MC78FC30HT1 - 3V 50mA Micropower LDO Regulator SOT-89 | onsemi
MPN: MC78FC30HT1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.55 | $5.50 |
| 100 | $0.42 | $42.00 |
| 500 | $0.34 | $170.00 |
| 1,000 | $0.27 | $270.00 |
MC78FC30HT1 Overview
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable output voltage even when the input voltage is very close to the output voltage. Unlike switching regulators, an LDO dissipates the difference between input and output as heat and adds no switching noise. Within the power management hierarchy, the LDO sits below DC-DC converters and above simple shunt regulators as a clean, low-noise point-of-load supply, typically used after a switching pre-regulator to remove ripple for analog and RF circuits.
Key features of the MC78FC30HT1 include ultra-low quiescent current for battery-powered applications, integrated thermal protection, fixed 3.0 V output eliminating external feedback resistors, and a small SOT-89-3 footprint. Internal current limit and short-circuit foldback protect the device in fault conditions, while the SOT-89-3 package provides a low-profile surface-mount form factor with good thermal dissipation for the 50 mA load level.
Technically, the MC78FC30HT1 uses a low-Iq PNP-pass architecture with an internal bandgap reference, achieving ultra-low quiescent current suitable for always-on battery systems. The 500 mV typical dropout at 50 mA allows the regulator to maintain regulation down to roughly 3.5 V input when powered from a single lithium cell discharging toward cutoff.
Typical applications include portable video instruments, handheld communication equipment such as two-way radios and remote controls, single-cell battery-powered devices, microcontroller standby rails, and reference supplies for low-power analog blocks.
When designing with this part, ensure input and output capacitors meet the datasheet ESR requirement for stability, and verify that the 50 mA continuous load is never exceeded since the SOT-89-3 package is limited in thermal dissipation.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MC78FC30HT1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC78FC30HT1G
✅ Drop-In📋 Reference alternative (not in catalog)
MC78FC25HT1
✅ Drop-In📋 Reference alternative (not in catalog)
MC78FC33HT1
✅ Drop-In📋 Reference alternative (not in catalog)
MC78FC40HT1
✅ Drop-In📋 Reference alternative (not in catalog)
MC78FC50HT1
✅ Drop-In📋 Reference alternative (not in catalog)
MC78FC30HT1 Maximum Ratings & Electrical Characteristics
| Output Type | Fixed Positive |
| Output Voltage | 3.0 V |
| Maximum Output Current | 50 mA |
| Input Voltage Range | 2 V to 10 V |
| Dropout Voltage | 500 mV typical at 50 mA |
| Package | SOT-89-3 |
| Mounting Type | Surface Mount |
| Number of Pins | 3 |
| Manufacturer | onsemi (originally Motorola Semiconductor) |
MC78FC30HT1 Pin Configuration
| Pin 1 | VIN — Input voltage (2 V to 10 V) |
| Pin 2 | GND — Ground reference |
| Pin 3 | VOUT — Regulated 3.0 V output |
Typical Applications
MC78FC30HT1 is suitable for 6 applications: Handheld Communication Equipment, Battery-Powered Portable Video Instruments, Microcontroller Standby Rail, Single-Cell Battery Powered Devices, Reference Supply for Low-Power Analog, IoT Sensor Node Power.
Handheld Communication Equipment
The MC78FC30HT1's fixed 3.0 V output, 50 mA capability, and ultra-low quiescent current make it well suited as a clean supply rail for handheld two-way radios, remote controls, and wireless sensor nodes. Its 500 mV typical dropout extends usable runtime on a single lithium cell, while the LDO's lack of switching noise prevents interference with the radio's RF stages and adjacent analog signal paths. Place a 1 uF ceramic input capacitor and a 1 uF to 10 uF ceramic output capacitor close to the SOT-89-3 pins per datasheet guidance; unlike a switching pre-regulator, the MC78FC30HT1 adds no EMI harmonics that would otherwise require shielding or extra filtering. Pair it with a low-power MCU such as the PIC32MZ1024EFH064 for a complete always-on handheld platform.
Recommended
Battery-Powered Portable Video Instruments
Portable camcorders, digital still cameras, and handheld test instruments benefit from the MC78FC30HT1's clean 3.0 V analog supply. The LDO's low output noise floor preserves video signal integrity on the bias rail feeding CCD or CMOS image sensors, while its 50 mA capacity is sufficient to power small image-processing front ends. The 500 mV dropout allows operation down to approximately 3.5 V input, maximizing usable battery capacity from a single Li-ion cell. Use low-ESR ceramic output capacitors within the datasheet ESR window to maintain loop stability; the SOT-89-3 tab should be soldered to a copper pour of at least 100 mm^2 to keep junction temperature in spec at full 50 mA load.
Recommended
Microcontroller Standby Rail
The MC78FC30HT1 is ideal as an always-on 3.0 V standby rail for microcontrollers, RTCs, and SRAM backup in low-power embedded systems. Its ultra-low quiescent current minimizes battery drain when the main system is asleep, while the 3.0 V output is well matched to RTC and low-power MCU core rails. The LDO can remain enabled while a downstream switching regulator is shut down, providing a quiet reference for brown-out detectors and power-management ICs. Verify that total standby load stays below 10 mA to keep self-heating negligible; the SOT-89-3 package dissipates only a few milliwatts under typical standby current draw.
Recommended
Single-Cell Battery Powered Devices
The MC78FC30HT1's 2 V to 10 V input range and 500 mV dropout make it a natural choice for single-cell alkaline, Ni-MH, or Li-ion powered products. Its 3.0 V fixed output can power low-voltage MCUs, sensors, and display drivers directly from a single cell that discharges from 4.2 V down to approximately 3.5 V before the LDO drops out. The ultra-low quiescent current extends shelf life in products that spend most of their time in standby. Add a reverse-battery protection diode at the input for handheld products that may be inserted incorrectly, and place a 1 uF ceramic bypass capacitor within 5 mm of the input pin to suppress battery-rail transients.
Recommended
Reference Supply for Low-Power Analog
Precision analog blocks such as low-power ADCs, DACs, and sensor signal-conditioning front ends require a low-noise, low-drift supply rail. The MC78FC30HT1's LDO architecture adds no switching ripple, providing a quiet 3.0 V reference for instrumentation and measurement subsystems in portable equipment. Pair it with the MC78FC30HT1G Pb-free variant for RoHS-compliant designs. Use a star-ground topology so the LDO's ground current return does not share a path with noisy digital returns, and add a 10 nF to 100 nF local bypass for high-frequency noise on the analog rail.
Recommended
IoT Sensor Node Power
Battery-powered IoT sensor endpoints such as BLE beacons, Zigbee nodes, and LoRaWAN devices benefit from the MC78FC30HT1's combination of low quiescent current, fixed 3.0 V output, and 50 mA peak capability for transmit bursts. The LDO can power both the radio's PA pre-regulation and the sensor MCU from a single CR2032 or AAA cell. Its low dropout maximizes runtime in the 3.3 V to 3.0 V discharge region of the cell. Verify that peak transmit current stays below the 50 mA limit; for higher peak loads consider cascading the MC78FC30HT1 with a small buck-boost pre-regulator upstream.
Recommended
Recommended Products Summary
Engineering reference data for MC78FC30HT1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC78FC30HT1G | MC78FC25HT1 | MC78FC33HT1 | MC78FC40HT1 | MC78FC50HT1 |
|---|---|---|---|---|---|---|
| Brand | onsemi | onsemi | onsemi | onsemi | onsemi | onsemi |
| Package | SOT-89-3 | SOT-89-3 - same | SOT-89-3 - same | SOT-89-3 - same | SOT-89-3 - same | SOT-89-3 - same |
| Output Voltage | 3.0 V | 3.0 V | 2.5 V | 3.3 V | 4.0 V | 5.0 V |
| Maximum Output Current | 50 mA | 50 mA | 50 mA | 50 mA | 50 mA | 80 mA |
| Input Voltage Range | 2 V to 10 V | 2 V to 10 V | 2 V to 10 V | 2 V to 10 V | 2 V to 10 V | 2 V to 10 V |
| Dropout Voltage | 500 mV at 50 mA | 500 mV at 50 mA | 500 mV at 50 mA | 500 mV at 50 mA | 500 mV at 50 mA | 500 mV at 80 mA |
| Pinout (SOT-89-3) | 1=VIN, 2=GND, 3=VOUT | 1=VIN, 2=GND, 3=VOUT | 1=VIN, 2=GND, 3=VOUT | 1=VIN, 2=GND, 3=VOUT | 1=VIN, 2=GND, 3=VOUT | 1=VIN, 2=GND, 3=VOUT |
Key Differentiators
- Pb-free drop-in variant available in same footprint (vs MC78FC30HT1G)
- Full MC78FC00 series coverage at 3.0 V (vs MC78FC50HT1)
- Same SOT-89-3 footprint across voltage options (vs MC78FC25HT1 / MC78FC33HT1 / MC78FC40HT1)
Design Notes
The SOT-89-3 package can dissipate approximately 500 mW to 1 W on a 1 oz copper pour of 100 mm^2 with still air. Estimated: at VIN=5 V, VOUT=3.0 V, IOUT=50 mA, dissipation is (5-3.0)*0.050 = 100 mW, well within thermal limits. Designers running continuous 50 mA from a 9 V input should add a copper pour of at least 200 mm^2 to keep junction temperature below 125 C.
Place input and output capacitors as close as possible (within 3 mm) to the SOT-89-3 pins to minimize parasitic inductance. Use a 1 uF X7R ceramic on VIN and a 1 uF to 10 uF X7R ceramic on VOUT. The package tab should be soldered to a ground-plane copper pour to maximize heat spreading. Keep noisy digital traces away from the LDO's output capacitor to preserve low-noise performance.
Do not exceed the absolute maximum input voltage of 10 V. According to the onsemi datasheet, output capacitors with ESR outside the recommended stability window can cause oscillation - verify capacitor ESR against the datasheet's stability curve. Do not parallel multiple MC78FC30HT1 outputs without external OR-ing diodes, as the internal pass devices do not share current equally. For designs requiring more than 50 mA, choose a higher-rated part rather than overstressing this regulator.
Compliance Information
The MC78FC30HT1 (no G suffix) is the legacy Motorola/onsemi ordering code with tin-lead (SnPb) terminal finish. For new RoHS-compliant designs, choose the MC78FC30HT1G variant which carries Pb-free finish and RoHS compliance. Not AEC-Q100 qualified - this part targets consumer handheld, video, and battery-powered equipment, not automotive.
