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onsemi CS5231-3GDF8
- Part No.:
- CS5231-3GDF8
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CS5231-3GDF8.pdf
- Description:
- IC REG LINEAR FIXED LDO REG
- Quantity:
- Payment:
- Shipping:
Inventory:3,724
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Product details
Overview
CS5231-3GDF8 from onsemi is a fixed-output 3.3 V, 500 mA linear regulator with integrated auxiliary supply control logic and an AuxDrv output pin for driving an external PFET. It delivers uninterrupted 3.3 V power by seamlessly switching between a 5.0 V main input and a 3.3 V auxiliary source during brownout events, meeting Intel's "Instantly Available" power requirements per ACPI standards. It features ±2.0% output accuracy, thermal shutdown with 25°C hysteresis, and reverse current protection.
For engineers reviewing the CS5231-3GDF8 datasheet, pinout, applications, or equivalent options, this device is selected for dual-supply redundancy in PCI NICs, desktop power management, and PCMCIA/PCI interface cards where glitch-free 3.3 V continuity and controlled PFET gate drive are required.
Technical Context
The CS5231-3GDF8 integrates a composite NPN-PNP pass transistor for low-dropout operation and fast transient response, with internal biasing enabling stable regulation at up to 500 mA. Its VIN threshold detection circuitry provides hysteresis (75–125 mV) between turn-on (4.35–4.65 V) and turn-off (4.25–4.55 V), ensuring robust transition control.
AuxDrv operates as an open-drain-like output with internal 10 kΩ pull-up to VIN and active-low saturation down to 0.1 V (at 100 µA), directly controlling the gate of an external PFET. The IC disables the linear regulator until VIN exceeds ~4.5 V, while maintaining load power via the auxiliary path - a behavior validated in Figures 13–19 of the datasheet for VAUX = 3.135 V to 3.465 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±2.0% (3.234–3.366 V); ensures ASIC power compliance across temperature and load. |
| Max Output Current | 500 mA continuous; supports mid-power ASIC loads on PCI NICs without derating below 5.25 V VIN. |
| Quiescent Current | 3.0 mA at 500 mA load; minimizes standby power loss in sleep-state systems. |
| VIN Threshold Hysteresis | 75–125 mV; prevents oscillatory switching during slow-ramp or noisy input transitions. |
| Reverse Output Current | ≤0.45 mA (typical) when VIN = 0 V, VOUT = 3.3 V; protects auxiliary rail from backfeed. |
| Thermal Shutdown | 150–210°C activation with 25°C hysteresis; enables autonomous recovery after overtemperature fault. |
| AuxDrv Sink Current | 50 mA max sink capability; sufficient to drive common PFET gates (e.g., MGSF1P02ELT1) into full enhancement. |
Pinout & Package
CS5231-3GDF8 is packaged in SOIC-8 (Case 751-07, DF suffix), with internally fused leads and GND-connected tab-equivalent pins (pins 2, 3, 6, 7). Pin 1 is NC; pin 5 is AuxDrv - critical for auxiliary supply handover logic.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | No Connect | Unused; must remain unconnected to avoid parasitic coupling or ESD path disruption. |
| Pin 2, 3, 6, 7 | GND | Common ground reference and substrate connection; all four pins must be soldered to PCB ground plane for thermal and noise integrity. |
| Pin 4 | VIN | Main 5.0 V input supply node; absolute max rating 14 V, but functional range is 4.75–6.0 V per spec. |
| Pin 5 | VOUT | Regulated 3.3 V output; requires ≥10 µF output capacitor (ESR < 1.0 Ω) for stability and transient response. |
| Pin 8 | AuxDrv | Active-low auxiliary drive output; sinks current to ground when VIN < ~4.5 V, turning on external PFET; pulled up to VIN via internal 10 kΩ resistor otherwise. |
Key Features
| Feature | Design Value |
|---|---|
| Glitch-free dual-supply handover | Ensures zero-voltage interruption during 5.0 V dropout by activating AuxDrv before VOUT collapses - verified in Figs. 13–19. |
| Internally fused SOIC-8 leads | Prevents lead damage during reflow; eliminates need for external fusing in high-reliability PCI/PCMCIA applications. |
| Composite PNP-NPN pass transistor | Delivers lower dropout and reduced quiescent current vs. standard PNP designs - critical for efficiency at 500 mA. |
| Reverse current limiting | Restricts VOUT-to-GND leakage to ≤0.45 mA, preserving auxiliary rail integrity when main supply fails. |
| ACPI-compliant power sequencing | Fulfills Intel's "Instantly Available" requirement for sleep/wake transitions in desktop and embedded systems. |
Applications
| PCI Network Interface Card (NIC) | Desktop Computer Power Management |
|---|---|
Use Scenario: System enters ACPI S3 Sleep State; 5.0 V rail drops below 4.4 V while 3.3 V auxiliary remains active. IC Role / Device Role / Timing Role: CS5231-3GDF8 detects VIN collapse, asserts AuxDrv low to enable external PFET, and maintains uninterrupted 3.3 V to ASIC - no voltage glitch observed. Use Value: Enables instant resume from sleep without ASIC reset or data loss, satisfying Intel platform certification requirements. | Use Scenario: Motherboard power delivery requires seamless fallback from ATX 5.0 V to standby 3.3 V during AC loss or soft shutdown. IC Role / Device Role / Timing Role: CS5231-3GDF8 acts as intelligent 3.3 V supervisor, managing PFET-based source selection with 100 mV hysteresis to prevent chatter. Use Value: Eliminates need for discrete comparators, MOSFET drivers, and timing RC networks - reduces BOM count by ≥4 components. |
| PCMCIA Interface Card | Industrial Embedded Controller |
Use Scenario: Hot-plug insertion causes transient 5.0 V instability; auxiliary 3.3 V rail sustains logic during stabilization. IC Role / Device Role / Timing Role: CS5231-3GDF8 holds VOUT steady via AuxDrv-controlled PFET while VIN ramps, with <10 µs response time (Fig. 11). Use Value: Prevents communication lockup or register corruption in PCMCIA peripherals during plug-in events. | Use Scenario: Field-deployed controller must retain real-time clock and SRAM state during main supply interruption. IC Role / Device Role / Timing Role: CS5231-3GDF8 supplies regulated 3.3 V to RTC/SRAM from backup auxiliary source, with thermal shutdown protecting against sustained overload. Use Value: Guarantees >10-year data retention in battery-backed modules without external supervision circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-supply linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A6033QDGQRQ1 | Automotive-grade 3.3 V LDO (500 mA), no auxiliary control; requires external circuitry for dual-supply handover. | Suitable only when system-level control (e.g., MCU GPIO) can manage PFET switching - adds latency and firmware dependency. | Select if AEC-Q100 qualification is mandatory and auxiliary control can be implemented externally. |
| MAX8521ESA+ | 3.3 V, 500 mA dual-input LDO with integrated PFET driver; wider VIN range (2.7–6.5 V) but no VIN hysteresis specification. | Supports lower main input voltages but lacks documented glitch-free transition validation under ACPI conditions. | Select for non-ACPI systems requiring broader input flexibility and integrated driver, accepting higher design verification burden. |
Compared with TPS7A6033QDGQRQ1 and MAX8521ESA+, the CS5231-3GDF8 uniquely embeds hysteresis-controlled, self-timed auxiliary handover logic validated for ACPI-compliant platforms - eliminating external timing components and firmware coordination overhead.
Availability
CS5231-3GDF8 is available at Aetrix Electronics and suitable for PCI NICs, desktop motherboard power management, and PCMCIA interface cards requiring stable component supply with guaranteed long-term sourcing.
Supply support for CS5231-3GDF8 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 ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and computing markets.
The CS5231-3GDF8 belongs to onsemi's legacy power management portfolio designed specifically for ACPI-compliant PC platform power sequencing - emphasizing reliability, low-noise regulation, and seamless dual-rail handover without microcontroller intervention.
FAQ
What is the maximum allowable input voltage for CS5231-3GDF8?
The absolute maximum VIN rating for CS5231-3GDF8 is 14 V, but its specified operating range is strictly 4.75 V to 6.0 V per the Electrical Characteristics table. Operation above 6.0 V risks exceeding thermal limits and invalidates parametric guarantees - e.g., at VIN = 7.0 V, output current must be derated per Figure 21 to avoid thermal shutdown.
Does CS5231-3GDF8 support remote output voltage sensing?
No, CS5231-3GDF8 does not support remote sensing. Its feedback network is internal and inaccessible; therefore, board layout must minimize IR drop in VOUT and GND traces. Per the datasheet, place the IC adjacent to both load and output capacitor, use wide copper traces, and tie IC ground to load ground at the load point to maintain ±2.0% regulation accuracy.
How does the AuxDrv pin behave during power-up and power-down sequences?
During power-up, AuxDrv remains low until VIN exceeds ~4.5 V (turn-on threshold), then pulls high via internal 10 kΩ resistor to disable the PFET. During power-down, AuxDrv goes low again when VIN falls below ~4.4 V (turn-off threshold), re-enabling the PFET. This hysteresis (≥75 mV) prevents oscillation - confirmed in Figures 13–19 using resistive and capacitive loads.
Can CS5231-3GDF8 operate without an external PFET?
Yes, CS5231-3GDF8 functions as a standard 3.3 V, 500 mA linear regulator without the PFET - AuxDrv will remain high (pulled up to VIN) and idle. However, auxiliary supply handover capability is lost. The IC still provides full regulation, current limit, thermal shutdown, and reverse current protection in standalone mode.
What is the recommended output capacitor for CS5231-3GDF8 stability?
The datasheet mandates ≥10 µF output capacitance with ESR < 1.0 Ω for guaranteed stability. Tantalum (e.g., AVX TAJD336K016) or low-ESR aluminum polymer capacitors are preferred. Using smaller or higher-ESR values may cause oscillation or poor transient response - validated in Figure 9's stability region plot and Figure 11's transient waveforms.
CS5231-3GDF8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 3 mA
- Current - Supply (Max):
- 6 mA
- PSRR:
- -
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
CS5231-3GDF8 FAQ
1.How can I place an order for CS5231-3GDF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for CS5231-3GDF8 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 CS5231-3GDF8 reliable?
The price and inventory of CS5231-3GDF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CS5231-3GDF8 is usually 5 days.
3.What payment methods are accepted for CS5231-3GDF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CS5231-3GDF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CS5231-3GDF8?
CS5231-3GDF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CS5231-3GDF8 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 CS5231-3GDF8?
For technical support, including CS5231-3GDF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CS5231-3GDF8 requirements.
6.How does Aetrix verify that CS5231-3GDF8 is sourced from the original manufacturer or authorized distributors?
All CS5231-3GDF8 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 CS5231-3GDF8 meets industry standards.
7.What is the process for return or replacement of CS5231-3GDF8?
All CS5231-3GDF8 units undergo pre-shipment inspection (PSI). If there is an issue with CS5231-3GDF8, 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 CS5231-3GDF8 part is unused and in its original packaging.
Return procedure for CS5231-3GDF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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