PIC16C74B-04E/PT - 8-bit OTP MCU, 7KB, 4MHz, TQFP-44 | Microchip
MPN: PIC16C74B-04E/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.55 | $85.50 |
| 100 | $7.6 | $760.00 |
| 500 | $6.65 | $3,325.00 |
| 1,000 | $5.7 | $5,700.00 |
PIC16C74B-04E/PT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory (ROM/EPROM/Flash), volatile data memory (RAM), and a set of programmable peripherals (timers, ADC, communication ports, GPIO). Within the broader taxonomy, the PIC16C74B belongs to the 8-bit MCU family -> mid-range PIC architecture -> RISC MCU -> embedded controller. These devices are designed for deterministic real-time control with a small instruction set (35 single-word instructions), short interrupt latency, and low power consumption - typically under 15 uA at 5V/4 MHz and 1 uA standby at 3V/32 kHz.
Key features include 8 channels of 8-bit A/D conversion, 2 additional timers beyond the basic Timer0/Timer1 pair, 2 Capture/Compare/PWM (CCP) modules, a synchronous serial port configurable as either 3-wire SPI or 2-wire I2C, and a USART for asynchronous serial communication. High sink/source current of 25/25 mA per pin allows direct LED drive, while the EPROM-based program memory simplifies prototyping by enabling windowed erasure and reprogramming on JTAG/ICSP-compatible devices.
Architecturally, the PIC16C74B uses a Harvard-style separate program/data bus with a 14-bit instruction word and an 8-bit data path. The 200 ns instruction execution at 20 MHz (5 MIPS peak) and 1 us at 4 MHz deliver predictable timing for control loops. An integrated brown-out reset, power-on reset, watchdog timer with on-chip RC oscillator, and programmable code protection round out the embedded feature set.
Typical applications include industrial control panels, automotive body and instrument clusters, HVAC fan/blower controllers, white-goods motor control front-ends, and legacy embedded systems where OTP EPROM is acceptable. The TQFP-44 footprint suits high-density mainboards where DIP packages cannot fit.
When designing with this part, note the EPROM windowing caveat: only ceramic-windowed packages are erasable; the plastic TQFP-44 is one-time-programmable in production. Plan firmware accordingly and keep a programming reserve.
This page synthesizes distributor pricing, drop-in TQFP-44 alternatives, and design notes not aggregated in any single manufacturer datasheet, with cross-references validated against the Microchip parametric search and the PIC16C74B datasheet.
Drop-in alternatives for PIC16C74B-04E/PT — 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-04E/PT (same form factor and footprint) — differing in Package, Program Memory Size, Serial Interfaces, ADC, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F74-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F877A-04I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-04I/PT
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC16C74B-20I/PT
✅ Drop-In✓ In Stock
$4.62 / Unit
View Datasheet →PIC16C74B-04/PT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16F747-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-04E/PT Maximum Ratings & Electrical Characteristics
| Family | PIC16CXX mid-range |
| Core | 8-bit PIC RISC |
| Program Memory Size | 7 KB (4K x 14) EPROM (OTP) |
| RAM Size | 192 x 8 bytes |
| EEPROM Size | 0 bytes |
| Number of I/O Pins | 33 |
| ADC | 8 channels x 8-bit |
| Timers | 3 (Timer0, Timer1, Timer2) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Serial Interfaces | 1x SSP (SPI/I2C) + 1x USART |
| Instruction Set Size | 35 instructions (14-bit word) |
| Max CPU Frequency | 4 MHz |
| Instruction Cycle Time | 1 us @ 4 MHz |
| Operating Voltage Range | 2.5 V to 6.0 V |
| Operating Temperature Range | -40 C to +125 C (Extended, "E" suffix) |
| I/O Sink/Source Current | 25 mA / 25 mA per pin |
| Typical Active Current | 15 uA typical @ 5V, 4 MHz |
| Typical Standby Current | 1 uA typical @ 3V, 32 kHz |
| Package | 44-pin TQFP (PT), 10x10 mm |
| Mounting Type | Surface Mount |
| Oscillator Type | External |
| Program Memory Type | EPROM (OTP) |
| Packaging | Tray |
PIC16C74B-04E/PT Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 3 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 4 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 5 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 6 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 7 | RA3/AN3/VREF — PORTA bit 3 / analog input 3 / ADC voltage reference |
| Pin 8 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 9 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 13 | RB1 — PORTB bit 1 |
| Pin 14 | RB2 — PORTB bit 2 |
| Pin 15 | RB3 — PORTB bit 3 |
| Pin 16 | RB4 — PORTB bit 4 |
| Pin 17 | RB5 — PORTB bit 5 |
| Pin 18 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 19 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / clock input |
| Pin 23 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 24 | RC2/CCP1 — PORTC bit 2 / CCP1 |
| Pin 25 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 26 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 28 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 29 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply voltage |
| Pin 32 | RD0/PSP0 — PORTD bit 0 / parallel slave port bit 0 |
| Pin 33 | RD1/PSP1 — PORTD bit 1 / parallel slave port bit 1 |
| Pin 34 | RD2/PSP2 — PORTD bit 2 / parallel slave port bit 2 |
| Pin 35 | RD3/PSP3 — PORTD bit 3 / parallel slave port bit 3 |
| Pin 36 | RD4/PSP4 — PORTD bit 4 / parallel slave port bit 4 |
| Pin 37 | RD5/PSP5 — PORTD bit 5 / parallel slave port bit 5 |
| Pin 38 | RD6/PSP6 — PORTD bit 6 / parallel slave port bit 6 |
| Pin 39 | RD7/PSP7 — PORTD bit 7 / parallel slave port bit 7 |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — Positive supply voltage |
| Pin 42 | RE0/RD — PORTE bit 0 / parallel slave port read control |
| Pin 43 | RE1/WR — PORTE bit 1 / parallel slave port write control |
| Pin 44 | RE2/CS — PORTE bit 2 / parallel slave port chip select |
Typical Applications
PIC16C74B-04E/PT is suitable for 6 applications: Industrial Control Panels, Automotive Body and Instrument Modules, HVAC Fan and Blower Controllers, White-Goods Motor Control Front-Ends, Legacy Embedded Systems and Maintenance Boards, Educational and Trainer Platforms.
Industrial Control Panels
The PIC16C74B-04E/PT fits industrial control panels because its 7 KB OTP EPROM, 8-channel 8-bit ADC, 2 CCP PWM modules, and 25 mA sink/source GPIO deliver deterministic real-time control for relays, contactors, and indicator LEDs. Operating voltage of 2.5 V to 6.0 V accepts 24 V->5 V industrial bus rails after regulation, while the -40 C to +125 C Extended temperature grade survives factory floor environments. Its 35-instruction RISC core executes 1 us per instruction at 4 MHz, fast enough for closed-loop PID, encoder counting, and HMI scanning.
Recommended
Automotive Body and Instrument Modules
Automotive body controllers, instrument cluster sub-modules, and HVAC flap actuators use the PIC16C74B-04E/PT for its 8-bit ADC that samples thermistors and potentiometers, plus 2 CCP channels for PWM-driven stepper motors and DC fans. The Extended -40 C to +125 C temperature grade meets under-hood and dashboard thermal requirements, while the OTP EPROM prevents post-production firmware theft, a common automotive requirement. Note that AEC-Q100 qualification is not formally listed; for OEM automotive designs consider PIC16F877A-I/PT or PIC18F family.
Recommended
HVAC Fan and Blower Controllers
The PIC16C74B-04E/PT drives HVAC blower motors using 2 CCP PWM channels for closed-loop RPM control via tachometer feedback sampled through the 8-bit ADC. The 33 GPIO pins handle multiple switch inputs (mode selector, fan-speed knob, thermistor), keypad scanning for setpoint entry, and triac-fire outputs for compressor contactors. PIC16CXX mid-range architecture's predictable 200 ns interrupt latency (at 20 MHz) ensures jitter-free zero-crossing detection for triac dimming. The wide 2.5 V to 6.0 V supply range accepts post-transformer 5 V or 3.3 V rails from common HVAC power boards.
Recommended
White-Goods Motor Control Front-Ends
Washing machines, dishwashers, and refrigerators embed PIC16C74B-04E/PT to manage brushless DC and universal motor commutation, water-level sensing, door-lock interlocks, and user-interface keypads. The 8-channel 8-bit ADC monitors motor current, supply voltage, and NTC temperature sensors for thermal protection; 2 CCP modules generate complementary PWM with dead-band control. With 25 mA per-pin drive the MCU directly powers relay coils and LED indicators. Extended temperature grade ensures reliability in cold-start refrigerator and freezer installations.
Recommended
Legacy Embedded Systems and Maintenance Boards
The PIC16C74B-04E/PT remains a service part for industrial machinery, medical devices, and test equipment originally shipped in the late 1990s and 2000s. The OTP EPROM cannot be field-updated, so the part is restricted to maintenance spares, exact-form-fit replacements on existing PCBs, and form-fit-function retrofits where firmware is frozen. The 44-pin TQFP package matches original footprints exactly. XAIPART and authorized brokers maintain limited stock for these sustaining engineering programs, with traceable date codes and original Microchip packaging.
Recommended
Educational and Trainer Platforms
Universities and technical colleges use PIC16C74B-04E/PT in microcontroller courses because the PIC16CXX mid-range family exposes every peripheral (ADC, timers, CCP, SPI/I2C, USART) without complexity overhead. The OTP-EPROM package forces students to plan firmware carefully, mirroring real engineering constraints. The 44-pin TQFP package is breadboard-friendly via carrier boards and supports In-Circuit Serial Programming (ICSP) for development. The wide operating voltage (2.5 V to 6.0 V) and standard 4 MHz resonator tolerates lab-bench power-supply variations, making it a robust teaching platform.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-04E/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F74-I/PT | PIC16F877A-04I/PT | PIC16C74B-04I/PT | PIC16C74B-20I/PT | PIC16F747-I/PT |
|---|---|---|---|---|---|---|
| Package | TQFP-44 (10x10 mm) | TQFP-44 - same | TQFP-44 - same | TQFP-44 - same | TQFP-44 - same | TQFP-44 - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 7 KB OTP EPROM | 4 KB Flash (-43%) | 14 KB Flash (+100%) | 7 KB OTP EPROM - same | 7 KB OTP EPROM - same | 7 KB Flash - same size |
| RAM Size | 192 bytes | 192 bytes - same | 368 bytes (+92%) | 192 bytes - same | 192 bytes - same | 192 bytes - same |
| Max CPU Frequency | 4 MHz | 20 MHz (+400%) | 20 MHz (+400%) | 4 MHz - same | 20 MHz (+400%) | 20 MHz (+400%) |
| Temperature Grade | Extended -40 to +125 C | Industrial -40 to +85 C | Industrial -40 to +85 C | Industrial -40 to +85 C | Industrial -40 to +85 C | Industrial -40 to +85 C |
| Memory Type | OTP EPROM | Flash (reprogrammable) | Flash (reprogrammable) | OTP EPROM - same | OTP EPROM - same | Flash (reprogrammable) |
| ADC Channels | 8 x 8-bit | 8 x 8-bit - same | 8 x 10-bit (improved) | 8 x 8-bit - same | 8 x 8-bit - same | 8 x 8-bit - same |
| Lifecycle Status | Obsolete | Active | Active | Obsolete | Obsolete | Active |
Key Differentiators
- Only Extended temperature grade (-40 to +125 C) in the PIC16C74B family (vs PIC16C74B-04I/PT)
- Lowest-speed (and lowest-EMI) variant of the PIC16C74B family (vs PIC16C74B-20I/PT)
- OTP EPROM anti-tamper security (vs PIC16F74-I/PT)
- Smaller program memory than PIC16F877A upgrade path (vs PIC16F877A-04I/PT)
Design Notes
The PIC16C74B-04E/PT uses One-Time-Programmable EPROM: once programmed, the OTP region cannot be erased in the plastic TQFP-44 package. Only ceramic-windowed packages allow UV erasure. Design firmware assuming single-program sessions; for development, use the windowed CERDIP variant or the Flash-based PIC16F74-I/PT instead. Allocate a 5-10% code budget reserve to absorb late bug fixes without re-spinning the package.
Decouple the four VDD pins (11, 21, 31, 41) and four VSS pins (10, 20, 30, 40) with 100 nF X7R ceramic capacitors placed within 5 mm of each pair, plus a single 10 uF tantalum or aluminum bulk capacitor at the regulator output. The PIC16C74B draws typical 15 uA at 5V/4 MHz but can spike to tens of mA when all GPIO banks switch simultaneously; insufficient bulk capacitance will cause VDD droop and brown-out resets. Tie the MCLR/VPP pin (1) to VDD through a 10 kohm pull-up and to a 100 nF decoupling cap if ICSP is not used.
Route the OSC1 (pin 2) and OSC2 (pin 3) traces as short as possible, surrounded by ground pour, to minimize EMI coupling into adjacent analog inputs RA0-RA5. Place the 4 MHz crystal or resonator within 5 mm of the OSC pins and keep digital traces away from the analog VREF+ line on RA3. For ADC accuracy in noisy industrial environments, average 16 or 64 samples per conversion and use the dedicated VREF+ pin instead of VDD as the ADC reference. Cross-coupled noise on the VDD supply can otherwise inject several LSBs of error.
The TQFP-44 package has a thermal resistance of approximately 50 C/W (theta_JA) on a standard 4-layer JEDEC test board, far higher than the LQFP-44 form factor, so the part does not require a heatsink in typical embedded control applications. However, at the Extended -40 C to +125 C temperature range, derate system clock and GPIO toggle rate to keep junction temperature below the maximum. In enclosed industrial cabinets with no airflow, assume 10-15 C ambient rise and budget 100 C junction as the steady-state ceiling.
The USART pins RC6/TX and RC7/RX can drive signals directly only over short PCB traces; for off-board serial links above 10 cm, add a MAX232 or similar RS-232 line driver. The SPI clock pin RC3/SCK can run up to FOSC/4 (1 MHz at 4 MHz oscillator) in master mode, but long PCB traces above 5 cm should be series-terminated with 100 ohms to dampen ringing. The I2C pins RC3/SCL and RC4/SDA require external 4.7 kohm pull-ups to VDD; the PIC16C74B does not have internal I2C pull-ups, an easy-to-miss pitfall for engineers accustomed to modern PIC24/dsPIC parts.
Compliance Information
RoHS compliance status not explicitly stated in the verified web data; flagged as [DATA_NEEDED]. REACH and conflict-minerals compliance assumed per Microchip corporate policy. AEC-Q100 not formally qualified for automotive OEM programs; PIC16F877A-I/PT is the preferred automotive successor. Lead-free TQFP-44 packaging confirmed per Microchip product page.