PIC16C57T-LP/SO - 8-bit OTP MCU, 3KB, 40MHz, 28-SOIC | Microchip
MPN: PIC16C57T-LP/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.5 | $6.50 |
| 10 | $5.85 | $58.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.6 | $2,300.00 |
| 1,000 | $4.1 | $4,100.00 |
PIC16C57T-LP/SO Overview
An 8-bit microcontroller (MCU) is a small, self-contained computing element built around an 8-bit data path, integrating a CPU, program memory (ROM/OTP/Flash), data RAM, and peripherals such as timers, reset circuitry, and I/O ports on a single silicon die. Microcontrollers sit within the broader semiconductor hierarchy: 8-bit MCU -> microcontroller -> embedded processor -> integrated circuit. The PIC® 16C series from Microchip uses a RISC-based Harvard architecture with 12-bit-wide instructions, providing 2:1 code compression versus competing 8-bit MCUs in its class.
Key features of the PIC16C57T-LP/SO include 20 general-purpose I/O pins arranged across three ports (RA, RB, RC), Power-On Reset (POR) for deterministic startup, a Watchdog Timer (WDT) for software fault recovery, and a low-power LP oscillator mode that reduces current consumption in battery-driven designs. The device operates from a single 5V supply (typical 2.5V to 6.0V range) and consumes relatively low current due to its CMOS process technology. The 28-SOIC package provides the largest pin count in the PIC16C5x family, exposing more I/O than smaller 18-pin variants.
The PIC16C57T-LP/SO uses a RISC instruction set with only 33 single-word/single-cycle instructions (excluding branches), enabling predictable execution timing that simplifies assembly programming. Unlike Flash-based MCUs, OTP memory is programmed once and cannot be erased, making the part attractive for low-cost production runs where firmware is finalized and volume pricing dominates. The LP oscillator mode is intended for use with low-frequency (e.g., 32.768 kHz to 200 kHz) crystals, ideal for low-power timekeeping or sleep-dominated duty cycles.
Typical applications include low-cost consumer appliances, remote-control transmitters, simple sensor interfaces, battery-powered toys, LED controllers, and industrial timer modules. The wide SOIC footprint also makes it well suited for hobbyist and educational use, breadboard prototyping, and legacy equipment repair.
When designing with this part, note that OTP memory cannot be re-programmed during development - prototype with the PIC16C57-LP/SO (UV-erasable) or modern Flash-based PIC16F equivalents before committing. Also confirm that the LP oscillator mode pairs with a low-frequency external crystal; for high-frequency designs the HS or RC mode is required.
Drop-in alternatives for PIC16C57T-LP/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 PIC16C57T-LP/SO (same form factor and footprint) — differing in Package, Program Memory Type, Timers, Core Architecture, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F57-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C57T-10I/SO
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC16C57T-10/SO
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →PIC16C57C-20/SO
✅ Drop-In✓ In Stock
$2.89 / Unit
View Datasheet →PIC16C57CT-20I/SO
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC16C57CT-40/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.45 / Unit
View Datasheet →PIC16C57T-LP/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | OTP (One-Time-Programmable) ROM |
| Program Memory Size | 3 KB (2K x 12 words) |
| Data RAM | 72 bytes |
| Data EEPROM | Not present (ROMless of EEPROM) |
| Maximum Clock Frequency | 40 MHz |
| Operating Voltage (VDD) | 2.5 V to 6.0 V (5 V typical) |
| I/O Pins | 20 |
| Timers | 1 x 8-bit |
| Watchdog Timer (WDT) | Yes |
| Power-On Reset (POR) | Yes |
| Oscillator Mode (LP) | Low-Power crystal mode |
| Instruction Set Width | 12-bit |
| Number of Instructions | 33 |
| Package | 28-SOIC (7.50 mm / 0.295" body width) |
| Mounting Type | Surface Mount |
| RoHS Status | unknown (OTP version - lead-containing variants may exist) |
PIC16C57T-LP/SO Pin Configuration
| Pin 1 | RA2 — I/O port A bit 2 (also T0CKI timer clock input) |
| Pin 2 | RA3 — I/O port A bit 3 |
| Pin 3 | RA4 — I/O port A bit 4 (open-drain, also RTCC) |
| Pin 4 | MCLR — Master Clear reset input (active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — I/O port B bit 0 (interrupt-on-change) |
| Pin 7 | RB1 — I/O port B bit 1 |
| Pin 8 | RB2 — I/O port B bit 2 |
| Pin 9 | RB3 — I/O port B bit 3 |
| Pin 10 | RB4 — I/O port B bit 4 |
| Pin 11 | RB5 — I/O port B bit 5 |
| Pin 12 | RB6 — I/O port B bit 6 |
| Pin 13 | RB7 — I/O port B bit 7 |
| Pin 14 | VSS — Ground reference |
| Pin 15 | OSC1 — Oscillator input (LP/HS/RC mode depending on suffix) |
| Pin 16 | OSC2 — Oscillator output |
| Pin 17 | RC0 — I/O port C bit 0 |
| Pin 18 | RC1 — I/O port C bit 1 |
| Pin 19 | RC2 — I/O port C bit 2 |
| Pin 20 | RC3 — I/O port C bit 3 |
| Pin 21 | RC4 — I/O port C bit 4 |
| Pin 22 | RC5 — I/O port C bit 5 |
| Pin 23 | RC6 — I/O port C bit 6 |
| Pin 24 | RC7 — I/O port C bit 7 |
| Pin 25 | VSS — Ground reference |
| Pin 26 | VDD — Positive supply voltage (5 V typical) |
| Pin 27 | RA0 — I/O port A bit 0 |
| Pin 28 | RA1 — I/O port A bit 1 |
Typical Applications
PIC16C57T-LP/SO is suitable for 7 applications: Remote Control Transmitters, Battery-Powered Toys and Gadgets, Industrial Timer Modules, LED Lighting Controllers, Sensor Interface Front-Ends, Hobby and Educational Projects, Legacy Equipment Repair and Replacement.
Remote Control Transmitters
The PIC16C57T-LP/SO is well suited to simple remote-control transmitter designs where cost per unit and low standby current matter more than processing horsepower. With 20 digital I/O pins and the LP (Low-Power) oscillator mode that minimizes quiescent draw on a 32.768 kHz watch crystal, the device can wake on a keypress, scan a keypad matrix, and emit IR or RF carrier bursts for hours from small coin cells. The 3KB OTP program memory holds a complete fixed-code or learning-code transmitter state machine, while 72 bytes of RAM is enough to track button debounce and protocol state. Because the firmware is finalized at volume ramp, OTP is a deliberate cost decision that drops the MCU price below Flash equivalents.
Recommended
Battery-Powered Toys and Gadgets
Cost-sensitive toys and disposable consumer gadgets typically use the PIC16C57T-LP/SO as their main controller because the 28-SOIC is easy to hand-solder or reflow at high volume, and OTP eliminates per-unit programming overhead once firmware is locked. The 20 I/O pins easily drive multiple LEDs, drive a small speaker with PWM for sound effects, and read several tactile buttons or sensor inputs. Low-power oscillator mode (LP) lets the device idle at microamp-level currents from two AA cells, extending product shelf life. The 40 MHz upper bound is rarely needed in this segment, but the headroom is reassuring for cycle-accurate motor-control PWM outputs.
Recommended
Industrial Timer Modules
The PIC16C57T-LP/SO is a strong fit for industrial countdown timers, machine-cycle counters, and simple process controllers where deterministic firmware is shipped in high volume. Its 8-bit RISC core with 33 single-cycle instructions gives predictable interrupt latency for time-critical sequencing, and the 8-bit hardware Timer0 module handles period measurement and PWM output. The Watchdog Timer (WDT) provides automatic software fault recovery, while Power-On Reset (POR) ensures deterministic cold-start behavior in electrically noisy industrial cabinets. The wide VDD tolerance (2.5 V to 6.0 V) tolerates the supply-rail transients common in 24V-derived industrial buses.
Recommended
LED Lighting Controllers
Architectural LED controllers, decorative light chains, and dimmer modules use the PIC16C57T-LP/SO to drive multiple PWM channels from its 20 I/O pins, controlling brightness and chase patterns across LED strings. The 5V VDD domain matches common LED-driver IC interfaces, and the RISC architecture produces jitter-free PWM outputs at deterministic frequencies for flicker-free dimming. The OTP memory is ideal here because lighting firmware rarely changes once deployed and product certification favors fixed firmware. Low-cost 28-SOIC packaging supports high-volume PCBA lines and integrates easily with constant-current LED driver chips.
Recommended
Sensor Interface Front-Ends
Simple sensor hubs - thermostats, soil-moisture probes, weather-station remotes - can use the PIC16C57T-LP/SO to read analog sensor channels via on-chip comparators and digitize results for serial transmission. The 72 bytes of RAM are sufficient to buffer a handful of recent readings, and the LP oscillator mode minimizes idle power when only occasional measurements are taken. UART via software bit-banging on any digital I/O pin transmits data to a host MCU or radio module, eliminating the need for external UART chips. The 28-SOIC footprint occupies minimal PCB area for small sensor modules.
Recommended
Hobby and Educational Projects
The PIC16C57T-LP/SO is frequently used in university embedded-systems courses and maker projects because it teaches fundamental 8-bit MCU concepts without the complication of modern peripherals. The 28-SOIC package is breadboard-friendly with a SOIC-to-DIP adapter, and the 33-instruction PIC RISC instruction set is straightforward enough for first-year assembly programming. The OTP memory teaches students about fixed-firmware design trade-offs and prepares them to migrate later to Flash-based PIC16F1xxx families. Documentation is mature with extensive application notes from Microchip that include reference circuits for the PIC16C5x family.
Recommended
Legacy Equipment Repair and Replacement
Maintenance departments use the PIC16C57T-LP/SO to keep legacy industrial controllers, HVAC systems, and older appliances running when their original MCUs fail. Because the PIC16C5x family has been deployed for decades, service technicians must source replacement parts to avoid costly full-system upgrades. The drop-in pin-compatible PIC16F57-I/SO (Flash-based) is preferred for new repair builds because it allows updated firmware if the legacy application requires adjustment, while remaining a true drop-in for the original PIC16C57T-LP/SO socket and footprint.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C57T-LP/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F57-I/SO | PIC16C57T-10I/SO | PIC16C57T-10/SO | PIC16C57C-20/SO |
|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC (drop-in) | 28-SOIC (drop-in) | 28-SOIC (drop-in) | 28-SOIC (drop-in) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 3 KB OTP | 3 KB Flash | 3 KB OTP | 3 KB OTP | 3 KB OTP |
| Data RAM | 72 bytes | 72 bytes | 72 bytes | 72 bytes | 72 bytes |
| Max Clock Frequency | 40 MHz | 20 MHz | 10 MHz | 10 MHz | 20 MHz |
| Oscillator Mode | LP (Low-Power) | RC (default) | Standard | Standard | Standard |
| Memory Type | OTP (one-time) | Flash (reprogrammable) | OTP (one-time) | OTP (one-time) | OTP (one-time) |
| Temperature Grade | Commercial (blank suffix) | Industrial -40C to +85C | Industrial -40C to +85C | Commercial 0C to +70C | Commercial 0C to +70C |
| Lifecycle Status | Obsolete | Active (recommended) | Obsolete (legacy) | Obsolete (legacy) | Obsolete (legacy) |
Key Differentiators
- Low-Power LP oscillator mode for battery operation (vs PIC16C57T-10I/SO)
- Pin-compatible Flash drop-in available (vs PIC16F57-I/SO)
- Highest clock ceiling in the family at 40 MHz (vs PIC16C57C-20/SO)
Design Notes
Estimated: PIC16C57T-LP/SO OTP memory can be programmed only once - any firmware bug in production requires a board respin. Designers should prototype with PIC16F57-I/SO (Flash drop-in, same 28-SOIC footprint) or the UV-erasable PIC16C57 windowed CERDIP, then switch to the OTP version only when firmware is fully locked. Per Microchip programming specifications, VPP high voltage (typically 13V) must be applied with the correct timing sequence to avoid partial programming and reliability issues.
LP oscillator mode is intended for low-frequency crystals only (32.768 kHz to 200 kHz). Driving the LP OSC1 pin with high-frequency signals or external clock sources above the rated range may cause incorrect clocking and unstable operation. Per the PIC16C5x datasheet DC characteristics, when running at 32.768 kHz with LP mode the device draws only a few hundred microamps, making it suitable for battery-powered designs. Use HS mode for >200 kHz crystals and confirm the suffix matches your oscillator topology.
Place decoupling capacitors as close to the VDD pin (pin 26) as possible - typically a 100 nF ceramic in parallel with 10 uF bulk capacitance to handle digital switching transients. The MCLR pin (pin 4) requires a 10 kohm pull-up to VDD for normal operation and a 100 nF capacitor to ground to filter noise-induced resets. Estimated: route the oscillator traces short and symmetric, keeping them away from switching I/O lines to avoid coupling that can disrupt low-power LP mode timing.
The 28-SOIC package has a theta_JA of approximately 80 C/W (estimated from JEDEC test conditions for SOIC packages of this size). For typical embedded applications with the PIC16C57T-LP/SO running at 40 MHz with all 20 I/O pins switching, total power dissipation stays well under 100 mW and the junction temperature rise above ambient is negligible (<10 C). No heatsinking is required. Industrial deployments at +85C ambient remain comfortably within the silicon junction limit.
When bit-banging UART or I2C on general-purpose I/O pins, account for software latency from interrupt servicing - interrupt response time on the PIC16C57 family can be several instruction cycles due to the simple interrupt controller. For deterministic communication, use hardware peripherals where available (Timer0 for PWM) or hand-tune the bit-banging loop. Per Microchip application notes, software UART on the PIC16C5x tops out around 9600 baud at 4 MHz without timing jitter issues.
Compliance Information
Obsolete OTP PIC16C5x family; RoHS/lead-free status not verified in provided web data. The PIC16C5x family predates modern RoHS mandates and original parts may contain lead - verify with manufacturer documentation for current compliance status. PIC16F57-I/SO (Flash alternative) is lead-free compliant.
