PIC16C74B-20I/L - 8-Bit 20MHz OTP MCU 7KB | 44-PLCC | Microchip
MPN: PIC16C74B-20I/L ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.97 | $12.97 |
| 10 | $12.18 | $121.80 |
| 100 | $11.04 | $1,104.00 |
| 500 | $9.85 | $4,925.00 |
| 1,000 | $8.92 | $8,920.00 |
PIC16C74B-20I/L Overview
An 8-bit microcontroller (MCU) is a small, self-contained computer-on-a-chip built around an 8-bit data path, on-chip program memory, RAM, and a set of peripherals. PIC16C MCUs are part of the broader category of RISC microcontrollers within the semiconductor power-management and embedded-control taxonomy: MCU -> microcontroller -> embedded processor -> semiconductor. They target deterministic, low-cost, low-power embedded control where a full 32-bit processor would be overkill.
Key features of the PIC16C74B include 8 channels of 8-bit Analog-to-Digital conversion, two additional timers, two Capture/Compare/PWM peripherals, and a synchronous serial port configurable as either 3-wire SPI or 2-wire I2C, plus a USART for asynchronous serial communication. The high-performance RISC CPU uses only 35 single-word instructions, with all instructions executing in one cycle except program branches (two cycles), enabling predictable real-time response.
The OTP program memory, parallel I/O architecture, and ceramic PLCC windowed package indicate this part is intended for prototype development, low-volume industrial production, and legacy industrial control systems where field-programmability is not required. Compared with flash-based successors like PIC16F74, this OTP variant offers lower unit cost in volume but cannot be re-programmed.
Typical applications include industrial control systems, motor control, sensor interfacing, building automation, embedded instrumentation, and legacy retrofit designs. The wide industrial temperature range and robust peripheral set make the PIC16C74B well suited for factory-floor equipment.
When designing with the PIC16C74B, ensure your programmer supports OTP devices - a windowed CERDIP/PLCC package allows UV erasure for development iteration, but production programming must be done before final encapsulation. Decoupling capacitors (100 nF plus 10 uF bulk) should be placed within 5 mm of VDD pins.
This page synthesizes verified distributor pricing, drop-in pin-compatible alternatives, and practical engineering notes not consolidated on any single distributor or manufacturer page, helping engineers make sourcing and substitution decisions in seconds.
Drop-in alternatives for PIC16C74B-20I/L — 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-20I/L (same form factor and footprint) — differing in Core Architecture, Timers, Package, Serial Interfaces, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-20/L
✅ Drop-In✓ In Stock
$8.2 / Unit
View Datasheet →PIC16C74B-04I/L
✅ Drop-In✓ In Stock
$2.61 / Unit
View Datasheet →PIC16C74B-04E/L
✅ Drop-In✓ In Stock
$9.3 / Unit
View Datasheet →PIC16C74A-20I/L
✅ Drop-In✓ In Stock
$8.75 / Unit
View Datasheet →PIC16C67-20I/PQ
✅ Drop-In✓ In Stock
$3.62 / Unit
View Datasheet →PIC16C74B-20I/L Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC |
| Program Memory Size | 7 KB (4K x 14) |
| Program Memory Type | OTP (One-Time Programmable) |
| RAM Size | 192 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle | 200 ns |
| Supply Voltage Range | 4.0 V to 5.5 V |
| Number of I/O Pins | 33 |
| ADC | 8 channels, 8-bit |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Capture/Compare/PWM | 2 modules |
| Communication Interfaces | SPI, I2C (MSSP), USART |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Package Type | 44-pin PLCC (J-Lead), windowed ceramic |
| Package Dimensions | 16.59 x 16.59 mm |
| Mounting Type | Surface Mount |
PIC16C74B-20I/L Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input |
| Pin 2 | RA0/AN0 — Port A bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 — Port A bit 1 / Analog input 1 |
| Pin 4 | RA2/AN2 — Port A bit 2 / Analog input 2 |
| Pin 5 | RA3/AN3/VREF — Port A bit 3 / Analog input 3 / Voltage Reference |
| Pin 6 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — Port A bit 5 / Analog input 4 / SPI Slave Select |
| Pin 8 | RE0/RD — Port E bit 0 / Read control for parallel slave port |
| Pin 9 | RE1/WR — Port E bit 1 / Write control for parallel slave port |
| Pin 10 | RE2/CS — Port E bit 2 / Chip Select for parallel slave port |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | VSS — Ground |
| Pin 13 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 14 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 15 | RC0/T1OSO/T1CKI — Port C bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer1 oscillator input / CCP2 |
| Pin 17 | RC2/CCP1 — Port C bit 2 / Capture/Compare/PWM1 |
| Pin 18 | RC3/SCK/SCL — Port C bit 3 / SPI clock / I2C clock |
| Pin 19 | RC4/SDI/SDA — Port C bit 4 / SPI data in / I2C data |
| Pin 20 | RC5/SDO — Port C bit 5 / SPI data out |
| Pin 21 | RC6/TX/CK — Port C bit 6 / USART transmit / USART clock |
| Pin 22 | RC7/RX/DT — Port C bit 7 / USART receive / USART data |
| Pin 23 | RD0/PSP0 — Port D bit 0 / Parallel Slave Port bit 0 |
| Pin 24 | RD1/PSP1 — Port D bit 1 / Parallel Slave Port bit 1 |
| Pin 25 | RD2/PSP2 — Port D bit 2 / Parallel Slave Port bit 2 |
| Pin 26 | RD3/PSP3 — Port D bit 3 / Parallel Slave Port bit 3 |
| Pin 27 | RD4/PSP4 — Port D bit 4 / Parallel Slave Port bit 4 |
| Pin 28 | RD5/PSP5 — Port D bit 5 / Parallel Slave Port bit 5 |
| Pin 29 | RD6/PSP6 — Port D bit 6 / Parallel Slave Port bit 6 |
| Pin 30 | RD7/PSP7 — Port D bit 7 / Parallel Slave Port bit 7 |
| Pin 31 | RB0/INT — Port B bit 0 / External interrupt |
| Pin 32 | RB1 — Port B bit 1 |
| Pin 33 | RB2 — Port B bit 2 |
| Pin 34 | RB3 — Port B bit 3 |
| Pin 35 | RB4 — Port B bit 4 |
| Pin 36 | RB5 — Port B bit 5 |
| Pin 37 | RB6/PGC — Port B bit 6 / ICSP clock |
| Pin 38 | RB7/PGD — Port B bit 7 / ICSP data |
| 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 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C74B-20I/L is suitable for 6 applications: Industrial Process Control Systems, Motor Control and PWM Drive, Sensor Interfacing and Data Acquisition, Building Automation and HVAC Control, Embedded Instrumentation and Test Equipment, Legacy Industrial Retrofit Systems.
Industrial Process Control Systems
The PIC16C74B-20I/L fits industrial process control because its 8-channel 8-bit ADC directly interfaces with 4-20 mA current loop sensors, thermocouples (via op-amp front-end), and pressure transducers without external signal conditioning ICs. Its 20 MHz clock and 200 ns instruction cycle execute PID control loops at update rates up to 5 kHz, sufficient for thermal regulation and flow control. The industrial temperature range of -40 C to +85 C supports factory-floor deployments. The 33 I/O lines drive relays, solenoids, and indicator LEDs directly when current is limited. Three timers generate precise PWM outputs for valve and damper actuators, while the USART communicates with HMI panels. The OTP memory protects production firmware from unauthorized field modifications, important in regulated process industries.
Recommended
Motor Control and PWM Drive
The PIC16C74B-20I/L drives small DC motors and stepper motor stages using its two Capture/Compare/PWM modules, which generate complementary PWM outputs with programmable dead-time insertion up to 20 kHz switching frequency. The 20 MHz instruction cycle supports closed-loop PID updates at 10 kHz, adequate for spindle speed regulation in benchtop equipment. Quadrature encoder feedback is decoded via the CCP capture inputs for position control. The 8-bit ADC samples motor current through shunt resistors for torque limiting and stall detection. With 33 I/O lines, the MCU coordinates direction logic, brake drivers, and limit-switch interlocks simultaneously. The wide 4.0 V to 5.5 V supply range tolerates noisy industrial DC bus rails typical of motor drive cabinets.
Recommended
Sensor Interfacing and Data Acquisition
The PIC16C74B-20I/L serves sensor-hub applications because its 8-channel 8-bit ADC multiplexes up to eight analog sensors - temperature, pressure, humidity, light, gas - through a single MCU, minimizing PCB area. The I2C/SPI MSSP port expands the channel count by interfacing external digital sensors (accelerometers, gyroscopes). The USART streams digitized sensor data to a host controller or PC at 115.2 kbps. With 192 bytes of RAM and 7 KB OTP, the firmware can implement calibration tables, linearization polynomials, and digital filtering (moving average, IIR) on-board. The industrial temperature rating and ceramic PLCC package suit long-life installations in unattended data-logger deployments such as weather stations and remote monitoring nodes.
Recommended
Building Automation and HVAC Control
The PIC16C74B-20I/L fits building automation controllers because it integrates analog sensing (via 8-channel ADC), digital I/O (33 lines for relay switching), and serial communication (USART for BACnet/Modbus gateways) in a single chip. Its 4.0 V to 5.5 V supply operates from 5 V regulated rails common in HVAC control panels. The PWM modules drive damper actuators and variable-speed fan motors with closed-loop feedback from temperature sensors. Three timers schedule daily HVAC cycles (occupied/unoccupied modes) without an external RTC. The OTP memory locks in certified control algorithms that cannot be field-tampered with, important for energy code compliance. Industrial temperature range ensures reliable operation in mechanical rooms and rooftop unit enclosures.
Recommended
Embedded Instrumentation and Test Equipment
The PIC16C74B-20I/L functions as the main controller in benchtop instruments where its 20 MHz clock drives real-time measurement displays and keypad menu navigation. The SPI port interfaces LCD graphic displays and digital potentiometers, while the I2C bus reads EEPROM calibration constants at startup. The USART outputs measurement data to a PC for logging and analysis. Three timers generate accurate time bases for frequency counters and pulse-width measurements. The 8-bit ADC digitizes analog inputs up to 100 kSPS aggregate rate. The industrial temperature rating supports laboratory and field service environments, while OTP memory protects proprietary calibration algorithms from copying during service or repair. The 44-PLCC package provides reliable socket-mounting in test fixtures.
Recommended
Legacy Industrial Retrofit Systems
The PIC16C74B-20I/L is the preferred replacement for obsolete or end-of-life microcontrollers in legacy industrial equipment because it shares the 44-PLCC J-Lead footprint with many older 8-bit designs from the 1990s. The OTP memory matches the production firmware model used in legacy installations. With 7 KB program memory and 192 bytes RAM, it is code-compatible with earlier PIC16C7x designs through the standard 35-instruction RISC set, simplifying firmware porting. The 33 I/O lines map directly to peripheral replacement boards. Microchip's continued active lifecycle status means long-term support is available for industrial customers maintaining 15-20 year equipment lifecycles. The ceramic windowed package allows UV erasure during development iteration before final production programming.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-20I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-20/L | PIC16C74B-04I/L | PIC16C74B-04E/L | PIC16C74A-20I/L | PIC16C67-20I/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC (J-Lead) | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same |
| Max Clock Frequency | 20 MHz | 20 MHz | 4 MHz | 4 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 |
| RAM Size | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| ADC Channels | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 0 (no ADC) |
| Operating Temperature | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| Supply Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V |
Key Differentiators
- Industrial temperature grade in standard product offering (vs PIC16C74B-20/L)
- Maximum 20 MHz clock performance within PIC16C74B family (vs PIC16C74B-04I/L)
- 8-channel 8-bit ADC integrated on-chip (vs PIC16C67-20I/PQ)
- Newer silicon revision (B) with improved electrical characteristics (vs PIC16C74A-20I/L)
Design Notes
The PIC16C74B-20I/L requires a regulated 5 V supply within 4.0 V to 5.5 V. Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD pin and a 10 uF bulk tantalum or aluminum electrolytic capacitor at the board entry point. For noisy industrial environments, add a ferrite bead in series with the VDD supply line to suppress conducted EMI from motor drives and switching relays. The MCLR (pin 1) should be tied to VDD through a 10 kohm pull-up resistor with a 100 nF capacitor to ground for power-on reset delay. Avoid long VDD traces that act as antennas - keep the supply loop area minimal.
The 44-PLCC J-Lead package requires a socket (e.g., 44-pin PLCC IC socket) for development iteration, since the ceramic windowed variant is intended for UV erasure during prototyping. For production, wave or reflow soldering is acceptable but ensure land pattern matches JEDEC PLCC-44 standard. Keep clock traces (OSC1/OSC2) short, less than 25 mm, and surround with a ground guard ring to reduce EMI pickup. Place the crystal or resonator within 10 mm of the OSC pins and connect the load capacitors (typically 15-33 pF) directly to ground. Route analog signals (RA0-RA5) away from digital switching traces to minimize ADC noise coupling.
OTP (One-Time Programmable) memory CANNOT be erased or rewritten once programmed. Verify your firmware completely using the windowed ceramic package (UV-erasable during development) before committing to production OTP programming. The configuration bits (fuses) control oscillator mode, watchdog timer, code protection, and brown-out voltage - incorrect settings can lock the device or cause erratic behavior. When using the ADC, the acquisition time must be accounted for by setting the appropriate Tad value based on the system clock. For interrupt-driven designs, save and restore the W register and STATUS register in the interrupt service routine to prevent context corruption. Do not exceed the absolute maximum ratings of 7.0 V on VDD or current per pin of 25 mA.
Compliance Information
RoHS/REACH/lead-free status not explicitly stated in provided data. Windowed ceramic CERDIP/PLCC packages are often non-RoHS; verify with Microchip directly. Conflict minerals compliance per Microchip standard policy.
