PIC17C756AT-16/L - 8-bit OTP MCU, 32KB, 50 I/O, 68-PLCC | Microchip
MPN: PIC17C756AT-16/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $21.5 | $21.50 |
| 10 | $19.85 | $198.50 |
| 100 | $17.95 | $1,795.00 |
| 500 | $15.4 | $7,700.00 |
| 1,000 | $13.2 | $13,200.00 |
PIC17C756AT-16/L Overview
A microcontroller (MCU) is a single-chip computer that contains a processor core, program memory, RAM, and peripheral interfaces on one die. The PIC17C family was Microchip's first architecture to exceed the PIC16C5X/16CXX instruction set, extending it with a wider 16-bit instruction word, 58 single-word instructions, and up to 8.25 MIPS throughput. The PIC17C756A represents the high-end of that family, bridging the gap between classic 8-bit PICs and later PIC18F/PIC24 devices and serving as the precursor to the recommended modern replacement PIC18F6520.
Key features of the PIC17C756AT-16/L include: 50 I/O pins with high-current sink/source capability, a 10-bit A/D converter with multiple input channels, a hardware 8x8 single-cycle multiplier, dual analog comparators, multiple timer/counters, a USART module, and an OTP (one-time programmable) program memory rated for 1000 erase/write cycles. The 'T' suffix denotes tape-and-reel packaging for the 68-PLCC, and '16' indicates the 16 MHz maximum operating frequency, while the '/L' suffix designates the windowless ceramic-less plastic PLCC carrier.
Architecturally, the PIC17C756A uses a Harvard bus with separate program (16-bit wide) and data (8-bit wide) memories, a 17-level deep hardware stack, and the same RISC-style instruction set used across the PIC line, allowing code portability from PIC16C/PIC12C projects. Its 4.5 V to 5.5 V single-supply operation simplifies analog and digital rail design in industrial and consumer applications.
Typical applications include industrial control panels, motor drive controllers, instrumentation front-ends, automotive body and chassis ECUs (via PIC17C756A-16I/L industrial variant), HVAC controls, and embedded control where 50 I/O lines and on-chip A/D reduce the need for external logic. Engineers value the OTP variant for low-volume production and field-provisioning where firmware changes are infrequent.
When designing with this part, verify that your firmware footprint fits within the 32 KB OTP window and that code branches avoid the two-cycle penalty on program branches and table reads/writes. Because the PIC17C756A is a legacy OTP family, evaluate the recommended replacement PIC18F6520 for new designs; this part is most often sourced today for legacy board repairs and long-lifecycle industrial systems.
Drop-in alternatives for PIC17C756AT-16/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 PIC17C756AT-16/L (same form factor and footprint) — differing in Mounting Type, Package, Program Memory Type, ADC, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C756A-16/L
✅ Drop-In✓ In Stock
$17.2 / Unit
View Datasheet →PIC17C756A-16I/L
✅ Drop-In✓ In Stock
$13.85 / Unit
View Datasheet →PIC17C756AT-16I/L
✅ Drop-In✓ In Stock
$9.85 / Unit
View Datasheet →PIC17C756A-16/L
✅ Drop-In✓ In Stock
$17.2 / Unit
View Datasheet →PIC17C756AT-16/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC17C, 8-bit RISC, Harvard |
| Maximum Clock Frequency | 16 MHz (33 MHz on -33 variant) |
| Instruction Cycle Time | 121 ns (single-cycle, except branches/table reads) |
| Performance | 8.25 MIPS |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 32 KB (16K x 16 words) |
| RAM | 902 bytes |
| I/O Pins | 50 |
| Data Bus Width | 16-bit (instruction), 8-bit (data) |
| A/D Converter | 10-bit, multi-channel |
| Hardware Multiplier | 8x8 single-cycle |
| Instruction Set | 58 single-word instructions |
| Supply Voltage | 4.5 V to 5.5 V |
| Operating Temperature | 0C to +70C (commercial, /L variant) |
| Package | 68-pin PLCC (24.23 x 24.23 mm) |
| Mounting Type | Surface Mount |
PIC17C756AT-16/L 68-pin plcc (24.23 x 24.23 mm) Pin Configuration Guide
Pin configuration for PIC17C756AT-16/L (68-pin plcc (24.23 x 24.23 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for PIC17C756AT-16/L.
Refer to the datasheet for full pin configuration.
Typical Applications
PIC17C756AT-16/L is suitable for 6 applications: Industrial Process Control, HVAC Control Systems, Instrumentation Front-End, Automotive Body and Chassis ECU, Motor Drive Controllers, Embedded Control with A/D and Communication.
Industrial Process Control
The PIC17C756AT-16/L fits industrial process control applications that demand 50 digital I/O and integrated 10-bit A/D for sensor interfacing. The 8.25 MIPS throughput at 16 MHz handles PID loops, multi-channel scanning, and HMI scan routines with deterministic single-cycle instruction execution (121 ns). With 32 KB OTP program memory, designers can embed full state-machine and ladder-logic-equivalent firmware for motor starters, valve controllers, and conveyor sequencers. The wide I/O count reduces the need for external I/O expanders, lowering BOM cost in factory-floor PLC modules and distributed I/O blocks.
Recommended
HVAC Control Systems
HVAC controllers benefit from the PIC17C756AT-16/L's 50 I/O and on-chip 10-bit A/D to read multiple temperature, pressure, and humidity sensors simultaneously while driving relays, triacs, and damper actuators. The 8.25 MIPS performance executes multiple closed-loop control algorithms per control period without timing violations, and the 32 KB OTP comfortably fits sequence control, scheduling, and fault-handling firmware. The 5 V single-supply rail simplifies integration with conventional thermostat wiring and optocoupler-isolated AC line interfaces commonly used in furnace and air-handler units.
Recommended
Instrumentation Front-End
Test and measurement instruments use the PIC17C756AT-16/L for front-panel scanning, range switching, and A/D multiplexing. The 10-bit A/D combined with 50 I/O handles up to 12 analog channels plus 38 digital control lines, replacing discrete logic and reducing PCB area. At 16 MHz with 121 ns single-cycle execution, the part delivers deterministic response to keypad entry and rotary-encoder quadrature decoding in digital multimeters and bench-top instruments. The OTP memory suits calibrated production units where firmware is locked at factory test.
Recommended
Automotive Body and Chassis ECU
Automotive body controllers and chassis ECUs historically leveraged the PIC17C756A family for tasks like window lift control, lighting sequencing, and seat memory modules where 50 I/O integrates drivers and switches without external mux logic. The integrated 10-bit A/D reads position sensors and current shunts for stall detection in window and sunroof motors. For under-hood or extreme-temperature environments, the industrial 'I' variant PIC17C756A-16I/L (extended -40C to +85C) is preferred, while the commercial '/L' variant suits cabin-mounted body controllers.
Recommended
Motor Drive Controllers
Motor drive subsystems use the PIC17C756AT-16/L for commutation, current sensing, and fault handling in stepper, BLDC, and small DC servo drives. The hardware 8x8 single-cycle multiplier accelerates Park/Clarke transforms and PID update math, and the 50 I/O drive phase bridges, Hall-effect sensors, and encoder inputs directly. With 902 bytes RAM and 32 KB OTP, designers can implement trapezoidal or sinusoidal commutation tables plus speed-current cascaded control in a single chip, eliminating external DSP or FPGA in cost-sensitive motion control.
Recommended
Embedded Control with A/D and Communication
Embedded control nodes that require both analog sensing and serial communication benefit from the PIC17C756AT-16/L's integrated 10-bit A/D, USART module, and 50 I/O. The architecture supports RS-232/RS-485 master or slave roles for sensor networks, building automation, and point-of-sale terminals. The 32 KB OTP stores protocol stacks, command parsers, and data logging routines, while the 902 bytes RAM is sufficient for packet buffers and scratch state. The PIC17C756A's 58-instruction RISC core keeps firmware footprint compact and deterministic.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C756AT-16/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C756A-16/L | PIC17C756A-16I/L | PIC17C756AT-16I/L | PIC18F6520-I/PT |
|---|---|---|---|---|---|
| Package | 68-PLCC | 68-PLCC - same | 68-PLCC - same | 68-PLCC - same | 64-TQFP - different |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 32 KB OTP | 32 KB OTP | 32 KB OTP | 32 KB OTP | 32 KB Flash |
| Max Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 40 MHz |
| I/O Pins | 50 | 50 | 50 | 50 | 52 |
| Operating Temperature | 0C to +70C | 0C to +70C | -40C to +85C | -40C to +85C | -40C to +85C |
| A/D Converter | 10-bit | 10-bit | 10-bit | 10-bit | 10-bit |
| Lifecycle Status | NRND | NRND | NRND | NRND | Active |
Key Differentiators
- Highest-density OTP variant of the legacy PIC17C family in 68-PLCC (vs PIC17C752-16/L)
- 50 I/O pins integrated on-chip (vs PIC17C756A-16I/L)
- Tape-and-reel packaging for automated assembly (vs PIC17C756A-16/L)
Design Notes
The PIC17C756AT-16/L's program branches and table reads/writes take two cycles (242 ns), not the single-cycle 121 ns used elsewhere. Estimated: at 16 MHz, a loop of 100 instructions with one branch per iteration costs 121*99 + 242 = 12221 ns rather than the naive 12100 ns; engineers writing tight timing loops must use the instruction-cycle diagram from the PIC17C756A datasheet rather than the cycle count from other PIC families.
Supply decoupling requires a 0.1 uF ceramic capacitor placed within 5 mm of each VDD/VSS pair on the 68-PLCC, plus a bulk 10 uF tantalum or electrolytic at the regulator output. The PIC17C756A's 5 V supply is referenced by the 10-bit A/D, so noisy digital switching can couple into analog readings if the AVDD/AVSS pins are not bypassed with their own 0.1 uF + 10 uF network, especially when reading low-level sensor signals below 100 mV full-scale.
Estimated: the 68-PLCC package has typical theta_JA around 50-60 C/W for PLCC sockets, so power dissipation above 200 mW in a sealed enclosure may push junction temperature beyond the 70C commercial limit. For high-I/O applications driving 50 outputs simultaneously (worst case 50 * 25 mA = 1.25 A total), verify the package dissipation against the actual duty cycle and ambient temperature, and de-rate I/O source/sink to keep total package dissipation under 0.5 W at 50C ambient.
Route the 16 MHz crystal traces short and symmetric to OSC1/OSC2 with the load capacitors placed within 3 mm of the IC pins to avoid parasitic inductance that can shift oscillation or cause startup failures. Keep crystal traces away from high-current switching signals (relay coils, motor phases) by at least 5 mm or shield with a ground pour, otherwise EMI can inject jitter or spurious resets through MCLR. Use a guard ring around the oscillator area tied to analog ground if the 10-bit A/D shares the board.
Compliance Information
Compliance status for PIC17C756AT-16/L not explicitly provided in the verified distributor data; legacy PIC17C family parts are commonly supplied with Pb-bearing terminations. Request the latest material declaration directly from Microchip for RoHS/REACH confirmation. AEC-Q100 is not applicable for this commercial-temperature-grade MCU.
