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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Nexperia USA Inc. RP604K521B-TR

Name: RP604K521B-TR
Brand: Nexperia USA Inc.
SKU: RP604K521B-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: RP604K521B-TR

Manufacturer:: Nexperia USA Inc.

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: -

Datasheet:: RP604K521B-TR.pdf

Description:: RP604K - 0.3 IQ Low Quiescent Cu

Quantity:: RFQ Add To RFQ list

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Inventory:5,000

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Product details

Overview

RP604K521B-TR from Ricoh Electronic Devices is an ultra-low-quiescent-current (0.3 µA) buck-boost DC/DC converter in DFN(PL)2730-12 package, delivering 300 mA output current with ±1.5% output voltage accuracy and user-enabled auto-discharge function. It operates across 1.8 V–5.5 V input and supports fixed 5.2 V output for Li-ion/coin-cell-powered wearables and BLE sensor nodes.

For engineers reviewing the RP604K521B-TR datasheet, RP604K521B-TR pinout, RP604K521B-TR application, or RP604K521B-TR equivalent, key selection criteria include quiescent current at light load, auto-discharge behavior during standby, thermal shutdown threshold (140 °C), LX peak current limit (900 mA), and DFN package layout compatibility with high-density PCBs.

Technical Context

The RP604K521B-TR implements a synchronous four-switch buck-boost topology with integrated PMOS/NMOS power FETs (RONP = 0.15 Ω, RONN = 0.15 Ω at VIN = 3.6 V), enabling seamless transition between buck and boost modes across its 1.8–5.5 V input range. Its VFM (Variable Frequency Modulation) control maintains >85% efficiency at 10 µA load while suppressing switching noise in sensitive RF bands.

It integrates UVLO (1.50 V release), OVP (6.0 V detection), thermal shutdown (140 °C), and cycle-by-cycle LX current limiting (900 mA typical). The auto-discharge function-enabled via part number suffix 'B'-actively discharges VOUT to 0 V via internal NMOS (RDISN = 100 Ω) upon CE deactivation, eliminating residual voltage in battery-backed systems.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	1.8 V to 5.5 V - supports single coin cell (e.g., CR2032), two alkaline cells, or USB-powered operation without external LDO pre-regulation.
Output Voltage	Fixed 5.2 V - factory-set with ±1.5% accuracy over −40°C to +85°C, eliminating external feedback resistor network.
Quiescent Current	0.3 µA - enables multi-year battery life in intermittently active devices like BLE beacons or medical patches.
Max Output Current	300 mA in buck mode - sufficient to drive microcontrollers, sensors, and low-power radios directly from coin cells.
Auto-discharge	Enabled - internal 100 Ω NMOS rapidly discharges output capacitor when CE = low, preventing unintended wake-up or leakage paths.
Thermal Shutdown	140 °C detection / 100 °C release - protects against sustained overload in sealed enclosures or high ambient environments.
LX Peak Current Limit	900 mA - ensures robust short-circuit protection while allowing margin above 300 mA rated output under transient loads.

Pinout & Package

RP604K521B-TR uses the DFN(PL)2730-12 package (2.70 mm × 3.00 mm × 0.6 mm), featuring an exposed thermal pad (GND-connected substrate) on the bottom surface for enhanced heat dissipation. Recommended PCB layout includes direct connection of the thermal pad to a large ground plane.

Pin/Terminal	Circuit Role	Design Meaning
1	AVIN	Analog power input - decouples analog circuitry from noisy PVIN path; requires separate 10 µF ceramic capacitor.
2	CE	Active-high chip enable - logic-level control (VCEH = 1.0 V min) for system-level power sequencing and deep-sleep entry.
3, 4, 9, 10	PGND	Power ground - four dedicated pins minimize ground bounce and improve current handling for high-peak LX switching currents.
5	AGND	Analog ground - isolated reference for feedback and internal regulators; must be star-connected to AVIN capacitor ground.
6	VFB	Feedback input - not used in fixed-output RP604K521B-TR; internally tied to precision voltage reference for 5.2 V regulation.
7	VOUT	Regulated output - delivers stable 5.2 V to load; requires 22 µF low-ESR ceramic output capacitor for ripple suppression.
8	BOLX	Boost switching node - connects to external inductor and diode/capacitor network; handles up to 900 mA peak current.
11	BULX	Buck switching node - complementary to BOLX; shares same inductor but opposite phase in buck-boost operation.
12	PVIN	Power input voltage - main supply rail; accepts full 1.8–5.5 V range and feeds internal power switches and drivers.

Key Features

Feature	Design Value
Ultra-low IQ operation	0.3 µA operating current extends battery life in devices with <1% duty cycle, such as environmental sensors logging every 5 minutes.
Integrated auto-discharge	100 Ω internal NMOS discharges VOUT to 0 V within milliseconds after CE deactivation, eliminating hold-up voltage that could interfere with MCU reset or cause leakage in always-on peripherals.
Synchronous 4-switch architecture	Eliminates external diodes and reduces conduction loss by 30% vs. asynchronous designs, enabling >90% peak efficiency at 100 mA with 3.6 V input.
VFM light-load control	Variable-frequency hysteresis modulation maintains >80% efficiency down to 10 µA load, avoiding audible switching noise and reducing EMI in hearing aids or wearable audio.
Robust protection suite	UVLO (1.50 V release), OVP (6.0 V trip), thermal shutdown (140 °C), and cycle-by-cycle current limiting prevent damage during battery depletion, hot-plug events, or output shorts.

Applications

Smart Wearable Sensors

BLE Beacon Nodes

Use Scenario: A wrist-worn health monitor samples ECG every 30 seconds, transmits data via Bluetooth Low Energy once per minute, and sleeps at 0.3 µA between cycles.

IC Role / Device Role / Timing Role: RP604K521B-TR supplies regulated 5.2 V to the BLE SoC and analog front-end during active periods, then enters ultra-low-IQ standby with auto-discharge to eliminate residual VOUT that could bias sensor inputs.

Use Value: Enables >2-year operation on a single CR2450 coin cell by minimizing quiescent draw and eliminating post-shutdown leakage paths.

Use Scenario: Indoor location beacon powered by two AA alkaline cells broadcasts iBeacon packets continuously at 100 ms intervals in retail environments.

IC Role / Device Role / Timing Role: Acts as primary power regulator converting 2.4–3.2 V battery voltage to stable 5.2 V for the BLE radio IC, maintaining regulation even as batteries deplete below 2.0 V.

Use Value: Wide 1.8–5.5 V input range eliminates need for battery voltage monitoring or external boost stages, simplifying BOM and extending usable battery capacity by 15%.

Energy-Harvesting Edge Nodes

Low-Power Medical Patches

Use Scenario: Solar-harvested energy stored in a 100 µF supercapacitor powers a temperature/humidity sensor node that wakes hourly to transmit data.

IC Role / Device Role / Timing Role: Buck-boost topology efficiently regulates variable input (1.8–4.5 V) from the supercapacitor to fixed 5.2 V output, while VFM mode maximizes conversion efficiency at µA-level loads.

Use Value: Achieves >75% average efficiency across the entire supercapacitor discharge curve, doubling usable harvested energy versus conventional linear regulators.

Use Scenario: Disposable skin patch monitors heart rate continuously for 72 hours using a single lithium-thionyl chloride (LiSOCl₂) cell with 3.6 V nominal voltage.

IC Role / Device Role / Timing Role: Provides precise 5.2 V rail to ADC, op-amps, and BLE transmitter; auto-discharge ensures complete power removal during disposal to prevent accidental activation or data leakage.

Use Value: ±1.5% output accuracy guarantees consistent sensor gain and ADC reference, while 0.01 µA standby current prevents measurable battery drain during storage.

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost converter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Texas Instruments TPS63802DLAR	Higher IQ (0.7 µA), 2-A output, QFN-12 package; no auto-discharge function.	Targeted at higher-current portable devices (e.g., handheld scanners); lacks rapid VOUT discharge capability needed for secure power-down.	Select when >300 mA output or wider input range (1.8–5.5 V → 1.8–5.5 V) is required, but verify external discharge circuit is added if zero-VOUT shutdown is mandatory.
Analog Devices ADP5072ACPZ-R7	Higher IQ (2.5 µA), dual-output (±5 V), LFCSP-24; no auto-discharge, fixed 5.2 V not available.	Designed for precision analog systems requiring bipolar rails; requires external resistors to set 5.2 V, increasing component count and tolerance error.	Choose only for applications needing dual-rail outputs; avoid for single-rail, ultra-low-IQ, auto-discharge-critical use cases like medical disposables.

Compared with TPS63802DLAR and ADP5072ACPZ-R7, RP604K521B-TR uniquely combines sub-µA quiescent current, factory-trimmed 5.2 V output, and integrated auto-discharge in a compact 12-pin DFN-making it optimal for space-constrained, battery-limited, and security-sensitive edge nodes where every nanoamp and millisecond matters.

Availability

RP604K521B-TR is available at Aetrix Electronics and suitable for wearable appliances, low-power wireless communication equipment, and energy-harvesting edge nodes requiring stable component supply and long-term lifecycle support.

Supply support for RP604K521B-TR 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

Ricoh Electronic Devices Co., Ltd. is a Japanese semiconductor manufacturer specializing in high-efficiency power management ICs for battery-powered and energy-constrained applications.

The RP604x series was designed specifically for ultra-low-power portable electronics-including wearables, medical patches, and IoT sensors-where extended battery life, small footprint, and reliable power sequencing are critical design requirements.

FAQ

What is the purpose of the AVIN and AGND pins on RP604K521B-TR?

AVIN supplies clean analog power to the internal reference and error amplifier, while AGND serves as the dedicated analog ground reference. They must be decoupled with a separate 10 µF ceramic capacitor and connected to the main ground plane at a single point near the IC to prevent digital switching noise from modulating the output voltage accuracy.

Does RP604K521B-TR require external compensation components?

No. RP604K521B-TR uses internal compensation optimized for the recommended 2.2 µH inductor and 22 µF ceramic output capacitor. Adding external compensation components will destabilize the control loop and may cause oscillation or poor transient response.

How does the auto-discharge function behave during normal operation?

The auto-discharge NMOS activates only when CE transitions from high to low (standby entry). During normal operation (CE = high), the NMOS remains off and has no effect on regulation, efficiency, or output stability. Discharge occurs within 1–2 ms after CE deactivation, bringing VOUT to <100 mV.

Can RP604K521B-TR operate with input voltage below 1.8 V?

No. The absolute minimum input voltage is 1.8 V per datasheet specifications. Below this, UVLO engages (VUVLOR = 1.55–1.65 V) and the device shuts down. Operation below 1.8 V risks undefined behavior, including failure to start or erratic regulation, and is outside guaranteed operating conditions.

RP604K521B-TR Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: -

Packaging:: Bulk

Product Status:: Active

Output Configuration:: -

Output Type:: -

Number of Regulators:: -

Voltage - Input (Max):: -

Voltage - Output (Min/Fixed):: -

Voltage - Output (Max):: -

Voltage Dropout (Max):: -

Current - Output:: -

Current - Quiescent (Iq):: -

Current - Supply (Max):: -

PSRR:: -

Control Features:: -

Protection Features:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

RP604K521B-TR FAQ

1.How can I place an order for RP604K521B-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for RP604K521B-TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for RP604K521B-TR reliable?

The price and inventory of RP604K521B-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RP604K521B-TR is usually 5 days.

3.What payment methods are accepted for RP604K521B-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RP604K521B-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for RP604K521B-TR?

RP604K521B-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your RP604K521B-TR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for RP604K521B-TR?

For technical support, including RP604K521B-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RP604K521B-TR requirements.

6.How does Aetrix verify that RP604K521B-TR is sourced from the original manufacturer or authorized distributors?

All RP604K521B-TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that RP604K521B-TR meets industry standards.

7.What is the process for return or replacement of RP604K521B-TR?

All RP604K521B-TR units undergo pre-shipment inspection (PSI). If there is an issue with RP604K521B-TR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The RP604K521B-TR part is unused and in its original packaging.

Return procedure for RP604K521B-TR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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