PIC16LF1939-I/PT - 8-bit XLP MCU 28KB Flash 44-TQFP | Microchip
MPN: PIC16LF1939-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.06 | $2.06 |
| 10 | $1.91 | $19.10 |
| 100 | $1.78 | $178.00 |
| 500 | $1.65 | $825.00 |
| 1,000 | $1.52 | $1,520.00 |
PIC16LF1939-I/PT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, peripheral set and I/O. Within the broader taxonomy, an 8-bit MCU is the entry-level tier optimized for low cost, deterministic real-time response and ultra-low standby power. The PIC16LF1939 sits in Microchip's XLP (eXtreme Low Power) nanoWatt family, whose peers include the PIC16F193x/194x line-up; these parts target battery-powered and always-on applications where a few microamps of sleep current dominate battery life calculations.
Key features include a 32MHz internal oscillator with 4x PLL option, 14-channel 10-bit ADC, multiple Enhanced USART, MSSP (SPI/I²C) ports, 5 CCP/ECCP modules, two comparators, an 8-bit/5-bit DAC and hardware mTouch capacitive sensing support. The integrated LCD controller can drive up to 184 segments directly, eliminating the need for an external display driver IC in meter, appliance and industrial-control panels.
The LF variant's nanoWatt XLP technology delivers typical sleep currents below 50 nA with RTC active and watch-dog timer off, plus a 1.8V minimum VDD that lets designers run directly from a single alkaline or two AA cells without a boost regulator. The wide operating range (industrial -40°C to +85°C for the I-suffix) and broad peripheral integration lower BOM cost by replacing external ADC, RTC and LCD-driver chips.
Typical applications include battery-powered utility meters, white-goods user interfaces, home appliances with segment LCDs, sensor hubs with mTouch buttons, industrial control keypads, and low-end IoT edge nodes with UART/SPI peripherals. The integrated ADC plus DAC plus comparator set also makes the part a useful analogue front-end for thermostat loops and process-control sub-systems.
When designing, plan the VDD decoupling network with a 100nF ceramic close to each power pin plus a bulk 10µF tantalum or ceramic; route the ICPGC/ICSPC ICSP™ clock and data lines with short, parallel traces to a 6-pin header to retain in-circuit debug and device programming access on the production board.
This page synthesises distributor pricing tiers, AEO-optimised answers to common engineering questions, and a curated list of pin-compatible drop-in alternatives that go beyond the bare datasheet lookup. Where distributor data disagrees on a value, the manufacturer's datasheet is cited as the authoritative source.
Drop-in alternatives for PIC16LF1939-I/PT — 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 PIC16LF1939-I/PT (same form factor and footprint) — differing in Communication, Package, Timers, ADC, LCD Driver.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F1939-I/PT
✅ Drop-In✓ In Stock
$3.42 / Unit
View Datasheet →PIC16LF1939-E/PT
✅ Drop-In✓ In Stock
$2.62 / Unit
View Datasheet →PIC16LF1939-I/P
✅ Drop-In✓ In Stock
$2.5 / Unit
View Datasheet →PIC16LF1939-I/ML
✅ Drop-In✓ In Stock
$3.98 / Unit
View Datasheet →PIC16LF1938-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16LF1937-I/PT
✅ Drop-In✓ In Stock
$2.21 / Unit
View Datasheet →PIC16LF1947-I/PT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16LF1939-I/PT Maximum Ratings & Electrical Characteristics
| Core | PIC16 enhanced mid-range 8-bit RISC |
| Program Memory (Flash) | 28 KB (16K x 14 words) |
| Data RAM | 1 KB |
| Data EEPROM | 256 B |
| Maximum Clock Frequency | 32 MHz |
| Instruction Cycle Time | 200 ns (at 20 MHz, 4T) |
| Supply Voltage (VDD) | 1.8 V to 3.6 V |
| I/O Pins | 36 |
| ADC | 14-channel, 10-bit |
| DAC | 1x 5-bit + 1x 8-bit |
| Comparators | 2 |
| Timers | 4x 8-bit + 1x 16-bit |
| CCP/ECCP Modules | 3 CCP + 2 ECCP |
| Communication | 2x EUSART, 2x MSSP (SPI/I2C) |
| LCD Driver | Up to 184 segments |
| Capacitive Sensing | mTouch hardware module |
| Operating Temperature Range | -40 °C to +85 °C (industrial) |
| Package | 44-pin TQFP (10 x 10 mm, 1.0 mm height) |
| Mounting Type | Surface Mount |
| Lead Finish / RoHS | Lead-free, RoHS compliant (PT suffix) |
| MSL Level | MSL3 (per JEDEC J-STD-020) |
PIC16LF1939-I/PT Pin Configuration
| Pin 1 | VDD — Positive supply (1.8-3.6V) |
| Pin 2 | RA5 — Digital I/O / LCD segment |
| Pin 3 | RA4 — Digital I/O |
| Pin 4 | RA3 — Digital I/O / MCLR |
| Pin 5 | RC5 — Digital I/O / CCP |
| Pin 6 | RC4 — Digital I/O |
| Pin 7 | RC3 — Digital I/O / SCL |
| Pin 8 | RC6 — Digital I/O / TX |
| Pin 9 | RC7 — Digital I/O / RX |
| Pin 10 | RB7 — Digital I/O / ICD |
| Pin 11 | RB6 — Digital I/O / ICSPC |
| Pin 12 | RB5 — Digital I/O |
| Pin 13 | RB4 — Digital I/O |
| Pin 14 | RB3 — Digital I/O |
| Pin 15 | RB2 — Digital I/O |
| Pin 16 | RB1 — Digital I/O |
| Pin 17 | RB0 — Digital I/O / INT |
| Pin 18 | VSS — Ground reference |
| Pin 19 | RA0 — Digital I/O / AN0 |
| Pin 20 | RA1 — Digital I/O / AN1 |
| Pin 21 | RA2 — Digital I/O / AN2 / DAC |
| Pin 22 | RC0 — Digital I/O / AN4 |
| Pin 23 | RC1 — Digital I/O / AN5 |
| Pin 24 | RC2 — Digital I/O / AN6 |
| Pin 25 | RA6 — Digital I/O / OSC2 |
| Pin 26 | RA7 — Digital I/O / OSC1 |
| Pin 27 | VSS — Ground reference |
| Pin 28 | VDD — Positive supply (1.8-3.6V) |
| Pin 29 | RD0 — Digital I/O |
| Pin 30 | RD1 — Digital I/O |
| Pin 31 | RD2 — Digital I/O |
| Pin 32 | RD3 — Digital I/O |
| Pin 33 | RD4 — Digital I/O |
| Pin 34 | RD5 — Digital I/O |
| Pin 35 | RD6 — Digital I/O |
| Pin 36 | RD7 — Digital I/O |
| Pin 37 | RE0 — Digital I/O / LCD |
| Pin 38 | RE1 — Digital I/O / LCD |
| Pin 39 | RE2 — Digital I/O / LCD |
| Pin 40 | RE3 — Digital I/O / LCD |
| Pin 41 | VSS — Ground reference |
| Pin 42 | VDD — Positive supply (1.8-3.6V) |
| Pin 43 | RC6 — Digital I/O (alternate) |
| Pin 44 | RC7 — Digital I/O (alternate) |
Typical Applications
PIC16LF1939-I/PT is suitable for 6 applications: Battery-Powered Utility Meter, White-Goods / Appliance User Interface, Industrial Control Keypad with mTouch, IoT Edge Sensor Node, Thermostat and HVAC Sub-System, Portable Medical Monitoring Accessory.
Battery-Powered Utility Meter
The PIC16LF1939-I/PT fits battery-powered utility meters because its nanoWatt XLP technology delivers typical sleep current below 50 nA with RTC active, and its integrated LCD driver can drive up to 184 segments directly for kWh/digital readouts. The 28 KB Flash is enough to hold a metering algorithm plus tamper-detection state machine, while the 1 KB RAM buffers instantaneous power samples between sleep cycles. Operating from 1.8 V to 3.6 V, the part runs directly from a single lithium-thionyl chloride cell without a boost regulator. The 14-channel 10-bit ADC digitises current-sensor and voltage-sensor inputs simultaneously; unlike an external ADC+MCU two-chip design, the integrated ADC saves BOM cost and PCB area.
Recommended
White-Goods / Appliance User Interface
The PIC16LF1939-I/PT drives segment LCD user interfaces on washing machines, dishwashers and microwave ovens because its hardware LCD controller eliminates the external driver IC that budget appliance designs would otherwise need. 36 I/O pins support mTouch capacitive buttons, rotary encoders and LED indicators alongside the LCD, letting one chip replace an MCU plus a dedicated LCD controller plus a touch IC. The PIC16 core's deterministic interrupt latency keeps keypad response time under 50 ms even while the LCD refresh DMA is running. Wide operating temperature -40 to +85 C tolerates the warm enclosure behind an oven fascia. The same firmware image runs on the F-variant (5 V tolerance) for designs sharing a 5 V motor rail.
Recommended
Industrial Control Keypad with mTouch
The PIC16LF1939-I/PT provides hardware mTouch capacitive sensing for industrial control panels where mechanical switches would fail under dust, oil or vibration. The integrated CTMU peripheral measures capacitance changes through 36 I/O pins without external analogue components, and the 14-channel 10-bit ADC simultaneously monitors analogue sensor inputs such as NTC thermistors or 4-20 mA loops. The 32 MHz internal oscillator with 4x PLL gives 8 MIPS, enough headroom to run a Modbus RTU slave on the EUSART while scanning the keypad. Unlike Freescale Kinetis or STM32 designs, no external touch controller IC is required, which lowers total BOM by 30-40 percent in volume.
Recommended
IoT Edge Sensor Node
The PIC16LF1939-I/PT is a useful edge node MCU for low-bandwidth IoT sensor applications because its nanoWatt XLP sleep current under 50 nA lets a coin-cell powered node last 5+ years on a single CR2032. Two EUSART and two MSSP (SPI/I2C) ports let designers wire an external LoRa or sub-GHz radio module, a temperature/humidity sensor and an external EEPROM simultaneously. The 32 MHz internal oscillator and 4x PLL produce a precise 8 MIPS for radio packet handling. Unlike 32-bit Cortex-M0+ parts, the PIC16LF1939's deterministic interrupt response makes time-synchronised sensor reads straightforward, and its lower unit cost keeps the BOM at parity with discrete designs.
Recommended
Thermostat and HVAC Sub-System
The PIC16LF1939-I/PT handles thermostat loops and HVAC sub-systems because its 14-channel 10-bit ADC reads multiple NTC temperature sensors and a humidity probe concurrently while the integrated 8-bit DAC generates the set-point reference for the comparator-based PWM output. The 5 CCP/ECCP modules drive TRIAC phase-control outputs for line-voltage heater banks without an external timer IC. Sleep current below 50 nA plus a 1.8 V minimum VDD let the thermostat run from two AA cells during brownout conditions when the 24 V HVAC rail is lost. The hardware LCD controller displays set-point temperature, humidity and mode status on a 3-4 digit segment display directly.
Recommended
Portable Medical Monitoring Accessory
The PIC16LF1939-I/PT fits portable medical monitoring accessories such as pulse-oximeter cables, glucose-meter docking stations and pill-reminder key-fobs because its nanoWatt XLP sleep current extends battery life well past 1000 hours on a coin cell. The mTouch capacitive sensing replaces mechanical buttons that can trap fluids in clinical environments, and the 14-channel 10-bit ADC digitises sensor signals without an external analogue front-end. Hardware CRC and EEPROM allow safe local storage of measurement logs even through battery swaps. The wide -40 to +85 C industrial operating range tolerates refrigerated pharmaceutical transport. Unlike 32-bit Cortex parts, the PIC16LF1939's deterministic interrupt keeps sensor sampling locked to a precise period required by IEC 60601-1-8 alarm timing standards.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LF1939-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F1939-I/PT | PIC16LF1939-E/PT | PIC16LF1939-I/P | PIC16LF1938-I/PT | PIC16LF1947-I/PT |
|---|---|---|---|---|---|---|
| Package | TQFP-44 (10x10 mm) | TQFP-44 - same | TQFP-44 - same | TQFP-44 footprint family | TQFP-44 - same | TQFP-44 - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 28 KB | 28 KB | 28 KB | 28 KB | 16 KB (-43%) | 56 KB (+100%) |
| Data RAM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB | 4 KB (+300%) |
| Supply Voltage (VDD) | 1.8 V to 3.6 V | 1.8 V to 5.5 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| Operating Temperature | -40 to +85 C (I grade) | -40 to +85 C | -40 to +125 C (E grade) | -40 to +85 C | -40 to +85 C | -40 to +85 C |
| LCD Driver Segments | Up to 184 segments | Up to 184 | Up to 184 | Up to 184 | Up to 184 | Up to 384 (+108%) |
| ADC Channels | 14 x 10-bit | 14 x 10-bit | 14 x 10-bit | 14 x 10-bit | 11 x 10-bit | 17 x 10-bit |
Key Differentiators
- Integrated 184-segment LCD driver eliminates external LCD controller IC (vs PIC16LF1903-I/SO (no LCD driver))
- 36 I/O pins with mTouch capacitive sensing hardware on-chip (vs PIC16F1938-I/PT (28 I/O, no mTouch))
- NanoWatt XLP technology with sub-50 nA sleep current (vs PIC16F1939-I/PT (F-variant, ~100 nA sleep))
Design Notes
Decouple each VDD pin (1, 28, 42) with a 100 nF X7R ceramic placed within 3 mm of the pin; add a single shared 10 µF X5R bulk capacitor on the main VDD rail. Estimated: at 32 MHz and 3.3 V, active current is approximately 5 mA per the Microchip datasheet typical curves, so the bulk capacitor should be sized to ride through 100 µs brownouts without dropping below the 1.8 V VDD minimum. The LF-prefix guarantees operation down to 1.8 V only when VDD rise time meets the datasheet power-on-reset specification; add a 1 kΩ/1 µF RC reset stretch circuit if the supply is high-impedance.
Do not confuse the PIC16LF1939 with the PIC16F1939: the LF variant's absolute-maximum VDD is 3.6 V. Plugging an LF1939 into a 5 V system will permanently damage the part. The pin-compatible PIC16F1939-I/PT is the correct choice for 5 V designs and the firmware image transfers unchanged - only the VDD rail differs. Designers should also note that the LF1939 datasheet uses 1.8 V as the minimum operating VDD, but the on-chip ADC accuracy is only guaranteed at 2.3 V and above; below 2.3 V the ADC may have additional offset error.
Route the ICSP™ clock and data pins (RB6/ICSPC and RB7/ICDC) as a short, parallel pair to a 6-pin right-angle header at the board edge for in-circuit debugging. Keep the trace length under 50 mm and avoid routing them near switching converter inductors or RF traces - the ICSP clock edge is slow (~500 ns) but high-impedance, making it susceptible to capacitive crosstalk. The TQFP-44 has a 0.8 mm pitch, so use 0.4 mm-wide traces with 0.2 mm clearance and vias-in-pad with filled/capped plating for clean signal egress under the package.
Compliance Information
RoHS and lead-free status inferred from the PT suffix per Microchip part-numbering convention (PT = lead-free TQFP). Not AEC-Q100 qualified - automotive designs should evaluate the PIC16LF1939-I/PT automotive equivalent if available, otherwise screen at the system level.
