PIC16C74A-20/PT - 8-Bit 20MHz OTP MCU 7KB Flash 44-TQFP | Microchip
MPN: PIC16C74A-20/PT β Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.55 | $85.50 |
| 100 | $7.6 | $760.00 |
| 500 | $6.85 | $3,425.00 |
| 1,000 | $6.2 | $6,200.00 |
PIC16C74A-20/PT Overview
Background - what is an OTP PIC16C microcontroller. An 8-bit OTP microcontroller is a Harvard-architecture CMOS device that executes one instruction per instruction cycle (200 ns at 20 MHz), offers 35 single-word instructions, and stores the program code in one-time-programmable EPROM rather than flash. PIC16C parts sit between simple PIC10/12/16 base-line devices and the flash-based PIC18 mid-range family, and were Microchip's mainstream mid-range 8-bit controller from the mid-1990s through the early 2000s before being superseded by flash PIC16F variants.
Key features of the PIC16C74A-20/PT include: 33 digital I/O pins, an 8-channel 8-bit ADC, two CCP modules, a USART, an MSSP (SPI / I2C) port, three timers, a watchdog timer with on-chip RC oscillator, and a brown-out reset. The 20 MHz oscillator speed corresponds to a 200 ns instruction cycle, suitable for real-time control loops up to a few kHz.
The device operates from 4.0 V to 6.0 V across 0 C to +70 C commercial temperature range (this -20/PT suffix indicates 20 MHz, commercial temp, TQFP package). Internal architecture uses a 14-bit instruction word with 8-bit data path, providing predictable interrupt latency of 5 instruction cycles and a single-level hardware stack depth of 8, which limits nested subroutine depth.
Typical applications include industrial control panels, appliance controllers, automotive body electronics, sensor signal conditioning, low-cost motor control and embedded data acquisition. The PIC16C74A is also widely used in legacy designs and educational labs.
A critical design consideration: OTP memory cannot be erased, so firmware must be fully validated before programming - the flash-based PIC16F74 is the recommended modern substitute when in-field firmware updates are needed.
This page consolidates distributor pricing, parametric drop-in alternatives, and design guidance that goes beyond the manufacturer's datasheet to support engineers sourcing legacy PIC16C74A inventory.
Drop-in alternatives for PIC16C74A-20/PT β 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/PT (same form factor and footprint) β differing in Program Memory Size, Package, Program Memory Type, Timers, Operating Temperature.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C74A-20I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16C74B-20I/PT
β Drop-Inβ In Stock
$4.62 / Unit
View Datasheet βPIC16C74A-20/PQ
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$6.1 / Unit
View Datasheet βPIC16F74-I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16F747-I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16C74A-20/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit Harvard RISC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 7 KB (4 K x 14) |
| RAM Size | 192 x 8 bytes |
| Maximum CPU Clock | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Number of I/O Pins | 33 |
| ADC | 8 channels, 8-bit |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Capture/Compare/PWM (CCP) | 2 modules |
| Communication | USART, MSSP (SPI / I2C) |
| Operating Voltage | 4.0 V to 6.0 V |
| Operating Temperature | 0 C to +70 C (commercial) |
| Package | 44-pin TQFP (10 x 10 mm) |
| Mounting Type | Surface Mount |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Brown-Out Reset (BOR) | Yes |
PIC16C74A-20/PT Pin Configuration
| Pin 1 | MCLR/VPP β Master clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 β PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 β PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 β PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3/VREF β PORTA bit 3 / analog input 3 / ADC voltage reference |
| Pin 6 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS β PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | RE0/RD β PORTE bit 0 / parallel port read control |
| Pin 9 | RE1/WR β PORTE bit 1 / parallel port write control |
| Pin 10 | RE2/CS β PORTE bit 2 / parallel port chip select |
| Pin 11 | VDD β Positive supply voltage |
| Pin 12 | VSS β Ground reference |
| Pin 13 | OSC1/CLKIN β Oscillator input / external clock in |
| Pin 14 | OSC2/CLKOUT β Oscillator output / clock out |
| Pin 15 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 16 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer1 oscillator in / CCP2 |
| Pin 17 | RC2/CCP1 β PORTC bit 2 / CCP1 PWM output |
| Pin 18 | RC3/SCK/SCL β PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RC4/SDI/SDA β PORTC bit 4 / SPI data in / I2C data |
| Pin 20 | RC5/SDO β PORTC bit 5 / SPI data out |
| Pin 21 | RC6/TX/CK β PORTC bit 6 / USART transmit / clock |
| Pin 22 | RC7/RX/DT β PORTC bit 7 / USART receive / data |
| Pin 23 | RD0/PSP0 β PORTD bit 0 / parallel slave port bit 0 |
| Pin 24 | RD1/PSP1 β PORTD bit 1 / parallel slave port bit 1 |
| Pin 25 | RD2/PSP2 β PORTD bit 2 / parallel slave port bit 2 |
| Pin 26 | RD3/PSP3 β PORTD bit 3 / parallel slave port bit 3 |
| Pin 27 | RD4/PSP4 β PORTD bit 4 / parallel slave port bit 4 |
| Pin 28 | RD5/PSP5 β PORTD bit 5 / parallel slave port bit 5 |
| Pin 29 | RD6/PSP6 β PORTD bit 6 / parallel slave port bit 6 |
| Pin 30 | RD7/PSP7 β PORTD bit 7 / parallel slave port bit 7 |
| Pin 31 | VSS β Ground reference |
| Pin 32 | VDD β Positive supply voltage |
| Pin 33 | RB0/INT β PORTB bit 0 / external interrupt |
| Pin 34 | RB1 β PORTB bit 1 |
| Pin 35 | RB2 β PORTB bit 2 |
| Pin 36 | RB3 β PORTB bit 3 |
| Pin 37 | RB4 β PORTB bit 4 |
| Pin 38 | RB5 β PORTB bit 5 |
| Pin 39 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 40 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 41 | NC β Not connected (per datasheet) |
| Pin 42 | NC β Not connected (per datasheet) |
| Pin 43 | NC β Not connected (per datasheet) |
| Pin 44 | NC β Not connected (per datasheet) |
Typical Applications
PIC16C74A-20/PT is suitable for 6 applications: Industrial Control Panel, Appliance Controller (Washing Machine / Dishwasher), Automotive Body Electronics (Legacy), Sensor Signal Conditioning & Data Acquisition, Low-Cost Motor Control (Brushed DC / Stepper), Educational & Legacy Embedded Designs.
Industrial Control Panel
The PIC16C74A-20/PT is well suited to industrial front-panel controllers because it integrates 33 I/O lines with 25 mA source/sink per pin (sufficient to drive relays, optocouplers and LED indicators without external buffers), an 8-channel 8-bit ADC for reading panel-mounted sensors, plus a USART for talking to a host PLC. The 200 ns instruction cycle at 20 MHz provides the throughput needed to scan key matrices and refresh 7-segment displays with no perceivable lag. Pair it with the PIC16F74-I/PT as the modern flash equivalent when in-circuit updates are required.
Recommended
Appliance Controller (Washing Machine / Dishwasher)
Major home appliances such as washing machines and dishwashers historically use the PIC16C74A-20/PT as the main controller because of its on-chip ADC for water-level and temperature sensing, two CCP modules for PWM-driven motor and valve control, and a robust instruction set that supports finite-state-machine firmware patterns. The 20 MHz core and 192 bytes of RAM are sufficient for the small scheduler tasks typical of these designs. The commercial 0 C to +70 C operating range covers indoor appliance environments without derating.
Recommended
Automotive Body Electronics (Legacy)
Body-electronics modules such as mirror controllers, seat-position memory and climate-control panels have used the PIC16C74A-20/PT because its 33 I/O lines can drive multiple DC loads directly, the USART connects to a body-controller network, and the MSSP supports SPI/I2C sensor links. However, automotive programs now mandate AEC-Q100 qualified parts; the PIC16C74A is not AEC-Q100 qualified, so new designs should use the PIC16F74-I/PT (extended temp) plus AEC-Q100 graded companion parts. Existing fleets continue to use PIC16C74A-20/PT for repair.
Recommended
Sensor Signal Conditioning & Data Acquisition
The PIC16C74A-20/PT serves as a low-cost sensor front-end with its 8-channel 8-bit ADC for thermocouple, pressure and flow sensors, MSSP for SPI/I2C digital sensors, and USART for forwarding readings to a host. At a 20 MHz clock the ADC achieves the datasheet's ~20 kSPS conversion rate, more than enough for slow process-control loops. With 192 bytes of RAM the part can buffer short acquisition bursts before transmitting.
Recommended
Low-Cost Motor Control (Brushed DC / Stepper)
The PIC16C74A-20/PT provides two CCP modules that can drive brushed DC motors via PWM and stepper motors via software sequencing, while the 20 MHz instruction cycle gives precise PWM resolution at typical 1-20 kHz switching frequencies. Its 25 mA per-pin drive simplifies H-bridge interface designs and reduces the bill of materials. Existing motor-control designs continue to use the PIC16C74A-20/PT as a stable, well-characterized solution.
Recommended
Educational & Legacy Embedded Designs
The PIC16C74A-20/PT is widely used in university courses and hobby projects because its 35-instruction PIC16C RISC architecture is easy to teach, the 44-pin TQFP package breaks out enough peripherals for serious projects, and abundant reference code exists online. New learners should know that the part is OTP (cannot be re-programmed) - the flash-based PIC16F74-I/PT is recommended for class projects where firmware will be iterated multiple times.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74A-20/PT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74A-20I/PT | PIC16C74B-20I/PT | PIC16C74A-20/PQ | PIC16F74-I/PT | PIC16F747-I/PT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin TQFP (10 x 10 mm) | 44-pin TQFP - same | 44-pin TQFP - same | 44-pin TQFP - same | 44-pin TQFP - same | 44-pin TQFP - same |
| Program Memory Type | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | Flash (7 KB) | Flash (7 KB) |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| RAM Size | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 256 bytes |
| Number of I/O | 33 | 33 | 33 | 33 | 33 | 36 |
| Operating Temperature | 0 C to +70 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| In-Circuit Programming | No (OTP) | No (OTP) | No (OTP) | No (OTP) | Yes (ICSP) | Yes (ICSP) |
Key Differentiators
- Drop-in silicon-replacement available (vs PIC16C74B-20I/PT)
- Flash-based modern equivalent (vs PIC16F74-I/PT)
- Higher peripheral density in same package (vs PIC16F747-I/PT)
Design Notes
PIC16C74A-20/PT is OTP EPROM - firmware cannot be erased and re-written. Always validate code on a flash equivalent (PIC16F74-I/PT) or a windowed PIC16C74A-20/JW sample before committing to OTP production parts. Also confirm the date code supports your lead-free or RoHS requirements, because pre-RoHS TQFP reels may contain Pb-bearing solder finish.
PIC16C74A-20/PT operates from 4.0 V to 6.0 V, not 3.3 V. Designs migrating from 5 V to 3.3 V systems must use the PIC16LF or PIC18F family instead. Place a 100 nF decoupling capacitor as close as possible to each VDD pin (11 and 32) and a bulk 10 uF tantalum or ceramic at the board entry. The brown-out reset should be enabled in configuration fuses to protect against unstable VDD at power-up.
Keep the OSC1/OSC2 traces short and surround them with a ground pour to minimize EMI, especially when using a high-speed 20 MHz crystal. The 44-pin TQFP (10 x 10 mm) is a fine-pitch surface-mount package (0.8 mm pitch) - use a reflow profile that respects the manufacturer's MSL rating and avoid hand-rework where possible. Tie the MCLR pin through a 10 kohm pull-up to VDD and place the reset capacitor close to the pin to ensure clean power-on-reset behavior.
When using the ADC, add a small RC filter (typically 100 ohm + 100 nF) on each analog input to suppress noise from digital switching. Avoid routing ADC traces parallel to high-frequency digital lines such as the oscillator or PWM outputs. Configure the ADC acquisition time and conversion clock according to the datasheet's electrical characteristics to maintain rated 8-bit accuracy across temperature.
Compliance Information
PIC16C74A-20/PT was originally released before RoHS became mandatory; lead-free status depends on date code. Not AEC-Q100 qualified - use PIC16F74-I/PT or higher-grade parts for automotive programs. Conflict-minerals compliance per Microchip's standard CMRT filings.
