN/RS-485 gateway duty via the USART. Drop-in 44-pin MQFP compatibility makes it easy to keep the existing PCB layout and I/O mapping.
Recommended
Sensor Signal Conditioning with ADC
The PIC16C64A-20I/PQ's 5-channel 8-bit ADC, combined with its 33 digital I/O, suits multi-sensor front-end modules reading thermistors, photocells, pressure sensors, and potentiometers. The 20 MHz instruction cycle (200 ns per instruction) gives enough headroom to run linearization math and digital filtering in real time, while the 128 bytes of RAM hold moving-average buffers. The analog reference can be tied to VDD or an external precision reference for higher-accuracy ratiometric measurements. Industrial -40C to +85C range plus 5V tolerance matches typical transducer signal levels.
Recommended
Motor Control via CCP/PWM
The PIC16C64A-20I/PQ drives small DC motors, solenoids, and stepper motor coils using its Capture/Compare/PWM module plus three hardware timers. The 20 MHz cycle produces 10-bit PWM at carrier frequencies above 20 kHz, which is above the audible band and keeps motor whine out of operator stations. With 33 I/O available, the part can control H-bridges, read Hall sensors, and handle end-stop switches on the same chip, simplifying PCB layout. The 5V-tolerant outputs and 20 mA source/sink per pin match typical MOSFET gate driver inputs directly.
Recommended
Embedded Serial-Connected Peripheral
The PIC16C64A-20I/PQ serves as a smart UART/SPI/I2C peripheral, offloading protocol handling from a host processor. Its USART plus SSP (SPI/I2C) cover the three most common serial buses, while the 8-bit parallel slave port allows DMA-style data exchange with a host CPU or DSP. The 200 ns instruction cycle handles 115200 baud UART with margin to spare for protocol parsing, command interpretation, and acknowledgement. Industrial temperature and 5V tolerance make it a good fit for benchtop test equipment and instrumentation peripherals.
Recommended
Legacy Factory Automation Controller
The PIC16C64A-20I/PQ is found in legacy factory automation controllers installed since the late 1990s, where its 20 MHz throughput and 3.5KB EPROM are sufficient to run proven ladder-replacement and sequencing firmware. The 44-pin MQFP PQ footprint remains in service on hundreds of thousands of boards still in operation, and the NRND status means field replacements and spares are the dominant ongoing use case. Watchdog timer and brown-out reset help recover from noisy 24V industrial supplies. The same die in extended temperature (PIC16C64A-20E/PQ) is a drop-in for cabinets running warmer than 85C.
Recommended
Benchtop Test and Measurement Equipment
The PIC16C64A-20I/PQ is well-suited to benchtop test equipment where deterministic 200 ns instruction execution and a 5-channel ADC support waveform sampling, threshold detection, and pass/fail reporting. Its 33 I/O drive 7-segment displays, keypads, status LEDs, and relay outputs without external bus expanders. The USART interfaces to a host PC for log upload, and the parallel slave port supports fast data dumps. The PIC16C6X core is mature, well-documented, and supported by MPLAB IDE and the HI-TECH C compiler, easing both legacy maintenance and code migration to PIC16C65B.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C64A-20I/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C64A-04I/PQ | PIC16C64A-10I/PT | PIC16C64A-20E/PT |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | MQFP-44 (PQ) | MQFP-44 (PQ) - same | MQFP-44 (PT) - same | MQFP-44 (PT) - same |
| Program Memory | 3.5 KB EPROM | 3.5 KB EPROM - same | 3.5 KB EPROM - same | 3.5 KB EPROM - same |
| Data RAM | 128 bytes | 128 bytes - same | 128 bytes - same | 128 bytes - same |
| I/O Pins | 33 | 33 - same | 33 - same | 33 - same |
| Maximum Clock | 20 MHz | 4 MHz (-80%) | 10 MHz (-50%) | 20 MHz - same |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) - same | -40 C to +85 C (Industrial) - same | -40 C to +125 C (Extended) +40 C upper |
| ADC | 8-bit, 5 channels | 8-bit, 5 channels - same | 8-bit, 5 channels - same | 8-bit, 5 channels - same |
Key Differentiators
- 20 MHz max clock with Industrial -40C to +85C range (vs PIC16C64A-04I/PQ)
- Highest speed grade in the C64A family (vs PIC16C64A-10I/PT)
- Industrial vs Extended temperature grade (vs PIC16C64A-20E/PT)
Design Notes
The PIC16C64A-20I/PQ requires a 100 nF ceramic decoupling capacitor placed within 5 mm of each VDD/VSS pair (pins 27 and 44 for VDD, pins 11 and 26 for VSS). A bulk 10 uF tantalum or aluminum polymer capacitor on the main 5V rail is also recommended. Brown-out reset should be enabled (BODEN configuration bit) to prevent code execution when VDD falls below 4.0V, which can otherwise corrupt EPROM program memory state during write cycles. Power-on reset timing of approximately 72 ms (with PWRT enabled) ensures the crystal oscillator is stable before code starts.
The 44-pin MQFP (PQ) has 0.8 mm lead pitch and requires careful PCB layout: keep trace width at least 0.2 mm and use a solder mask defined (SMD) pad. The exposed die pad is on the underside of the package; place a 5 mm x 5 mm copper pad connected to VSS for thermal dissipation and mechanical stress relief. Place the MCLR pull-up resistor (typically 10 kohm) and the MCLR capacitor (typically 10 nF) close to pin 1 to ensure clean reset pulses. Route the OSC1/OSC2 traces over a continuous ground plane and keep them short to minimize EMI coupling into the analog reference.
Because the PIC16C64A-20I/PQ is an EPROM/OTP device, code must be fully verified before programming - there is no in-circuit reprogramming option on the PQ package. Do not connect MCLR directly to VDD without a 10 kohm pull-up; an RC reset with a diode is recommended for noise immunity. When using the ADC, ensure adequate acquisition time (typically 20 us at 5V) by adding software delay between channel select and conversion start. The CCP1 module output pin (RC2) is shared with PORTC bit 2, so peripheral overrides must clear the corresponding TRISC bit. Finally, do not exceed 20 MHz clock input at VDD below 4.5V, or the device may malfunction.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified; choose automotive-grade PIC16 family parts (e.g., PIC16F1xxx with AEC-Q100) for vehicle applications. Lead-free and halogen-free per modern Microchip product environmental statements.
