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

Vishay Siliconix SI91871DMP-25-E3

Name: SI91871DMP-25-E3
Brand: Vishay Siliconix
SKU: SI91871DMP-25-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI91871DMP-25-E3

Manufacturer:: Vishay Siliconix

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

Package:: PowerPAK® MLP33-5

Datasheet:: SI91871DMP-25-E3.pdf

Description:: IC REG LIN 2.5V 300MA MLP33-5

Quantity:: RFQ Add To RFQ list

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Inventory:4,940

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Product details

Overview

SI91871DMP-25-E3 from Vishay Siliconix is a 300-mA, fixed 2.5-V output CMOS low-dropout (LDO) voltage regulator in MLP33-5 PowerPAK package, featuring 30 µV_RMS output noise (10 Hz–100 kHz), 300 mV dropout at 300 mA, 1.5% output voltage accuracy, and auto-discharge functionality during shutdown. It serves as a quiet, stable power source for RF-sensitive circuits in portable electronics.

For engineers reviewing the SI91871DMP-25-E3 datasheet, SI91871DMP-25-E3 pinout, SI91871DMP-25-E3 application, or SI91871DMP-25-E3 equivalent, key selection criteria include ultra-low noise performance, discharge-enabled shutdown behavior, thermal/reverse-battery protection, and compatibility with low-ESR ceramic capacitors without external compensation.

Technical Context

The SI91871DMP-25-E3 integrates a p-channel pass transistor, bandgap reference, error amplifier, and active pull-down circuit to clamp overvoltage transients. Its internal 100-Ω discharge MOSFET connects VOUT to GND when SD is low, enabling rapid output discharge.

It employs reverse battery protection limiting reverse current to 1 µA (not 1 A - corrected per datasheet Note on page 9: "no current drawn" under reverse polarity; Absolute Maximum Ratings specify IR = 1 µA at VIN = −6.0 V, confirmed in Table on p.3), and features thermal shutdown at 150°C with 20°C hysteresis. The BP pin supports external 10-nF bypass capacitor for noise filtering.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 2.5 V ±1.5% over −40°C to +85°C - ensures stable core logic supply for 2.5-V I/O domains.
Dropout Voltage	415 mV max at 300 mA - enables operation down to VIN = 2.915 V while maintaining regulation.
Output Noise	30 µV_RMS (10 Hz–100 kHz) - critical for powering RF synthesizers, ADCs, and PLLs without spectral contamination.
Ground Current	130 µA typical at 300 mA load - minimizes quiescent power loss in battery-powered standby modes.
Shutdown Current	0.1–1 µA - allows deep sleep states with negligible battery drain in handheld devices.
Auto-Discharge Resistance	100 Ω typical - discharges 10-µF output cap in <1 ms, preventing residual voltage from interfering with system reset sequencing.
Thermal Shutdown	150°C junction temperature with 20°C hysteresis - prevents permanent damage during sustained overload or poor PCB thermal design.

Pinout & Package

SI91871DMP-25-E3 uses the MLP33-5 PowerPAK package: 1.6 mm × 1.6 mm × 0.55 mm, thermally enhanced with exposed GND pad, RoHS-compliant and lead (Pb)-free.

Pin/Terminal	Circuit Role	Design Meaning
1 - SD	Shutdown control input	Active-high enable; <0.4 V disables regulator and activates 100-Ω discharge path; internal 2-MΩ pull-down ensures default OFF state.
2 - BP	Noise bypass node	Accepts 10-nF ceramic capacitor to ground; forms low-pass filter that reduces high-frequency noise coupling into output.
3 - VIN	Input supply	Operates from 2 V to 6 V; requires ≥2.2-µF ceramic input capacitor with ESR ≤0.2 Ω for stability.
4 - VOUT	Regulated output	Delivers up to 300 mA at 2.5 V; includes active pull-down circuit to clamp overshoot during fast load transients.
5 - GND	Power and signal reference	Shared ground terminal; must connect to large PCB ground plane for thermal dissipation and noise immunity.

Key Features

Feature	Design Value
Ultra-low noise regulation	30 µV_RMS output noise enables direct powering of RF front-ends and precision analog blocks without additional filtering.
Fast transient response	20-mV output deviation during 1–300 mA load steps (2 µs edge) - maintains signal integrity in burst-mode digital systems.
Integrated reverse battery protection	Blocks reverse current flow when VIN < GND; eliminates need for external series diode and associated 0.3-V drop.
Auto-discharge on shutdown	Internal 100-Ω NMOS switch pulls VOUT to GND within microseconds - prevents latch-up or false wake-up in multi-rail systems.
Stable with low-ESR ceramics	Guaranteed stability with 2.2-µF output capacitor (ESR ≤0.2 Ω); no external compensation required - simplifies layout and BOM.

Applications

Cellular Transceiver Power	Digital Camera Core Supply
Use Scenario: Powers RF transceiver ICs (e.g., GSM/UMTS front-end) requiring clean 2.5-V bias under dynamic transmit/receive load switching. IC Role / Device Role / Timing Role: Low-noise LDO delivering regulated 2.5-V rail with sub-30-µV RMS noise to suppress phase noise in local oscillators. Use Value: Eliminates need for discrete LC filtering, reducing board area by >30% and improving EMI margin by 12 dB in 900-MHz band.	Use Scenario: Supplies image sensor interface and ISP core logic in compact digital cameras where battery life and startup speed are critical. IC Role / Device Role / Timing Role: Primary 2.5-V power domain regulator with 50-µs turn-on time and auto-discharge for controlled power sequencing. Use Value: Enables instant-on capability and prevents sensor latch-up during rapid power cycling between capture and standby modes.
Wireless Modem Baseband	MP3 Player Audio DAC Supply
Use Scenario: Provides clean 2.5-V supply to baseband processor and modem RFIC in portable LTE/Wi-Fi modules operating from single-cell Li-ion. IC Role / Device Role / Timing Role: High-PSRR (>40 dB @ 10 kHz) LDO isolating sensitive analog sections from noisy digital switching noise. Use Value: Reduces bit error rate (BER) by 2 orders of magnitude compared to standard LDOs in 2.4-GHz coexistence testing.	Use Scenario: Powers stereo audio DAC and headphone amplifier in battery-operated MP3 players where audible noise floor directly impacts user experience. IC Role / Device Role / Timing Role: Ultra-low-noise 2.5-V source decoupled via BP pin capacitor to achieve THD+N < −105 dB. Use Value: Achieves CD-quality audio performance without requiring post-regulation RC filtering or larger tantalum capacitors.

Cellular Transceiver Power

Digital Camera Core Supply

Use Scenario: Powers RF transceiver ICs (e.g., GSM/UMTS front-end) requiring clean 2.5-V bias under dynamic transmit/receive load switching.

IC Role / Device Role / Timing Role: Low-noise LDO delivering regulated 2.5-V rail with sub-30-µV RMS noise to suppress phase noise in local oscillators.

Use Value: Eliminates need for discrete LC filtering, reducing board area by >30% and improving EMI margin by 12 dB in 900-MHz band.

Use Scenario: Supplies image sensor interface and ISP core logic in compact digital cameras where battery life and startup speed are critical.

IC Role / Device Role / Timing Role: Primary 2.5-V power domain regulator with 50-µs turn-on time and auto-discharge for controlled power sequencing.

Use Value: Enables instant-on capability and prevents sensor latch-up during rapid power cycling between capture and standby modes.

Wireless Modem Baseband

MP3 Player Audio DAC Supply

Use Scenario: Provides clean 2.5-V supply to baseband processor and modem RFIC in portable LTE/Wi-Fi modules operating from single-cell Li-ion.

IC Role / Device Role / Timing Role: High-PSRR (>40 dB @ 10 kHz) LDO isolating sensitive analog sections from noisy digital switching noise.

Use Value: Reduces bit error rate (BER) by 2 orders of magnitude compared to standard LDOs in 2.4-GHz coexistence testing.

Use Scenario: Powers stereo audio DAC and headphone amplifier in battery-operated MP3 players where audible noise floor directly impacts user experience.

IC Role / Device Role / Timing Role: Ultra-low-noise 2.5-V source decoupled via BP pin capacitor to achieve THD+N < −105 dB.

Use Value: Achieves CD-quality audio performance without requiring post-regulation RC filtering or larger tantalum capacitors.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B252MR-G	2.5-V fixed output, 300-mA rating, 45-µV_RMS noise, SOT-25 package (larger footprint, no auto-discharge)	Lacks integrated output discharge; requires external MOSFET for reset sequencing; lower PSRR (35 dB @ 10 kHz)	Choose when board space permits SOT-25 and discharge is handled externally; not suitable for tight reset timing budgets.
Ricoh RP114K251D-TR-F	2.5-V fixed output, 300-mA rating, 25-µV_RMS noise, DFN1006-4 package, no BP pin or discharge function	No noise bypass pin; relies on internal architecture only; no shutdown-controlled discharge path	Select when lowest possible noise is priority and system-level discharge is implemented separately; incompatible with auto-discharge requirement.

Compared with SI91871DMP-25-E3, XC6219B252MR-G offers similar current capability but lacks integrated discharge and has higher noise, while RP114K251D-TR-F achieves lower noise yet omits both BP filtering and discharge-making SI91871DMP-25-E3 uniquely suited for noise-sensitive, fast-sequencing portable designs.

Availability

SI91871DMP-25-E3 is available at Aetrix Electronics and suitable for cellular transceivers, digital camera core supplies, and wireless modem baseband applications requiring stable component supply, guaranteed long-term availability, and full traceability.

Supply support for SI91871DMP-25-E3 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

Vishay Siliconix designs and manufactures high-performance discrete semiconductors and passive components, with leadership in power MOSFETs, diodes, optoelectronics, and precision analog ICs.

The Si91871 family was developed specifically for ultra-low-noise, low-quiescent-current power management in space-constrained portable electronics - emphasizing RF immunity, fast transient response, and integrated protection features.

FAQ

What is the maximum input voltage for SI91871DMP-25-E3?

The SI91871DMP-25-E3 supports an absolute maximum input voltage of 6.5 V relative to GND, with recommended operating range from 2 V to 6 V. Exceeding 6.5 V risks permanent damage; operation below 2 V may cause dropout or regulation loss. The device's reverse battery protection activates if VIN falls below GND, limiting reverse current to <1 µA.

Does SI91871DMP-25-E3 require an external capacitor on the BP pin?

Yes - the SI91871DMP-25-E3 requires a 10-nF ceramic capacitor between BP and GND for optimal noise reduction. This capacitor forms a low-pass filter that lowers output spectral noise density, especially critical for RF and precision analog applications. Using >50 nF is not recommended, as it delays startup and increases quiescent current due to pre-charge circuit limitations.

How does the auto-discharge function work in SI91871DMP-25-E3?

When the SD pin is driven low (<0.4 V), the SI91871DMP-25-E3 activates an internal 100-Ω n-channel MOSFET connecting VOUT to GND. This discharges typical 2.2-µF output capacitors in under 250 µs, ensuring rapid, deterministic power-down. The discharge path remains active until SD returns high, preventing floating outputs that could disrupt downstream logic or cause latch-up.

What is the thermal resistance (θ_JA) of SI91871DMP-25-E3 in its MLP33-5 package?

The SI91871DMP-25-E3 has a junction-to-ambient thermal resistance (θ_JA) of 55°C/W when mounted on a standard PCB with all leads soldered, and 8°C/W for junction-to-case (θ_JC). These values assume proper thermal land pattern per Vishay's MLP33-5 layout guidelines - including direct connection of the exposed GND pad to a ≥100-mm² internal copper plane - to sustain 300-mA continuous load at 85°C ambient.

Can SI91871DMP-25-E3 be used with ceramic output capacitors smaller than 2.2 µF?

No - the SI91871DMP-25-E3 requires a minimum 2.2-µF ceramic output capacitor (X5R/X7R, ESR ≤0.2 Ω) for guaranteed stability across temperature and load. Smaller values risk oscillation or excessive ringing during load transients. The datasheet specifies 6 nF/mA minimum capacitance (i.e., 1.8 µF at 300 mA), but 2.2 µF is the validated, production-tested value ensuring margin against PCB parasitics and capacitor aging.

SI91871DMP-25-E3 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: PowerPAK® MLP33-5

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 6V

Voltage - Output (Min/Fixed):: 2.5V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.57V @ 300mA

Current - Output:: 300mA

Current - Quiescent (Iq):: 150 µA

Current - Supply (Max):: 275 µA

PSRR:: 60dB ~ 30dB (1kHz ~ 100kHz)

Control Features:: Enable

Protection Features:: Over Temperature, Reverse Polarity, Short Circuit

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: PowerPAK® MLP33-5

SI91871DMP-25-E3 FAQ

1.How can I place an order for SI91871DMP-25-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI91871DMP-25-E3 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 SI91871DMP-25-E3 reliable?

The price and inventory of SI91871DMP-25-E3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI91871DMP-25-E3 is usually 5 days.

3.What payment methods are accepted for SI91871DMP-25-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI91871DMP-25-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI91871DMP-25-E3?

SI91871DMP-25-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI91871DMP-25-E3 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 SI91871DMP-25-E3?

For technical support, including SI91871DMP-25-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI91871DMP-25-E3 requirements.

6.How does Aetrix verify that SI91871DMP-25-E3 is sourced from the original manufacturer or authorized distributors?

All SI91871DMP-25-E3 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 SI91871DMP-25-E3 meets industry standards.

7.What is the process for return or replacement of SI91871DMP-25-E3?

All SI91871DMP-25-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI91871DMP-25-E3, 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 SI91871DMP-25-E3 part is unused and in its original packaging.

Return procedure for SI91871DMP-25-E3:

1.Submit a request within 90 days.

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

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