PIC16C57-HSI/SO - 8-Bit 20MHz OTP MCU 3KB | Microchip
MPN: PIC16C57-HSI/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.95 | $5.95 |
| 10 | $5.35 | $53.50 |
| 100 | $4.76 | $476.00 |
| 500 | $4.25 | $2,125.00 |
| 1,000 | $3.85 | $3,850.00 |
PIC16C57-HSI/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, RAM, non-volatile program memory, and peripheral I/O on one die. The PIC16C5X family specifically sits within the broader taxonomy of microcontrollers -> 8-bit microcontrollers -> CMOS microcontrollers -> RISC microcontrollers -> embedded controllers. Its Harvard architecture separates program and data buses, while 12-bit-wide instructions deliver roughly 2:1 code compression versus competing 8-bit CISC architectures, allowing more functionality in less program memory.
Key features include a 20MHz high-speed internal oscillator variant (the HSI suffix denotes factory-programmed HS oscillator mode with internal clock options), 8-bit real-time clock/counter (TMR0), two-level deep hardware stack, and seven or eight special function hardware registers. The device supports direct, indirect, and relative addressing modes for both data and instructions, and operates from a single 5V supply over the commercial/industrial temperature range.
The PIC16C57 architecture uses a fully static CMOS design, meaning the clock can be stopped without losing internal state. This makes it well suited for low-power or battery-friendly designs where the oscillator is duty-cycled. The 12-bit instruction set and 33 single-word/single-cycle instructions reduce program-memory pressure, while the two-level hardware stack constrains subroutine nesting to two levels, an important constraint for C or high-level-language users porting code.
Typical applications include appliance control, sensor signal conditioning, LED drivers, simple motor control, remote keyless entry, security panels, and consumer white-goods user interfaces. The 20 I/O pins can directly drive LEDs, sink relays via transistors, and read keypad matrices, making the device a versatile general-purpose controller.
When designing with this part, observe the OTP programming limitation: the device cannot be re-flashed after programming, so debug must occur on a windowed (JW) or EPROM emulator variant first. Decoupling VDD with a 0.1 microfarad ceramic capacitor placed within 5mm of the pin is essential for stable HS-oscillator operation.
This page synthesizes distributor pricing, parametric drop-in alternatives, and practical design notes not found in the manufacturer datasheet, drawing on PIC16C5X family documentation and Microchip application notes.
Drop-in alternatives for PIC16C57-HSI/SO — 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 PIC16C57-HSI/SO (same form factor and footprint) — differing in Package, Core Architecture, Program Memory Size, Program Memory Type, Oscillator Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F57-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C57-HSI/P
✅ Drop-In✓ In Stock
$1.89 / Unit
View Datasheet →PIC16C57-HSE/SO
✅ Drop-In✓ In Stock
$5.18 / Unit
View Datasheet →PIC16C57C-20/SO
✅ Drop-In✓ In Stock
$2.89 / Unit
View Datasheet →PIC16C57C-20E/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16C57C-04/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C57-HSI/SO Maximum Ratings & Electrical Characteristics
| Product Series | PIC® 16C |
| Core | 8-bit RISC |
| Core Architecture | Harvard (separate program/data buses) |
| Maximum CPU Frequency | 20 MHz |
| Program Memory Size | 3 KB (2K x 12) OTP |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| RAM Size | 72 bytes |
| Number of I/O Pins | 20 |
| Number of Timers | 1 (TMR0, 8-bit) |
| Hardware Stack Depth | 2 levels |
| Instruction Word Width | 12 bits |
| Package | 28-SOIC (7.50 mm / 0.295 in width) |
| Mounting Type | Surface Mount |
| Oscillator Mode (HSI) | HS (High-Speed) oscillator, internal clock option |
| Addressing Modes | Direct, Indirect, Relative |
PIC16C57-HSI/SO Pin Configuration
| Pin 1 | RA2 — PORT A digital I/O bit 2 |
| Pin 2 | RA3 — PORT A digital I/O bit 3 |
| Pin 3 | RA4/T0CKI — PORT A bit 4 / Timer0 clock input |
| Pin 4 | MCLR/VPP — Master Clear (reset) input / Programming voltage |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — PORT B bit 0 / External interrupt input |
| Pin 7 | RB1 — PORT B digital I/O bit 1 |
| Pin 8 | RB2 — PORT B digital I/O bit 2 |
| Pin 9 | RB3 — PORT B digital I/O bit 3 |
| Pin 10 | RB4 — PORT B digital I/O bit 4 |
| Pin 11 | RB5 — PORT B digital I/O bit 5 |
| Pin 12 | RB6 — PORT B digital I/O bit 6 |
| Pin 13 | RB7 — PORT B digital I/O bit 7 |
| Pin 14 | VSS — Ground reference (alternate VSS pin) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / Clock out |
| Pin 16 | OSC1/CLKIN — Oscillator input / Clock in |
| Pin 17 | RC0 — PORT C digital I/O bit 0 |
| Pin 18 | RC1 — PORT C digital I/O bit 1 |
| Pin 19 | RC2 — PORT C digital I/O bit 2 |
| Pin 20 | RC3 — PORT C digital I/O bit 3 |
| Pin 21 | RC4 — PORT C digital I/O bit 4 |
| Pin 22 | RC5 — PORT C digital I/O bit 5 |
| Pin 23 | RC6 — PORT C digital I/O bit 6 |
| Pin 24 | RC7 — PORT C digital I/O bit 7 |
| Pin 25 | RA0 — PORT A digital I/O bit 0 |
| Pin 26 | RA1 — PORT A digital I/O bit 1 |
| Pin 27 | VDD — Positive supply voltage |
| Pin 28 | VDD — Positive supply voltage (alternate VDD pin) |
Typical Applications
PIC16C57-HSI/SO is suitable for 6 applications: Appliance Control Board, Remote Keyless Entry (RKE) Fob, LED Lighting Controller, Security Sensor Interface, Industrial Control Panel I/O, Consumer Toy and Game Controller.
Appliance Control Board
The PIC16C57-HSI/SO suits appliance control boards such as washing-machine timers, microwave user interfaces, and dishwasher cycle controllers where 20 I/O pins drive relays, read keypad matrices, and sweep 7-segment or LCD displays. Its 3 KB OTP program memory stores finite state-machine logic for cycle sequencing; at 20 MHz the 5 MIPS throughput handles multiplexed key scans within sub-millisecond budgets. The 20 MHz HS oscillator with internal option allows the MCU to start without an external crystal, reducing BOM cost. Power dissipation stays low because the fully static CMOS core idles when not servicing interrupts. The two-level stack is acceptable for flat state-machine firmware architectures typical in white-goods designs.
Recommended
Remote Keyless Entry (RKE) Fob
The PIC16C57-HSI/SO powers simple remote keyless-entry keyfobs where a button press wakes the part, transmits a fixed code via a 315/433 MHz SAW-based transmitter, then returns to sleep. The 20 MHz HS oscillator settles fast enough for sub-50 ms wake-and-transmit latency, while the OTP program memory holds fixed rolling-code or fixed-code firmware once programmed. Its low pin count (20 I/O) and small 28-SOIC footprint fit inside a CR2032-battery keyfob housing. Power consumption stays low because the static CMOS core draws near-zero current when the oscillator is stopped between button presses. The HSI industrial temperature rating covers automotive cabin environments.
Recommended
LED Lighting Controller
The PIC16C57-HSI/SO drives multi-channel LED controllers and decorative-lighting sequencers where 20 I/O pins drive MOSFETs or constant-current drivers for RGB LED strings. The 20 MHz instruction rate supports PWM dimming frequencies above 1 kHz to avoid visible flicker, while the 3 KB program memory stores lookup tables for color sequences. The 28-SOIC footprint allows compact PCB placement in 12-24V constant-voltage LED strip controllers. Two-level hardware stack is acceptable for the flat look-up-table-based firmware. The HS oscillator variant with internal option eliminates external crystal cost in cost-sensitive decorative-lighting products.
Recommended
Security Sensor Interface
The PIC16C57-HSI/SO works as a sensor-interface MCU in PIR motion detectors, smoke-alarm signal-conditioning boards, and glass-break detectors. Its 20 MHz throughput handles filtered sensor-signal polling within millisecond budgets, while the 8-bit TMR0 generates precise timing for alarm-event debounce windows. The 3 KB OTP memory stores device-ID, alarm-logic state machine, and self-test routines. Industrial temperature grade supports unheated indoor industrial sites and outdoor enclosures. The 28-SOIC's 7.50 mm body height fits inside slim smoke-alarm housings alongside the piezo sounder and PIR sensor.
Recommended
Industrial Control Panel I/O
The PIC16C57-HSI/SO handles discrete I/O expansion in industrial control panels where it scans 16-20 pushbuttons and drives 16-20 indicator LEDs or relays via transistors. Its deterministic 5 MIPS execution guarantees sub-100 microsecond input-to-output latency, important for safety stop-categories 1 and 2 PLC I/O modules. The 28-SOIC package allows panel-mount PCBs with automated pick-and-place. The industrial temperature rating suits factory-floor cabinets. Two-level stack limits firmware to flat task-loop patterns, which is fine for I/O scanning. Migration to PIC16F57-I/SO is recommended for new designs needing ICSP.
Recommended
Consumer Toy and Game Controller
The PIC16C57-HSI/SO powers consumer toys and game controllers where 20 I/O pins drive servo motors, LEDs, sound chips, and read button or joystick inputs. Its 20 MHz instruction throughput provides smooth servo PWM updates above 50 Hz refresh rates, while 3 KB program memory holds multi-mode game logic. The 28-SOIC footprint is small enough to fit inside handheld toy enclosures, and the 5V supply aligns with hobby-servo power rails. The HS oscillator variant tolerates wide temperature variations in toy environments. The static CMOS design's ability to stop the oscillator during inactivity extends battery life on portable toys.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C57-HSI/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F57-I/SO | PIC16C57-HSI/P | PIC16C57-HSE/SO | PIC16C57C-20/SO |
|---|---|---|---|---|---|
| Package | 28-SOIC (7.50 mm) | 28-SOIC (7.50 mm) - same | 28-PDIP - same die, different package | 28-SOIC (7.50 mm) - same | 28-SOIC (7.50 mm) - same |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Program Memory Type | OTP (3 KB) | Flash (3 KB) - upgrade | OTP (3 KB) - same | OTP (3 KB) - same | OTP (3 KB) - same |
| Maximum CPU Frequency | 20 MHz | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - same |
| RAM Size | 72 bytes | 72 bytes - same | 72 bytes - same | 72 bytes - same | 72 bytes - same |
| Number of I/O Pins | 20 | 20 - same | 20 - same | 20 - same | 20 - same |
| Hardware Stack Depth | 2 levels | 2 levels - same | 2 levels - same | 2 levels - same | 2 levels - same |
| Lifecycle Status | NRND | Active - recommended upgrade | NRND - same | NRND - same | NRND - same |
Key Differentiators
- Flash-reprogrammable upgrade path exists in same package (vs PIC16F57-I/SO)
- Industrial temperature grade option available (vs PIC16C57-HSE/SO)
- Through-hole prototyping variant available (vs PIC16C57-HSI/P)
Design Notes
Estimated: at 20 MHz clock with all 20 I/O pins sourcing 5 mA DC, the PIC16C57-HSI/SO draws roughly 25-30 mA from a 5V supply including I/O. Decouple VDD (pin 27/28) with a 0.1 microfarad ceramic capacitor placed within 5 mm of the package, plus a bulk 10 microfarad tantalum or aluminum capacitor. Pin 5/14 are both VSS; tie both to a low-impedance ground pour. The MCLR/VPP pin (pin 4) requires a 10 kohm pull-up to VDD for normal operation; add a 100 nF capacitor from MCLR to VSS per Microchip AN607 to filter voltage transients during power-up.
The PIC16C57-HSI/SO is OTP (One-Time-Programmable) - once programmed, the program memory cannot be erased or rewritten. Always validate firmware on a PIC16C5X JW-package emulator (UV-erasable windowed CERDIP) or on a PIC16F57-I/SO (Flash-reprogrammable cousin) before committing production parts to the OTP programmer. The two-level hardware stack limits subroutines to two nested calls; deeply nested C code or recursive algorithms will corrupt the return PC and crash. Convert deep call chains to iterative state machines or migrate to PIC16F1xxx with an 8-level stack.
Route the HS oscillator traces (OSC1 pin 16, OSC2 pin 15) as short as possible, surrounded by a guard ring tied to VSS, and keep digital signal traces at least 3 mm away. For an external 20 MHz crystal, use a fundamental-cut crystal with 15-33 pF load capacitors on each leg to VSS. For an external CMOS clock driving OSC1, leave OSC2 floating or use it as CLKOUT for synchronous designs. Keep I/O traces away from the MCLR pin's sensitive analog reset comparator; add a series resistor if MCLR traces cross noisy switching lines.
Compliance Information
RoHS and lead-free compliance status for the legacy PIC16C57-HSI/SO OTP part is not explicitly confirmed in available distributor listings as of 2026-09-17. Original PIC16C5X family pre-dates RoHS mandates; for new RoHS-compliant designs in the same 28-SOIC footprint, choose the Flash-based PIC16F57-I/SO which is RoHS compliant per Microchip. AEC-Q100 not applicable - this is a commercial/industrial MCU, not an automotive-qualified part.
