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Texas Instruments LP38843S-1.5/NOPB
- Part No.:
- LP38843S-1.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LP38843S-1.5/NOPB.pdf
- Description:
- IC REG LIN 1.5V 3A DDPAK/TO263-5
- Quantity:
- Payment:
- Shipping:
Inventory:169
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Product details
Overview
LP38843S-1.5/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 1.5V output, N-MOS pass transistor architecture, 210mV dropout at 3A, ±1.5% initial output accuracy, and dual-supply operation (VIN + VBIAS). It delivers stable core power to FPGA I/O banks and DSP subsystems in server and graphics card applications.
For engineers reviewing the LP38843S-1.5/NOPB datasheet, LP38843S-1.5/NOPB pinout, LP38843S-1.5/NOPB application, or LP38843S-1.5/NOPB equivalent, key selection criteria include bias-rail dependency (4.5–5.5V), ceramic-capacitor stability (≥22µF), shutdown current (30nA), thermal resistance (35°C/W on 1-in² copper), and DDPAK/TO-263 package layout constraints.
Technical Context
The LP38843S-1.5/NOPB employs a CMOS-based N-MOS pass transistor driven by an independent VBIAS rail, enabling operation with VIN as low as VOUT + 210mV. Its control loop is optimized for stability with low-ESR ceramic output capacitors (≥22µF) and includes internal over-temperature and over-current protection.
It features separate input (VIN) and bias (VBIAS) supplies: VIN powers the load while VBIAS (4.5–5.5V) drives gate circuitry, decoupling regulation performance from input voltage headroom. Shutdown is active-low via the S/D pin, with 20µs turn-off delay and 15µs turn-on delay under light-load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.5V ±1.5% at room temperature; maintains regulation across −40°C to +125°C junction range. |
| Max Output Current | 3A continuous; internally current-limited; short-circuit current ≈8A. |
| Dropout Voltage | 210mV typical at 3A load; enables use with input rails as low as 1.71V for 1.5V output. |
| Quiescent Current | 30mA typical from VIN at full load; 2mA typical from VBIAS; drops to 30nA in shutdown. |
| PSRR | 80dB at 120Hz on VIN; 58dB at 1kHz on VBIAS; supports clean power delivery in noisy SMPS post-regulator roles. |
| Thermal Resistance | θJ-A = 35°C/W when soldered to ≥1 in² copper plane-critical for thermal design in compact server PCBs. |
| Output Noise | 150µVrms (10Hz–100kHz); suitable for noise-sensitive analog and mixed-signal loads. |
Pinout & Package
LP38843S-1.5/NOPB uses the DDPAK/TO-263 (KTT) 5-pin surface-mount package. The exposed metal tab is electrically connected to GND and serves as primary thermal path to PCB copper.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN | Main power input | High-current path for load power; requires ≥10µF ceramic input capacitor within 1 cm. |
| BIAS | Bias supply input | Provides gate drive voltage (4.5–5.5V) to N-MOS pass transistor; must be externally regulated. |
| GND | Power and analog ground | Common return for IN, BIAS, and OUTPUT; tab is GND-must be soldered to large copper pour. |
| OUT | Regulated output | Delivers 1.5V/3A; requires ≥22µF ceramic output capacitor with X5R/X7R dielectric. |
| S/D | Shutdown control | Active-low enable; pull to VBIAS for normal operation; 1µA max input current at 1.3V. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 210mV at 3A enables direct conversion from 1.8V SMPS rails without intermediate stages. |
| Ceramic capacitor stability | Stable with ≥22µF X5R/X7R ceramic output cap-eliminates ESR requirements of tantalum alternatives. |
| Dual-rail architecture | Separate VIN and VBIAS inputs isolate gate drive from load current, preserving regulation at ultra-low VIN. |
| Low-noise output | 150µVrms broadband noise supports precision analog circuits and high-speed digital cores. |
| Robust protection | Integrated thermal shutdown and current limiting prevent damage during overload or poor heatsinking. |
Applications
| ASIC Power Supplies in Graphics Cards | Server Core and I/O Supplies |
|---|---|
Use Scenario: Powers GPU memory interface and display engine logic on PCIe add-in cards with tight board space and thermal constraints. IC Role / Device Role / Timing Role: Primary LDO post-regulator delivering clean 1.5V to high-speed SerDes and memory PHYs. Use Value: 210mV dropout allows direct use of 1.8V intermediate rail; 35°C/W θJ-A enables conduction cooling via PCB copper. | Use Scenario: Supplies 1.5V I/O banks for multi-core Xeon processors in 1U rack servers where airflow is restricted. IC Role / Device Role / Timing Role: Low-noise, high-current LDO ensuring signal integrity for DDR5 address/command buses. Use Value: 150µVrms output noise prevents timing jitter; 3A rating supports burst-mode I/O loading without droop. |
| DSP and FPGA Power Supplies | SMPS Post-Regulator |
Use Scenario: Provides 1.5V core voltage to FPGA configuration logic and transceiver banks in industrial vision systems. IC Role / Device Role / Timing Role: Fast-transient-response LDO compensating for dynamic current demands of programmable logic. Use Value: 15µs turn-on delay and 20µs turn-off delay support controlled power sequencing; ceramic-stable design simplifies BOM. | Use Scenario: Final-stage regulator after 3.3V buck converter in telecom baseband processing modules. IC Role / Device Role / Timing Role: Ripple-rejection LDO suppressing switching noise from upstream DC/DC stage. Use Value: 80dB PSRR at 120Hz attenuates fundamental ripple; dual-rail architecture avoids VIN headroom penalty. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ultra-low-dropout LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A8300RGRT | 3A, 1.5V fixed, single-supply (no VBIAS required); higher IQ (1.2mA); 175mV dropout at 3A. | Eliminates external bias rail but requires ≥2.5V VIN; less suitable for sub-2V input systems. | Select when system lacks dedicated 4.5–5.5V bias rail and VIN ≥2.5V is guaranteed. |
| LP3985IM5-1.5/NOPB | 150mA max, 1.5V fixed, single-supply; 120mV dropout at 150mA; SOT-23-5 package. | Not a current-scalable alternative; intended for low-power logic, not FPGA/ASIC core rails. | Use only for auxiliary 1.5V biasing of low-current peripherals-not as main 3A supply replacement. |
Compared with TPS7A8300RGRT, LP38843S-1.5/NOPB trades bias-rail complexity for lower dropout at ultra-low VIN; compared with LP3985IM5-1.5/NOPB, it delivers 20× more current in a thermally robust DDPAK package-making it the sole viable option for high-power 1.5V point-of-load regulation.
Availability
LP38843S-1.5/NOPB is available at Aetrix Electronics and suitable for server power delivery, graphics card design, and FPGA-based embedded systems requiring stable component supply, long-term lifecycle assurance, and RoHS-exempt material compliance.
Supply support for LP38843S-1.5/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability linear regulators and power delivery solutions.
The LP38843S-1.5/NOPB belongs to TI's ultra-low-dropout LDO family designed specifically for high-current, low-noise point-of-load regulation in computing, networking, and industrial equipment where thermal efficiency and transient response are critical.
FAQ
What is the minimum input voltage required for LP38843S-1.5/NOPB to regulate 1.5V output at 3A?
The LP38843S-1.5/NOPB requires a minimum input-to-output differential of 210mV at 3A load, meaning VIN must be at least 1.71V. However, the device also requires a separate 4.5–5.5V VBIAS supply to operate its gate driver-this bias rail is mandatory and independent of VIN.
Can LP38843S-1.5/NOPB operate without the VBIAS supply?
No. LP38843S-1.5/NOPB cannot function without the VBIAS supply. The VBIAS pin provides gate drive voltage for the internal N-MOS pass transistor. If VBIAS is below ~4V, an internal undervoltage lockout disables the output-even if VIN is sufficient.
What output capacitor is required for stable operation of LP38843S-1.5/NOPB?
LP38843S-1.5/NOPB requires a minimum 22µF X5R or X7R ceramic output capacitor placed within 1 cm of the OUT and GND pins. Tantalum capacitors are not recommended; if used, minimum capacitance rises to 4.7µF but with degraded transient response and higher ESR.
Is LP38843S-1.5/NOPB pin-compatible with other variants in the LP38843 family?
Yes. All LP38843S-x.x/NOPB variants in the DDPAK/TO-263 (KTT) package share identical 5-pin pinout and footprint. The LP38843S-1.5/NOPB can be substituted for LP38843S-1.2/NOPB or LP38843S-0.8/NOPB without PCB changes-only the output voltage differs.
Does LP38843S-1.5/NOPB include thermal shutdown protection?
Yes. LP38843S-1.5/NOPB integrates thermal shutdown protection that disables the output when junction temperature exceeds safe limits. Recovery is automatic once temperature falls below the hysteresis threshold. This feature is documented in the Absolute Maximum Ratings and Electrical Characteristics tables of the official datasheet.
LP38843S-1.5/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.5V @ 3A
- Current - Output:
- 3A
- Current - Quiescent (Iq):
- 30 µA
- Current - Supply (Max):
- 40 mA
- PSRR:
- 80dB ~ 65dB (120Hz ~ 1kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LP38843S-1.5/NOPB FAQ
1.How can I place an order for LP38843S-1.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38843S-1.5/NOPB 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 LP38843S-1.5/NOPB reliable?
The price and inventory of LP38843S-1.5/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP38843S-1.5/NOPB is usually 5 days.
3.What payment methods are accepted for LP38843S-1.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38843S-1.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38843S-1.5/NOPB?
LP38843S-1.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38843S-1.5/NOPB 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 LP38843S-1.5/NOPB?
For technical support, including LP38843S-1.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38843S-1.5/NOPB requirements.
6.How does Aetrix verify that LP38843S-1.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LP38843S-1.5/NOPB 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 LP38843S-1.5/NOPB meets industry standards.
7.What is the process for return or replacement of LP38843S-1.5/NOPB?
All LP38843S-1.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP38843S-1.5/NOPB, 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 LP38843S-1.5/NOPB part is unused and in its original packaging.
Return procedure for LP38843S-1.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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