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STMicroelectronics LDQ40PU18RY
- Part No.:
- LDQ40PU18RY
- Manufacturer:
- STMicroelectronics
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LDQ40PU18RY.pdf
- Description:
- 250 MA LOW DROPOUT LDO
- Quantity:
- Payment:
- Shipping:
Inventory:2,990
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Product details
Overview
LDQ40PU18RY from STMicroelectronics is a 1.8 V fixed-output, 250 mA low-dropout linear regulator (LDO) with AEC-Q100 Grade 1 qualification, -40 °C to 150 °C operating junction temperature, 500 mV typical dropout at 250 mA, and Power Good output - designed for always-on battery-connected automotive subsystems including instrument clusters and ADAS domain controllers.
For engineers reviewing the LDQ40PU18RY datasheet, LDQ40PU18RY pinout, LDQ40PU18RY application, or LDQ40PU18RY equivalent, key selection criteria include its automotive-grade thermal robustness (170 °C shutdown), ultra-low 2 µA quiescent current at no load, ±1.5% output voltage tolerance over full temperature range, and integrated output active discharge function.
Technical Context
The LDQ40PU18RY employs a P-channel MOSFET pass element enabling low dropout and high PSRR (60 dB for adjustable version at 1 kHz). Its internal bandgap reference and error amplifier deliver tight regulation across input voltage (3.3 V–40 V) and load (1–250 mA) variations, with remote sensing via VSENSE pin on fixed versions.
It integrates logic-controlled enable (EN), open-drain Power Good (PG) with 93–98% VOUT threshold and 30–70 mV hysteresis, thermal shutdown (170 °C typ.), short-circuit protection (65–250 mA), and internal current limiting (350–1000 mA), all within a DFN 2×2 mm 6L wettable flanks package qualified for automotive use.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±0.5% at 25 °C; ±1.5% over -40 °C to 125 °C - ensures stable MCU core supply under thermal stress. |
| Max Output Current | 250 mA guaranteed - sufficient for powering microcontrollers, CAN transceivers, and sensor interfaces in compact ECUs. |
| Dropout Voltage | 500 mV typical at 250 mA - enables operation down to VIN = 2.3 V while maintaining regulated 1.8 V output. |
| Quiescent Current | 2 µA typical at no load - minimizes battery drain in always-on vehicle networks (e.g., body control modules). |
| Power Good Threshold | Rising edge at 93–98% VOUT, falling at 86–95% VOUT - provides precise system-level power sequencing and fault detection. |
| Thermal Shutdown | 170 °C junction temperature with 20 °C hysteresis - protects against sustained overload in enclosed automotive enclosures. |
| ESD Protection | HBM: 2 kV; CDM (DFN WF corners): 750 V - meets automotive board-level ESD immunity requirements. |
Pinout & Package
LDQ40PU18RY is housed in a DFN 2×2 mm 6-lead wettable flanks package (ECOPACK® compliant), featuring an exposed thermal pad connected to GND for enhanced thermal dissipation (RthJA = 62 °C/W on FR4 with 1 sq-in copper pad).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Accepts 3.3 V to 40 V; includes undervoltage lockout (2.55–2.65 V rising edge) to prevent erratic startup. |
| EN | Enable logic input | Active-high; drives device into shutdown with <0.3 µA total current when pulled low - critical for system-level power gating. |
| GND | Ground reference | Common return path for input/output currents and internal circuitry; must be connected to exposed pad for thermal performance. |
| PG | Power Good open-drain output | Signals valid regulation status; requires external pull-up; asserts low if VOUT falls below 93% of nominal value. |
| VSENSE | Output voltage sense (fixed version) | Connected internally to VOUT for remote sensing - improves regulation accuracy under PCB trace IR drop. |
| VOUT | Regulated output | Delivers 1.8 V ±1.5% over temperature; supports ceramic output capacitors from 1 µF to 200 µF (X5R/X7R recommended). |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for -40 °C to +150 °C junction operation - suitable for engine bay and transmission control units. |
| Output active discharge | 70 Ω internal MOSFET discharges VOUT when EN is deasserted - prevents floating rail during power-down sequences. |
| Low-noise regulation | 90 µVRMS output noise (10 Hz–100 kHz) - preserves signal integrity for analog sensors and ADC references. |
| High PSRR | 55 dB (fixed version) / 60 dB (adjustable) at 1 kHz - suppresses ripple from noisy DC-DC pre-regulators in multi-rail systems. |
| Short-circuit protection | Limits output current to 65–250 mA depending on temperature - prevents catastrophic failure during wiring faults. |
Applications
| Instrument Cluster Power Supply | ADAS Camera Module Bias Rail |
|---|---|
|
Use Scenario: Supplies 1.8 V core voltage to display controller SoC and graphics memory in digital instrument clusters. IC Role / Device Role / Timing Role: Primary LDO delivering clean, sequenced, and monitored 1.8 V rail with PG assertion before SoC boot. Use Value: ±1.5% output accuracy and 90 µVRMS noise ensure stable GPU operation and eliminate visual artifacts under thermal cycling. |
Use Scenario: Powers image signal processor (ISP) core logic in forward-facing ADAS cameras mounted behind windshield. IC Role / Device Role / Timing Role: Always-on LDO with ultra-low IQ (2 µA) sustaining bias during vehicle sleep mode. Use Value: 250 mA capability and 500 mV dropout allow direct step-down from 12 V battery without intermediate buck stage, reducing BOM count. |
| Body Control Module (BCM) Microcontroller Core | Automotive Infotainment System PMIC Auxiliary Rail |
|
Use Scenario: Provides 1.8 V core supply to ARM Cortex-M7 MCU managing door locks, lighting, and HVAC functions. IC Role / Device Role / Timing Role: Regulator with EN-controlled shutdown and PG feedback for coordinated power management across distributed BCM nodes. Use Value: Integrated thermal shutdown (170 °C) and short-circuit protection enable reliable operation in unventilated under-dash locations. |
Use Scenario: Generates auxiliary 1.8 V rail for audio codec, touch controller, and CAN FD transceiver in head unit mainboard. IC Role / Device Role / Timing Role: Secondary LDO with remote sensing (VSENSE) compensating for PCB trace resistance between regulator and load. Use Value: Wettable flanks DFN package enables automated optical inspection (AOI) and improves solder joint reliability in high-vibration environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLD5098EL | 1.8 V fixed, 250 mA, AEC-Q100 Grade 1, but lacks Power Good output and active discharge. | Suitable for non-sequenced, non-monitored rails where system-level supervision is handled externally. | Select when PG signaling and fast output discharge are not required - lower cost, same thermal envelope. |
| TPS7B8118QDDARQ1 | 1.8 V fixed, 300 mA, AEC-Q100 Grade 1, 350 mV dropout, but higher IQ (12 µA typ.) and no wettable flanks. | Better for high-current loads near thermal limit; less suited for ultra-low-power always-on domains. | Choose when >250 mA margin is needed and AOI compatibility is secondary to peak current capability. |
Compared with TLD5098EL, LDQ40PU18RY adds critical system-level features (PG, active discharge) without sacrificing thermal robustness; versus TPS7B8118QDDARQ1, it trades 50 mA headroom for 6× lower quiescent current and superior manufacturability via wettable flanks.
Availability
LDQ40PU18RY is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, and body control modules requiring stable component supply with AEC-Q100 compliance and long-term lifecycle support.
Supply support for LDQ40PU18RY 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
STMicroelectronics is a global semiconductor leader specializing in automotive, industrial, and power management ICs, with over 40 years of analog design heritage and ISO/TS 16949-certified manufacturing.
The LDQ40 series belongs to ST's automotive-qualified LDO portfolio, engineered specifically for demanding always-on battery-connected applications where ultra-low IQ, thermal resilience, and functional safety awareness are mandatory.
FAQ
What is the minimum input voltage required for LDQ40PU18RY to regulate 1.8 V output?
The device requires VIN ≥ VOUT + VDROP. With 500 mV typical dropout at 250 mA, minimum VIN is 2.3 V. However, undervoltage lockout activates below 2.55 V (rising edge), so stable regulation begins at ~2.65 V. Below this, EN must remain low to prevent brownout behavior.
Can LDQ40PU18RY be used with ceramic output capacitors smaller than 1 µF?
No. The datasheet specifies a minimum 1 µF X5R/X7R ceramic capacitor for loop stability. Using smaller values risks oscillation or poor transient response. Capacitor ESR must stay within 5 mΩ–10 Ω across -40 °C to 125 °C, and derating for temperature/voltage is mandatory.
How does the Power Good (PG) pin behave during enable/disable transitions?
PG is open-drain and high-impedance when EN = LOW or VOUT is invalid. It pulls low only when VOUT drops below 93% of 1.8 V (≈1.67 V). During startup, PG asserts high after VOUT reaches 98% of target and remains high until regulation fails - enabling precise power sequencing in multi-rail systems.
Is the exposed thermal pad on the DFN6 WF package electrically isolated?
No. The exposed pad is internally connected to GND and must be soldered to a PCB ground plane. Failure to connect it degrades thermal performance (RthJA increases from 62 °C/W to >100 °C/W) and may cause thermal shutdown under load. Thermal vias to inner ground layers are strongly recommended.
LDQ40PU18RY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 6-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1V @ 250mA
- Current - Output:
- 250mA
- Current - Quiescent (Iq):
- 5 µA
- Current - Supply (Max):
- 500 µA
- PSRR:
- 55dB (1kHz)
- Control Features:
- Current Limit, Enable
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-DFN (2x2)
LDQ40PU18RY FAQ
1.How can I place an order for LDQ40PU18RY through Aetrix?
Please submit a Request for Quotation (RFQ) for LDQ40PU18RY 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 LDQ40PU18RY reliable?
The price and inventory of LDQ40PU18RY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDQ40PU18RY is usually 5 days.
3.What payment methods are accepted for LDQ40PU18RY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDQ40PU18RY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LDQ40PU18RY?
LDQ40PU18RY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LDQ40PU18RY 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 LDQ40PU18RY?
For technical support, including LDQ40PU18RY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDQ40PU18RY requirements.
6.How does Aetrix verify that LDQ40PU18RY is sourced from the original manufacturer or authorized distributors?
All LDQ40PU18RY 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 LDQ40PU18RY meets industry standards.
7.What is the process for return or replacement of LDQ40PU18RY?
All LDQ40PU18RY units undergo pre-shipment inspection (PSI). If there is an issue with LDQ40PU18RY, 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 LDQ40PU18RY part is unused and in its original packaging.
Return procedure for LDQ40PU18RY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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