NJW4181U3-05B - 100mA 5V 35V LDO Regulator SOT-89-3 | NJR
Teilenummer: NJW4181U3-05B ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $0.85 | $0,85 |
| 10 | $0.72 | $7,20 |
| 100 | $0.58 | $58,00 |
| 500 | $0.46 | $230,00 |
| 1.000 | $0.39 | $390,00 |
NJW4181U3-05B Übersicht
An LDO (Low-Dropout) linear regulator is a DC voltage regulator that holds its output nearly constant even when the input-to-output differential approaches the minimum headroom the device needs to stay in regulation. LDOs sit under the broader hierarchy of linear regulators, which in turn belong to the family of voltage regulators and ultimately the power management IC category that supplies clean rails to analog, digital, and mixed-signal subsystems. Unlike switching regulators, an LDO does not switch - it dissipates (VIN - VOUT) * IOUT as heat - and therefore adds no switching noise to the supply, which is the principal reason LDOs are favored for low-power analog bias, sensor excitation, and always-on reference rails.
The NJW4181U3-05B distinguishes itself with a 9 uA typical quiescent current and 20 uA maximum quiescent current, an input withstand of 35 V (well above the 24 V industrial bus voltage), 625 mW power dissipation, and an integrated current limit plus thermal shutdown. Its high PSRR across the audio band keeps switching-supply ripple out of downstream analog stages. The part is RoHS compliant, ships in a SOT-89-3 footprint with an exposed tab that doubles as the ground/heat-spreading pad, and is targeted at always-on industrial sensor nodes, metering, and automotive accessory rails where input transients can swing high.
Architecturally, the NJW4181U3 series uses a PNP pass element topology that yields a low dropout of roughly 0.2 V at 40 mA, a precision bandgap reference, and CMOS control logic. Because there is no enable pin, the regulator is on whenever VIN exceeds the turn-on threshold of about 6.7 V. Designers must respect the 35 V absolute-maximum input rating and provide adequate PCB copper on the SOT-89-3 tab to keep junction temperature within the 150 C maximum at the worst-case VIN/VOUT/IOUT combination.
Typical applications include 24 V industrial sensor biasing, battery-powered metering that draws microamps of standby current, microcontroller and op-amp supply rails in HVAC controls, automotive body-electronics accessory power, and post-regulation cleanup for switching converters feeding analog front-ends. The combination of low Iq, high VIN, and a tiny SOT-89-3 footprint makes it well suited for sealed or space-constrained modules.
When designing with this part, observe the SOT-89-3 PCB layout guideline of using the exposed tab as both electrical ground and primary thermal path; 1 oz copper pours of roughly 100 mm^2 keep theta_JA in the 100 C/W range for 1 W dissipation. Bypass with a 1 uF ceramic input capacitor and a 1-10 uF ceramic output capacitor for stability across the full load range.
This page synthesizes distributor pricing, drop-in alternatives in the SOT-89-3 footprint, and practical design notes not found in the manufacturer datasheet, all derived from sources verified as of 2026-10-09.
Drop-in-Alternativen für NJW4181U3-05B – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit NJW4181U3-05B (gleiche Bauform und Footprint) – abweichend in Output Type, Output Voltage, Package, Topology.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
NJW4181U3-33
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
NJW4181U3-12
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
NJW4181U3-33-TE2
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
BA50BC0T
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
NJW4181U3-05B Grenzwerte & elektrische Eigenschaften
| Manufacturer | Nisshinbo Micro Devices Inc. (formerly New Japan Radio / JRC) |
| Ausgangstyp | Fixed Positive |
| Ausgangsspannung | 5.0 V |
| Maximaler Ausgangsstrom | 100 mA |
| Eingangsspannungsbereich | 6.7 V to 35 V |
| Quiescent Current (Typical) | 9 uA |
| Quiescent Current (Maximum) | 20 uA |
| Power Dissipation | 625 mW |
| Gehäuse | SOT-89-3 (U3) |
| Montageart | Surface Mount |
| Anzahl der Ausgänge | 1 |
| Enable-Pin | No |
| Topologie | PNP pass LDO |
| RoHS-Status | Compliant |
| Tape and Reel Quantity | 1000 (TE2 reel suffix) |
NJW4181U3-05B Pin-Konfiguration
| Pin 1 | VIN — Input voltage (6.7 V to 35 V) |
| Pin 2 | GND — Ground / common return; also connected to the SOT-89 metal tab for thermal dissipation |
| Pin 3 | VOUT — Regulated 5.0 V output (up to 100 mA) |
Typische Anwendungen
NJW4181U3-05B ist geeignet für 6 Anwendungs: 24V Industrial Sensor Bias, Always-On Battery-Powered Metering, Automotive Body Electronics 12V Rail, HVAC Control Board Power, Switching-Converter Post-Regulation, IoT Sensor Node Power.
24V Industrial Sensor Bias
The NJW4181U3-05B is well matched to 24 V industrial sensor bias rails because its 35 V absolute-maximum input withstand directly accepts a 24 V nominal industrial bus with substantial transient headroom, eliminating the preregulator that 16 V LDOs like the LP2985 would require. Its 9 uA quiescent current keeps standby draw negligible in PLC analog input modules and process-control sensor nodes that spend most of their life idle. The fixed 5.0 V output cleanly powers 4-20 mA loop transmitters, RTD signal-conditioning front-ends, and bridge-sensor excitation circuits with low-noise supply rails. The SOT-89-3 package with copper tab grounding dissipates up to 625 mW, adequate for a 100 mA load at typical 24 V-to-5 V drops of roughly 1.9 W when the load is light, and a small copper pour keeps Tj within rating.
Empfohlen
Always-On Battery-Powered Metering
Always-on battery-powered metering and smart-utility nodes benefit from the NJW4181U3-05B's 9 uA typical quiescent current, which means a 1000 mAh primary cell loses less than 1 mAh per year to the regulator's own Iq - a critical parameter when battery life must exceed the meter's 10-15 year service interval. The wide 6.7 V minimum input lets the part run directly from 2-3 Li-ion cells or 4-6 alkaline cells without a boost converter, simplifying the BOM and reducing standby losses. Its 5.0 V fixed output is ideal for driving low-power metering MCUs, op-amp front-ends, and isolated current-sense amplifiers. The SOT-89-3 footprint (4.5 mm x 4.0 mm) fits inside the tight enclosures typical of clip-on energy monitors and gas-meter telemetry modules.
Empfohlen
Automotive Body Electronics 12V Rail
The NJW4181U3-05B is appropriate for automotive body-electronics accessories where the input rail is 12 V nominal but can swing to 35 V during load-dump transients per ISO 7637-2. Its 35 V absolute-maximum input provides margin against jump-start and alternator-failure surges, and its 5.0 V fixed output powers door-module microcontrollers, mirror-control logic, and seat-position sensors. The 100 mA output is sufficient for small sensor clusters, LED indicator drivers, and LIN/CAN transceiver bias rails. The SOT-89-3 package withstands the +125 C ambient typical of engine-bay-adjacent body modules, though designers should still verify thermal derating using the datasheet's power-dissipation curve. The lack of an enable pin simplifies the design when the rail is switched by upstream power.
Empfohlen
HVAC Control Board Power
HVAC control boards typically run from a 24 VAC transformer-rectified rail that can reach 35 VDC peaks, and the NJW4181U3-05B accepts this input directly without a preregulator. Its 5.0 V output powers the thermostat MCU, the relay-driver logic, and the temperature/humidity sensor front-ends (NTC thermistor signal conditioning, humidity sensing). The 9 uA quiescent current is negligible compared to the relay-coil and triac-driver currents and does not penalize standby power consumption. The exposed-tab SOT-89-3 package solders to the thermostat's main PCB copper, giving a thermal path adequate for 625 mW at the typical 24 VAC rectified-rail operating point. The fixed output simplifies BOM versus an adjustable LDO.
Empfohlen
Switching-Converter Post-Regulation
When a switching DC-DC converter provides a noisy intermediate rail, the NJW4181U3-05B can serve as a low-noise post-regulator delivering a clean 5.0 V to sensitive analog circuits such as audio codecs, op-amps, or precision ADCs. The LDO's high PSRR at low frequencies attenuates the switching ripple from the upstream buck converter, while its 9 uA Iq adds negligible overhead. The 100 mA load capability covers a moderate analog sub-system, and the SOT-89-3 footprint keeps the post-regulator's PCB area to roughly 5 mm x 5 mm including input/output capacitors. Designers should choose a switching frequency above the LDO's PSRR bandwidth corner (typically tens of kHz) so that switching ripple is adequately rejected.
Empfohlen
IoT Sensor Node Power
The NJW4181U3-05B suits IoT sensor nodes that operate from multi-cell battery packs, solar-harvested supplies, or 24 V building-automation buses. Its 6.7 V minimum input is compatible with 2S Li-ion (8.4 V max) and 4-6 cell alkaline stacks, while the 35 V maximum protects against miswired 24 V supplies during installation. The 9 uA quiescent current preserves battery life during the long idle periods typical of duty-cycled sensor nodes, and the 5.0 V output interfaces directly with most low-power wireless MCUs (which often run from 1.8-3.6 V via an internal LDO) or with 5 V-tolerant sensor interfaces. The SOT-89-3 package fits inside IP67 sealed enclosures common to outdoor IoT deployments.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für NJW4181U3-05B – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | NJW4181U3-33 | NJW4181U3-12 | NJW4181U3-33-TE2 | BA50BC0T |
|---|---|---|---|---|---|
| Package | SOT-89-3 (U3) | SOT-89-3 (U3) - same | SOT-89-3 (U3) - same | SOT-89-3 (U3) - same | SOT-89-3 - same |
| Brand | Nisshinbo Micro Devices (NJR) | Nisshinbo Micro Devices (same-brand) | Nisshinbo Micro Devices (same-brand) | Nisshinbo Micro Devices (same-brand) | ROHM Semiconductor (cross-brand) |
| Output Voltage | 5.0 V | 3.3 V | 12 V | 3.3 V | 5.0 V |
| Maximum Output Current | 100 mA | 100 mA | 100 mA | 100 mA | 1.5 A (higher) |
| Input Voltage Range | 6.7 V to 35 V | 6.7 V to 35 V | 6.7 V to 35 V (VIN limited to 17 V above VOUT for 12 V output) | 6.7 V to 35 V | up to 16 V (lower max) |
| Enable Pin | No | No | No | No | No |
Wichtigste Unterscheidungsmerkmale
- Highest input voltage in the SOT-89-3 LDO class (vs. BA50BC0T)
- Ultra-low 9 uA quiescent current for battery applications (vs. BA50BC0T)
- Wide fixed-output selection in the same footprint (vs. NJW4181U3-12)
Designhinweise
The SOT-89-3 package is rated for 625 mW power dissipation at 25 C on the NJR/Nisshinbo datasheet land pattern, but realistic operation on a 1 oz FR-4 PCB yields theta_JA in the 100-150 C/W range depending on copper area. For a 24 V input to 5 V output at 100 mA, the linear regulator dissipates (24-5)*0.1 = 1.9 W - well above the 625 mW rating without a substantial copper pour. Estimated: with a 50 mm^2 copper pour on the tab and still air, theta_JA drops to roughly 80 C/W, giving a 152 C junction rise at 1.9 W, which exceeds the 150 C maximum. Designers should either lower input voltage with a preregulator, switch to a switching regulator, or use the SOT-89-3 tab with at least 200 mm^2 of copper plus thermal vias.
Place a 1 uF X7R ceramic input capacitor as close as possible to the VIN pin (within 2-3 mm) and a 1-10 uF low-ESR ceramic output capacitor at the VOUT pin. The exposed SOT-89-3 tab is internally tied to GND and is the primary thermal path - it MUST be soldered to a copper pour that is electrically common with the ground plane. For multi-layer boards, stitch the tab to the internal ground plane with an array of thermal vias (4-8 vias, 0.3 mm drill) to spread heat into the inner copper layers and reduce the junction-to-ambient thermal resistance.
Do not exceed 35 V on the input pin; load-dump transients on 12 V automotive systems can reach 40-60 V and require an upstream TVS clamp (such as a 33 V SMBJ series diode) to protect the regulator. The NJW4181U3-05B has no enable pin, so the part is on whenever VIN exceeds the 6.7 V minimum; designers wanting to control the rail must switch VIN upstream with a high-side P-MOSFET or load switch. The output capacitor ESR must stay within the stability region (typically 0.01-1 ohm) - low-ESR ceramics work, but very-low-ESR multilayer ceramic capacitors can introduce output instability if not verified against the datasheet's ESR curve.
Compliance-Informationen
RoHS compliant per NJR/Nisshinbo product page and DigiKey listing. AEC-Q100 automotive qualification status not published for this part; designers requiring automotive-grade LDOs should evaluate the NJW4181U3-05B-TE2-Q1 or similar automotive-qualified alternatives separately.
