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onsemi FAN2558S25X
- Part No.:
- FAN2558S25X
- Manufacturer:
- onsemi
- Package:
- SC-74A, SOT-753
- Datasheet:
-
FAN2558S25X.pdf
- Description:
- IC REG LINEAR 2.5V 180MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,378
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Product details
Overview
FAN2558S25X from onsemi (formerly Fairchild) is a fixed-output 3.3V, 180mA low-dropout linear regulator with power-good indicator, 1% output accuracy, and ultra-low ground current (100µA). It operates from 2.7V to 5.5V input and delivers stable voltage for processor core and I/O rail sequencing in space-constrained portable electronics.
For engineers reviewing the FAN2558S25X datasheet, pinout, applications, or equivalent options, key selection considerations include its 3.3V fixed output, SOT-23-5 package footprint, open-drain PG signal timing (1–5ms delay), 400mV dropout at 180mA, and compatibility with 0–300mΩ ESR output capacitors without external compensation.
Technical Context
The FAN2558S25X uses a P-channel MOSFET pass element controlled by a CMOS error amplifier referenced to a trimmed 0.59V internal bandgap, enabling precise 3.3V regulation across temperature and load. Its control loop is optimized for stability with ceramic, tantalum, or electrolytic output capacitors ranging from 1µF to ≥4.7µF and ESR up to 300mΩ.
Power management functions include TTL-compatible enable (VENH = 1.6V min, VENL = 0.4V max), active output discharge via internal 100Ω resistor during shutdown, and open-drain Power Good (PG) that asserts low when VOUT falls below 89% of nominal (2.937V) and releases above 97% (3.201V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1% over -40°C to +85°C - ensures reliable logic-level compliance for 3.3V I/O domains. |
| Max Output Current | 180mA continuous - supports single-core microcontrollers, PMIC auxiliary rails, and low-power FPGA I/O banks. |
| Dropout Voltage | 400mV at 180mA - enables operation down to VIN = 3.7V while maintaining regulation, critical for Li-ion battery discharge profiles. |
| Ground Current | 100µA typical at no load - minimizes quiescent power loss in always-on subsystems like RTC or wake-up circuitry. |
| PSRR | 50dB (DC–100kHz) - suppresses switching noise from upstream DC/DC converters feeding the LDO input. |
| Power Good Delay | 1–5ms - provides deterministic reset timing for downstream logic after power stabilization. |
| Enable Response Time | 30–300µs - supports fast dynamic power gating in CDMA and LTE modem power sequencing. |
| Thermal Shutdown | 150°C with 10°C hysteresis - protects against sustained overload or poor PCB thermal design without latch-up. |
Pinout & Package
Package: 5-Lead SOT-23 (SC-74A), 2.9mm × 1.6mm × 1.1mm body, surface-mount, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Input Power Supply | Accepts 2.7–5.5V; requires local 2.2µF input capacitor for optimal transient response and ripple rejection. |
| 2 - GND | Ground Reference | Primary return path for load current and internal bias; must connect to low-impedance local ground plane near output capacitor. |
| 3 - EN | Enable Control Input | TTL-compatible; high ≥1.6V enables regulator, low ≤0.4V disables output and reduces IQ to 0.1µA. |
| 4 - PG | Open-Drain Power Good | Asserts low when VOUT < 2.937V; requires external 47kΩ pull-up to monitor regulation status for system reset or fault logging. |
| 5 - VOUT | Regulated Output | Delivers 3.3V ±1%; stable with 1µF ceramic capacitor and ESR 0–300mΩ; includes internal discharge path during shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V Output | Factory-trimmed to ±1% accuracy eliminates external feedback resistors and saves board space in compact designs. |
| Power Good Indicator | Open-drain PG with programmable delay (1–5ms) enables synchronized system boot and safe power-down sequencing. |
| Ultra-Low Ground Current | 100µA typical at no load - extends battery life in standby modes for handheld and IoT edge devices. |
| Fast Enable Response | 30–300µs turn-on time meets CDMA/LTE RF power amplifier ramp requirements without external timing components. |
| Wide Capacitor Compatibility | Stable with 1µF output capacitor and ESR from 0 to 300mΩ - supports low-cost ceramic, tantalum, or polymer caps without tuning. |
| Integrated Protection | Current limit (260–500mA) and thermal shutdown (150°C) prevent damage during short-circuit or high ambient conditions. |
Applications
| Processor Power Sequencing | Cell Phone Baseband Power |
|---|---|
|
Use Scenario: Coordinating startup order between CPU core (1.2V), I/O (3.3V), and memory interface rails in ARM-based smartphones. IC Role / Device Role / Timing Role: FAN2558S25X supplies clean 3.3V I/O rail and signals readiness via PG to enable subsequent power stages. Use Value: Ensures 3.3V rail stabilizes before enabling dependent peripherals, preventing bus contention or configuration errors. |
Use Scenario: Providing regulated 3.3V supply to baseband processor analog sections and RF transceiver interfaces. IC Role / Device Role / Timing Role: FAN2558S25X acts as low-noise post-regulator after main buck converter, with PG confirming valid voltage before RF activation. Use Value: 50dB PSRR suppresses switching noise from primary DC/DC, preserving ADC/DAC SNR and RF receiver sensitivity. |
| PCMCIA Card Vcc Regulation | Portable Medical Monitor Sensors |
|
Use Scenario: Delivering compliant 3.3V Vcc to PCMCIA Type II cards in industrial data loggers and field test equipment. IC Role / Device Role / Timing Role: FAN2558S25X regulates card power and asserts PG only after output reaches 97% of 3.3V, satisfying PCMCIA hot-plug timing specs. Use Value: Meets JEIDA/PCMCIA Vcc ramp and hold requirements without external timing circuitry or microcontroller intervention. |
Use Scenario: Powering low-power analog front-end sensors (ECG, SpO₂) in battery-operated patient monitors. IC Role / Device Role / Timing Role: FAN2558S25X supplies ultra-stable 3.3V reference for precision ADCs and isolates sensor analog section from noisy digital subsystems. Use Value: 30µVRMS output noise and 1% accuracy ensure sub-12-bit measurement integrity over full temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1700T-3302E/TT | 3.3V fixed, 250mA, 6µA IQ, SOT-23-5 - lower quiescent current but no PG output or fast enable. | Lacks power-good signaling and CDMA-fast enable; suitable only where sequencing and diagnostics are handled externally. | Select when ultra-low IQ dominates over system-level power sequencing needs. |
| NCP1117ST33T3G | 3.3V fixed, 1A, 6mA IQ, SOT-223 - higher current, higher dropout (1.2V), no PG, larger package. | Requires minimum 4.5V input; unsuitable for single-cell Li-ion systems; lacks diagnostic capability. | Choose only for high-current, non-battery applications where thermal mass and board area permit SOT-223. |
Compared with MCP1700T-3302E/TT and NCP1117ST33T3G, the FAN2558S25X uniquely balances 3.3V precision, integrated PG signaling, fast enable, and SOT-23-5 footprint - making it optimal for battery-powered sequenced power systems where diagnostics and space are constrained.
Availability
FAN2558S25X is available at Aetrix Electronics and suitable for processor power sequencing, portable medical sensor modules, and PCMCIA card regulation requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for FAN2558S25X 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
onsemi (formerly Fairchild Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The FAN2558S25X belongs to the FAN2558 family of low-voltage CMOS LDOs designed specifically for battery-powered portable electronics requiring high PSRR, low noise, fast enable, and accurate fixed-output regulation in minimal footprint packages.
FAQ
What is the output voltage tolerance of the FAN2558S25X over temperature and load?
The FAN2558S25X guarantees ±1% output voltage accuracy over the full operating temperature range (-40°C to +85°C) and load current (0–180mA), as confirmed in the Electrical Characteristics table under VOUT parameter. This specification holds with VIN between 2.7V and 5.5V and includes line and load regulation contributions. The 1% tolerance is factory-trimmed and does not require external calibration.
Does the FAN2558S25X require an external bypass capacitor for stable operation?
No, the FAN2558S25X does not require an external bypass capacitor for basic stability - it is fully functional with only a 1µF output capacitor and supports ESR from 0 to 300mΩ. However, a 10nF bypass capacitor between BYP and GND (not applicable to FAN2558S25X, which uses SOT-23-5 and lacks BYP pin) is specified only for the FAN2559 variant. The FAN2558S25X achieves low noise and high PSRR without it.
What is the minimum input voltage required for the FAN2558S25X to maintain 3.3V output at full load?
The minimum input voltage for the FAN2558S25X to sustain 3.3V output at 180mA load is 3.7V, calculated as VOUT + VDROPOUT = 3.3V + 0.4V. This is consistent with the Recommended Operating Conditions table specifying VIN ≥ VOUT + VDROPOUT for VOUT ≥ 2.0V. Below 3.7V, the device enters dropout and output voltage declines linearly with VIN.
Can the FAN2558S25X be used in new designs despite "DISCONTINUED" notices in the datasheet?
Yes - the "DISCONTINUED" banner applies only to the FAN2559 and certain MLP-6 variants, not the FAN2558S25X. The Ordering Information table explicitly lists FAN2558S25X as an active part number in 5-Lead SOT-23 packaging with marking "58K". onsemi continues to manufacture and support this variant for new designs requiring its specific feature set.
How does the Power Good (PG) pin behave during startup and fault conditions?
The PG pin of the FAN2558S25X is an open-drain output that remains low until VOUT reaches ≥97% of 3.3V (≥3.201V), then transitions high after a 1–5ms delay. During faults - including input undervoltage, thermal shutdown, or overcurrent - PG pulls low within microseconds. A 47kΩ external pull-up resistor to VIN is required for proper logic-level signaling, and PG stays low until regulation is fully restored.
FAN2558S25X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Last Time Buy
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 180mA
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- -
- PSRR:
- 50dB (100kHz)
- Control Features:
- Enable, Power Good
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
FAN2558S25X FAQ
1.How can I place an order for FAN2558S25X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN2558S25X 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 FAN2558S25X reliable?
The price and inventory of FAN2558S25X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN2558S25X is usually 5 days.
3.What payment methods are accepted for FAN2558S25X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN2558S25X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN2558S25X?
FAN2558S25X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN2558S25X 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 FAN2558S25X?
For technical support, including FAN2558S25X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN2558S25X requirements.
6.How does Aetrix verify that FAN2558S25X is sourced from the original manufacturer or authorized distributors?
All FAN2558S25X 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 FAN2558S25X meets industry standards.
7.What is the process for return or replacement of FAN2558S25X?
All FAN2558S25X units undergo pre-shipment inspection (PSI). If there is an issue with FAN2558S25X, 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 FAN2558S25X part is unused and in its original packaging.
Return procedure for FAN2558S25X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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