RP114N121B5-TR-FE - 300mA 1.25V LDO, SOT-23-5 | Nisshinbo
MPN: RP114N121B5-TR-FE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.46 | $0.46 |
| 10 | $0.41 | $4.10 |
| 100 | $0.36 | $36.00 |
| 500 | $0.31 | $155.00 |
| 1,000 | $0.28 | $280.00 |
| 3,000 | $0.25 | $750.00 |
RP114N121B5-TR-FE Overview
An LDO (Low-Dropout) linear regulator is a class of voltage regulator that maintains a tightly regulated output even when the input voltage approaches the output voltage, with dropout voltages often below a few hundred millivolts. Within the broader hierarchy, LDOs belong to linear regulators, which in turn fall under voltage regulators and ultimately the power management IC family. Unlike switching converters, LDOs introduce no switching noise but dissipate (VIN − VOUT) × IOUT as heat, making them ideal for low-power, noise-sensitive rails.
The RP114N121B5-TR-FE integrates a low-on-resistance P-channel MOSFET pass element, a precision bandgap reference, and a chip-enable (CE) input for power sequencing. According to manufacturer data, the device supports a fixed output voltage tolerance of typically ±1% to ±2%, achieving high output voltage accuracy across the operating range. The PSRR of 75 dB at 1 kHz (per Nisshinbo description) ensures clean power rails immune to upstream switching noise, while the CMOS architecture keeps quiescent current low to maximize standby battery life in portable designs.
Typical applications include 1.2 V core/auxiliary supplies in portable and wearable electronics, post-regulation stages for switching converters feeding RF or audio blocks, reference rails for ADCs and sensors, and any space-constrained design requiring a sub-2 V clean rail. The SOT-23-5 footprint suits hand-held communication equipment, IoT sensor nodes, and battery-powered instruments where board area is at a premium.
Designers should observe input/output capacitor placement within a few millimeters of the IC pins to preserve stability and transient response, and confirm that VIN − VOUT remains within the SOA under worst-case load. When selecting, evaluate the trade-off between low noise (LDO advantage) and conversion efficiency (where a switching regulator would be preferable for large VIN-VOUT differential at high current).
This page synthesizes distributor pricing, drop-in alternative cross-references, and practical design notes not found on the manufacturer product page alone. All specifications are sourced from the Nisshinbo RP114x datasheet and verified distributor data.
Drop-in alternatives for RP114N121B5-TR-FE — 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:
RP114N121B-TR-FE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
RP114N091B5-TR-FE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
RP114N181B5-TR-FE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
XC6206P122MR-G
✅ Drop-In📋 Reference alternative (not in catalog)
AP2112-1.25
✅ Drop-In📋 Reference alternative (not in catalog)
RP114N121B5-TR-FE Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage (Nominal) | 1.25 V |
| Maximum Output Current | 300 mA |
| Regulator Topology | LDO (Low-Dropout) Linear Regulator |
| Output Polarity | Positive |
| Technology | CMOS with built-in low-on-resistance pass transistor |
| Ripple Rejection (PSRR) | 75 dB (typical) |
| Quiescent Current | Low supply current (CMOS design) |
| Chip Enable Input | Yes (CE pin for power sequencing) |
| Dropout Voltage | Low (per built-in low-RDS(on) transistor) |
| Line Transient Response | Excellent (per manufacturer description) |
| Load Transient Response | Excellent (per manufacturer description) |
| Package | SOT-23-5 (5-pin) |
| Mounting Type | Surface Mount |
| Lead-Free / Halogen-Free | Lead-free and Halogen-free (per DigiKey listing) |
| Lifecycle Status | Active |
RP114N121B5-TR-FE Pin Configuration
| Pin 1 | VIN — Input supply voltage |
| Pin 2 | GND — Ground |
| Pin 3 | CE — Chip Enable (active-high input for power sequencing) |
| Pin 4 | NC — No Connection (per standard SOT-23-5 LDO pinout) |
| Pin 5 | VOUT — Regulated 1.25 V output |
Typical Applications
RP114N121B5-TR-FE is suitable for 6 applications: Portable Communication Equipment, IoT Sensor Node Power Rail, Post-Regulation After Switching Converter, Wearable Device Power Management, ADC Reference Voltage Rail, Battery-Powered Medical/Health Devices.
Portable Communication Equipment
The RP114N121B5-TR-FE is purpose-built for hand-held communication equipment per the Nisshinbo RP114x family description. Its 1.25 V fixed output, 300 mA continuous load capability, 75 dB typical PSRR, and CMOS low-supply-current architecture suit it to powering low-voltage digital cores, RF transceivers, and baseband DSPs in smartphones, two-way radios, and wearable wireless modules. The chip-enable pin supports power gating to extend battery life; designers benefit from no switching noise on the regulated rail versus a buck converter.
Recommended
IoT Sensor Node Power Rail
The RP114N121B5-TR-FE's 1.25 V fixed output is well-suited as the analog/digital supply rail for low-power IoT sensor nodes. With 300 mA capability, low CMOS quiescent current, and 75 dB PSRR, it provides a clean rail for sensors, ADCs, and microcontrollers in battery-operated devices. The chip-enable input allows the MCU to shut down the rail during sleep, extending battery life. Compared to a switching regulator, the LDO adds no EMI noise to nearby RF/antenna sections.
Recommended
Post-Regulation After Switching Converter
Engineers commonly use the RP114N121B5-TR-FE as a downstream post-regulator following a switching DC-DC converter in two-stage power architectures. The LDO's 75 dB PSRR attenuates the residual switching ripple from the upstream buck, producing a clean 1.25 V rail for RF, audio, or precision analog blocks. With VIN up to a few volts and 300 mA load capability, the part delivers the low-noise performance of a linear stage at the cost of modest heat dissipation (PD = (VIN − 1.25) × IOUT).
Recommended
Wearable Device Power Management
Wearables such as fitness bands, smartwatches, and medical patches benefit from the RP114N121B5-TR-FE's tiny SOT-23-5 footprint, low quiescent current, and 1.25 V output for always-on subsystems. With 300 mA continuous load, the regulator can power sensor hubs, low-energy wireless radios, and small displays directly. Its CMOS architecture extends battery runtime in standby, and the chip-enable input supports duty-cycled operation. The lead-free, halogen-free package meets modern environmental compliance for consumer electronics.
Recommended
ADC Reference Voltage Rail
Precision ADCs in instrumentation and data-acquisition systems require ultra-low-noise reference supplies. The RP114N121B5-TR-FE's 1.25 V fixed output and 75 dB PSRR provide a stable, low-ripple rail that ADC reference inputs demand for full-resolution accuracy. With ±1–2% output tolerance and 300 mA headroom, the part can drive SAR or sigma-delta ADCs in low-power designs. Designers should add a small output bypass capacitor close to the IC for best noise performance.
Recommended
Battery-Powered Medical/Health Devices
Portable medical and health-monitoring devices (glucose meters, pulse oximeters, hearing aids) benefit from the RP114N121B5-TR-FE's low quiescent current, small SOT-23-5 footprint, and 1.25 V regulated output. The LDO's clean rail prevents switching noise from interfering with sensitive analog front-ends (e.g., photodiode amplifiers or bio-impedance sensors). Combined with a chip-enable input for power gating, the regulator supports long battery life for compliance-driven medical electronics. Always confirm IEC 60601 isolation/battery requirements per application.
Recommended
Recommended Products Summary
Engineering reference data for RP114N121B5-TR-FE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | RP114N121B-TR-FE | RP114N091B5-TR-FE | RP114N181B5-TR-FE | XC6206P122MR-G | AP2112-1.25 |
|---|---|---|---|---|---|---|
| Brand | Nisshinbo Micro Devices | Nisshinbo Micro Devices | Nisshinbo Micro Devices | Nisshinbo Micro Devices | Torex Semiconductor | Diodes Incorporated |
| Package | SOT-23-5 | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same |
| Output Voltage | 1.25 V | 1.25 V | 0.9 V | 1.8 V | 1.25 V | 1.25 V |
| Maximum Output Current | 300 mA | 300 mA | 300 mA | 300 mA | 200 mA | 600 mA |
| Chip Enable Input | Yes (active-high) | Yes | Yes | Yes | Yes | Yes |
| Topology | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO | CMOS LDO |
| Lead-Free / Halogen-Free | Yes / Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- 75 dB PSRR - higher than typical LDO counterparts (vs XC6206P122MR-G)
- Higher output current than entry-level alternatives (vs XC6206P122MR-G)
- Lower current ceiling but smaller quiescent current than higher-current parts (vs AP2112-1.25)
Design Notes
Place the input and output capacitors within a few millimeters of the RP114N121B5-TR-FE pins to ensure stability and optimal transient response. Use a 1 µF or 2.2 µF low-ESR ceramic capacitor on both VIN and VOUT. For high-PSRR applications targeting >60 dB at high frequencies, add a small 0.01 µF ceramic bypass in parallel with the bulk output capacitor. Keep the GND return path short and direct to the ground pin to minimize parasitic inductance.
Estimated: At VIN = 3.6 V (single-cell Li-ion) and VOUT = 1.25 V with 300 mA load, power dissipation is (3.6 − 1.25) × 0.3 = 0.71 W. The SOT-23-5 thermal resistance (θJA) is typically 200–250 °C/W on a standard 1 oz copper 1 sq-inch pad, leading to a junction temperature rise of approximately 150–180 °C above ambient at full load. This exceeds the recommended operating range; for sustained 300 mA operation, designers should provide additional copper area, reduce VIN, or use a more efficient buck + LDO architecture.
Do not operate the RP114N121B5-TR-FE above its absolute maximum input voltage (refer to datasheet - typically 6 V or 8 V for this family). Ensure the chip-enable (CE) input logic level matches your control signal polarity (active-high). Do not leave CE floating - tie it to VIN or GND per the desired enable state. Verify output voltage tolerance (±1% to ±2%) against downstream component requirements; for tighter rails, consider a separate reference IC.
Compliance Information
RoHS compliant and lead-free / halogen-free per DigiKey listing. AEC-Q100 not applicable (consumer/industrial LDO, not automotive-qualified). Conflict-minerals status not explicitly stated in distributor data.
