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Analog Devices Inc. LT1581CT7#PBF
- Part No.:
- LT1581CT7#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LT1581CT7#PBF.pdf
- Description:
- IC REG CONV PENTIUM 1OUT TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:1,307
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Product details
Overview
LT1581CT7#PBF from Analog Devices (formerly Linear Technology) is a 10A, fixed 2.5V low-dropout linear regulator with dual-supply architecture, remote sense capability, and 430mV dropout at full load. It delivers precise microprocessor core voltage on motherboards using separate 3.3V power and 5V control rails, supporting Pentium® and PowerPC™ processors operating at 90–166MHz.
For engineers reviewing the LT1581CT7#PBF datasheet, LT1581CT7#PBF pinout, LT1581CT7#PBF application, or LT1581CT7#PBF equivalent, key selection criteria include guaranteed 2.475–2.525V output over 0–10A load and −40°C to 125°C junction range, fast transient response under 1mV load regulation, and Kelvin-sense-enabled load-point regulation.
Technical Context
The LT1581CT7#PBF uses an NPN pass transistor driven by a dedicated VCONTROL rail ≥1V above VOUT, enabling 100mV dropout at light loads and 430mV at 10A-significantly lower than conventional LDOs. Its dual-supply topology separates drive current (≈1% of IOUT) from main power path, eliminating supply sequencing issues.
Remote SENSE pin enables true Kelvin sensing at the load, achieving ≤1mV load regulation from 100mA to 10A. The ADJUST pin is exposed even on the fixed 2.5V variant to allow external bypass capacitance (0.1–1µF), improving transient response and ripple rejection (55–80dB).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5V ±0.6% at 25°C; maintained within 2.475–2.525V over 0–10A load and full temperature range |
| Max Output Current | 10A continuous; current limit threshold 10.1–11A with 100mV output droop |
| Dropout Voltage | 0.43–0.70V at 10A depending on VPOWER–VOUT differential; minimum VPOWER = VOUT + 0.10V at light load |
| Load Regulation | ≤1mV typical from 100mA to 10A measured at SENSE pin; enabled by remote sensing |
| Ripple Rejection | 55–80dB at 120Hz, 1VP-P, supporting noisy switcher post-regulation |
| Thermal Resistance | Junction-to-case: 0.65°C/W (control section), 2.50°C/W (power transistor) |
| Operating Temp | Junction range: 0°C to 125°C (control), 0°C to 150°C (power transistor) |
Pinout & Package
LT1581CT7#PBF is housed in a 7-lead plastic TO-220 (T7) package with electrically connected tab serving as OUTPUT terminal. Thermal resistance θJA = 50°C/W; tab must be mounted to heatsink with thermal compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: ADJ | Reference divider negative node | Exposed for fixed-output variant to add 0.1–1µF bypass capacitor, improving transient response and ripple rejection |
| Pin 2: NC/GND | No-connect / Ground reference | NC for LT1581CT7#PBF; GND only on -2.5 suffix variants-confirms this is adjustable-core variant with fixed 2.5V output |
| Pin 3: SENSE | Positive reference input | Enables Kelvin sensing at load; eliminates trace/connector IR drop impact on regulation accuracy |
| Pin 4: OUTPUT | Main power output | Tab-connected terminal delivering up to 10A; electrically tied to case |
| Pin 5: VPOWER | Power transistor collector supply | Supplies main load current; must be ≥VOUT + 0.10V (at light load) to 0.70V (at 10A) |
| Pin 6: VCONTROL | Control circuit & base drive supply | Provides bias for internal circuitry and NPN drive; must be ≥VOUT + 1.02V (min) to maintain regulation |
| Pin 7: NC | No-connect | Unused terminal; no internal connection |
Key Features
| Feature | Design Value |
|---|---|
| Dual-supply architecture | Separates VPOWER (main current path) and VCONTROL (control/drive rail), enabling sub-0.5V dropout at 10A without sacrificing stability |
| Remote SENSE capability | Delivers ≤1mV load regulation from 100mA to 10A by closing feedback loop directly at load terminals |
| Exposed ADJUST pin | Allows external capacitor (0.1–1µF) to enhance transient response and reduce output voltage overshoot/undershoot |
| Guaranteed 1% total output accuracy | Maintains 2.475–2.525V over full temperature and 0–10A load range, critical for Pentium®/PowerPC™ core voltage compliance |
| Integrated protection | Internal current limiting and thermal shutdown prevent damage during overload or inadequate heatsinking |
Applications
| Microprocessor Core Supply | Switching Regulator Post-Regulator |
|---|---|
Use Scenario: Generating stable 2.5V core voltage for Pentium® processors running at 90–166MHz on desktop motherboards with available 3.3V and 5V rails. IC Role / Device Role / Timing Role: Primary linear regulator providing tightly regulated DC voltage with <1mV load step deviation at the CPU socket. Use Value: Enables reliable high-frequency CPU operation by meeting Intel's tight transient voltage tolerance specs without excessive bulk capacitance. | Use Scenario: Cleaning residual ripple from a 3.3V switching supply feeding a 2.5V logic subsystem in industrial controllers. IC Role / Device Role / Timing Role: Low-noise post-regulator rejecting >55dB of 120Hz switcher ripple while sustaining 10A peak current. Use Value: Eliminates need for additional LC filtering stages, reducing BOM cost and board area while maintaining clean power for sensitive analog interfaces. |
| High-Current FPGA I/O Bank Supply | Portable Pentium® Processor Supply |
Use Scenario: Delivering 10A at 2.5V to FPGA I/O banks requiring precise voltage and fast transient recovery during configuration bursts. IC Role / Device Role / Timing Role: High-current LDO with Kelvin sensing ensuring voltage accuracy at each I/O pin cluster despite PCB trace resistance. Use Value: Prevents I/O timing violations caused by IR drop across long traces, supporting reliable high-speed parallel bus operation. | Use Scenario: Powering mobile Pentium® processors stepping from 3.3V to 2.9V in portable computing systems with constrained thermal envelope. IC Role / Device Role / Timing Role: Efficient dual-rail LDO minimizing power loss via low 430mV dropout at full load, reducing heat generation. Use Value: Extends battery life and avoids thermal throttling by dissipating <3.9W at 4A (vs >6W for conventional LDOs), verified at 70°C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3085EDE#PBF | Single-supply 3A LDO with integrated PMOS pass device; no VCONTROL pin; max 2.5V output; 300mV dropout at 3A | Lower current capacity; lacks remote sense and dual-supply architecture; suited for space-constrained 3A designs | Select LTC3085EDE#PBF only when 3A output suffices and board layout cannot accommodate dual-input routing. |
| TPS75725KTTT | Single-supply 3A LDO with PMOS pass element; 1.2V dropout at 3A; fixed 2.5V output; no SENSE pin; 1% initial accuracy | Higher dropout, no Kelvin sensing, lower current rating; optimized for simpler point-of-load use cases | Choose TPS75725KTTT for cost-sensitive, lower-current applications where remote sensing and ultra-low dropout are not required. |
Compared with LTC3085EDE#PBF and TPS75725KTTT, LT1581CT7#PBF uniquely supports 10A output with dual-rail architecture and remote sensing-enabling sub-0.5V dropout and <1mV load regulation unattainable in single-supply alternatives.
Availability
LT1581CT7#PBF is available at Aetrix Electronics and suitable for high-reliability microprocessor core supplies, switching regulator post-regulation, and FPGA I/O bank power delivery requiring stable component supply across extended production lifecycles.
Supply support for LT1581CT7#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains its high-performance analog IC portfolio, emphasizing precision power management, signal conditioning, and RF solutions for demanding industrial and computing applications.
The LT1581 series was designed specifically for next-generation microprocessor core voltage regulation, addressing the need for ultra-low dropout, fast transient response, and Kelvin-sense accuracy in dual-rail motherboard environments.
FAQ
What is the maximum output current specification for LT1581CT7#PBF?
The LT1581CT7#PBF is rated for 10A continuous output current. Its current limit is specified at 10.1–11A with 100mV output droop, and it maintains regulation across the full 0–10A range with ≤1mV load regulation when using the SENSE pin. Derating is required above 70°C ambient due to thermal limits.
Does LT1581CT7#PBF require both VPOWER and VCONTROL supplies to operate?
Yes, LT1581CT7#PBF requires two independent supplies: VPOWER (≥VOUT + 0.10V) for the main current path and VCONTROL (≥VOUT + 1.02V) for control circuitry and NPN base drive. If only one supply is available, it can be connected to both pins-but dropout then follows the higher VCONTROL requirement, degrading efficiency.
Can LT1581CT7#PBF be used without connecting the SENSE pin?
Yes, LT1581CT7#PBF will function with SENSE tied to OUTPUT, but load regulation degrades to ~10mV per 0.001Ω of trace resistance at 10A. For guaranteed ≤1mV regulation over 0–10A, SENSE must be routed directly to the load terminals-this is the intended use case per the datasheet.
What is the purpose of the ADJ pin on the fixed-output LT1581CT7#PBF?
The ADJ pin on LT1581CT7#PBF is exposed to allow connection of a 0.1–1µF capacitor to ground, which improves transient response and ripple rejection. Though the output is fixed at 2.5V, this bypass reduces output voltage deviation during rapid load steps-confirmed in Typical Performance Characteristics Figure G06.
Is LT1581CT7#PBF RoHS compliant and lead-free?
Yes, LT1581CT7#PBF carries the #PBF suffix indicating lead-free (Pb-free) and RoHS-compliant construction. It uses matte tin plating and meets JEDEC J-STD-020 moisture sensitivity level 3, with reflow peak temperature up to 260°C.
LT1581CT7#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-220-7 Formed Leads
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Converter, Intel Pentium®
- Voltage - Input:
- 1.68V ~ 6V
- Number of Outputs:
- 1
- Voltage - Output:
- 1.25V ~ 4.65V
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
LT1581CT7#PBF FAQ
1.How can I place an order for LT1581CT7#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1581CT7#PBF 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 LT1581CT7#PBF reliable?
The price and inventory of LT1581CT7#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1581CT7#PBF is usually 5 days.
3.What payment methods are accepted for LT1581CT7#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1581CT7#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1581CT7#PBF?
LT1581CT7#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1581CT7#PBF 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 LT1581CT7#PBF?
For technical support, including LT1581CT7#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1581CT7#PBF requirements.
6.How does Aetrix verify that LT1581CT7#PBF is sourced from the original manufacturer or authorized distributors?
All LT1581CT7#PBF 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 LT1581CT7#PBF meets industry standards.
7.What is the process for return or replacement of LT1581CT7#PBF?
All LT1581CT7#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1581CT7#PBF, 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 LT1581CT7#PBF part is unused and in its original packaging.
Return procedure for LT1581CT7#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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