PIC16C74AT-04/PT - 8-bit MCU 7KB OTP 33 I/O 4MHz TQFP44 | Microchip
MPN: PIC16C74AT-04/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.55 | $85.50 |
| 100 | $7.65 | $765.00 |
| 500 | $6.8 | $3,400.00 |
| 1,000 | $6.05 | $6,050.00 |
PIC16C74AT-04/PT Overview
A microcontroller (MCU) is a single-chip computer containing a processor core, program memory, working RAM, and integrated peripherals. Microcontrollers sit within the broader hierarchy of: microcontroller -> embedded processor -> semiconductor IC. The PIC16C74A belongs to the PIC16 mid-range family, which uses a 14-bit instruction word and a Harvard memory architecture that separates program and data buses for deterministic execution. OTP and EPROM-based PIC16C devices were the predecessors of today's flash-based PIC16F parts, and they remain in use for legacy industrial and embedded designs where the program code is finalized in production.
Key differentiating features of the PIC16C74AT-04/PT include its integrated 8-channel 8-bit ADC, dual-capture/compare/PWM modules with a 16-bit timer, and the MSSP peripheral that supports both SPI and I2C communication. The 33 I/O pins are organized across five ports (PORTA through PORTE), providing flexible mixed-signal interfacing. The 4 MHz maximum oscillator frequency is appropriate for cost-sensitive and low-power applications that do not require higher computational throughput. The TQFP-44 package with 0.80 mm pitch allows reflow soldering on standard SMT lines.
Architecturally, the PIC16C74A uses an enhanced mid-range core with a hardware multiplier, an 8-level deep stack, and interrupt-driven I/O. Its EPROM program memory is one-time-programmable via a UV-erasable windowless package, allowing rapid prototyping with production-cost OTP units. The integrated brown-out detect and power-on reset reduce external component count, while the watchdog timer with on-chip RC oscillator improves field reliability.
Typical applications include industrial control logic, automotive body electronics, sensor interfaces, low-end motor control, simple human-machine interfaces, and embedded data acquisition systems. The 8-bit ADC and serial peripherals suit battery chargers, HVAC controllers, and appliance controllers. Engineers commonly deploy the PIC16C74A where code stability, long-life production parts, and proven toolchains outweigh the need for higher-speed modern cores.
When designing with this part, allocate the OTP programming step into the production flow: PIC16C OTP cannot be erased in-circuit. The MSSP peripheral requires careful pin remapping for SPI versus I2C modes, and the ADC reference selection (VDD or external) must be set in software before the first conversion. Pin-compatible flash-based PIC16F74A parts exist for prototyping.
This page synthesizes distributor stock, parametric alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C74AT-04/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 PIC16C74AT-04/PT (same form factor and footprint) — differing in Package, ADC, Core Architecture, Operating Temperature Range, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04I/PT
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC16C74A-04I/P
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74A-04/PQ
✅ Drop-In✓ In Stock
$5.8 / Unit
View Datasheet →PIC16C74A-20I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74A-20E/PQ
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →PIC16C67-04/PT
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C74AT-04/PT Maximum Ratings & Electrical Characteristics
| Core | PIC16 mid-range 8-bit RISC |
| Program Memory Type | EPROM (OTP) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 192 bytes |
| Number of I/O Pins | 33 |
| Maximum Clock Frequency | 4 MHz |
| Supply Voltage (Vcc/Vdd) | 4 V to 6 V |
| ADC | 8-channel, 8-bit |
| Timers | Two 8-bit + one 16-bit (with CCP) |
| Serial Interfaces | USART + MSSP (SPI/I2C) |
| Package | 44-pin TQFP (PT) |
| Mounting Type | Surface Mount |
| RoHS Status | ROHS3 Compliant (per ics-embedded listing) |
PIC16C74AT-04/PT Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | OSC1/CLKIN — Oscillator crystal input / external clock |
| Pin 3 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 4 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 5 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 6 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / ADC VREF- |
| Pin 7 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC VREF+ |
| 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 |
| 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 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / clock input |
| Pin 21 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 22 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| Pin 23 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 24 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 25 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 26 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 27 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 28 | VSS — Ground |
| Pin 29 | VDD — Positive supply voltage |
| Pin 30 | RD0/PSP0 — PORTD bit 0 / parallel slave port |
| Pin 31 | RD1/PSP1 — PORTD bit 1 / parallel slave port |
| Pin 32 | RD2/PSP2 — PORTD bit 2 / parallel slave port |
| Pin 33 | RD3/PSP3 — PORTD bit 3 / parallel slave port |
| Pin 34 | RD4/PSP4 — PORTD bit 4 / parallel slave port |
| Pin 35 | RD5/PSP5 — PORTD bit 5 / parallel slave port |
| Pin 36 | RD6/PSP6 — PORTD bit 6 / parallel slave port |
| Pin 37 | RD7/PSP7 — PORTD bit 7 / parallel slave port |
| Pin 38 | VSS — Ground |
| Pin 39 | VDD — Positive supply voltage |
| Pin 40 | RE0/RD/AN5 — PORTE bit 0 / read control / analog input 5 |
| Pin 41 | RE1/WR/AN6 — PORTE bit 1 / write control / analog input 6 |
| Pin 42 | RE2/CS/AN7 — PORTE bit 2 / chip select / analog input 7 |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C74AT-04/PT is suitable for 6 applications: Industrial Control Logic, Automotive Body Electronics, HVAC and Appliance Controllers, Sensor Interface and Data Acquisition, Low-End Motor Control, Human-Machine Interface (HMI) Panels.
Industrial Control Logic
The PIC16C74AT-04/PT fits industrial control logic because its 33 I/O pins drive relays, solenoids, and indicator LEDs directly through current-limited ports. The 7 KB OTP memory holds typical ladder-logic-equivalent C or assembly code for PLC-style sequencing, while the 8-channel 8-bit ADC reads 4-20 mA loop sensors through external current-sense resistors. At 4 MHz the core executes 1 MIPS, sufficient for state-machine control loops under 1 ms. The integrated watchdog timer improves field reliability, and the 4 V to 6 V supply range accommodates 5 V industrial rails. Designers prefer the OTP variant in mature production lines where firmware changes are undesired.
Recommended
Automotive Body Electronics
The PIC16C74AT-04/PT is deployed in automotive body modules controlling window lifts, mirror adjustments, seat position, and interior lighting. Its 8-bit ADC reads potentiometer positions from seat-track sensors, while the PWM channels drive DC motors through H-bridge drivers like the MCP1755. The PIC16C74A-04I/PT industrial temperature variant operates from -40 C to +85 C under-hood, sufficient for cabin modules. The OTP memory prevents unauthorized firmware modification and matches automotive production volumes where code stability is paramount. The MSSP peripheral interfaces with SPI-controlled LED drivers for ambient lighting networks.
Recommended
HVAC and Appliance Controllers
The PIC16C74AT-04/PT is widely used in HVAC thermostats, washing machine controllers, and refrigerator control boards. Its 8-channel ADC monitors temperature sensors (NTC thermistors via resistor divider), humidity sensors, and pressure switches. The 16-bit timer with capture/compare drives TRIAC phase-angle control for heater elements. The PIC16C74A's 4 MHz clock provides sufficient MIPS for PID temperature loops at 100 ms update rates. The integrated USART connects to remote control panels or wireless modules like the MRF24J40, while the MSSP reads digital temperature sensors via I2C.
Recommended
Sensor Interface and Data Acquisition
The PIC16C74AT-04/PT serves as a low-cost data acquisition front-end for environmental monitoring and process sensor hubs. The 8-channel 8-bit ADC samples multiple sensors at up to 30 kS/s aggregate throughput when the A/D clock is properly derived. The MSSP reads I2C sensor chains (e.g., pressure sensors like the MPL115A2), while the USART forwards aggregated data to a host controller or wireless module. The OTP memory prevents firmware tampering in unattended field installations. Brown's-out detect protects against sensor data corruption during supply dips, a common issue in solar-powered remote monitoring.
Recommended
Low-End Motor Control
The PIC16C74AT-04/PT handles BLDC, stepper, and brushed DC motor control in low-power applications like small pumps and fans. The 16-bit timer with PWM generates switching frequencies up to 20 kHz at 8-bit resolution or 10 kHz at 10-bit resolution, sufficient for sensorless BLDC using back-EMF zero-crossing detection. The 8-bit ADC reads back-EMF voltages through resistor dividers. OTP memory locks the firmware against unauthorized tuning of motor control parameters, which is valuable in OEM motor integration. The PIC16C74A-04I/PT industrial temp variant suits underhood motor installations.
Recommended
Human-Machine Interface (HMI) Panels
The PIC16C74AT-04/PT drives simple HMI panels with LED indicators, 7-segment displays, and matrix keypads in industrial equipment and consumer appliances. The 33 I/O pins directly drive up to 32 LEDs in a 4x8 matrix without external drivers, while the MSSP connects to LED driver ICs like the MCP23S17 for larger displays. The USART interfaces with character LCD modules or external graphics controllers. OTP memory prevents end-users from modifying behavior, which is critical in medical and regulatory equipment. The 4 MHz clock suffices for slow display refresh and key debounce routines.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74AT-04/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04I/PT | PIC16C74A-04I/P | PIC16C74A-04/PQ | PIC16C74A-20I/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | TQFP-44 (PT) | TQFP-44 (PT) - same | TQFP-44 (PT) - same | TQFP-44 (PT) - same | TQFP-44 (PT) - same |
| Program Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM |
| Program Memory Size | 7 KB | 7 KB | 7 KB | 7 KB | 7 KB |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| RAM Size | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes |
| Number of I/O Pins | 33 | 33 | 33 | 33 | 33 |
| RoHS Status | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant |
Key Differentiators
- Wide 4V to 6V supply tolerance with brown-out detect (vs PIC16C74A-04/PQ)
- Standardized industrial 4 MHz operation for low-power designs (vs PIC16C74A-20I/PT)
- Tape-and-reel packaging optimized for SMT production lines (vs PIC16C74A-04I/P)
Design Notes
Decoupling: place a 100 nF ceramic capacitor within 5 mm of each VDD/VSS pin pair (the TQFP-44 has multiple VDD pins: 11, 29, 39). Add a 10 uF bulk tantalum or ceramic at the board entry point. The PIC16C74A's analog and digital sections share VDD - high-frequency digital noise can couple into the ADC; separate analog VDD with a ferrite bead if ADC accuracy is critical.
Crystal placement: keep the 4 MHz crystal or resonator within 10 mm of OSC1 (pin 2) and OSC2 (pin 3). Use short traces, guard the crystal with a ground ring, and avoid routing digital signals under the crystal traces. For noisy environments, use a four-pin through-hole resonator with internal capacitors instead of a two-pin crystal with external capacitors.
OTP programming limitation: PIC16C74A OTP memory cannot be erased in-circuit. Once programmed, the part is locked to its firmware. For prototyping, use the PIC16F74A-I/PT (pin-compatible flash equivalent) or use a windowed ceramic DIP version for UV erasure. The /PT suffix denotes TQFP tape-and-reel packaging; engineering samples often ship in different packaging.
ICSP programming: pins RB6/PGC and RB7/PGD are used for In-Circuit Serial Programming. Add 4.7 kohm pull-up resistors on RB6/RB7 to keep them stable during run-mode, and ensure the ICSP connector does not load these lines during programming. The MCLR/VPP pin requires a 10 kohm pull-up to VDD and a diode to VDD for proper reset behavior during ICSP.
Compliance Information
ROHS3 compliant per ics-embedded listing. REACH SVHC declarations available from Microchip. Not AEC-Q100 qualified; for automotive safety-critical applications use AEC-Q100-qualified PIC16F variants. Lead-free SnAgCu terminations since 2006.