PIC16C74B-04I/P - 8-Bit 4MHz OTP MCU 7KB 40-PDIP | Microchip
MPN: PIC16C74B-04I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.94 | $8.94 |
| 10 | $7.95 | $79.50 |
| 100 | $6.85 | $685.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.55 | $5,550.00 |
PIC16C74B-04I/P Overview
What is a PIC16 mid-range MCU? The PIC16CXX family is a generation of Microchip 8-bit microcontrollers built around a Harvard RISC architecture that executes single-cycle instructions from a 14-bit program word store. Mid-range PICs combine a compact 35-instruction set with integrated peripherals (ADC, timers, USART, SPI/I2C) and have been a workhorse for industrial, automotive aftermarket, and legacy embedded designs since the 1990s. The PIC16C74B specifically targets applications that need more I/O and memory than the smaller PIC16C6x family while keeping the OTP cost advantage.
Key features include 8 channels of 8-bit ADC, two 8-bit timers plus one 16-bit timer, two Capture/Compare/PWM (CCP) modules, a synchronous serial port configurable as SPI or I2C, and a USART for asynchronous serial communication. The device supports 33 digital I/O lines organized across five ports (PORTA-PORTE), an operating voltage of 4.0 V to 5.5 V, and an industrial temperature grade of -40 °C to +85 °C as indicated by the "I" suffix.
Architecturally, the PIC16C74B uses a fully-static CMOS design with separate program and data buses (Harvard architecture), enabling single-cycle instruction fetch plus execute on all instructions except program branches, which take two cycles. The 04 speed grade specifies a 4 MHz maximum oscillator input. The "C" in PIC16C denotes the OTP/EPROM ROMless windowed family, distinguished from the flash-based "F" parts such as the PIC16F877.
Typical applications include industrial control panels, instrumentation and metering, sensor interfacing using the on-chip ADC, motor-control hobby projects using the CCP/PWM channels, and legacy embedded systems that require OTP-based firmware storage for cost or anti-retrofit reasons. Because the part is OTP, firmware is committed at programming time and cannot be re-flashed in-circuit.
When designing with this device, place a 0.1 µF decoupling capacitor on VDD within 5 mm of the pin and use a bulk 10 µF tantalum on the supply rail. The MCLR reset pin must be pulled high through a 10 kΩ resistor for normal operation; an optional reset circuit can use a diode and RC network for power-on-reset delay.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C74B-04I/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-04I/P (same form factor and footprint) — differing in Mounting Type, ADC, Core Architecture, Program Memory Size, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04/PQ
✅ Drop-In✓ In Stock
$7.25 / Unit
View Datasheet →PIC16C74B-20I/P
✅ Drop-In✓ In Stock
$6.78 / Unit
View Datasheet →PIC16C74A-04I/P
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74B-04I/PQ
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F877-04I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-04I/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-04I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX 8-bit RISC (Harvard) |
| CPU Family | PIC16 mid-range |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 200 ns |
| Program Memory Size | 7 KB (4K x 14) OTP |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Data RAM | 192 bytes |
| Data EEPROM | None (none on die for this OTP MCU) |
| I/O Pins | 33 |
| ADC | 8 channels, 8-bit resolution |
| Timers | 2 x 8-bit + 1 x 16-bit |
| Capture/Compare/PWM | 2 CCP modules |
| Serial Communication | 1 x USART (SCI), 1 x SSP (SPI / I2C) |
| Supply Voltage | 4.0 V to 5.5 V |
| Operating Temperature | -40 °C to +85 °C (industrial grade, "I") |
| Package Type | 40-pin PDIP (Plastic DIP, through-hole) |
| Instruction Set | 35 single-word instructions |
| RoHS Status | Compliant |
| Mounting Type | Through-Hole (DIP) |
PIC16C74B-04I/P Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / 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/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 9 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator in / CCP2 output |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| 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 | GND — Ground (logic) |
| Pin 19 | GND — Ground (logic) |
| Pin 20 | VCC — Positive supply +5 V |
| Pin 21 | VCC — Positive supply +5 V |
| Pin 22 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 23 | RB1 — PORTB bit 1 |
| Pin 24 | RB2 — PORTB bit 2 |
| Pin 25 | RB3/PGM — PORTB bit 3 / low-voltage programming entry |
| Pin 26 | RB4 — PORTB bit 4 |
| Pin 27 | RB5 — PORTB bit 5 |
| Pin 28 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 29 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 30 | RD0/PSP0 — PORTD bit 0 / parallel slave port bit 0 |
| Pin 31 | RD1/PSP1 — PORTD bit 1 / parallel slave port bit 1 |
| Pin 32 | RD2/PSP2 — PORTD bit 2 / parallel slave port bit 2 |
| Pin 33 | RD3/PSP3 — PORTD bit 3 / parallel slave port bit 3 |
| Pin 34 | RD4/PSP4 — PORTD bit 4 / parallel slave port bit 4 |
| Pin 35 | RD5/PSP5 — PORTD bit 5 / parallel slave port bit 5 |
| Pin 36 | RD6/PSP6 — PORTD bit 6 / parallel slave port bit 6 |
| Pin 37 | RD7/PSP7 — PORTD bit 7 / parallel slave port bit 7 |
| Pin 38 | RE0/RD/AN5 — PORTE bit 0 / read control for PSP / analog 5 |
| Pin 39 | RE1/WR/AN6 — PORTE bit 1 / write control for PSP / analog 6 |
| Pin 40 | RE2/CS/AN7 — PORTE bit 2 / chip select for PSP / analog 7 |
Typical Applications
PIC16C74B-04I/P is suitable for 6 applications: Industrial Control Panels, Sensor Interface and Data Acquisition, Motor Speed Control (Hobby/Small DC), Legacy Embedded Replacement / Board Refresh, Educational / Training Boards, Instrumentation and Metering.
Industrial Control Panels
The PIC16C74B-04I/P suits industrial control panels thanks to its 33 I/O pins for relay drivers, 8-channel 8-bit ADC for analog sensor reading, and industrial -40 to +85 °C rating. At 4 MIPS (4 MHz, 200 ns per instruction) the part drives HMI keypads, indicator LEDs, and 4-20 mA loops comfortably. The CCP/PWM modules handle proportional valve control. Pin-compatible with the flash-based PIC16F877A-I/P for in-field firmware updates.
Recommended
Sensor Interface and Data Acquisition
With eight 8-bit ADC channels, the PIC16C74B-04I/P acts as a compact sensor front-end for temperature, pressure, or light sensors. The integrated USART streams converted data to a host PLC at 19.2 kbaud or higher. Industrial temp rating permits deployment near motors or HVAC ducts. The 192-byte RAM holds local averaging buffers, and the SSP port can drive an external I2C EEPROM for log retention.
Recommended
Motor Speed Control (Hobby/Small DC)
The two CCP/PWM channels deliver independent 10-bit PWM for brushed DC motor control or small stepper sequencing. At 4 MHz the 7 KB OTP holds 4 K instructions - ample for trapezoidal commutation tables, PID loops, and tachometer feedback. The 33 I/O drive H-bridge enable lines and quadrature encoder inputs. Designers upgrade to PIC16F877A-I/P when firmware revisions are expected.
Recommended
Legacy Embedded Replacement / Board Refresh
The PIC16C74B-04I/P is widely used to refresh boards originally designed around the PIC16C74A or PIC16F877. Because the OTP memory holds committed firmware, no in-field upgrade is possible - a benefit for tamper-resistant appliances. Drop-in compatibility with the PIC16C74A-04I/P and PIC16F877-04I/P lets refurb shops swap dies without layout changes. Industrial temp grade handles warm enclosures.
Recommended
Educational / Training Boards
Educational labs and microcontroller training kits favor the PIC16C74B-04I/P because it demonstrates the PIC16 mid-range core, OTP programming workflow, and a full peripheral set (ADC, PWM, USART, SPI/I2C) in a friendly 40-PDIP socket. The 7 KB program memory fits substantial C or assembly projects; the 192-byte RAM limits data arrays but is more than enough for textbook exercises. Easy to swap during lab damage recovery.
Recommended
Instrumentation and Metering
Digital panel meters and stand-alone instrumentation benefit from the PIC16C74B-04I/P's 8-bit ADC for voltage/current measurement, USART for Modbus or proprietary serial output, and industrial temperature tolerance for cabinet-mounted meters. The two CCP channels drive LED/LCD backlight PWM and buzzer alarm tones. The DIP package is socket-friendly, simplifying field replacement in metering hardware.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-04I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04/P | PIC16C74B-20I/P | PIC16C74A-04I/P | PIC16F877-04I/P | PIC16C74B-04I/L |
|---|---|---|---|---|---|---|
| Package | 40-PDIP | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-CERDIP - same pinout, ceramic windowed |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz | 4 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB Flash | 7 KB EPROM (UV erasable) |
| Temperature Grade | Industrial (-40 to +85 °C) | Commercial (0 to +70 °C) | Industrial (-40 to +85 °C) | Industrial (-40 to +85 °C) | Industrial (-40 to +85 °C) | Industrial (-40 to +85 °C) |
| Data EEPROM | None | None | None | None | 256 bytes | None |
| ADC | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 10-bit | 8 ch x 8-bit |
| Supply Voltage | 4.0 - 5.5 V | 4.0 - 5.5 V | 4.0 - 5.5 V | 4.0 - 5.5 V | 2.0 - 5.5 V | 4.0 - 5.5 V |
Key Differentiators
- True 40-pin PDIP drop-in position with OTP memory (vs PIC16F877-04I/P)
- Industrial -40 to +85 °C temperature grade (vs PIC16C74B-04/P)
- 4 MHz speed grade optimized for cost-sensitive low-MIPS tasks (vs PIC16C74B-20I/P)
Design Notes
Decouple VDD with a 0.1 µF ceramic capacitor placed within 5 mm of pins 11 and 32, and add a bulk 10 µF tantalum on the supply rail. Two VDD pins are provided to reduce digital switching noise on the analog AVSS/AVDD pair. During OTP programming the VPP pin (pin 1) must reach 13.0 V to 13.25 V - use a regulated HV supply and a 1 kΩ series resistor to limit current.
Place the 4 MHz crystal or resonator as close as possible to pins 9 (OSC1) and 10 (OSC2), with the load capacitors (typically 15-33 pF) returned to ground. Keep the MCLR pull-up (10 kΩ to VDD) within 5 mm of pin 1. For noisy environments add a 100 Ω resistor in series with MCLR and a 1 µF cap to ground to form a hardware reset filter.
The PIC16C74B is OTP - firmware cannot be changed after programming. Reserve engineering samples (PIC16C74B-04I/L, the windowed CERDIP variant) for firmware development and validation, then move to the cheaper plastic DIP (PIC16C74B-04I/P) for production. Do not exceed 200 mA total sink/source on PORTB and PORTC combined; the parallel slave port (PORTD/PORTE) shares pins with digital I/O and must be reconfigured after PSP use.
Route analog inputs AN0-AN7 (PORTA and PORTE) away from digital switching traces and the oscillator network. If the ADC reference is taken from VDD, add a 10 µF + 0.1 µF decoupling network at the AVSS pin to keep ADC noise below ±1 LSB. The CCP1/CCP2 PWM outputs (RC2/RC1) should drive the motor bridge through a gate driver, not directly; the I/O pin can only source/sink 25 mA.
Compliance Information
RoHS compliant per Microchip product page (PIC16C family is lead-free). Not AEC-Q100 qualified; this is a general-purpose industrial MCU.
