PIC17C42AT-33E/PT - 8-bit 33MHz PIC MCU, 4KB OTP, 44-TQFP | Microchip
MPN: PIC17C42AT-33E/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.5 | $14.50 |
| 10 | $12.95 | $129.50 |
| 100 | $11.4 | $1,140.00 |
| 500 | $10.05 | $5,025.00 |
| 1,000 | $9.2 | $9,200.00 |
PIC17C42AT-33E/PT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program and data memory, I/O peripherals, and often analog or communication blocks into one IC. The PIC17C family sits at the high-performance end of Microchip's 8-bit portfolio and uses a RISC (Reduced Instruction Set Computer) Harvard architecture with a separate program and data bus; in this family hierarchy, PIC17C42A is a member of the PIC17C sub-family -> PIC17 family -> PICmicro 8-bit MCUs -> microcontrollers -> embedded processors. The 16-bit-wide program word (2K x 16 = 4KB) and single-cycle instruction execution give the PIC17C42A substantially higher throughput than mid-range PIC16 parts, while remaining code-compatible at the architectural level with PIC17C4X designs.
Key features include a 33 MHz external oscillator input, 33 bidirectional I/O pins, two 8-bit and one 16-bit timer/counter, a watchdog timer with on-chip RC oscillator, power-on reset, brown-out reset, and power-saving SLEEP mode. The PIC17C42A supports external, internal RC, and crystal oscillator modes, and provides multiple interrupt sources including external INT pins, timer overflow, and peripheral events. The 44-pin TQFP package offers a compact 10x10 mm footprint suitable for space-constrained boards while exposing the full 33-I/O complement.
Typical applications include industrial control systems, motor control front-ends, automotive body and chassis modules, consumer appliances with HMI control, and embedded data-acquisition front-ends. The PIC17C42A was a popular choice in the mid-to-late 1990s for designs that needed more horsepower than the PIC16 series but did not yet require the PIC18 architecture. Because the program memory is OTP EPROM (not flash), this part is intended for mature, high-volume production where field re-programmability is not required.
When designing with the PIC17C42AT-33E/PT, ensure the Vdd supply is decoupled with a 0.1 uF ceramic capacitor placed within 5 mm of the Vdd/Vss pins, and that the OSC1/OSC2 crystal or resonator tracks the 33 MHz maximum clock. The 'E' suffix extends the operating range to -40C to +125C, so verify that brown-out and power-on-reset thresholds are configured for the chosen Vdd rail. Note that OTP EPROM requires windowed erasure only by UV; in-circuit re-programming is not supported - plan firmware carefully or use the equivalent PIC17C42A flash-based PIC18 successor for prototyping.
This page synthesizes distributor stock data, Microchip's PIC17C42A datasheet (DS30412C family), and parametric cross-references not available on any single distributor page, giving engineers a single consolidated view of the part's lifecycle, pricing, and drop-in alternatives.
Drop-in alternatives for PIC17C42AT-33E/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 PIC17C42AT-33E/PT (same form factor and footprint) — differing in Core Architecture, Package, Packaging, Program Memory Type, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-33E/PT
✅ Drop-In✓ In Stock
$8.5 / Unit
View Datasheet →PIC17C42AT-33I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42A-33I/PQ
✅ Drop-In✓ In Stock
$11.4 / Unit
View Datasheet →PIC17C42AT-25/PT
✅ Drop-In✓ In Stock
$10.5 / Unit
View Datasheet →PIC17C42A-25/PT
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC18F452-I/PT
✅ Drop-In✓ In Stock
$5.84 / Unit
View Datasheet →PIC17C42AT-33E/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC Harvard |
| Family | PIC17C |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 (232 bytes) |
| Data EEPROM | Not present |
| Maximum Clock Frequency | 33 MHz |
| Instruction Cycle Time | 120 ns (at 33 MHz, 4 TCY per instruction) |
| Number of I/O Pins | 33 |
| Timers | 2 x 8-bit + 1 x 16-bit |
| Watchdog Timer | Yes (on-chip RC oscillator) |
| Oscillator Type | External (Crystal/Resonator/RC) |
| Operating Voltage (Vdd) | 4.5 V to 5.5 V |
| Operating Temperature Range | -40 C to +125 C (E suffix, extended) |
| Package | 44-pin TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Peripherals | POR, BOR, SLEEP mode, interrupts |
PIC17C42AT-33E/PT Pin Configuration
| Pin 1 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 6 | RA5/AN4 — Port A bit 5 / analog input 4 |
| Pin 7 | VSS — Ground |
| Pin 8 | OSC1 — Crystal/oscillator input |
| Pin 9 | OSC2 — Crystal/oscillator output |
| Pin 10 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 11 | RB1 — Port B bit 1 |
| Pin 12 | RB2 — Port B bit 2 |
| Pin 13 | RB3 — Port B bit 3 |
| Pin 14 | RB4 — Port B bit 4 |
| Pin 15 | RB5 — Port B bit 5 |
| Pin 16 | RB6 — Port B bit 6 |
| Pin 17 | RB7 — Port B bit 7 |
| Pin 18 | VSS — Ground |
| Pin 19 | RC0 — Port C bit 0 |
| Pin 20 | RC1 — Port C bit 1 |
| Pin 21 | RC2 — Port C bit 2 |
| Pin 22 | RC3 — Port C bit 3 |
| Pin 23 | RC4 — Port C bit 4 |
| Pin 24 | RC5 — Port C bit 5 |
| Pin 25 | RC6 — Port C bit 6 |
| Pin 26 | RC7 — Port C bit 7 |
| Pin 27 | VDD — Positive supply (4.5 V - 5.5 V) |
| 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 | VSS — Ground |
| Pin 37 | RE0 — Port E bit 0 |
| Pin 38 | RE1 — Port E bit 1 |
| Pin 39 | MCLR#/VPP — Master clear (active low) / programming voltage |
| Pin 40 | VDD — Positive supply (4.5 V - 5.5 V) |
| Pin 41 | RE2 — Port E bit 2 |
| Pin 42 | RE3 — Port E bit 3 |
| Pin 43 | VDD — Positive supply (4.5 V - 5.5 V) |
| Pin 44 | TEST — Test pin (factory use) |
Typical Applications
PIC17C42AT-33E/PT is suitable for 6 applications: Industrial Control Systems, Automotive Body and Chassis Modules, Consumer Appliance HMI Controllers, Motor Drive and Stepper Controllers, Embedded Data Acquisition Front-Ends, Legacy Embedded Communication Gateways.
Industrial Control Systems
The PIC17C42AT-33E/PT fits industrial PLC and machine-control designs because its 33 MHz RISC core (~8.33 MIPS) executes deterministic scan loops faster than mid-range PIC16 parts, while the 44-pin TQFP exposes 33 I/O for direct sensor and actuator wiring. The 'E' (extended) -40 C to +125 C rating tolerates cabinet-side thermal stress, and the OTP memory is sufficient for fixed-function ladder replacements. Pair it with an external watchdog supervisor and isolated I/O for fail-safe machinery control.
Recommended
Automotive Body and Chassis Modules
For 1990s and early-2000s automotive body controllers, the PIC17C42AT-33E/PT offered 33 I/O for driving lamps, relays, and switches plus timers for PWM motor control. The extended -40 C to +125 C operating range matches under-hood and cabin environments. Note that this part predates AEC-Q100 qualification and is generally NRND/EOL - new automotive designs must migrate to PIC18F or dsPIC33 families with full automotive-grade certification.
Recommended
Consumer Appliance HMI Controllers
The PIC17C42AT-33E/PT was widely used in washing machines, dishwashers, and microwave ovens where a 4 KB OTP firmware image, 33 I/O, and a fast interrupt response drive HMI scan and motor commutation. The TQFP-44 package mounts cleanly behind the front-panel PCB, and the RISC core handles multi-tasking between button polling, display refresh, and sensor sampling. For new appliances, the flash-based PIC18F452 keeps the same pinout but adds field-upgrade capability.
Recommended
Motor Drive and Stepper Controllers
Stepper and DC motor controllers benefit from the PIC17C42AT-33E/PT's two 8-bit timers and one 16-bit timer, which can generate PWM signals at multiple frequencies simultaneously. The 33 MHz core updates PID loops in microseconds, and 33 I/O handle direction, enable, fault, and quadrature feedback lines. The extended temperature rating suits motor-drive enclosures. Pair the MCU with external MOSFET drivers since the PIC17C42A's I/O cannot source motor current directly.
Recommended
Embedded Data Acquisition Front-Ends
The PIC17C42AT-33E/PT's 33 MHz instruction throughput and 33 I/O let it multiplex multiple ADC channels, drive LCDs or LED bar graphs, and stream serial data to a host. Its 232-byte RAM is sufficient for sample buffering in fixed-cycle acquisition loops. While it lacks an internal ADC, external 8/10-bit ADCs (e.g., MCP3001) connect via SPI with the PIC17C42A as the SPI master. The extended temp grade supports industrial instrumentation cabinets.
Recommended
Legacy Embedded Communication Gateways
Serial-port-to-I/O gateways and protocol converters were a classic PIC17C42A application, where the RISC core handled UART-to-parallel or UART-to-I2C bridging at 33 MHz. The 33 I/O accommodate parallel keypad or matrix-scanned interfaces. For modern replacements, Microchip's PIC18F452 in the same 44-TQFP footprint gives identical pinout plus USB and enhanced USART for contemporary protocol stacks.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42AT-33E/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-33E/PT | PIC17C42AT-33I/PT | PIC17C42AT-25/PT | PIC18F452-I/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin TQFP | 44-pin TQFP - same | 44-pin TQFP - same | 44-pin TQFP - same | 44-pin TQFP - same |
| Max Clock Frequency | 33 MHz | 33 MHz | 33 MHz | 25 MHz | 40 MHz |
| Program Memory | 4 KB OTP EPROM | 4 KB OTP EPROM | 4 KB OTP EPROM | 4 KB OTP EPROM | 32 KB Flash |
| RAM Size | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 1536 bytes |
| Operating Temperature | -40C to +125C (E) | -40C to +125C | -40C to +85C (I) | -40C to +125C | -40C to +85C |
| I/O Pins | 33 | 33 | 33 | 33 | 34 |
| Memory Type | OTP EPROM (one-time) | OTP EPROM | OTP EPROM | OTP EPROM | Flash (re-programmable) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Active |
Key Differentiators
- Extended -40C to +125C operating temperature (vs PIC17C42AT-33I/PT)
- 33 MHz top-of-class 8-bit performance in the PIC17C family (vs PIC17C42AT-25/PT)
- Same 44-TQFP footprint as the modern PIC18F452 flash MCU (vs PIC18F452-I/PT)
Design Notes
The PIC17C42AT-33E/PT requires a regulated 4.5 V to 5.5 V supply; place a 0.1 uF ceramic decoupling capacitor within 5 mm of each Vdd/Vss pair (pins 27, 36, 40, 43 are Vdd; pins 7, 18, 36 are Vss). Add a bulk 10 uF tantalum or aluminum cap on the main 5 V rail to suppress motor or relay transients common in industrial and appliance designs.
OTP EPROM is one-time programmable only - there is no in-circuit re-programming. Verify firmware on a UV-erasable windowed PIC17C42A (same die) before committing production volumes. A misprogrammed OTP part must be discarded; this is the single most common engineering mistake when migrating from flash-based PIC16/PIC18 designs.
Estimated: at 33 MHz with all 33 I/O toggling worst-case CMOS load, the PIC17C42AT-33E/PT draws approximately 50 mA from Vdd (~250 mW). The 44-pin TQFP has a theta_JA around 50 C/W on a standard 4-layer JEDEC test board, so junction rise is roughly 12.5 C above ambient at full load. At 125 C ambient, junction temperature approaches the 150 C absolute maximum - derate clock or I/O loading in sealed enclosures.
Route the OSC1/OSC2 traces (pins 8-9) as a short differential pair with a ground guard ring; keep digital switching traces away from the crystal to avoid injection-locking or extra jitter. Place MCLR#/Vpp (pin 39) trace away from switching nodes and use the standard 10 kohm pull-up to Vdd with a 100 nF cap to ground for clean reset behavior.
Compliance Information
PIC17C42AT-33E/PT family predates RoHS transition; many lots use SnPb finish (non-RoHS). REACH compliance is per Microchip's standard declaration. AEC-Q100 not qualified - the part was not designed for new automotive programs.