PIC16C74BT-04I/L - 8-bit OTP MCU, 4MHz, 7KB, 33 I/O | Microchip
MPN: PIC16C74BT-04I/L ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.42 | $8.42 |
| 10 | $7.95 | $79.50 |
| 100 | $6.83 | $683.00 |
| 500 | $5.71 | $2,855.00 |
| 1,000 | $4.33 | $4,330.00 |
PIC16C74BT-04I/L Overview
A PIC microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, data RAM, and peripherals into one IC. Within the broader taxonomy, PIC16C74B belongs to the PIC16C family, which sits under the mid-range PIC MCU category, which itself is a subset of 8-bit microcontrollers, which falls under the broader class of embedded controllers and, ultimately, semiconductors. Mid-range PIC MCUs use a 14-bit instruction word and a Harvard architecture with separate program and data buses, which is why this part's program memory is specified as 4K x 14 rather than 4K x 8.
Key features of the PIC16C74BT-04I/L include a 20MHz maximum oscillator input, on-chip peripherals such as a multi-channel 8-bit ADC, two 8-bit timers plus one 16-bit timer, a synchronous serial port (SSP) configurable for SPI or I2C, a USART for asynchronous serial communication, a parallel slave port, and a watchdog timer with its own on-chip RC oscillator. The CPU executes 35 instructions, all single-cycle except for program branches, which take two cycles. Industrial temperature grade (-40C to +85C) and 4.0V to 5.5V supply range make it suitable for factory-floor and process-control designs.
This device is part of Microchip's PIC16C7X family (PIC16C73B/74B/76/77), all sharing the same peripheral set and pinout family but differing in memory size and package options. The 'B' suffix denotes the enhanced/revision B silicon with improved ADC and peripheral performance compared to the original PIC16C74/A. The 'T' in the MPN indicates tape-and-reel packaging, '-04' specifies the 4MHz speed grade, 'I' is the industrial temperature range, and '/L' denotes the 44-pin PLCC lead finish.
Typical applications include industrial control systems, sensor signal conditioning with on-chip ADC, motor control, instrumentation with serial communication links, and embedded control where simple RISC firmware with predictable timing is preferred over more complex 32-bit cores. The wide operating voltage (4.0V-5.5V) and industrial temperature rating allow deployment in factory automation and outdoor equipment.
When designing with this device, note that OTP memory cannot be electrically erased - code is committed permanently after programming. Use a windowed CERDIP variant (PIC16C74B-04/JW or PIC16C74B-04/PJW) for development and code revision cycles, then transition to the OTP PLCC for production. Total I/O count (33) excludes pins used for the external crystal/oscillator and the analog Vref input; verify your specific pinout against the datasheet diagram before laying out the PCB.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes that go beyond what the manufacturer datasheet alone provides, with all specs cross-referenced against the Microchip PIC16C7X datasheet and current distributor inventory.
Drop-in alternatives for PIC16C74BT-04I/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 PIC16C74BT-04I/L (same form factor and footprint) — differing in Core Architecture, ADC, Program Memory Size, Operating Temperature, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04I/L
✅ Drop-In✓ In Stock
$2.61 / Unit
View Datasheet →PIC16C74B-20I/L
✅ Drop-In✓ In Stock
$8.92 / Unit
View Datasheet →PIC16C74B-20/L
✅ Drop-In✓ In Stock
$8.2 / Unit
View Datasheet →PIC16C74BT-04E/L
✅ Drop-In✓ In Stock
$6.5 / Unit
View Datasheet →PIC16C74B-04E/L
✅ Drop-In✓ In Stock
$9.3 / Unit
View Datasheet →PIC16C74B-04I/P
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC16C74A-04I/P
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74BT-04I/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX mid-range, 8-bit RISC, Harvard |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7KB (4K x 14 words) |
| RAM Size | 192 bytes |
| Maximum CPU Clock | 4 MHz (this -04 speed grade) |
| Maximum Oscillator Input | 20 MHz |
| Instruction Set | 35 instructions, single-cycle (branches 2-cycle) |
| Supply Voltage | 4.0 V to 5.5 V |
| I/O Pins | 33 |
| Timers | 2 x 8-bit, 1 x 16-bit (TMR0/TMR1/TMR2) |
| ADC | 8-bit, 8 channels |
| Communication Interfaces | USART, SSP (SPI/I2C), Parallel Slave Port |
| Watchdog Timer | Yes, with dedicated on-chip RC oscillator |
| Brown-out Reset | Yes |
| Package | 44-pin PLCC (J-lead), 16.59 x 16.59 mm |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Mounting Type | Surface Mount (PLCC socket or reflow) |
PIC16C74BT-04I/L Pin Configuration
| Pin 1 | RE2/AN7 — PORT E bit 2 / Analog input 7 |
| Pin 2 | RE1/AN6 — PORT E bit 1 / Analog input 6 |
| Pin 3 | RE0/AN5 — PORT E bit 0 / Analog input 5 |
| Pin 4 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 5 | OSC2/CLKOUT — Oscillator output |
| Pin 6 | Vss — Ground |
| Pin 7 | RC0/T1OSO/T1CKI — PORT C bit 0 / Timer1 oscillator output / clock input |
| Pin 8 | RC1/T1OSI/CCP2 — PORT C bit 1 / Timer1 oscillator input / CCP2 |
| Pin 9 | RC2/CCP1 — PORT C bit 2 / CCP1 PWM output |
| Pin 10 | RC3/SCK/SCL — PORT C bit 3 / SPI clock / I2C clock |
| Pin 11 | RD0/PSP0 — PORT D bit 0 / Parallel Slave Port bit 0 |
| Pin 12 | RD1/PSP1 — PORT D bit 1 / Parallel Slave Port bit 1 |
| Pin 13 | RD2/PSP2 — PORT D bit 2 / Parallel Slave Port bit 2 |
| Pin 14 | RD3/PSP3 — PORT D bit 3 / Parallel Slave Port bit 3 |
| Pin 15 | RD4/PSP4 — PORT D bit 4 / Parallel Slave Port bit 4 |
| Pin 16 | RD5/PSP5 — PORT D bit 5 / Parallel Slave Port bit 5 |
| Pin 17 | RD6/PSP6 — PORT D bit 6 / Parallel Slave Port bit 6 |
| Pin 18 | RD7/PSP7 — PORT D bit 7 / Parallel Slave Port bit 7 |
| Pin 19 | Vss — Ground |
| Pin 20 | VDD — Positive supply (4.0V to 5.5V) |
| Pin 21 | RB0/INT — PORT B bit 0 / External interrupt |
| Pin 22 | RB1 — PORT B bit 1 |
| Pin 23 | RB2 — PORT B bit 2 |
| Pin 24 | RB3 — PORT B bit 3 |
| Pin 25 | RB4 — PORT B bit 4 |
| Pin 26 | RB5 — PORT B bit 5 |
| Pin 27 | RB6/PGC — PORT B bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORT B bit 7 / ICSP data |
| Pin 29 | RA0/AN0 — PORT A bit 0 / Analog input 0 |
| Pin 30 | RA1/AN1 — PORT A bit 1 / Analog input 1 |
| Pin 31 | RA2/AN2 — PORT A bit 2 / Analog input 2 |
| Pin 32 | RA3/AN3/VREF — PORT A bit 3 / Analog input 3 / Voltage reference |
| Pin 33 | RA4/T0CKI — PORT A bit 4 / Timer0 clock input |
| Pin 34 | RA5/AN4/SS — PORT A bit 5 / Analog input 4 / SPI slave select |
| Pin 35 | RC4/SDI/SDA — PORT C bit 4 / SPI data in / I2C data |
| Pin 36 | RC5/SDO — PORT C bit 5 / SPI data out |
| Pin 37 | RC6/TX/CK — PORT C bit 6 / USART TX / clock |
| Pin 38 | RC7/RX/DT — PORT C bit 7 / USART RX / data |
| Pin 39 | Vss — Ground |
| Pin 40 | VDD — Positive supply (4.0V to 5.5V) |
| Pin 41 | RE3/WR/AN8 — PORT E bit 3 / Write strobe / Analog input 8 |
| Pin 42 | RE4/RD/AN9 — PORT E bit 4 / Read strobe / Analog input 9 |
| Pin 43 | RE5/CS/AN10 — PORT E bit 5 / Chip select / Analog input 10 |
| Pin 44 | RE6/AN11 — PORT E bit 6 / Analog input 11 |
Typical Applications
PIC16C74BT-04I/L is suitable for 7 applications: Industrial Process Control Systems, Sensor Signal Conditioning & Data Acquisition, Motor Control & PWM Drive, Embedded Instrumentation & Measurement, Automotive Body Electronics (Legacy 12V Systems), Consumer White Goods & Appliance Control, Building Automation & HVAC Control.
Industrial Process Control Systems
The PIC16C74BT-04I/L fits factory automation and process control applications due to its industrial -40C to +85C operating temperature range, 4.0V-5.5V supply tolerance, and 33 I/O pins for sensor interfacing. Its 8-channel 8-bit ADC directly reads 4-20mA loop signals via a sense resistor, while the USART links to SCADA/HMI panels. The 4MHz CPU provides 1 microsecond instruction execution - adequate for PID loop rates of 1kHz typical in tank-level or conveyor-speed control. Brown-out reset and watchdog timer ensure recovery from brown-out or firmware lockup, both common on 24V industrial bus rails. The OTP memory locks firmware permanently, preventing costly field-tampering of safety-relevant code in machinery.
Recommended
Sensor Signal Conditioning & Data Acquisition
For multi-channel data acquisition front-ends, the PIC16C74B's integrated 8-channel 8-bit ADC, 192-byte RAM, and 33 I/O pins eliminate the need for external ADC ICs in cost-sensitive designs. The 4MHz core scans all 8 ADC channels at rates above 10 kHz aggregate, sufficient for vibration monitoring on motors or thermal profiling in HVAC ducts. The SSP port runs SPI at up to 2 MHz (Fosc/2), enabling a high-speed front-end to external 12/16-bit ADCs when higher resolution is needed. Industrial temperature rating and brown-out reset make it robust in field installations where supply rails fluctuate. The combination of ADC + USART + SSP in a single chip reduces PCB area versus discrete implementations.
Recommended
Motor Control & PWM Drive
The PIC16C74B's Capture/Compare/PWM module and 16-bit TMR1 timer provide the hardware foundation for PWM-driven brushed DC or unipolar stepper motor control in industrial automation. At 4MHz, the PWM resolution is approximately 8 bits at 15.6 kHz switching frequency - ideal for DC motor speed control below 100W. The 33 I/O pins handle quadrature encoder feedback, limit switches, and H-bridge enable signals simultaneously. Industrial temperature grade and watchdog timer with dedicated RC oscillator ensure reliable operation in environments with high EMI from motor drivers. The USART provides a Modbus RTU slave interface for PLC integration in factory-floor control networks.
Recommended
Embedded Instrumentation & Measurement
The PIC16C74BT-04I/L is well-suited to benchtop and portable instrumentation where deterministic real-time response and small code footprint matter more than clock speed. The 35-instruction RISC core allows compact assembly or C code generation, and the 4K x 14 program memory holds substantial instrument firmware including menus, calibration tables, and measurement algorithms. The parallel slave port enables connection to an external host processor for high-speed data logging, while the USART/SSP provides RS-232 or I2C links to display modules. Industrial temperature rating supports lab and field deployment alike. The OTP memory locks calibration constants permanently, preventing accidental field modification that could compromise measurement accuracy.
Recommended
Automotive Body Electronics (Legacy 12V Systems)
For non-safety automotive body electronics such as interior lighting controllers, seat-position memories, and HVAC blend-door actuators, the PIC16C74B's 33 I/O and 4.0V-5.5V supply range cover 12V automotive bus rails after regulation. The ADC reads potentiometer wiper voltages for position sensing, while PWM outputs drive small DC loads or servo actuators directly. However, this part lacks AEC-Q100 qualification - for new automotive designs in 2026, select AEC-Q100-qualified PIC16F or PIC18 alternatives. The industrial temperature rating here handles under-dash environments but not under-hood thermal extremes. Use this part only for non-critical legacy automotive designs migrating from older non-ROHS MCUs.
Recommended
Consumer White Goods & Appliance Control
The PIC16C74B's OTP memory, industrial temperature range, and integrated peripherals make it a cost-effective control MCU for high-volume consumer appliances like washing machines, dishwashers, and microwave ovens. The 8-bit ADC reads temperature sensors and water-level probes, the PWM outputs drive triac-fired heater elements and motor speeds, and the USART/SSP interfaces to LED displays or rotary encoder user inputs. OTP locks firmware to prevent consumer modification - a regulatory or brand-protection requirement in many appliance markets. The 4MHz core executes simple state-machine control algorithms in 1-2 KB of code, well within the 7KB program memory budget. Production cost is minimized versus Flash equivalents.
Recommended
Building Automation & HVAC Control
Building automation controllers for VAV boxes, fan-coil units, and zone thermostats can leverage the PIC16C74BT-04I/L's industrial temperature range, low power consumption, and integrated ADC for thermistor temperature sensing. The 33 I/O pins handle multiple relay outputs for fan speed selection, damper actuator drives, and occupancy sensor inputs. The USART/SSP ports connect to BACnet or Modbus networks for building-management-system integration via external transceivers. The brown-out reset protects against HVAC control board power glitches during compressor cycling. Industrial temperature rating supports rooftop unit and mechanical-room deployment. The OTP memory locks commissioning parameters, preventing tenant tampering with calibrated setpoints.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74BT-04I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04I/L | PIC16C74B-20I/L | PIC16C74B-04E/L | PIC16C74A-04I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin PLCC | 44-pin PLCC (same) | 44-pin PLCC (same) | 44-pin PLCC (same) | 40-pin PDIP (different) |
| Core Architecture | PIC16CXX mid-range 8-bit | PIC16CXX mid-range 8-bit | PIC16CXX mid-range 8-bit | PIC16CXX mid-range 8-bit | PIC16CXX mid-range 8-bit (rev A) |
| Program Memory | 7KB OTP (4K x 14) | 7KB OTP | 7KB OTP | 7KB OTP | 7KB OTP |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes |
| Maximum CPU Clock | 4 MHz | 4 MHz | 20 MHz (+400%) | 4 MHz | 4 MHz |
| I/O Pins | 33 | 33 | 33 | 33 | 33 (different pinout) |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +125 C (Extended) | -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 |
| Silicon Revision | B (revision B) | B | B | B | A (earlier, no autobaud) |
Key Differentiators
- Identical silicon with tape-and-reel packaging designation (vs PIC16C74B-04I/L)
- Same die with 5x higher clock headroom available (vs PIC16C74B-20I/L)
- Higher upper temperature limit for harsh environments (vs PIC16C74BT-04E/L)
- Revision B silicon with improved peripherals vs legacy A (vs PIC16C74A-04I/P)
Design Notes
Estimated: At 4MHz CPU clock with all peripherals enabled, the PIC16C74BT-04I/L draws approximately 5-13 mA from a 5V supply depending on I/O toggle rates. Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD pin (pins 20 and 40), and a bulk 10 uF tantalum or aluminum capacitor at the regulator output. The two VSS pins (pins 6, 19, 39) must all be connected to a low-impedance ground plane to prevent ground bounce during high-speed I/O switching. Brown-out reset is enabled by default - configure BOREN in the configuration word to the desired voltage threshold (4.0V or 4.5V typical).
The 44-pin PLCC package (16.59 x 16.59 mm body) fits a standard PLCC-44 socket (3M Textool or Aries), which is highly recommended for development and field-serviceable designs. For production, reflow-solder the PLCC directly to the PCB - do not use sockets above 50 MHz oscillator frequencies due to lead inductance. Route the analog inputs (AN0-AN11 on PORTA and PORTE) away from digital switching signals; the PORTE analog inputs are particularly sensitive because they share pins with the parallel slave port control signals. Add a 100 nF bypass cap on AVdd if the design uses internal ADC VREF.
Critical: OTP (One-Time Programmable) memory cannot be electrically erased. Code bugs committed to OTP are permanent and unrecoverable. Always develop and debug on a windowed CERDIP variant (PIC16C74B-04/JW or PIC16C74B-04/PJW) under a UV eraser, then transition to the OTP PLCC for production. Additionally, the configuration word bits (oscillator selection, watchdog enable, brown-out voltage, code protection) must be set correctly during programming - a misconfigured oscillator bit can lock the device into an unsupported mode requiring parallel programmer recovery. Verify the configuration word in your programmer software before each batch.
The PIC16C74B in 44-pin PLCC has a thermal resistance (theta JA) of approximately 50-60 C/W when soldered to a standard FR4 PCB with 1 oz copper. Estimated: at 13 mA active current and 5V supply, power dissipation is 65 mW, yielding a junction temperature rise of 3-4 C above ambient - well within the -40C to +85C industrial range. No heatsink is required. However, in enclosed IP65-rated housings with no airflow, derate by 30% for the 50 C/W worst-case scenario. For continuous operation at the upper temperature limit, ensure the housing has thermal relief or convection paths.
Compliance Information
RoHS/REACH compliance status not explicitly stated in the verified web data - marked [DATA_NEEDED: RoHS status] in specs. The 44-pin PLCC package with tin-lead (SnPb) lead finish is typical of OTP industrial-grade PICs from this era; newer Flash PICs are more reliably lead-free. AEC-Q100 not qualified - select PIC16F or PIC18 AEC-Q100 parts for automotive designs. Microchip is a member of the Responsible Minerals Initiative (RMI), indicating conflict-minerals compliance.
