RP173N301B-TR-FE - 3.0V 150mA CMOS LDO | Nisshinbo
MPN: RP173N301B-TR-FE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.55 | $5.50 |
| 100 | $0.46 | $46.00 |
| 500 | $0.39 | $195.00 |
| 1,000 | $0.33 | $330.00 |
| 3,000 | $0.28 | $840.00 |
RP173N301B-TR-FE 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. Within the broader power management hierarchy, an LDO is a sub-category of linear regulator, which itself sits under voltage regulators and ultimately under power management ICs. LDOs are preferred over switching regulators in noise-sensitive applications because they introduce no switching ripple, at the cost of lower efficiency when the input-to-output voltage differential is large.
Key features of the RP173N301B-TR-FE include a low typical supply current of 2.0 µA, integrated reverse-current (back-flow) protection, a fixed 3.0 V output trimmed at the factory, and an 11 V maximum input rating that supports 2-cell alkaline or 1-cell Li-ion derived rails. The device is part of the broader RP173 series, which offers multiple fixed output voltages and two output-grade variants (A/B) for different load-capability profiles.
The RP173 uses a CMOS pass element with a precision bandgap reference. Its low Iq minimizes battery drain during standby, and the reverse-current block prevents current flow from a higher downstream rail back into the LDO output, which is critical when the device is paralleled with another supply or when the load is hot-plugged.
Typical applications include standby-power rails in microcontroller-based appliances, IoT sensor nodes, and battery-powered portable equipment. The 150 mA current capability and 3.0 V fixed output are well matched to RTC backup domains, low-power MCU cores, and wireless SoC sleep rails.
When designing with this part, ensure that the input supply does not exceed 11 V and that the load does not demand more than 150 mA continuously. Place the input and output decoupling capacitors immediately adjacent to the IC pins to maintain loop stability.
This page synthesizes distributor stock data, parametric drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for RP173N301B-TR-FE — 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 RP173N301B-TR-FE (same form factor and footprint) — differing in Output Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
RP173N301A-TR-FE
✅ Drop-In📋 Reference alternative (not in catalog)
RP173N301D-TR-FE
✅ Drop-In📋 Reference alternative (not in catalog)
RP173N181D-TR-FE
✅ Drop-In📋 Reference alternative (not in catalog)
RP173N331B-TR-FE
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$0.27 / Unit
View Datasheet →RP173N251B-TR-FE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
RP173N121B-TR-FE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
RP173N301B-TR-FE Maximum Ratings & Electrical Characteristics
| Regulator Type | LDO (Low-Dropout), Positive Fixed |
| Output Type | Fixed |
| Output Voltage | 3.0 V |
| Output Current (Typ.) | 150 mA |
| Input Voltage (Max.) | 11 V |
| Quiescent Current (Typ.) | 2.0 µA |
| Reverse Current Protection | Yes (built-in) |
| Number of Outputs | 1 |
| Topology | CMOS |
| Package | SOT-23-5 |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (-TR) |
| Termination Finish | Lead-free / Pb-free (-FE) |
| RoHS Status | Compliant |
RP173N301B-TR-FE Pin Configuration
| Pin 1 | VIN — Input supply voltage (max 11 V) |
| Pin 2 | GND — Ground reference |
| Pin 3 | CE — Chip enable (active-high or active-low per datasheet variant) |
| Pin 4 | NC — Not connected (per datasheet) |
| Pin 5 | VOUT — Regulated 3.0 V output |
Typical Applications
RP173N301B-TR-FE is suitable for 6 applications: Standby / Always-On MCU Rail, IoT Sensor Node Power, Portable / Wearable Electronics, Industrial Sensor Conditioning, Home Appliance Standby Supply, Battery-Powered Measurement Instrument.
Standby / Always-On MCU Rail
The RP173N301B-TR-FE's 2.0 µA typical quiescent current and 3.0 V fixed output make it ideal for always-on standby rails in low-power MCUs. Placed between a battery or main rail and the MCU's backup domain, it supplies 150 mA continuously while drawing only microamps of Iq, directly extending battery life in sleep-mode designs. Compared to a switching regulator, it adds zero switching noise to the rail, which is critical for RTC accuracy and brown-out-free wake-up. Built-in reverse-current protection also prevents back-flow when the main rail is removed, eliminating the need for an external blocking diode.
Recommended
IoT Sensor Node Power
Battery-powered IoT sensor nodes benefit from the RP173N301B-TR-FE's 150 mA output and 11 V input tolerance, which supports 2-cell alkaline or 1-cell Li-ion sources. Its 2.0 µA Iq minimizes sleep-mode drain between sensor transmissions, while the SOT-23-5 footprint keeps the solution size minimal. Unlike a buck converter, the LDO topology adds no EMI that could couple into the wireless SoC's RF section. Reverse-current protection is valuable when the node is hot-plugged into a charger or host that may briefly back-drive the rail.
Recommended
Portable / Wearable Electronics
Wearable devices demand compact power solutions with low standby drain, both of which the RP173N301B-TR-FE provides in SOT-23-5 form factor with 2.0 µA Iq. The 3.0 V fixed output matches the typical operating voltage of BLE SoCs and low-power display drivers used in fitness bands and smart watches. The LDO's lack of switching ripple preserves clean power for touch-sensing and heart-rate monitor analog front-ends. The 11 V input rating also tolerates USB or wireless-charging rectified rails after initial regulation.
Recommended
Industrial Sensor Conditioning
Industrial 4-20 mA loop sensors and 24 V-derived rail sensors can leverage the RP173N301B-TR-FE's 11 V input rating for local post-regulation. Its 150 mA capability powers analog front-ends, ADC references, and isolated transceiver logic from a single 3.0 V rail. The CMOS topology provides stable output across temperature, and the SOT-23-5 package suits compact sensor modules. The wide operating temperature range (industrial -40 C to +85 C [DATA_NEEDED]) supports factory-floor deployments.
Recommended
Home Appliance Standby Supply
White goods and home appliances require standby rails that meet strict energy-efficiency regulations. The RP173N301B-TR-FE's 2.0 µA Iq helps designers hit <0.5 W standby budgets while still supplying 150 mA for MCU + display wake-up. The 11 V input accommodates rectified 9-12 V AC adapters commonly used in appliances. Reverse-current protection prevents back-feeding when the appliance is plugged into a USB service port or programming fixture during manufacturing test.
Recommended
Battery-Powered Measurement Instrument
Handheld multimeters, clamp meters, and field-instrumentation tools benefit from the RP173N301B-TR-FE's low Iq and clean 3.0 V rail. The LDO supplies analog signal-conditioning and ADC reference circuits where switching-noise-induced measurement error is unacceptable. With 150 mA output capability, it can power both analog and low-speed digital sections from a single cell. The SOT-23-5 package supports compact PCB layouts typical of handheld form factors.
Recommended
Recommended Products Summary
Engineering reference data for RP173N301B-TR-FE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | RP173N301A-TR-FE | RP173N301D-TR-FE | RP173N181D-TR-FE | RP173N331B-TR-FE | RP173N251B-TR-FE |
|---|---|---|---|---|---|---|
| Package | SOT-23-5 | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same |
| Brand | Nisshinbo | Nisshinbo | Nisshinbo | Nisshinbo | Nisshinbo | Nisshinbo |
| Output Voltage | 3.0 V | 3.0 V | 3.0 V | 1.8 V | 3.3 V | 2.5 V |
| Output Current (Max.) | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA |
| Input Voltage (Max.) | 11 V | 11 V | 11 V | 11 V | 11 V | 11 V |
| Quiescent Current (Typ.) | 2.0 µA | 2.0 µA | 2.0 µA | 2.0 µA | 2.0 µA | 2.0 µA |
| Reverse Current Protection | Yes | Yes | Yes | Yes | Yes | Yes |
| Output Grade | B | A | D | D | B | B |
| Topology | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO |
Key Differentiators
- Ultra-low 2.0 µA quiescent current for always-on standby rails (vs Generic 150 mA CMOS LDOs (e.g., typical 50-100 µA Iq parts))
- Built-in reverse-current protection eliminates an external blocking diode (vs Standard LDOs without reverse-current blocking)
- Wide 11 V input range supports 2-cell alkaline and 1-cell Li-ion rails (vs 5-6 V input limited LDOs)
Design Notes
Place a 1 µF (or higher) ceramic input capacitor immediately adjacent to the VIN pin and a 1 µF (or higher) ceramic output capacitor adjacent to VOUT to ensure regulator stability. Low-ESR ceramic capacitors (X5R/X7R) are recommended. Estimated: at VIN=5 V, VOUT=3.0 V, and 150 mA load, the LDO dissipates roughly 0.3 W; ensure the PCB copper pour under the SOT-23-5 thermal pad (or exposed lead frame) is adequate to keep junction temperature within ratings.
Do not exceed the absolute maximum input voltage of 11 V, even during transients. If the upstream rail is hot-plugged or inductive, add a TVS or zener clamp. The CE pin polarity (active-high vs active-low) varies across RP173 variants; always verify the specific datasheet revision before connecting CE to a GPIO. Reverse-current protection is built in, but the device is not intended for continuous reverse conduction - keep VIN above VOUT during normal operation.
Estimated: at maximum VIN=11 V, VOUT=3.0 V, and 150 mA load, the LDO dissipates approximately (11 V - 3.0 V) × 0.150 A = 1.2 W. The SOT-23-5 package has a thermal resistance of roughly 250 C/W on a minimal copper footprint, which would push junction temperature >250 C above ambient - well beyond safe limits. Reduce VIN-VOUT differential, lower load current, or expand copper pour to keep junction rise under 100 C.
Route the GND pin directly to a low-impedance ground plane via a short trace or via-in-pad. Keep the input/output capacitor ground returns close together to minimize high-frequency loop area. Avoid routing noisy digital or switching traces near the VOUT node to preserve the LDO's low-noise output. The SOT-23-5 land pattern should follow the recommended pattern in the Nisshinbo RP173 datasheet family.
Compliance Information
Lead-free / Pb-free termination designated by -FE suffix. RoHS compliant per Nisshinbo product page. Not AEC-Q100 qualified. Halogen-free and conflict-mineral status not stated in verified data.
