PIC12F635T-I/MD - 8-bit PIC MCU, 1.75KB Flash, 6 I/O | Microchip
MPN: PIC12F635T-I/MD β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.5412 | $0.54 |
| 10 | $0.49 | $4.90 |
| 100 | $0.43 | $43.00 |
| 500 | $0.38 | $190.00 |
| 1,000 | $0.34 | $340.00 |
| 3,000 | $0.3 | $900.00 |
PIC12F635T-I/MD Overview
An 8-bit PIC microcontroller is a low-power, deterministic single-core processor built on a Harvard architecture with separate program and data buses, belonging to the broader microcontroller -> embedded controller -> semiconductor category. Its strengths are low cost, low quiescent current, fast interrupt response, and a tiny instruction set that compiles to highly compact code - making PIC MCUs dominant in cost-sensitive, pin-constrained, battery-powered applications such as remote controls, sensor nodes, and appliance front panels.
Key features include 6 general-purpose I/O pins (each capable of interrupt-on-change and weak pull-up), one analog comparator with internal programmable reference, an 8-bit and a 16-bit timer, a hardware UART, and the LF (low-frequency) signal-chain block for KEELOQ-compatible security learning applications. The device includes an internal 4/8 MHz oscillator calibrated to +/-1 percent, supporting both INTOSC and low-power LFINTOSC modes for sleep-current-sensitive designs. Hardware diagnostic features such as on-chip debug and In-Circuit Serial Programming (ICSP) are retained on dedicated pins.
Architecturally, the PIC12F635 uses a 14-bit wide instruction word with single-cycle execution except for program branches, and an 8-level deep hardware stack. The AES encryption engine, security lock bits, and KEELOQ decoder are integrated to support encrypted remote-entry receivers. Internal peripherals connect via an 8-bit data bus and are mapped into the SFR space; the device supports up to 256 bytes of register-mapped SRAM with banked access for low-end C compilers.
Typical applications include automotive RKE/remote keyless entry receivers, secure token and authentication peripherals, simple sensor signal-conditioning front ends with on-chip comparator output, low-power remote-control transmitters, and consumer appliance user-interface controllers. The DFN-8 package is suited to space-limited designs where height must stay under 1 mm, including key fobs, smart-card readers, and sealed sensor pods.
When designing with this device, place the ICSPDAT/ICSPCLK trace pair symmetrically to avoid coupling noise into the analog comparator input, and provide a bulk decoupling capacitor (>=1 uF) plus a high-frequency 100 nF cap directly across VDD/VSS. Programming must leave both the clock and data ICSP lines accessible through test points or pads to allow in-field firmware updates via Microchip's MPLAB tools.
Drop-in alternatives for PIC12F635T-I/MD β 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 PIC12F635T-I/MD (same form factor and footprint) β differing in Timers, Package, Core Architecture, Program Memory (Flash), Communication.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC12F635-I/MD
β Drop-Inπ Reference alternative (not in catalog)
PIC12F635T-I/MF
β Drop-Inπ Reference alternative (not in catalog)
PIC12F636-I/MD
β Drop-Inπ Reference alternative (not in catalog)
PIC12F609-I/MD
β Drop-Inβ In Stock
$0.71 / Unit
View Datasheet βPIC12F615-I/MD
β Drop-Inβ In Stock
$0.64 / Unit
View Datasheet βPIC12F635T-I/MD Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-bit |
| Program Memory Size | 1.75 KB Flash |
| RAM Size | 64 bytes |
| EEPROM Size | 128 bytes |
| Maximum Clock Speed | 20 MHz |
| Supply Voltage Range | 2.0 V to 5.5 V |
| Number of I/O Pins | 6 |
| Peripherals | Brown-out Detect, Comparator, POR, WDT |
| Connectivity | UART/USART |
| Timers | 1 x 8-bit, 1 x 16-bit |
| Data Converters | Analog comparator only (no ADC) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 8-pin DFN (3 x 3 x 0.9 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (Unlimited) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC12F635T-I/MD Pin Configuration
| Pin 1 | VDD β Positive power supply (2.0 V to 5.5 V) |
| Pin 2 | GP5/T1CKI/OSC1/CLKIN/ICSPCLK β GPIO5 / Timer1 clock / external oscillator input / ICSP clock |
| Pin 3 | GP4/AN3/T1G/OSC2/CLKOUT/ICSPDAT β GPIO4 / analog channel 3 / Timer1 gate / oscillator output / ICSP data |
| Pin 4 | GP3/MCLR/VPP β GPIO3 / Master Clear reset (active-low) / programming voltage input |
| Pin 5 | GP2/AN2/T0CKI/INT/COUT/CCP1 β GPIO2 / analog channel 2 / Timer0 clock / external interrupt / comparator output / CCP1 |
| Pin 6 | GP1/AN1/CIN-/VREF/ICSPCLK β GPIO1 / analog channel 1 / comparator inverting / voltage reference / ICSP clock |
| Pin 7 | GP0/AN0/CIN+/INT0/ICSPDAT β GPIO0 / analog channel 0 / comparator non-inverting / external interrupt / ICSP data |
| Pin 8 | VSS β Ground reference |
Typical Applications
PIC12F635T-I/MD is suitable for 6 applications: Automotive Remote Keyless Entry (RKE) Receivers, Secure Authentication Tokens and Encrypted Fobs, Low-Power Remote Control Transmitters, Compact Sensor Signal-Conditioning Front Ends, Consumer Appliance User-Interface Controllers, Industrial Sensor Pods and Edge Nodes.
Automotive Remote Keyless Entry (RKE) Receivers
The PIC12F635T-I/MD is a workhorse for automotive RKE receiver nodes thanks to its integrated KEELOQ hardware decoder and hardware AES block, which decode encrypted rolling-code transmissions from a key fob with zero software overhead. Its 8-pin DFN package (3 x 3 mm) and 2.0-5.5 V supply operate directly from a 3 V coin cell or 5 V regulated body rail, while the on-chip analog comparator and CVREF simplify wake-on-RF signal conditioning without an external op-amp. With 1.75 KB Flash and 128 B EEPROM, the firmware fits a full KEELOQ decoder plus an LED/Horn driver state machine. Compared with a software-only AES approach on a generic 8-bit MCU, the hardware block reduces code size by 1.5-2 KB and shortens decode latency, helping meet the strict response-time budget required for body-control modules.
Recommended
Secure Authentication Tokens and Encrypted Fobs
Authentication peripherals such as banking dongles, smart-card readers, and access-control fobs benefit from the PIC12F635T-I/MD's hardware AES block and code-protect lock bits, which provide tamper-resistant key storage without external secure elements. The 8-pin DFN footprint keeps the BOM small enough to fit inside an inline key-fob shell, and the 20 MHz clock allows sub-50 ms cryptographic challenge-response operations at typical security-token rates. Its -40 C to +85 C industrial temperature range ensures operation in outdoor or vehicle cabin environments. Compared with software-AES on a generic PIC10F or AVR, the dedicated hardware AES engine reduces active current and shortens wake-to-respond latency, critical for battery-life targets above 3 years on a CR2032.
Recommended
Low-Power Remote Control Transmitters
The PIC12F635T-I/MD suits low-power remote-control transmitters where sleep current below 1 uA is mandatory and a small, cheap 8-pin controller is preferred over a larger Cortex-M device. Its LFINTOSC (low-frequency internal oscillator) drives Watchdog wake-up cycles that allow years of standby on a CR2032 cell. The integrated analog comparator can be wired to the SAW or MEMS sensor for proximity-trigger functions, and the 6 GPIO pins support matrix-key or pushbutton inputs plus an IR LED driver output. Compared with a discrete 555 timer + button matrix, the PIC12F635 firmware-defined behavior lets one device cover multiple SKUs with different key codes - a major logistics simplification for consumer electronics OEMs.
Recommended
Compact Sensor Signal-Conditioning Front Ends
In compact sensor modules where PCB area is at a premium, the PIC12F635T-I/MD provides a comparator-based signal-conditioning front end that filters and digitizes analog sensor outputs without an external op-amp chain. The on-chip CVREF (programmable voltage reference) supplies a stable threshold for window-comparator arrangements, while the UART/USART ports the conditioned digital signal to a host MCU or wireless transceiver. The 8-pin DFN package enables the entire analog front end plus digital interface to occupy less than 25 mm squared of PCB. Compared with a discrete op-amp + comparator + MCU chain, the PIC12F635 solution reduces BOM cost by 30-50 percent and shrinks the bill-of-materials for thermocouples, photo-diodes, and Hall-effect sensors.
Recommended
Consumer Appliance User-Interface Controllers
The PIC12F635T-I/MD fits appliance user-interface controllers such as coffee machines, microwave ovens, and air purifiers that need a small, reliable 8-bit MCU to scan a key matrix, drive a 7-segment display or LED bar, and talk to the main appliance MCU over UART. The 6 GPIO support a 3x3 key matrix with interrupt-on-change wake-up, the 16-bit timer provides accurate debounce and LED-PWM dimming, and the on-chip comparator supports capacitive-touch sensing via an external RC network. The 2.0-5.5 V supply works directly from a 3.3 V or 5 V rail, while -40 C to +85 C operation covers kitchen and laundry environments. Compared with mechanical switches and discrete logic, the firmware-driven approach enables multiple SKUs on a single hardware platform.
Recommended
Industrial Sensor Pods and Edge Nodes
Industrial sensor pods for temperature, pressure, and process monitoring benefit from the PIC12F635T-I/MD's small footprint, wide supply range, and industrial temperature rating. The internal 4/8 MHz calibrated oscillator eliminates external clock components, the BOD (brown-out detect) prevents corruption during supply dips, and the 6 GPIO can drive a sensor, LED indicator, and UART/RS-485 link without expansion. The hardware AES engine lets the pod sign data packets before transmission, supporting authenticated telemetry in SCADA systems. Compared with a fully analog sensor pod, the PIC12F635 delivers digital calibration, remote firmware update via ICSP, and signed telemetry at minimal incremental cost - key features for Industry 4.0 retrofits.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F635T-I/MD β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F635-I/MD | PIC12F635T-I/MF | PIC12F636-I/MD | PIC12F609-I/MD | PIC12F615-I/MD |
|---|---|---|---|---|---|---|
| Package | DFN-8 (3x3 mm) | DFN-8 (3x3 mm) - same | DFN-8 (6x5 mm) - same family, larger | DFN-8 (3x3 mm) - same | DFN-8 (3x3 mm) - same | DFN-8 (3x3 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.75 KB Flash | 1.75 KB Flash | 1.75 KB Flash | 2 KB Flash | 1 KB Flash | 1.75 KB Flash |
| EEPROM Size | 128 bytes | 128 bytes | 128 bytes | 256 bytes | 0 bytes | 0 bytes |
| KEELOQ Hardware Decoder | Yes | Yes | Yes | Yes | No | No |
| ADC | No (comparator only) | No (comparator only) | No (comparator only) | No (comparator only) | No (comparator only) | 10-bit ADC |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
Key Differentiators
- Integrated KEELOQ hardware decoder and AES engine (vs PIC12F609-I/MD)
- EEPROM-equipped for parameter storage (vs PIC12F615-I/MD)
- Comparator-based analog front end without external op-amp (vs PIC10F320-E/MC)
Design Notes
Place a 100 nF decoupling capacitor as close as possible to the VDD pin (pin 1) and a bulk 1 uF or 10 uF capacitor on the same power rail to suppress VDD glitches when the internal oscillator switches banks. The PIC12F635's brown-out detect (BOD) must be enabled in configuration words for safety-critical applications to avoid corruption during supply brown-out; set the BOD threshold to 2.0 V minimum to ensure full Flash read/write integrity across the entire supply range.
When laying out the 8-pin DFN (3 x 3 mm) package, route the ICSPDAT/ICSPCLK pair on adjacent layers to keep programming-trace lengths symmetric and short (<25 mm). The exposed thermal pad (EP) on pin 8 / VSS must be soldered to a continuous ground pour that is stitched with multiple vias to the inner ground plane for thermal dissipation - on battery applications, this also lowers the impedance of the VSS return path. Avoid routing RF or analog signal traces under the ICSP lines to minimize crosstalk into the comparator inputs.
A common pitfall when migrating PIC12F635 firmware between DFN and DIP packages is forgetting that the MCLR pin (pin 4) is enabled by default; if the application does not need an external reset, configure MCLR as an internal-only reset (CONFIG_MCLRE_OFF) and use GP3 as GPIO, otherwise the pin remains an input with weak pull-up. Another frequent mistake is leaving the LVP (low-voltage programming) bit enabled in production code - this converts the PGM pin into a programming input and can cause unexpected behavior if the pin floats. Set LVP off for production firmware to free the pin for GPIO or peripheral use.
Compliance Information
RoHS compliant and lead-free per Microchip product page; halogen-free status not explicitly stated in verified web data. Not AEC-Q100 qualified (industrial grade only).
