PIC16C74AT-04/PQ - 8-Bit 4MHz OTP MCU 7KB 44-MQFP | Microchip
MPN: PIC16C74AT-04/PQ ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.85 | $9.85 |
| 10 | $9.1 | $91.00 |
| 100 | $8.25 | $825.00 |
| 250 | $7.8 | $1,950.00 |
| 500 | $7.2 | $3,600.00 |
PIC16C74AT-04/PQ Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (ROM/OTP/Flash), data memory (RAM), and a set of peripheral interfaces on one die. PIC16C-series MCUs sit in Microchip's mid-range architecture hierarchy (PIC10/12/16/18 families), where they supersede the baseline PIC16C5X and are themselves superseded by the PIC18 enhanced 8-bit family. Their position in the broader taxonomy is: 8-bit MCU -> microcontroller -> embedded processor -> semiconductor IC.
Key features of the PIC16C74AT-04/PQ include an 8-channel, 8-bit successive-approximation Analog-to-Digital Converter (ADC), 33 digital I/O lines, and serial connectivity through I2C, SPI, and UART/USART peripherals. The 04 speed grade limits the oscillator input to 4 MHz at 5 V, and the device operates across a 3.0 V to 6.0 V supply range per the PIC16C74A datasheet. The 'T' suffix denotes Tape & Reel packaging, and 'PQ' designates the 44-pin MQFP (10x10 mm) footprint.
Architecturally, the PIC16C74AT-04/PQ uses a Harvard RISC core with separate program and data buses, a 14-bit wide instruction word, and a single accumulator (W register). This simplified architecture, combined with 35 single-word instructions, allows most instructions to execute in a single instruction cycle (4 oscillator clocks), giving roughly 1 MIPS of throughput at 4 MHz - adequate for control-loop, sensor-interface, and human-machine-interface applications.
Typical applications include industrial process control, sensor signal conditioning, embedded control boards, instrumentation front-ends, and legacy consumer-electronics controllers. Engineers use the PIC16C74A family wherever a 5 V, 8-bit mid-range MCU with on-chip ADC and multiple serial ports is needed without paying for a flash-based MCU. Note that OTP memory requires a device programmer and cannot be reprogrammed in-circuit.
When designing with this part, plan for the OTP programming model: code must be verified on a windowed or FLASH prototype part (e.g. PIC16F74A in the same 44-pin QFP) before committing to OTP production units. Always check the latest Microchip product change notifications, as the original PIC16C OTP family has been progressively migrated to PIC16F flash parts over the last decade.
This page synthesizes current distributor pricing, pin-compatible alternatives, and practical design notes - information not collated in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C74AT-04/PQ — 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/PQ (same form factor and footprint) — differing in Core Architecture, Package, Operating Temperature Range, Maximum Clock Frequency, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74A-04/PQ
✅ Drop-In✓ In Stock
$5.8 / Unit
View Datasheet →PIC16C74A-10I/P
✅ Drop-In✓ In Stock
$4.95 / Unit
View Datasheet →PIC16C74A-20I/L
✅ Drop-In✓ In Stock
$8.75 / Unit
View Datasheet →PIC16C74A-04I/P
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74A-20E/PQ
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →PIC16C74A-20/PQ
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC16C74AT-04/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C, 8-bit RISC (Harvard) |
| Instruction Word Width | 14 bits |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 192 bytes |
| Maximum Clock Frequency | 4 MHz (04 speed grade) |
| Supply Voltage Range | 3.0 V to 6.0 V |
| Number of I/O Pins | 33 |
| ADC | 8-channel, 8-bit successive approximation |
| Serial Interfaces | I2C, SPI, UART/USART |
| Timers | 3 (Timer0, Timer1, Timer2) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Watchdog Timer | Yes |
| Brown-out Reset | Yes |
| Package / Case | 44-MQFP (Metric Quad Flat Pack, 10x10 mm) |
| Packaging Format | Tape & Reel (T suffix) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | 0C to +70C (commercial) |
PIC16C74AT-04/PQ Pin Configuration
| Pin 1 | OSC1/CLKIN — Oscillator input or external clock input |
| Pin 2 | OSC2/CLKOUT — Oscillator output or clock output (Fosc/4) |
| Pin 3 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 4 | RA0/AN0 — Port A bit 0 / ADC analog input 0 |
| Pin 5 | RA1/AN1 — Port A bit 1 / ADC analog input 1 |
| Pin 6 | RA2/AN2 — Port A bit 2 / ADC analog input 2 |
| Pin 7 | RA3/AN3/VREF — Port A bit 3 / ADC input 3 / ADC reference voltage |
| Pin 8 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 9 | RA5/AN4/SS — Port A bit 5 / ADC input 4 / SPI slave select |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage (3.0 V to 6.0 V) |
| Pin 12 | RB0/INT — Port B bit 0 / external interrupt input |
| Pin 13 | RB1 — Port B bit 1 |
| Pin 14 | RB2 — Port B bit 2 |
| Pin 15 | RB3/PGM — Port B bit 3 / low-voltage programming input |
| Pin 16 | RB4 — Port B bit 4 |
| Pin 17 | RB5 — Port B bit 5 |
| Pin 18 | RB6/PGC — Port B bit 6 / ICSP clock (programming) |
| Pin 19 | RB7/PGD — Port B bit 7 / ICSP data (programming) |
| Pin 20 | RC0/T1OSO/T1CKI — Port C bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 21 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer1 oscillator input / CCP2 output |
| Pin 22 | RC2/CCP1 — Port C bit 2 / CCP1 output |
| Pin 23 | RC3/SCK/SCL — Port C bit 3 / SPI clock / I2C clock |
| Pin 24 | RC4/SDI/SDA — Port C bit 4 / SPI data in / I2C data |
| Pin 25 | RC5/SDO — Port C bit 5 / SPI data out |
| Pin 26 | RC6/TX/CK — Port C bit 6 / UART transmit / USART clock |
| Pin 27 | RC7/RX/DT — Port C bit 7 / UART receive / USART data |
| Pin 28 | RD0 — Port D bit 0 |
| Pin 29 | RD1 — Port D bit 1 |
| Pin 30 | RD2 — Port D bit 2 |
| Pin 31 | RD3 — Port D bit 3 |
| Pin 32 | RD4 — Port D bit 4 |
| Pin 33 | RD5 — Port D bit 5 |
| Pin 34 | RD6 — Port D bit 6 |
| Pin 35 | RD7 — Port D bit 7 |
| Pin 36 | RE0/RD/AN5 — Port E bit 0 / read control / ADC input 5 |
| Pin 37 | RE1/WR/AN6 — Port E bit 1 / write control / ADC input 6 |
| Pin 38 | RE2/CS/AN7 — Port E bit 2 / chip select / ADC input 7 |
| Pin 39 | VSS — Ground reference (secondary) |
| Pin 40 | VDD — Positive supply voltage (secondary) |
| 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
PIC16C74AT-04/PQ is suitable for 7 applications: Industrial Process Control, Sensor Signal Conditioning, Embedded Control Boards, Instrumentation Front-Ends, Legacy Consumer Electronics Controllers, Automotive Aftermarket Modules, Educational and Training Boards.
Industrial Process Control
The PIC16C74AT-04/PQ fits industrial process control applications because its 8-channel 8-bit ADC and 33 digital I/O pins handle multiple sensor inputs and actuator outputs in a single chip. The integrated I2C, SPI, and UART peripherals connect directly to sensor front-ends, EEPROM data logs, and host PLCs without external interface ICs. Operating across 3.0 V to 6.0 V with on-chip Brown-out Reset and Watchdog Timer, the MCU tolerates the noisy 24 V industrial bus environment when properly regulated. Engineers commonly use the PIC16C74A family for PID loops, valve drivers, and motor-speed controllers where 1 MIPS of throughput is sufficient. Choose the 20 MHz grade (PIC16C74A-20/PQ) for faster loops; the 04 grade suits sub-100 Hz control tasks.
Recommended
Sensor Signal Conditioning
The PIC16C74AT-04/PQ serves well in sensor signal conditioning modules that must digitize analog inputs, apply linearization in firmware, and forward calibrated data over SPI or UART. The 8-channel 8-bit ADC multiplexes across multiple transducer types (thermistors, strain gauges, photodiodes) with adequate resolution for non-precision applications; for 10-bit or 12-bit needs, step up to PIC16F77A. The 192-byte RAM and 7 KB OTP program memory comfortably hold lookup tables and simple digital filters. Brown-out Reset prevents erroneous readings during supply transients, and the PIC RISC core at 4 MHz delivers deterministic 1-microsecond-per-instruction-cycle response.
Recommended
Embedded Control Boards
Engineers select the PIC16C74AT-04/PQ for general-purpose embedded control boards because it packs ADC, three timers, two CCP (Capture/Compare/PWM) modules, and three serial interfaces into one 44-MQFP IC. The two CCP modules generate PWM outputs for motor speed control, LED dimming, or servo positioning, while the timers handle event counting and real-time interrupts. With 33 I/O pins available, the MCU interfaces directly to keypads, character LCDs, and parallel peripherals without external glue logic. Designers should note that OTP memory requires a one-time production programming step, so plan code verification on a flash-equipped PIC16F74A or windowed PIC16C74A JW before committing to OTP production.
Recommended
Instrumentation Front-Ends
The PIC16C74AT-04/PQ provides an effective instrumentation front-end controller with its integrated 8-bit ADC, UART for host communication, and timers for precise sample-rate generation. Bench instruments benefit from the MCU's deterministic interrupt response and on-chip peripherals that minimize external component count. Brown-out Reset and Watchdog Timer protect against the lockup conditions common in electrically noisy lab environments. For higher-resolution measurements, the same board layout can accept the PIC16F77A (12-bit ADC) in the same 44-MQFP footprint, enabling a smooth upgrade path without PCB rework.
Recommended
Legacy Consumer Electronics Controllers
The PIC16C74AT-04/PQ remains in use for maintenance and repair of legacy consumer appliances, HVAC thermostats, and small-format home appliances whose original designs specified this OTP MCU. Because the part is now in Last Time Buy status, sourcing the exact MPN from distributor allocation stock is the only way to keep legacy products in production. The PIC16C74A instruction set is forward-compatible with newer PIC16F74A flash parts in the same 44-pin MQFP, allowing repair shops to substitute the flash equivalent in non-OTP-critical applications. Cross-reference the part number to PIC16C74A-04/PQ (tray variant) when checking spare-parts inventories.
Recommended
Automotive Aftermarket Modules
Outside of OEM automotive safety systems, the PIC16C74AT-04/PQ has historically powered aftermarket automotive accessories like alarm systems, remote-start modules, and auxiliary lighting controllers. Its wide 3.0 V to 6.0 V supply range tolerates 12 V vehicle rails when paired with a 5 V regulator, and the three timers/CCPs manage PWM outputs for LED drivers and relay sequencing. For new automotive designs, however, engineers must select AEC-Q100-qualified parts such as the PIC16F74A-E/PQ rather than this commercial-temperature-grade MCU. The 04 MHz speed grade is sufficient for slow-switching accessory control but is inadequate for CAN-bus or LIN-bus transceivers.
Recommended
Educational and Training Boards
The PIC16C74AT-04/PQ frequently appears in university microcontroller courses and embedded-systems training kits because the PIC16 mid-range family is well-documented and supported by free MPLAB X IDE tools. Students benefit from the rich peripheral set (ADC, SPI, I2C, UART, CCP) and the availability of low-cost programmers like the PICkit 3. While modern curricula prefer flash-based PIC16F1xxx parts, instructors using legacy PIC16C74A boards rely on the T&R-packaged PIC16C74AT-04/PQ for restocking lab kits. The DIP-package PIC16C74A-04/P (not PQ) is the preferred variant for breadboard-friendly training.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74AT-04/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74A-04/PQ | PIC16C74A-10I/P | PIC16C74A-20I/L | PIC16C74A-04I/P | PIC16C74A-20E/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10 mm) | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same |
| Program Memory | 7 KB OTP (4K x 14) | 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 |
| Max Clock Frequency | 4 MHz | 4 MHz | 10 MHz (+150%) | 20 MHz (+400%) | 4 MHz | 20 MHz (+400%) |
| Temperature Range | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +125C (extended) |
| Packaging Format | Tape & Reel | Tray | Tray | Tray | Tray | Tray |
| ADC Channels | 8 channels, 8-bit | 8 channels, 8-bit | 8 channels, 8-bit | 8 channels, 8-bit | 8 channels, 8-bit | 8 channels, 8-bit |
Key Differentiators
- Same-die drop-in compatibility with full PIC16C74A 44-MQFP family (vs PIC16C74A-04/PQ (tray variant))
- Higher speed grade available in same package (vs PIC16C74A-20/PQ (20 MHz variant))
- On-chip peripherals eliminate external glue logic (vs Discrete MCU + external ADC (e.g. PIC16C73 + ADC0808))
Design Notes
OTP memory cannot be erased or rewritten - verify firmware on a flash-based PIC16F74A-I/PQ (same 44-MQFP footprint) or windowed JW-package PIC16C74A before committing to OTP production. Once the PIC16C74AT-04/PQ is programmed, any firmware bug requires a new physical part. Plan ICSP programming fixtures that accommodate T&R-packaged devices if programming in-house.
Decouple VDD (pins 11 and 40) with a 100 nF ceramic capacitor placed within 5 mm of each supply pin, plus a bulk 10 uF tantalum or aluminum electrolytic capacitor on the main 5 V rail. PIC microcontrollers can exhibit code-execution errors if VDD drops below the Brown-out Reset threshold during ADC conversion - place the decoupling capacitors as close to the MCU as possible. For battery-powered designs, note that the PIC16C74AT-04/PQ does not include low-power sleep modes as comprehensive as the PIC16F family; verify sleep current against battery budget.
Keep the oscillator traces (OSC1/OSC2, pins 1-2) as short as possible and surround them with a ground guard ring to minimize EMI coupling into the ADC inputs. Route the analog signals (RA0-RA5, RE0-RE2) away from the digital I/O bus and the UART lines (RC6/RC7) which carry fast edges. Place the ADC VREF bypass capacitor directly on pin 7 (RA3/AN3/VREF) when used as an external reference. The 44-MQFP package has a center thermal pad - connect it to ground plane for mechanical stability even though the silicon does not require thermal dissipation.
The PIC16C74AT-04/PQ UART (RC6/TX, RC7/RX) shares pins with the Parallel Slave Port - disable PSP via the PSPMODE bit when using the UART to avoid bus contention. The MSSP peripheral's I2C mode requires external pull-up resistors on SDA (RC4) and SCL (RC3); values between 4.7 kohm (at 400 kHz) and 10 kohm (at 100 kHz) are typical. For SPI master mode with high-speed slave devices, the SDO output may need a series resistor to dampen ringing on long PCB traces.
Compliance Information
RoHS and lead-free status not explicitly stated in Verified Web Data. AEC-Q100 not applicable - this is a commercial-temperature-grade MCU. For automotive designs, use AEC-Q100-qualified PIC16F variants. Conflict-mineral compliance per Microchip's standard supplier declarations.
