PIC16C74A-20/PQ - 8-Bit 20MHz OTP MCU w/ A/D | Microchip 44-MQFP
MPN: PIC16C74A-20/PQ ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.95 | $9.95 |
| 10 | $8.86 | $88.60 |
| 100 | $7.74 | $774.00 |
| 500 | $6.85 | $3,425.00 |
| 1,000 | $6.1 | $6,100.00 |
PIC16C74A-20/PQ Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, program memory, working RAM, I/O peripherals, and (in this case) an A/D converter on one die. PIC16C7X mid-range MCUs sit in the taxonomy: microcontroller -> embedded controller -> 8-bit MCU -> PIC mid-range -> PIC16C7X family. The 'C' suffix denotes OTP EPROM program memory, and 'A' marks the silicon revision; the -20 speed grade runs up to 20 MHz at 4.0 V to 5.5 V supply.
Key features include 192 bytes of data RAM, 22 digital I/O lines, an 8-channel 8-bit A/D converter, three timers (Timer0, Timer1, Timer2 with PWM), a USART/SCI asynchronous serial port, an SPI/I2C synchronous serial port, 13 interrupt sources, and a watchdog timer with on-chip RC oscillator for reliable operation. The architecture uses a Harvard design with separate program and data buses, allowing instruction fetch and operand read in the same cycle.
Typical applications include industrial process control, instrumentation front-ends, embedded sensor hubs, and low-cost motor control where on-chip A/D conversion and PWM generation eliminate external components. When migrating, Microchip recommends the flash-based PIC16F74 as the modern equivalent with identical pinout and peripheral set. Industrial users designing around the C-series should note the OTP windowed package supports limited reprogramming during development and that the part has been superseded by flash-based F-series for new designs.
Drop-in alternatives for PIC16C74A-20/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 PIC16C74A-20/PQ (same form factor and footprint) — differing in Package, Timers, I/O Pins, A/D Converter, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74A-20I/PQ
✅ Drop-In✓ In Stock
$5.95 / Unit
View Datasheet →PIC16C74A-20E/PQ
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →PIC16C74AT-20/PQ
✅ Drop-In✓ In Stock
$9.9 / Unit
View Datasheet →PIC16C74B-20/PQ
✅ Drop-In✓ In Stock
$5.95 / Unit
View Datasheet →PIC16F74-I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74A-04/PQ
✅ Drop-In✓ In Stock
$5.8 / Unit
View Datasheet →PIC16C74A-20/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 (8-bit RISC, Harvard) |
| Program Memory Size | 7 KB (4K x 14) OTP EPROM |
| Data RAM | 192 bytes |
| Data EEPROM | Not present (OTP family) |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage | 4.0 V to 5.5 V |
| I/O Pins | 22 |
| A/D Converter | 8 channels, 8-bit resolution |
| Timers | 3 (Timer0, Timer1, Timer2/PWM) |
| Serial Interfaces | USART/SCI + SPI/I2C (SSP) |
| Instruction Set | 35 single-word instructions |
| Interrupt Sources | 13 |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Package | 44-MQFP (10x10 mm), PQ suffix |
| Operating Temperature | Commercial (0C to +70C) |
PIC16C74A-20/PQ Pin Configuration
| Pin 1 | Vss — Ground reference |
| Pin 2 | RA0/AN0 — PORTA bit 0 / A/D channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / A/D channel 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / A/D channel 2 |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / A/D channel 3 / A/D Vref+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / A/D channel 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / parallel port read / A/D ch5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / parallel port write / A/D ch6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / parallel port CS / A/D ch7 |
| Pin 11 | Vdd — Positive supply (4.0 V to 5.5 V) |
| Pin 12 | Vss — Ground |
| Pin 13 | OSC1/CLKIN — Crystal oscillator input / external clock |
| Pin 14 | OSC2/CLKOUT — Crystal oscillator output |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / T1 clock |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator in / CCP2 |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM1 |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 20 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 21 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 22 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 23 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 24 | RB1 — PORTB bit 1 |
| Pin 25 | RB2 — PORTB bit 2 |
| Pin 26 | RB3 — PORTB bit 3 |
| Pin 27 | RB4 — PORTB bit 4 |
| Pin 28 | RB5 — PORTB bit 5 |
| Pin 29 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 30 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 31 | Vss — Ground |
| Pin 32 | VDD — Positive supply |
| Pin 33 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 34 | RD1/PSP1 — PORTD bit 1 / PSP bit 1 |
| Pin 35 | RD2/PSP2 — PORTD bit 2 / PSP bit 2 |
| Pin 36 | RD3/PSP3 — PORTD bit 3 / PSP bit 3 |
| Pin 37 | RD4/PSP4 — PORTD bit 4 / PSP bit 4 |
| Pin 38 | RD5/PSP5 — PORTD bit 5 / PSP bit 5 |
| Pin 39 | RD6/PSP6 — PORTD bit 6 / PSP bit 6 |
| Pin 40 | RD7/PSP7 — PORTD bit 7 / PSP bit 7 |
| Pin 41 | MCLR/VPP — Master clear reset / programming voltage |
| Pin 42 | NC — Not connected |
| Pin 43 | NC — Not connected |
| Pin 44 | NC — Not connected |
Typical Applications
PIC16C74A-20/PQ is suitable for 6 applications: Industrial Process Control, Embedded Sensor Hubs, Low-Cost Motor Control, Instrumentation Front-Ends, Automotive Body Electronics (Legacy), Educational Development Boards.
Industrial Process Control
The PIC16C74A-20/PQ fits industrial process control with its 8-channel 8-bit A/D converter sampling thermocouple, pressure, and flow sensors at up to 50 ksps aggregate. The 22 digital I/O pins drive relay coils, solenoid valves, and indicator LEDs while the three timers generate PWM outputs for proportional valve control. At 20 MHz the MCU executes control loops in well under 1 ms, fast enough for closed-loop PID at 1 kHz update rate. The integrated USART connects to RS-485 transceivers for Modbus RTU master/slave nodes in factory automation networks. Compared with discrete 8051 designs, the integrated peripherals reduce PCB area by approximately 40 percent in panel-meter and PLC I/O module designs.
Recommended
Embedded Sensor Hubs
The PIC16C74A-20/PQ serves as a low-cost sensor hub aggregating multiple analog and digital sensors over SPI and I2C buses. The on-chip 8-bit A/D handles up to 8 sensor channels while the MSSP module simultaneously talks to SPI sensors and I2C peripherals without CPU intervention. The 192-byte RAM accommodates buffering for local decision logic before forwarding data via the USART to a host processor. At 20 MHz, the PIC16 mid-range core executes a single instruction in 200 ns, sufficient for sensor fusion at 100 Hz update rates. The compact 44-MQFP package allows the hub to fit alongside sensors in 50 mm by 50 mm enclosures typical of HVAC and environmental monitoring equipment.
Recommended
Low-Cost Motor Control
The PIC16C74A-20/PQ drives small BLDC and stepper motors using its Timer2 PWM module and Capture/Compare/PWM (CCP) peripherals. The PWM resolution at 20 MHz reaches 10 bits with a 19.5 kHz switching frequency, smooth enough for quiet fan and pump operation. The 8-channel A/D samples back-EMF and current-sense amplifiers for sensorless commutation algorithms in BLDC applications. Quadrature encoder inputs on PORTC handle closed-loop position control for stepper and servo motors. The 22 I/O lines drive H-bridge gate drivers directly, eliminating external logic in 24 V brushed DC and small three-phase inverter designs under 100 W.
Recommended
Instrumentation Front-Ends
The PIC16C74A-20/PQ is well-suited to bench-top instrumentation including digital multimeters, panel meters, and signal generators. Its 8-channel 8-bit A/D handles true-RMS AC voltage measurement via external signal conditioning, while the USART streams readings to a host PC or display module. The three timers produce precise 1 ms and 1 s timing references for frequency-counter and period-measurement functions. The 192-byte RAM stores calibration coefficients and running statistics. Compared with pure hardware meters, the programmable PIC16C7X allows one firmware image to support multiple product variants via OTP code-only differentiation, reducing SKU count.
Recommended
Automotive Body Electronics (Legacy)
The PIC16C74A-20/PQ powered 1990s automotive body controllers for window lift, mirror adjust, and interior lighting modules. While modern designs use CAN-bus microcontrollers, legacy sockets often retain the PIC16C7X because of firmware certification cost. The 8-channel A/D reads switch positions and potentiometric sensors, while the PWM outputs dim incandescent and early LED lamps. Note that the 'PQ' package in automotive body modules is typically the commercial-temperature grade; for under-hood applications the PIC16C74A-20I/PQ or 20E/PQ industrial/extended variants are required. New automotive designs should migrate to dsPIC33 or PIC18 K-series with CAN FD.
Recommended
Educational Development Boards
The PIC16C74A-20/PQ is popular in university embedded-systems curricula because its 35-instruction PIC16 mid-range ISA is teachable in a single semester. The 44-MQFP package is breadboard-compatible through adapter PCBs and exposes all 22 I/O pins plus A/D, timers, USART, and SPI/I2C peripherals for student labs. The OTP nature forces students to plan code carefully, teaching resource constraints and code-density optimization. Modern curricula typically pair PIC16C74A boards with the PIC16F74 flash variant to allow in-lab reprogramming without UV erasure. The Microchip MPLAB IDE and PICkit programmers support the full PIC16C7X family for academic use.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74A-20/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74A-20I/PQ | PIC16C74A-20E/PQ | PIC16C74AT-20/PQ | PIC16C74B-20/PQ | PIC16F74-I/PQ | PIC16C74A-04/PQ |
|---|---|---|---|---|---|---|---|
| Package | 44-MQFP (PQ) 10x10 mm | 44-MQFP (PQ) 10x10 mm - same | 44-MQFP (PQ) 10x10 mm - same | 44-MQFP (PQ) 10x10 mm - same | 44-MQFP (PQ) 10x10 mm - same | 44-MQFP (PQ) 10x10 mm - same | 44-MQFP (PQ) 10x10 mm - same |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Program Memory Type | 7 KB OTP EPROM | 7 KB OTP EPROM - same | 7 KB OTP EPROM - same | 7 KB OTP EPROM - same | 4 KB Flash (reprogrammable) | 7 KB OTP EPROM - same | |
| Maximum Clock Speed | 20 MHz | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - same | 4 MHz (-80%) | |
| Operating Temperature | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +125C (extended) | 0C to +70C - same | -40C to +85C (industrial) | 0C to +70C - same | |
| Data RAM | 192 bytes | 192 bytes - same | 192 bytes - same | 192 bytes - same | |||
| A/D Converter | 8 channels, 8-bit | 8 channels, 8-bit - same | 8 channels, 8-bit - same | 8 channels, 8-bit - same | |||
| Lifecycle Status | Last-time-buy | Last-time-buy | Active (recommended migration) | Mature (production) | |||
| Supply Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V - same | 4.0 V to 5.5 V - same | 2.0 V to 5.5 V (wider range) | 4.0 V to 5.5 V - same |
Key Differentiators
- Industrial and extended temperature drop-in variants available in identical package (vs PIC16C74A-20I/PQ (industrial) and PIC16C74A-20E/PQ (extended))
- Newer silicon revision B offers improved peripherals (vs PIC16C74B-20/PQ)
- Flash-based PIC16F74-I/PQ replaces OTP with in-system reprogrammability (vs PIC16F74-I/PQ)
Design Notes
PIC16C74A-20/PQ supply decoupling requires a 0.1 uF ceramic capacitor placed within 5 mm of the Vdd pin (pin 11 or 32) and a 10 uF tantalum or aluminum bulk capacitor at the PCB power entry. The MCU can source/sink up to 25 mA per I/O pin (200 mA absolute) and brief inrush during A/D conversion at 20 MHz requires low-inductance supply routing to avoid Vdd droop triggering brown-out reset.
The 44-MQFP package has a 10x10 mm footprint with 0.8 mm pitch gull-wing leads. Recommended PCB land pattern is per IPC-7351 nominal-density with 0.4 mm wide pads. Exposed lead frames on PQ variants are not present (unlike QFN), so thermal dissipation occurs only through the four Vdd/Vss pins plus the lead frame; for 20 MHz continuous operation a small copper pour of at least 100 mm squared is recommended.
OTP EPROM programming requires the device to enter programming mode by raising MCLR/VPP to 13.5 V typical; failure to sequence the Vdd/Vpp/MCLR pins per datasheet timing will lock the part in run mode and prevent code programming. The 'PQ' suffix denotes the windowed CERDIP-style MQFP, which supports limited UV erasure only on JW variants - the /PQ is NOT erasable and is intended for production use only.
OSC1 and OSC2 traces should be routed as a short differential pair (under 10 mm) with a grounded guard ring to prevent coupling of 20 MHz clock harmonics into adjacent analog inputs. Place the crystal load capacitors (typically 15-33 pF) within 3 mm of OSC1/OSC2. For noisy industrial environments, switching from a crystal to an external clock source via OSC1 with OSC2 left open reduces EMI by approximately 6 dB on the second harmonic.
Compliance Information
Compliance data not present in verified web sources; refer to Microchip product environmental compliance page for RoHS/REACH declarations. Not AEC-Q100 qualified.
