PIC16C74AT-04I/L - 8-Bit 4MHz OTP MCU 7KB 33 I/O | Microchip
MPN: PIC16C74AT-04I/L ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $15.03 | $15.03 |
| 10 | $13.5 | $135.00 |
| 100 | $11.95 | $1,195.00 |
| 500 | $10.65 | $5,325.00 |
| 1,000 | $9.45 | $9,450.00 |
PIC16C74AT-04I/L Overview
What is a PIC16C 8-bit microcontroller? The PIC16C family is Microchip's mid-range 8-bit MCU architecture that uses a Harvard-style separate program/data bus, a RISC instruction set, and integrated peripherals such as A/D converters. PIC16C sits in the hierarchy: PIC16C -> PIC16 mid-range -> 8-bit MCU -> microcontroller -> semiconductor. OTP (One-Time-Programmable) variants are programmed once at production time and are typically used where code stability, low unit cost, and short programming lead times outweigh the need for in-field re-programmability.
Key features of the PIC16C74AT-04I/L include 35 single-word instructions (most executing in a single instruction cycle except branches which take two cycles), an integrated 8-channel 8-bit A/D converter, three timer modules, a synchronous/asynchronous serial port (SSP) and a Universal Synchronous Asynchronous Receiver Transmitter (USART) for multi-protocol serial communication. The device operates from a 4V to 5.5V supply rail and provides 22 high-current I/O ports capable of directly driving LEDs and small relays.
Architecturally, the PIC16C74A uses a 14-bit-wide program word and an 8-bit data path, with a hardware multiplier-free ALU optimized for low cost. The fully-static CMOS core eliminates the need for a minimum clock, allowing the MCU to be clocked down to DC for power-sensitive applications. Power-on reset, brown-out detection, watchdog timer with on-chip RC oscillator, and code protection fuses provide field-deployment robustness.
Typical applications include industrial control logic boards, automotive body and chassis subsystems, appliance controllers, sensor interface front-ends, and embedded control modules where deterministic interrupt latency and proven long-term supply are critical. The PIC16C74AT-04I/L is shipped in Tape & Reel (T/R) form factor and is well suited for medium-volume production runs that require Microchip's classic mid-range toolchain (MPLAB IDE, MPASM assembler, ICD in-circuit debugging).
When designing with this part, remember that OTP memory cannot be re-programmed, so production firmware must be fully validated before programming. Consider the PIC16F74 flash-based variant for prototyping and low-volume runs; consider the PIC16C74B-04I/L for enhanced silicon revisions while keeping the same 44-PLCC footprint. All variants share the same instruction set and pinout for drop-in compatibility.
This page synthesizes distributor pricing, drop-in alternatives, parametric comparisons, and practical design notes not found in any single manufacturer or distributor listing - giving engineers a one-stop reference for the PIC16C74AT-04I/L.
Drop-in alternatives for PIC16C74AT-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 PIC16C74AT-04I/L (same form factor and footprint) — differing in Package, Core Architecture, Mounting Type, Program Memory Type, Data EEPROM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04I/L
✅ Drop-In✓ In Stock
$2.61 / Unit
View Datasheet →PIC16C74A-04I/L
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74A-10I/L
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC16C74A-20I/L
✅ Drop-In✓ In Stock
$8.75 / Unit
View Datasheet →PIC16F74-I/L
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74AT-04/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74A-04I/P
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74AT-04I/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C mid-range 8-bit RISC |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 192 bytes |
| Maximum CPU Clock | 4 MHz |
| Supply Voltage (Vdd) | 4 V to 5.5 V |
| I/O Pins | 33 |
| High-Current I/O Ports | 22 |
| A/D Converter | 8 channels x 8-bit |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Serial Interfaces | SSP (SPI/I2C) + USART (SCI) |
| Instruction Set | 35 single-word instructions, 14-bit wide |
| Instruction Cycle | Single cycle (branches 2 cycles) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 44-pin PLCC (16.59 mm x 16.59 mm) |
| Mounting Type | Surface Mount |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Brown-out Reset | Yes |
| Power-on Reset | Yes |
| Code Protection | Yes (fuse programmable) |
| Packaging | Tape & Reel (T/R) |
PIC16C74AT-04I/L Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / Analog input channel 2 |
| Pin 4 | RA3/AN3/VREF — PORTA bit 3 / Analog input 3 / A/D VREF |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| Pin 6 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 7 | OSC1/CLKIN — Crystal oscillator input / external clock in |
| Pin 8 | OSC2/CLKOUT — Crystal oscillator output / clock out (Fosc/4) |
| Pin 9 | MCLR/Vpp — Master clear reset (active low) / programming voltage |
| Pin 10 | Vss — Ground reference |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator in / CCP2 module |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 (Capture/Compare/PWM) |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 19 | Vss — Ground reference |
| Pin 20 | Vdd — Positive supply (4V-5.5V) |
| Pin 21 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 22 | RB1 — PORTB bit 1 |
| Pin 23 | RB2 — PORTB bit 2 |
| Pin 24 | RB3 — PORTB bit 3 |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / In-circuit debugger clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / In-circuit debugger data |
| Pin 29 | RD0 — PORTD bit 0 |
| Pin 30 | RD1 — PORTD bit 1 |
| Pin 31 | RD2 — PORTD bit 2 |
| Pin 32 | RD3 — PORTD bit 3 |
| Pin 33 | RD4 — PORTD bit 4 |
| Pin 34 | RD5 — PORTD bit 5 |
| Pin 35 | RD6 — PORTD bit 6 |
| Pin 36 | RD7 — PORTD bit 7 |
| Pin 37 | RE0/RD — PORTE bit 0 / Read control for parallel slave port |
| Pin 38 | RE1/WR — PORTE bit 1 / Write control for parallel slave port |
| Pin 39 | RE2/CS — PORTE bit 2 / Chip select for parallel slave port |
| Pin 40 | Vdd — Positive supply (4V-5.5V) |
| Pin 41 | Vss — Ground reference |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C74AT-04I/L is suitable for 6 applications: Industrial Control Logic Boards, Automotive Body and Chassis ECUs, Appliance Control Modules, Sensor Interface Front-Ends, Embedded Control Modules with LED Display, Educational and Hobby Embedded Platforms.
Industrial Control Logic Boards
The PIC16C74AT-04I/L fits industrial control logic boards because its 33 I/O pins can directly drive relays, solenoids, and indicator LEDs while the 8-channel 8-bit A/D converter reads multiple analog sensors (temperature, pressure, flow) simultaneously. The 4 MHz CPU clock and 35-instruction RISC core deliver deterministic interrupt latency, which is essential for closed-loop PID control. Industrial 4V-5.5V supply compatibility and -40C to +85C operation allow deployment in factory-floor enclosures without additional conditioning. The brown-out reset and watchdog timer with on-chip RC oscillator provide field-deployment robustness against supply transients common in motor-drive cabinets. OTP programming secures the firmware against accidental in-field rewrite, which is desirable for certified industrial equipment.
Recommended
Automotive Body and Chassis ECUs
The PIC16C74AT-04I/L is well suited to automotive body and chassis ECUs (seat controllers, mirror modules, lighting drivers) because of its 5V operation tolerant of 12V-bus transients when paired with a TVS-protected supply, and its -40C to +85C industrial temperature range covering cabin and under-hood near-engine environments. The 33 digital I/O lines handle multiple low-side and high-side driver interfaces, while the 8-channel A/D monitors analog switches and potentiometers. The PIC16C74AT-04I/L's OTP memory prevents unauthorized firmware modification, important for OEM-controlled modules. For safety-critical systems choose the AEC-Q100-qualified PIC16F variant instead, but for non-safety body modules the C74A provides decades-proven reliability at low cost.
Recommended
Appliance Control Modules
The PIC16C74AT-04I/L integrates all peripherals required for white-goods appliance controllers: 33 I/O for keypad scanning, relay drivers, and seven-segment LED multiplexing, plus an 8-channel A/D for NTC temperature sensors, water-level probes, and motor current monitoring. The 4 MHz instruction rate gives a 250 ns instruction cycle, sufficient for real-time control loops running at 1 kHz update rates in washing machines, dishwashers, and HVAC blowers. The 4-5.5V supply rails accept standard 5V regulator outputs. The OTP memory locks in UL/CE-certified firmware revisions, eliminating field firmware drift that could compromise safety certifications across appliance product families.
Recommended
Sensor Interface Front-Ends
The PIC16C74AT-04I/L serves as a multi-sensor front-end controller where its 8-channel 8-bit A/D converter reads analog sensors (thermistors, photocells, strain gauges) and its SSP/USART serial interfaces forward the digitized data to a host processor. With 192 bytes of RAM the MCU can buffer multi-channel sample sets, perform moving-average filtering, and respond to host queries over SPI or RS-232 without external logic. The 4 MHz CPU is sufficient for low-rate environmental monitoring (1-100 Hz sample rates) typical of building automation and HVAC sensor networks. The small 44-PLCC footprint fits into compact sensor hub boards.
Recommended
Embedded Control Modules with LED Display
The PIC16C74AT-04I/L drives multiplexed LED displays and seven-segment readouts directly through its high-current I/O ports (up to 25 mA per pin on PORB), eliminating external driver transistors for small displays. The 22 high-current I/O lines comfortably handle 8-digit seven-segment plus 8-key matrix keypads. The 4 MHz instruction rate executes display-refresh loops at kilohertz rates with zero visible flicker. The integrated brown-out reset prevents display corruption during brown-out events. This combination makes the PIC16C74AT-04I/L an excellent fit for user-interface panels in vending machines, point-of-sale terminals, and instrument front panels.
Recommended
Educational and Hobby Embedded Platforms
The PIC16C74AT-04I/L is widely used in university embedded systems courses and hobby projects because the 35-instruction RISC core is teachable in a single semester, the PIC16C7X family has 30+ years of stable documentation, and Microchip's MPLAB IDE with MPASM assembler is freely available. The 44-PLCC package is breadboard-friendly via PLCC-to-DIP adapters. The 7 KB OTP memory supports substantial student projects including motor controllers, PID loops, and serial-protocol implementations. The 33 I/O pins interface directly with common educational peripherals: 7-segment displays, keypads, servo motors, character LCDs, and EEPROM memories, providing a complete hands-on learning platform.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74AT-04I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04I/L | PIC16C74A-10I/L | PIC16C74A-20I/L | PIC16F74-I/L |
|---|---|---|---|---|---|
| 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 | 44-pin PLCC - same |
| Max CPU Clock | 4 MHz | 4 MHz | 10 MHz | 20 MHz | 4 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB Flash |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| A/D Converter | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
Key Differentiators
- 44-PLCC package gives 33 I/O and 8 A/D channels in mid-range family (vs PIC16C73B-04I/SP)
- OTP memory prevents accidental in-field firmware modification (vs PIC16F74-I/L)
- Industrial -40C to +85C temperature range at the 04 MHz speed grade (vs PIC16C74AT-04/L (commercial))
Design Notes
PIC16C74AT-04I/L uses One-Time-Programmable memory - once a bit is programmed to '0' it cannot be reset to '1'. Verify your firmware image (HEX file) exhaustively with MPLAB SIM and ICD hardware debug before committing to OTP programming, because OTP rejects are unrecoverable and incur full per-unit programming cost. Always keep one PIC16F74-I/L or PIC16C74B-04I/L socketed alongside the production line for code verification prior to OTP programming.
Power the PIC16C74AT-04I/L from a 5V +/-10% regulated rail (4.0V-5.5V) with decoupling capacitors: place one 100 nF ceramic within 5 mm of each Vdd/Vss pair (the part has multiple Vdd pins at 20 and 40 plus multiple Vss pins at 10, 19, and 41). For high-noise industrial environments, add a 10 uF bulk capacitor and a series ferrite bead on the supply input to suppress conducted transients. The brown-out reset is factory-trimmed to ~4.0V; if your rail droops near this threshold, external supervisory reset (e.g., MCP100) is recommended.
Keep the 4 MHz crystal/oscillator traces short (under 10 mm) and surround them with a ground pour to minimize EMI pickup. The OSC2/CLKOUT pin toggles at Fosc/4 (1 MHz) and can couple noise into nearby analog inputs if traces are routed in parallel - keep at least 5 mm separation between OSC traces and A/D input traces. PORTB pins RB6 and RB7 are shared with the in-circuit debugger (PGC/PGD); ensure your PCB layout leaves access to these pins via a 6-pin ICSP header for production-line programming.
The PIC16C74AT-04I/L in 44-PLCC package dissipates approximately 10 mW typical at 4 MHz and 5V, yielding negligible junction self-heating. The plastic PLCC package is rated for -40C to +85C operation; for continuous operation at 85C ambient, derate the supply voltage to 4.5V or implement clock gating via the Timer1 oscillator to reduce dynamic power. No external heatsink is required at any supported operating point.
Compliance Information
PIC16C legacy OTP family. RoHS/REACH/lead-free status not explicitly stated in the verified distributor data; check Microchip product declaration documents for the latest compliance attestations. Not AEC-Q100 qualified - choose a Q100-grade PIC16F variant for safety-critical automotive designs.
