PIC16C56A-20E/SS - 8-bit OTP MCU, 1.5KB, 20MHz | Microchip
MPN: PIC16C56A-20E/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.69 | $1.69 |
| 10 | $1.49 | $14.90 |
| 100 | $1.28 | $128.00 |
| 500 | $1.05 | $525.00 |
| 1,000 | $0.94 | $940.00 |
PIC16C56A-20E/SS Overview
What is an 8-bit OTP microcontroller? An OTP (One-Time Programmable) MCU is a class of microcontroller whose program memory can be written exactly once after manufacture, using a device programmer, and then behaves like a mask-ROM part for the rest of its life. The PIC16C5X series falls under the broader hierarchy: microcontroller -> embedded controller -> semiconductor. It uses a RISC-style 12-bit instruction word with only 33 single-cycle instructions, which gives roughly 2:1 code compression versus typical 8-bit CISC competitors and allows a 20 MHz oscillator to deliver up to 5 MIPS of throughput.
Key features include 12 bidirectional I/O pins with individual direction control, a watchdog timer for fault recovery, a power-on reset circuit, and an internal 4 MHz RC oscillator option for low-cost designs. The 20 MHz external clock version (-20) delivers 5 MIPS peak throughput. Power consumption is dominated by CMOS static design with sleep-mode current on the order of microamps, enabling battery-friendly standby behavior. The SSOP-20 footprint occupies only 5.30 mm of board width.
Typical applications include low-cost appliance controllers, sensor front-ends, white-goods human-machine interfaces, automotive body modules, smart metering, and industrial timer/counter boards. The combination of OTP memory, 12-bit instruction set, and extended temperature range has made the PIC16C56A a long-lifecycle workhorse for products that ship in high volume and rarely change firmware.
When designing with this device, ensure that oscillator start-up time is budgeted in the reset vector and that the configuration word is set correctly for the chosen oscillator mode (XT, HS, LP, or RC). Because OTP cannot be erased, firmware validation should be performed on a windowed (JW) or flash equivalent (PIC16F56 family) before committing code to production parts.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives within the PIC16C5X family, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC16C56A-20E/SS — 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 PIC16C56A-20E/SS (same form factor and footprint) — differing in Core Architecture, Package, Operating Temperature, Program Memory Size, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55A-20E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54A-20E/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C56A-20E/SO
✅ Drop-In✓ In Stock
$1.04 / Unit
View Datasheet →PIC16F54-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56A-20I/SS
✅ Drop-In✓ In Stock
$0.67 / Unit
View Datasheet →PIC16C56A-20E/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC |
| Family | PIC16C5X |
| Program Memory | 1.5 KB (1K x 12) OTP |
| RAM | 25 bytes |
| Data EEPROM | Not present (ROM-less data side) |
| Maximum Clock Speed | 20 MHz |
| Instruction Throughput | 5 MIPS (DC to 20 MHz) |
| Instruction Set Size | 33 single-cycle instructions |
| I/O Pins | 12 digital bidirectional |
| Supply Voltage (Vdd) | 4.5 V to 5.5 V |
| Operating Temperature | -40 C to +125 C (Extended, "-E") |
| Package | SSOP-20 (5.30 mm body width) |
| Mounting Type | Surface Mount |
| Timers | 1 x 8-bit (TMR0 with watchdog option) |
| Watchdog Timer | Yes (shared with TMR0) |
| Power-On Reset | Yes |
| ADC | None |
PIC16C56A-20E/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RA4/RTCC — Bidirectional I/O port A bit 4 / TMR0 clock input |
| Pin 4 | RB0 — Bidirectional I/O port B bit 0 |
| Pin 5 | GND — Ground reference |
| Pin 6 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 7 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 8 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 9 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 10 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 11 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 12 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 13 | OSC2/CLKOUT — Oscillator output / clockout (Fosc/4) |
| Pin 14 | OSC1/CLKIN — Oscillator input / external clock in |
| Pin 15 | VDD — Positive supply (4.5V to 5.5V) |
| Pin 16 | /MCLR — Master Clear reset input (active low) |
| Pin 17 | RC0 — Bidirectional I/O port C bit 0 |
| Pin 18 | RC1 — Bidirectional I/O port C bit 1 |
| Pin 19 | RC2 — Bidirectional I/O port C bit 2 |
| Pin 20 | RC3 — Bidirectional I/O port C bit 3 |
Typical Applications
PIC16C56A-20E/SS is suitable for 6 applications: Appliance Control Board, Smart Metering Front-End, Industrial Timer / Counter Module, Automotive Body Electronics (Legacy), Consumer White Goods HMI, Sensor Front-End and Signal Conditioning.
Appliance Control Board
The PIC16C56A-20E/SS fits appliance control boards because its 12 bidirectional I/O pins can directly drive relays, triac optocouplers, keypads, and 7-segment LED displays without external glue logic. With 1.5KB of OTP program memory it can hold a complete state machine for wash cycles, microwave programs, or HVAC timing patterns, and its 5 MIPS throughput at 20 MHz keeps scan loops tight. The -40C to +125C extended temperature range handles under-cabinet and motor-compartment thermal stress. The SSOP-20 footprint (5.30 mm body) keeps board area minimal inside space-constrained appliance chassis. Watchdog timer + power-on reset provide reliable recovery from supply brown-outs common in compressor-driven loads. PIC16C56A-20E/SS pairs naturally with ULN2003 line drivers and MOC3021 triac optos on the AC load side.
Recommended
Smart Metering Front-End
The PIC16C56A-20E/SS is well matched to single-phase smart-meter front-ends where its 12 I/O pins can read metrology pulses, drive a calibration LED, scan a tamper switch matrix, and bit-bang a UART to a companion communication module. The 5 MIPS instruction throughput keeps pulse-counting latency under 200 ns, meeting IEC 62053-21 class-1 accuracy budgets. 25 bytes of RAM is sufficient for rolling pulse accumulators and tamper flags. OTP memory locks the calibration firmware to prevent tampering with revenue metering constants. Extended -40C to +125C operation suits outdoor meter enclosures from arctic to desert climates. The 5V CMOS design pairs cleanly with external op-amp current-sensor front-ends such as the MCP6001. PIC16C56A-20E/SS is also a proven platform for IEC 61036 / IEC 62053 billing-grade embedded designs.
Recommended
Industrial Timer / Counter Module
The PIC16C56A-20E/SS is well suited to DIN-rail industrial timer and counter modules where deterministic timing is critical. The TMR0 counter with watchdog option provides both timing and fault-recovery in one peripheral, and the 33-instruction PIC16C5X set makes cycle-time calculations trivial - each instruction is exactly one oscillator cycle. With 12 I/O pins the MCU can drive 4-digit 7-segment displays, accept encoder inputs, and switch 4 isolated outputs without external logic. The 5 MIPS peak throughput supports encoder-quadrature decoding up to 1 MHz input frequency. Extended temperature operation to +125C handles sealed enclosure derating. OTP memory locks calibration and prevents unauthorized firmware changes in safety-related equipment. SSOP-20 fits behind a small display window with through-hole-friendly land pads if hand-rework is needed.
Recommended
Automotive Body Electronics (Legacy)
The PIC16C56A-20E/SS has been used in long-lifecycle automotive body modules where OTP memory locking and a wide operating temperature range (-40C to +125C) are required. 12 I/O pins comfortably drive seat-control switches, lighting dimmers, mirror adjusters, and RKE receiver handshake lines. 1.5KB of OTP program memory holds complete body-control state machines for seat memory, intermittent wipe, and welcome-light fade patterns. Note that the PIC16C56A is NOT AEC-Q100 qualified; it is best suited to non-safety body modules rather than airbag or ABS subsystems. For new automotive designs requiring firmware updates or functional safety, migrate to the PIC16F1xxx family with AEC-Q100 Grade 0/1 qualification. PIC16C56A-20E/SS remains in production for low-cost aftermarket automotive accessories where OTP is acceptable.
Recommended
Consumer White Goods HMI
The PIC16C56A-20E/SS is a strong fit for white-goods human-machine interfaces (washing machines, dishwashers, refrigerators, microwave ovens) where a low-cost MCU scans a 4x4 keypad, drives a character LCD or LED matrix, and orchestrates appliance cycles. The 12 I/O pins handle keypad scanning, LED row/column multiplexing, buzzer PWM-via-bit-bang, and a single UART to the power-conversion board. 1.5KB OTP memory holds complete cycle tables and country-specific variant menus without external storage. 5 MIPS throughput keeps keypad debounce latency imperceptible (<5 ms). The extended temperature grade +125C supports under-cabinet and compressor-adjacent placement. OTP locks the firmware image so end users cannot accidentally reflash or corrupt the cycle table.
Recommended
Sensor Front-End and Signal Conditioning
The PIC16C56A-20E/SS can act as a low-cost digital front-end for analog sensors, reading comparator or op-amp outputs and producing a clean PWM, frequency, or UART output for downstream controllers. The 5 MIPS throughput enables software-implemented sigma-delta or pulse-width modulation with sub-1% linearity on slow signals like thermistor bridges and photodiodes. 12 I/O pins can be split between sensor inputs, alarm outputs, and serial communication, eliminating the need for a dedicated signal-conditioning ASIC. Extended -40C to +125C operation supports outdoor solar and weather-station deployments. OTP memory locks calibration coefficients so that drift over the product lifetime is prevented. The 5.30 mm SSOP-20 body fits in tight sensor housings where larger QFP packages would not.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A-20E/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55A-20E/SS | PIC16C54A-20E/SS | PIC16C56A-20I/SS | PIC16F54-I/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SSOP-20 | SSOP-20 (same) | SSOP-20 (same) | SSOP-20 (same) | SSOP-20 (same) |
| Program Memory | 1.5 KB (1K x 12) OTP | 1.0 KB (768 x 12) OTP | 0.75 KB (512 x 12) OTP | 1.5 KB (1K x 12) OTP | 0.75 KB (512 x 12) Flash |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| Memory Type | OTP | OTP | OTP | OTP | Flash |
| Temperature Grade | Extended -40C to +125C | Extended -40C to +125C | Extended -40C to +125C | Industrial -40C to +85C | Industrial -40C to +85C |
Key Differentiators
- Largest OTP memory in the PIC16C5X SSOP-20 family (vs PIC16C55A-20E/SS)
- Highest temperature grade in the PIC16C56A family (vs PIC16C56A-20I/SS)
- Extended OTP migration path to flash memory with same footprint (vs PIC16F54-I/SS)
Design Notes
The PIC16C56A-20E/SS operates from a single 4.5V to 5.5V supply on VDD (pin 15) with GND on pin 5. Bulk-decouple VDD with a 10 uF electrolytic plus 100 nF ceramic placed within 10 mm of the package. For sleep-mode designs, the device draws only microamp-level standby current when the watchdog is disabled, but enabling the watchdog adds the internal RC oscillator current - budget ~5-10 uA additional Iq. Ensure /MCLR (pin 16) is held high through a 10 kohm pull-up to VDD; an RC network (47 kohm + 100 nF) on /MCLR provides a clean power-on reset delay. Brown-out thresholds are not documented in the simplified datasheet, so an external voltage supervisor such as MCP100 or TPS3823 is recommended for brown-out-sensitive loads.
Choose the oscillator mode via the configuration word: XT for 4-10 MHz crystals, HS for 10-20 MHz, LP for 32.768 kHz low-power watch crystals, and RC for cost-sensitive designs with the internal 4 MHz RC option. The PIC16C56A-20E/SS supports crystals with two external load capacitors typically in the 15-22 pF range for a 20 MHz fundamental crystal. For EMI-sensitive applications, route the crystal traces short and symmetric, and place a ground guard ring around the oscillator block to prevent injection of switching noise into the clock.
The SSOP-20 (5.30 mm body, 0.65 mm pitch) is a fine-pitch surface-mount package. Use a PCB land pattern with NSMD (non-solder-mask-defined) pads and 0.4 mm wide pads with 0.2 mm mask openings for reliable paste release. Hand-soldering is impractical at this pitch - plan for reflow or hot-air rework with magnification. Pin 1 identification by the molded dot or chamfer on the package must match the silk-screen arrow on the PCB; reverse insertion is not recoverable without desoldering. Route VDD and GND traces on a dedicated inner layer with stitching vias to minimize supply inductance for the 20 MHz switching transients.
Because the PIC16C56A-20E/SS uses OTP memory, once programmed the firmware is permanent. Validate firmware on a windowed PIC16C56/JW or a flash-based PIC16F54-I/SS sibling before committing code to OTP parts. Do not leave unused I/O pins floating - either set them as outputs or tie them to VDD/GND through a 100 kohm resistor to prevent shoot-through and supply-current spikes. Configuration-word programming must explicitly disable the watchdog if it is not needed, otherwise the device will reset unexpectedly. Finally, never program OTP parts in-circuit without isolating the /MCLR line; use a dedicated programmer socket or in-system programming header.
Compliance Information
RoHS, REACH, lead-free, halogen-free, and conflict-mineral data not present in the verified web results - confirm with the manufacturer's product environmental compliance page before quoting for new EU or restricted-substance-sensitive designs. PIC16C56A is explicitly NOT AEC-Q100 qualified.
