PIC16C64AT-04/PQ - 8-Bit 4MHz OTP MCU 44-MQFP | Microchip
MPN: PIC16C64AT-04/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.2 | $112.00 |
| 100 | $9.85 | $985.00 |
| 500 | $8.4 | $4,200.00 |
| 1,000 | $7.1 | $7,100.00 |
PIC16C64AT-04/PQ Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, data RAM, and peripheral interfaces such as timers, serial ports, and I/O lines. The PIC16C series belongs to the broader hierarchy: microcontroller -> embedded processor -> semiconductor IC. The PIC16C64A core implements a RISC Harvard architecture with only 35 single-word instructions, enabling compact code density and deterministic interrupt response favored in legacy industrial and embedded designs.
Key differentiating features include the OTP program memory (factory- or field-programmable, not re-programmable in-circuit), 33 digital I/O pins distributed across multiple ports, three timers including a watchdog timer, a synchronous serial port (SSP) supporting SPI and I2C master modes, and a USART for asynchronous serial communication. The device supports a commercial operating temperature range of 0C to +70C.
At the architectural level, the PIC16C64AT-04/PQ uses a 14-bit instruction word with an 8-bit data path. The 4 MHz oscillator input yields a 1 MHz instruction cycle (4 clocks per instruction), which is adequate for control-loop and human-interface tasks typical of late-1990s embedded products. Power consumption is held low through CMOS design and the SLEEP power-down mode.
Typical applications include industrial control panels, HVAC thermostat controllers, automotive body electronics (non-safety), consumer appliance interfaces, and legacy communication equipment where PIC16C firmware is already deployed. The 'T' suffix denotes tape-and-reel packaging, and the '04' speed grade corresponds to a 4 MHz maximum clock.
When designing with this part, note that OTP memory requires a device programmer and a UV-eprom eraser if windowed parts are used; the part cannot be re-flashed in the field. Engineers migrating designs to flash-based PIC16F equivalents benefit from code-compatibility and pin-compatibility for most PIC16C64A variants.
This page synthesizes distributor pricing, drop-in alternatives, application notes, and practical design guidance not consolidated in the manufacturer datasheet.
Drop-in alternatives for PIC16C64AT-04/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 PIC16C64AT-04/PQ (same form factor and footprint) — differing in Operating Temperature Range, Package, Timers, Maximum Clock Frequency, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C64A-04/PQ
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →PIC16C64A-20I/PQ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$12.2 / Unit
View Datasheet →PIC16C64A-04I/PQ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$6.4 / Unit
View Datasheet →PIC16C64A-04E/PQ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.4 / Unit
View Datasheet →PIC16F877A-04/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C64AT-04/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 3.5 KB (2K x 14 words) |
| Data RAM | 128 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 1 us at 4 MHz |
| Supply Voltage | 5 V (typical; range per datasheet) |
| I/O Pins | 33 |
| Timers | 3 (Timer0, Timer1, Timer2 + WDT) |
| Communication Interfaces | SSP/SPI/I2C, USART (SCI) |
| A/D Converter | None |
| Package | 44-pin MQFP (PQ) 10x10 mm |
| Operating Temperature | 0C to +70C (commercial) |
| Mounting Type | Surface Mount |
| Speed Grade | 04 (4 MHz) |
PIC16C64AT-04/PQ Pin Configuration
| Pin 1 | RA2/AN2 — Port A bit 2 (digital I/O; no ADC on this part) |
| Pin 2 | RA3/AN3 — Port A bit 3 (digital I/O) |
| Pin 3 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 4 | RA5/SS — Port A bit 5 / SSP slave select |
| Pin 5 | RE0/RD — Port E bit 0 / Parallel Slave Port read |
| Pin 6 | RE1/WR — Port E bit 1 / Parallel Slave Port write |
| Pin 7 | RE2/CS — Port E bit 2 / Parallel Slave Port chip select |
| Pin 8 | OSC1/CLKIN — Oscillator input / external clock in |
| Pin 9 | OSC2/CLKOUT — Oscillator output / clock out (Fosc/4) |
| Pin 10 | RC0/T1OSO/T1CKI — Port C bit 0 / Timer1 oscillator output |
| Pin 11 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer1 oscillator in / CCP2 |
| Pin 12 | RC2/CCP1 — Port C bit 2 / Capture-Compare-PWM1 |
| Pin 13 | RC3/SCK/SCL — Port C bit 3 / SSP serial clock |
| Pin 14 | RC4/SDI/SDA — Port C bit 4 / SSP data in / I2C data |
| Pin 15 | RC5/SDO — Port C bit 5 / SSP data out |
| Pin 16 | RC6/TX/CK — Port C bit 6 / USART TX / clock |
| Pin 17 | RC7/RX/DT — Port C bit 7 / USART RX / data |
| Pin 18 | GND — Ground |
| Pin 19 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 20 | RB1 — Port B bit 1 |
| Pin 21 | RB2 — Port B bit 2 |
| Pin 22 | RB3 — Port B bit 3 |
| Pin 23 | RB4 — Port B bit 4 |
| Pin 24 | RB5 — Port B bit 5 |
| Pin 25 | RB6/PGC — Port B bit 6 / ICSP clock |
| Pin 26 | RB7/PGD — Port B bit 7 / ICSP data |
| Pin 27 | RD0/PSP0 — Port D bit 0 / Parallel Slave Port data |
| Pin 28 | RD1/PSP1 — Port D bit 1 / Parallel Slave Port data |
| Pin 29 | RD2/PSP2 — Port D bit 2 / Parallel Slave Port data |
| Pin 30 | RD3/PSP3 — Port D bit 3 / Parallel Slave Port data |
| Pin 31 | RD4/PSP4 — Port D bit 4 / Parallel Slave Port data |
| Pin 32 | RD5/PSP5 — Port D bit 5 / Parallel Slave Port data |
| Pin 33 | RD6/PSP6 — Port D bit 6 / Parallel Slave Port data |
| Pin 34 | RD7/PSP7 — Port D bit 7 / Parallel Slave Port data |
| Pin 35 | VSS — Ground (second ground pin) |
| Pin 36 | VDD — Positive supply (5 V) |
| Pin 37 | NC — Not connected (per datasheet) |
| Pin 38 | NC — Not connected (per datasheet) |
| Pin 39 | NC — Not connected (per datasheet) |
| 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 | MCLR/VPP — Master clear reset / programming voltage |
Typical Applications
PIC16C64AT-04/PQ is suitable for 6 applications: Industrial Control Panels, HVAC Thermostat Controllers, Automotive Body Electronics (Non-Safety), Consumer Appliance Interfaces, Legacy Communication Equipment, Educational and Training Boards.
Industrial Control Panels
The PIC16C64AT-04/PQ fits industrial control panels because its 33 digital I/O lines can directly drive indicator LEDs, scan 4x4 membrane keypads, and interface to relay-driver ULN2803 arrays for solenoid and motor control. Its 4 MHz instruction rate (1 us per instruction) is fast enough for deterministic scan loops at 10 ms cycle time, and the integrated USART supports Modbus RTU slave communication over RS-485 transceivers. The PIC16C64A core's 35-instruction RISC architecture keeps firmware small and reviewable for IEC 61131-style control logic, while the 128-byte RAM handles small state machines without external memory expansion.
Recommended
HVAC Thermostat Controllers
The PIC16C64AT-04/PQ suits HVAC thermostat designs where 3.5 KB of OTP program memory holds the proportional-integral control algorithm plus a multi-stage schedule table without external program store. The integrated SSP port interfaces directly to I2C temperature sensors such as the TC74 or LM75, while the USART enables connection to BACnet or Modbus building-automation networks. With three on-chip timers the MCU can drive a 7-segment multiplexed LED display, debounce pushbuttons, and generate PWM for a 3-wire fan controller, all from a single 5 V rail. The commercial 0C to +70C rating covers indoor wall-mount installations.
Recommended
Automotive Body Electronics (Non-Safety)
For non-safety automotive body modules such as seat controllers, mirror adjusters, and interior lighting, the PIC16C64AT-04/PQ's 33 I/O pins directly drive H-bridge drivers and PWM-controlled lighting MOSFETs. The 4 MHz clock handles debounced switch scanning and LIN-like single-wire UART protocols for body-electronics sub-nets. Note that this '04' part is commercial-grade (0C to +70C); for cabin-mounted automotive applications, designers should select the PIC16C64A-04I/PQ industrial variant (-40C to +85C) which is pin-compatible. AEC-Q100-qualified parts are not available in this PIC16C64A family, so safety-critical systems should use PIC16F or PIC18 K-grade parts.
Recommended
Consumer Appliance Interfaces
The PIC16C64AT-04/PQ works well in washing-machine, dishwasher, and microwave-oven user-interface modules where the OTP memory locks in firmware for FCC/CE compliance and prevents field tampering. The USART and SSP ports simultaneously drive a character LCD via parallel interface and read a rotary encoder through Timer0's external clock input. With the SLEEP power-down mode and CMOS design, idle current drops below 1 mA, suitable for Energy Star standby requirements. The 44-MQFP package reflows cleanly on standard SMT lines and survives the +245C peak reflow profile common to lead-free assembly.
Recommended
Legacy Communication Equipment
The PIC16C64AT-04/PQ remains in service maintaining legacy modems, paging-system controllers, and early point-of-sale terminals where the OTP memory's write-once security model prevents firmware tampering in the field. Its 4 MHz core with hardware USART achieves reliable 9600 to 38400 baud async serial communication, while the SSP port handles SPI peripherals such as RTC chips or character LCDs. Engineers servicing these legacy products can use the same PIC16C64A instruction set and development tools already in their workflow. The PIC16C64A's deterministic interrupt latency and 14-bit instruction word simplify code review for telecom-grade reliability requirements.
Recommended
Educational and Training Boards
The PIC16C64AT-04/PQ is well-suited for university embedded-systems courses and hobbyist training kits because its 44-MQFP package exposes ample I/O for breadboard-friendly breakout boards while remaining surface-mount-repairable with hot air. The PIC16C64A instruction set is small (only 35 opcodes) and well-documented in Microchip application notes, making it pedagogically ideal for teaching RISC concepts, interrupt-driven design, and peripheral programming. The 'T' tape-and-reel suffix supports automated pick-and-place for class-scale production, and OTP memory forces students to verify code before programming, reinforcing good engineering practices. Migrating to PIC16F877A later preserves the same I/O map.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C64AT-04/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C64A-04/PQ | PIC16C64A-20I/PQ | PIC16C64A-04I/PQ | PIC16C64A-04E/PQ | PIC16F877A-04/PQ |
|---|---|---|---|---|---|---|
| Package | 44-MQFP (PQ) 10x10 mm | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 3.5 KB OTP | 3.5 KB OTP | 3.5 KB OTP | 3.5 KB OTP | 3.5 KB OTP | 14 KB Flash |
| Data RAM | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 368 bytes |
| Max Clock Frequency | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz | 20 MHz |
| Operating Temperature | 0C to +70C | 0C to +70C | -40C to +85C | -40C to +85C | -40C to +125C | -40C to +85C |
| A/D Converter | None | None | None | None | None | 10-bit 8-ch |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | Flash |
Key Differentiators
- Lower unit cost versus higher-speed 20 MHz grade (vs PIC16C64A-20I/PQ)
- OTP memory provides write-once security (vs PIC16F877A-04/PQ)
- Commercial temperature grade for indoor use (vs PIC16C64A-04I/PQ)
Design Notes
Decouple VDD (pin 36) and VSS (pin 35, pin 18) with 100 nF ceramic capacitors placed within 5 mm of the package pins to suppress switching noise from the internal oscillator. The PIC16C64AT-04/PQ draws approximately 2-5 mA active and under 1 mA in SLEEP mode at 5 V. For battery-backed applications, add a 10 kohm pull-up on MCLR (pin 44) and a bulk 10 uF tantalum near the supply pins to handle inrush during oscillator startup. Estimated: active current 3 mA at 4 MHz, 5 V, typical load.
Route the 4 MHz crystal traces (OSC1/OSC2, pins 8-9) with short, symmetric traces and guard them with a ground pour to minimize EMI coupling into adjacent analog or RF traces. Keep the crystal within 5 mm of the MCU and avoid routing signal traces under the crystal can. For SMT crystals, place a 4-layer ground plane directly under the oscillator to provide a low-impedance return path. The 44-MQFP land pattern requires 0.8 mm pitch pads with 0.4 mm stencil apertures for reliable reflow.
Do not assume the PIC16C64AT-04/PQ can be re-programmed in-circuit; the OTP memory is write-once and a device programmer is mandatory. Windowed (JW) packages must be erased under UV light for 20+ minutes before reprogramming. The 4 MHz '04' speed grade must NOT be overclocked to 20 MHz - use the '20' grade part (PIC16C64A-20I/PQ, pin-compatible) instead. Also, RB0 doubles as the external INT pin; configure TRISB correctly before enabling interrupts to avoid spurious wakeups. Per Microchip errata, some early PIC16C64A silicon revs had POR brown-out sensitivity below 4.5 V.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. Lead-free (Pb-free) reflow-compatible per JEDEC J-STD-020. Halogen-free per IEC 61249-2-21. AEC-Q100 is not_applicable because this commercial-grade part is not intended for automotive safety-critical use; choose I/E-grade variants for industrial/automotive cabin applications. Conflict-minerals statement available from Microchip.
