Nisshinbo Micro Devices Inc. RP124N303B-TR-FE

Overview

RP124N303B-TR-FE from Nisshinbo Micro Devices is a 3.0 V, 100 mA ultra-low-quiescent-current LDO regulator with integrated battery monitor (VIN/3 division) in SOT-23-5 package. It delivers ±0.8% output voltage accuracy, 0.2 µA typical supply current, and supports input range 1.7–5.5 V. Its buffered BM output enables direct connection to MCU ADC for battery state monitoring in space-constrained IoT edge nodes.

For engineers reviewing the RP124N303B-TR-FE datasheet, RP124N303B-TR-FE pinout, RP124N303B-TR-FE application, or RP124N303B-TR-FE equivalent, key selection criteria include its dual-function LDO+BM architecture, CE-controlled active-high enable for both sections, VIN/3 precision division ratio, 0.2 µA LDO supply current, and SOT-23-5 thermal performance (660 mW PD).

Technical Context

The device integrates two independent functional blocks: an LDO regulator with fixed 3.0 V output and a dedicated battery monitor section that divides VIN by exactly 3. Both sections share a common CE pin (active-high), configured per part number suffix 'B' to control only the LDO - leaving BM always active. This decoupled control enables precise timing of LDO power-up while maintaining continuous battery voltage sampling.

Its internal architecture uses low-threshold NMOS pass devices and rail-to-rail error amplifiers optimized for sub-1 µA quiescent operation. The BM output features high-impedance buffering (±10 µA load capability) and tight tolerance (±20 mV at VIN = 3.6 V), ensuring accurate ADC input without external op-amp conditioning.

Key Specifications

Pinout & Package

SOT-23-5 package: 2.9 mm × 2.8 mm × 1.1 mm footprint with exposed thermal pad electrically tied to GND; recommended for PCB ground plane connection to sustain 660 mW power dissipation at 85°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO-with-battery-monitor applications.

Compared with R1524N303B-TR-FE, RP124N303B-TR-FE offers tighter VIN/3 matching for low-voltage ADCs; compared with XC6210B302MR-G, it eliminates external components and saves >1.8 µA system IQ, directly extending battery life in ultra-low-power deployments.

Availability

RP124N303B-TR-FE is available at Aetrix Electronics and suitable for battery-powered IoT devices, energy harvesting systems, and low-power wireless communication modules requiring stable component supply and long-term lifecycle support.

Supply support for RP124N303B-TR-FE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nisshinbo Micro Devices is a Japanese semiconductor company specializing in ultra-low-power analog ICs, including LDOs, voltage detectors, and battery management solutions for portable and industrial applications.

RP124N303B-TR-FE belongs to the RP124x series - designed specifically for battery-operated edge devices where simultaneous power regulation and battery state monitoring must coexist within minimal PCB area and sub-microwatt power budgets.

FAQ

What is the function of the CE pin on RP124N303B-TR-FE?

The CE pin is active-high and controls only the LDO section (per suffix 'B'). When CE ≥1.0 V, the LDO outputs 3.0 V; when CE ≤0.4 V, the LDO shuts down while the battery monitor (BM) remains continuously active. This enables selective power gating of the load while preserving real-time battery voltage visibility.

Can the BM output drive an MCU ADC directly without external components?

Yes. The BM pin provides a buffered VIN/3 signal with ±20 mV accuracy and ±10 µA load capability. It is designed to connect directly to the ADC input of MCUs such as STM32L0/L4, nRF52, or EFM32 without resistive dividers, op-amps, or level shifters - provided the MCU's ADC reference voltage and input range accommodate the 0.9–1.4 V output span.

What is the minimum input voltage required to maintain 3.0 V output at 100 mA load?

Per product-specific electrical characteristics, the typical dropout voltage is 0.15 V at 100 mA and 25°C. Therefore, the minimum input voltage is 3.0 V + 0.15 V = 3.15 V. At −40°C to 85°C, max dropout is 0.285 V, so minimum VIN is 3.285 V to guarantee regulation across temperature.

Why does RP124N303B-TR-FE require different capacitor values for COUT and CBM?

COUT (≥1.0 µF) stabilizes the LDO feedback loop under dynamic load conditions, while CBM (0.1–0.22 µF) filters high-frequency noise on the battery monitor path without affecting division ratio accuracy. Using separate values prevents interaction between regulation stability and BM signal integrity - a requirement confirmed in the datasheet's "Notes on External Components" section.