PIC16C74B-20/P - 8-bit OTP MCU 7KB Flash 20MHz 40-PDIP | Microchip
MPN: PIC16C74B-20/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.44 | $8.44 |
| 10 | $7.61 | $76.10 |
| 100 | $6.78 | $678.00 |
| 500 | $6.05 | $3,025.00 |
| 1,000 | $5.42 | $5,420.00 |
PIC16C74B-20/P Overview
Background: An 8-bit OTP microcontroller is a single-chip processor with on-chip non-volatile program memory that can be written exactly once via external programming voltage, then behaves like mask-ROM. OTP parts sit in the hierarchy: microcontroller -> embedded processor -> semiconductor IC. Compared to flash-based MCUs (e.g. PIC16F), OTP MCUs offer lower per-unit cost at high volume and are typically used for mature, locked firmware designs in appliance, industrial, and automotive subsystems where firmware updates are not expected in the field.
Key features include Harvard RISC architecture with only 35 single-word instructions, all single-cycle except program branches (which take two cycles), 8-channel 8-bit ADC with input multiplexing, dual CCP modules for PWM and event capture, brown-out reset and power-on reset, watchdog timer with on-chip RC oscillator, and an industrial temperature grade. The device is code- and pin-compatible with the PIC16C73B and PIC16C65B predecessors, simplifying upgrades.
Typical applications include motor control (BLDC and stepper), industrial process control, sensor interfacing, embedded control in appliance and HVAC, automotive body and chassis subsystems, and general-purpose 8-bit control boards. The DIP-40 package and breadboard-friendly pinout also make it suitable for educational, prototyping, and legacy replacement scenarios.
When designing with this part, note that OTP memory cannot be erased or rewritten; firmware must be fully verified before programming. Always provide a decoupling capacitor on VDD, and respect the programming voltage specification on the MCLR/VPP pin if in-circuit programming is intended.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives (PIC16C73B, PIC16C74A), and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C74B-20/P — 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 PIC16C74B-20/P (same form factor and footprint) — differing in Package, Instruction Set, Mounting Type, Operating Temperature, Serial Interfaces.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04/PQ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$7.25 / Unit
View Datasheet →PIC16C74B-04I/P
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC16C74B-20I/P
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$6.78 / Unit
View Datasheet →PIC16C74A-20/PQ
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC16C73B-20/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65B-20/P
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74B-20/P Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | PIC® 16C |
| Core Processor | PIC |
| Core Size | 8-bit |
| Program Memory Size | 7 KB (4K x 14) OTP |
| RAM Size | 192 bytes |
| EEPROM Size | 0 bytes (none on this family) |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| Number of I/O Pins | 33 |
| A/D Converter | 8 channels x 8-bit |
| Timers | 2 x 8-bit + 1 x 16-bit |
| Capture/Compare/PWM | 2 CCP modules |
| Serial Interfaces | SPI, I²C, USART |
| Package | 40-pin PDIP (0.600 in / 15.24 mm) |
| Mounting Type | Through-Hole |
| Operating Temperature | 0°C to +70°C (commercial) |
| Instruction Set | 35 single-word instructions (RISC) |
| Oscillator Type | External or internal RC option |
| Watchdog Timer | Yes (with on-chip RC) |
| Brown-out Reset / POR | Yes |
| Program Memory Type | OTP (One-Time Programmable) |
PIC16C74B-20/P Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / Analog input channel 2 |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input channel 3 / ADC positive reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / Analog input channel 4 / SPI slave select |
| Pin 8 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 9 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 I/O |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / CCP1 I/O |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 18 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 19 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port bit 1 |
| Pin 20 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port bit 2 |
| Pin 21 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port bit 3 |
| Pin 22 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 23 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port bit 5 |
| Pin 24 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port bit 6 |
| Pin 25 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port bit 7 |
| Pin 26 | RE0/RD/AN5 — PORTE bit 0 / read control for PSP / Analog input channel 5 |
| Pin 27 | RE1/WR/AN6 — PORTE bit 1 / write control for PSP / Analog input channel 6 |
| Pin 28 | RE2/CS/AN7 — PORTE bit 2 / chip select for PSP / Analog input channel 7 |
| Pin 29 | VSS — Ground reference |
| Pin 30 | VDD — Positive supply (4.0 V to 5.5 V) |
| Pin 31 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 32 | RB1 — PORTB bit 1 |
| Pin 33 | RB2 — PORTB bit 2 |
| Pin 34 | RB3/PGM — PORTB bit 3 / low-voltage programming input |
| Pin 35 | RB4 — PORTB bit 4 |
| Pin 36 | RB5 — PORTB bit 5 |
| Pin 37 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 38 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 39 | NC — Not connected (per datasheet) |
| Pin 40 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C74B-20/P is suitable for 6 applications: Motor Control (BLDC and Stepper), Industrial Process Control and Sensor Interfacing, Appliance and HVAC Control, Automotive Body and Chassis Subsystems, Embedded Control Boards and Legacy Replacement, Display and Keypad Human-Machine Interfaces.
Motor Control (BLDC and Stepper)
The PIC16C74B-20/P's two CCP modules deliver PWM outputs suitable for driving BLDC and stepper motor H-bridges, while its 8-bit ADC samples back-EMF, current shunt, and position feedback at the typical PWM-update cadence. The 20 MHz instruction cycle (200 ns) provides the throughput required for field-oriented control loops on small motors, and the 33 I/O pins accept multiple Hall-sensor or encoder inputs. Compared with a discrete PWM controller, the integrated MCU reduces BOM and PCB area for low-cost appliance-class drives where OTP memory lock is acceptable.
Recommended
Industrial Process Control and Sensor Interfacing
The 8-channel 8-bit ADC makes the PIC16C74B-20/P a natural fit for multi-sensor industrial nodes (temperature, pressure, flow, level) where several analog channels are read at modest rates. The 4.0-5.5 V supply range tolerates 24V-transducer-derived 5V rails, and the USART plus SPI/I²C ports connect to downstream PLCs, HMIs, or sensor buses. OTP memory is well-matched to industrial nodes with locked calibration profiles. Estimated: at the 20 MHz clock, an 8-channel ADC round-robin scan can run at roughly 5 kHz aggregate sample rate using the A/D conversion clock derived from the system clock.
Recommended
Appliance and HVAC Control
White-goods controllers (washing machines, dishwashers, refrigerators, HVAC thermostats) historically use PIC16C74B-class MCUs because the OTP memory gives the lowest unit cost at high volume while the integrated ADC, timers, and PWM are sufficient for motor and valve control. The commercial 0°C to +70°C operating range covers indoor appliance environments, and the 40-pin PDIP package eases assembly and rework. The 35-instruction RISC core also simplifies firmware certification for safety-relevant functions.
Recommended
Automotive Body and Chassis Subsystems
Although not AEC-Q100 qualified, the PIC16C74B-20/P is widely used in non-safety automotive subsystems such as seat controllers, mirror adjusters, lighting controllers, and HVAC blend-door actuators where OTP cost advantage outweighs the need for flash updates. The 33 I/O pins drive multiple relays, LEDs, and H-bridges directly, while the USART connects to body-control networks. For under-hood or safety applications, choose an AEC-Q100 qualified flash MCU instead.
Recommended
Embedded Control Boards and Legacy Replacement
The 40-pin PDIP package, breadboard-friendly pinout, and rich peripheral set make the PIC16C74B-20/P a long-lived choice for educational labs, legacy equipment maintenance, and drop-in PCB replacements. PIC instruction-set continuity means firmware can be recompiled and ported across decades of PIC16C and PIC16F parts. Designers maintaining 1990s and 2000s-era equipment find this part useful because the source code still builds and the timing behavior is well-characterized.
Recommended
Display and Keypad Human-Machine Interfaces
The PIC16C74B-20/P's 33 I/O pins scan up to a 4x5 keypad matrix or drive multiplexed 7-segment / character LCD modules without external glue logic, while the USART and SPI ports talk to graphic LCD controllers or remote displays. The 200 ns instruction cycle is more than adequate for debounce, key encoding, and display refresh tasks at human-input speeds (sub-100 Hz). For designs needing only keypad scanning, the smaller PIC16C73B is a cost-down alternative.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-20/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04/P | PIC16C74B-04I/P | PIC16C74B-20I/P | PIC16C74A-20/P | PIC16C73B-20/P | PIC16C65B-20/P |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-pin PDIP | 40-pin PDIP (same) | 40-pin PDIP (same) | 40-pin PDIP (same) | 40-pin PDIP (same) | 40-pin PDIP (same) | 40-pin PDIP (same) |
| Max Clock Speed | 20 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 4 KB OTP (-43%) |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 22 (-33%) | 33 |
| ADC Channels | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 5 x 8-bit | None |
| Operating Temperature | 0°C to +70°C (commercial) | 0°C to +70°C | -40°C to +85°C (industrial) | -40°C to +85°C (industrial) | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C |
| Silicon Revision | B (revised) | B | B | B | A (earlier, different errata) | B | B |
Key Differentiators
- Wider I/O and ADC count than PIC16C73B at same package (vs PIC16C73B-20/P)
- Full 7 KB program memory vs smaller PIC16C65B (vs PIC16C65B-20/P)
- Revised silicon 'B' with fixed errata vs 'A' revision (vs PIC16C74A-20/P)
Design Notes
Place a 0.1 µF ceramic decoupling capacitor as close as possible to the VDD pin (pin 32) and a bulk capacitor (≥10 µF) at the supply entry point. The PIC16C74B-20/P draws tens of mA during EEPROM programming pulses, so the bulk cap prevents VDD sag that can cause code corruption. Tie MCLR/VPP (pin 1) to VDD through a 10 kΩ resistor with a 100 nF cap to ground for proper reset behavior and ICSP compatibility.
OTP memory cannot be erased or rewritten - a single programming error or firmware bug permanently bricks the device in production. Always verify firmware on a flash-based sibling (e.g. PIC16F877A-I/P) before committing to OTP. Also note that the A/D converter's VREF+ shares pin RA3; if using external VREF, RA3 digital I/O is unavailable. Brown-out reset (BOR) must be enabled in the configuration word for reliable operation across noisy industrial environments.
Keep the 20 MHz crystal or resonator traces short (under 10 mm) and symmetric. Place the load capacitors (typically 15-33 pF per datasheet) close to the OSC1/OSC2 pins. If using the internal RC oscillator instead, leave OSC1/OSC2 as no-connect or drive them only from a clean external source. Route analog inputs (AN0-AN7) away from digital switching lines and add a small RC filter (1 kΩ + 100 pF) at the ADC input to attenuate injected noise.
For the 40-pin PDIP package, use a DIP-40 footprint with 0.100 inch (2.54 mm) pin pitch and 0.600 inch (15.24 mm) row-to-row spacing. Through-hole pads should be at least 1.6 mm drill diameter with 2.5 mm annular ring for wave-solder reliability. Place a ground plane on the bottom side of the PCB if possible, and route the VDD trace with at least 0.5 mm width to handle programming current spikes. Estimated: at typical 50 mA programming current, a 0.5 mm trace on 1 oz copper has less than 50 mV drop over 50 mm.
Compliance Information
RoHS, REACH, lead-free and halogen-free status were not in the verified web data - see [DATA_NEEDED] markers in specs. The PIC16C74B is not AEC-Q100 qualified; it is intended for industrial and consumer applications. Per Microchip's standard policy, all modern PIC parts are conflict-minerals compliant.
