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Texas Instruments UC285TDKTTT-ADJ
- Part No.:
- UC285TDKTTT-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
UC285TDKTTT-ADJ.pdf
- Description:
- IC REG LIN POS ADJ 5A DDPAK
- Quantity:
- Payment:
- Shipping:
Inventory:2,930
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Product details
Overview
UC285TDKTTT-ADJ from Texas Instruments is a 5-A adjustable low-dropout linear regulator with separate bias (VB) and input (VIN) pins, 350 mV typical dropout at 5 A, Kelvin-sense capability via 5-pin TO-263 (TD) package, and fast transient response optimized for GTL/BTL bus termination in high-speed digital systems.
For engineers reviewing the UC285TDKTTT-ADJ datasheet, UC285TDKTTT-ADJ pinout, UC285TDKTTT-ADJ application, or UC285TDKTTT-ADJ equivalent, this page delivers verified specifications, thermal and PSRR performance data, Kelvin-sense implementation guidance, and validated alternatives for high-current, low-noise power regulation in telecom and computing infrastructure.
Technical Context
The UC285TDKTTT-ADJ employs a Darlington output stage powered by VB to achieve inherently low output impedance and sub-500 mV dropout across −40°C to 100°C. Its internal 1.2 V bandgap reference feeds a noninverting op-amp configuration, enabling precise external resistor programming of VOUT.
Separate VIN and VB rails decouple power delivery: VIN supplies only the output transistor collector, while VB powers all control circuitry - enabling independent optimization of PSRR (80–110 dB on VIN, 50–67 dB on VB) and thermal management. The 5-pin layout supports true Kelvin sensing at the load to eliminate trace IR drop errors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Rated for continuous 5-A load current with thermal shutdown protection. |
| Dropout Voltage (VIN−VOUT) | Max 500 mV at 5-A load and −40°C to 100°C - enables operation with minimal headroom from 3.3-V or 5-V sources. |
| Adjustable Output Range | 1.2 V default (ADJ tied to VOUT); programmable up to >6 V using R1/R2 - supports GTL (1.2 V), BTL (2.1/2.5 V), and custom logic rails. |
| PSRR (VIN) | 80–110 dB from 100 Hz to 1 MHz - suppresses switching noise from upstream DC/DC converters feeding VIN. |
| Load Regulation | 0.5–4 mV over 10 mA to 5 A - ensures stable voltage under dynamic CPU/GPU load transients. |
| Short-Circuit Limit | 5.1–7.5 A - provides robust fault containment without latch-up during bus contention or hot-plug events. |
| Operating Temp Range | −40°C to 100°C - qualified for industrial and telecom base station environments. |
Pinout & Package
UC285TDKTTT-ADJ is housed in a 5-pin TO-263 (TD) thermally enhanced flange-mount package (package drawing KTT), with the center lead and metal tab electrically connected to GND for optimal heat dissipation and low-inductance grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ADJ | Feedback reference input | Connects to resistor divider to set VOUT; tied to VOUT for 1.2-V default; enables Kelvin sensing at load node. |
| VOUT | Regulated output | Delivers up to 5 A; must connect via low-impedance path to load - trace inductance directly adds to effective dropout. |
| VB | Bias supply input | Powers internal circuitry (reference, error amp); requires ≥2 V headroom above VOUT for Darlington stage operation. |
| VIN | Main power input | Supplies only output transistor collector; dropout (VIN−VOUT) is minimized independently of VB rail. |
| GND | Signal and power ground | Reference for ADJ and feedback; tab connection provides low-impedance thermal path and EMI return. |
Key Features
| Feature | Design Value |
|---|---|
| Fast transient response | ΔVOUT ≤ ±20 mV for 10 mA → 3 A/µs load steps - reduces required bulk capacitance by >50% vs. standard LDOs. |
| Kelvin voltage sensing | 5-pin layout isolates sense point (ADJ) from power path (VOUT) - eliminates regulation error from PCB trace resistance. |
| Separate VB and VIN rails | Enables independent noise filtering: low-ESR ceramic on VB, high-capacitance OSCON/tantalum on VIN - maximizes PSRR across frequency bands. |
| Reverse current protection | Prevents backfeed from VOUT to VIN or VB during shutdown or fault - critical for multi-rail systems with sequencing requirements. |
| Thermal shutdown | Activates at ~150°C junction temperature with hysteresis - protects against sustained overload or inadequate heatsinking. |
Applications
| GTLC Bus Termination | BTL Logic Supply |
|---|---|
|
Use Scenario: Powering GTL+ (Gunning Transceiver Logic) termination networks in high-speed memory controllers and chipset interconnects. IC Role / Device Role / Timing Role: Low-noise, fast-response voltage source delivering stable 1.2 V to parallel bus stubs with <100-ps edge rates. Use Value: Maintains signal integrity under 3-A transient loads with <20-mV droop, eliminating need for large local bulk caps near each receiver. |
Use Scenario: Supplying BTL (Backplane Transceiver Logic) drivers in telecom line cards requiring 2.1 V or 2.5 V rails. IC Role / Device Role / Timing Role: Precision-adjustable LDO providing regulated, low-ripple power to differential line drivers with tight common-mode control. Use Value: Kelvin sensing compensates for PCB voltage drop across long backplane traces, ensuring accurate 2.1 V at driver inputs despite >100-mΩ path resistance. |
| ASIC Core Voltage Regulator | Hot-Swap Power Sequencing |
|
Use Scenario: Delivering clean core voltage to FPGA or ASIC I/O banks with rapidly varying current demands (e.g., DDR interface bursts). IC Role / Device Role / Timing Role: High-current linear regulator acting as post-regulator after a switching converter, smoothing ripple and suppressing transients. Use Value: 80–110 dB VIN PSRR attenuates 500-kHz switching noise to <10 µV RMS, preventing timing jitter in high-speed SerDes links. |
Use Scenario: Controlled power-up of 1.2-V or 1.5-V logic rails in modular systems with hot-swap controllers and OR-ing FETs. IC Role / Device Role / Timing Role: Adjustable LDO with reverse current blocking and soft-start behavior (via ADJ capacitor) for inrush-limited sequencing. Use Value: Prevents backfeed into upstream supplies during insertion/removal, and enables precise ramp rate control via RC network on ADJ pin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable high-current LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A8300RGRT | 3-A max, 1.1-V min dropout at 3 A, integrated enable/PG, 6-pin WQFN; no separate VB pin. | Lacks Kelvin sensing and dual-rail architecture; suited for space-constrained, lower-current apps where PSRR >70 dB suffices. | Choose when board area is critical and load current ≤3 A; not suitable for >5-A GTL/BTL bus termination. |
| LT3089EDD#PBF | 8-A max, 0.3-V dropout at 8 A, single-rail input, current-source-based architecture; no VB/VIN separation. | Higher current but lower PSRR (65 dB @ 100 kHz); requires external current-set resistor instead of voltage-divider programming. | Prefer for ultra-low dropout at >5 A where VB rail isolation and >80 dB PSRR are secondary to raw current capacity. |
Compared with TPS7A8300RGRT and LT3089EDD#PBF, UC285TDKTTT-ADJ uniquely combines 5-A capability, dual-rail (VB/VIN) noise isolation, Kelvin sensing, and >80 dB PSRR - making it irreplaceable for GTL/BTL bus power where trace IR drop and upstream switching noise must both be eliminated.
Availability
UC285TDKTTT-ADJ is available at Aetrix Electronics and suitable for high-reliability industrial computing, telecom infrastructure, and test equipment applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for UC285TDKTTT-ADJ 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-performance linear regulators and power solutions.
The UC285 series belongs to TI's precision high-current LDO family, engineered specifically for GTL, BTL, and other high-speed digital interface power delivery where fast transient response, Kelvin sensing, and dual-rail PSRR are mandatory design requirements.
FAQ
What is the maximum load current supported by UC285TDKTTT-ADJ?
The UC285TDKTTT-ADJ is rated for continuous 5-A output current across its full operating temperature range of −40°C to 100°C. It incorporates thermal shutdown and short-circuit current limiting (5.1–7.5 A) to protect against overload conditions. Derating is required only above 100°C junction temperature, per the absolute maximum ratings table in the SLUS212E datasheet.
How does the separate VB pin improve performance in UC285TDKTTT-ADJ?
The VB pin in UC285TDKTTT-ADJ powers all internal circuitry except the output transistor, enabling independent optimization of noise rejection and headroom. With ≥2 V headroom (VB−VOUT), the Darlington output stage achieves low impedance and fast response. This separation yields 50–67 dB PSRR on VB versus 80–110 dB on VIN - allowing cleaner biasing than single-rail LDOs.
Can UC285TDKTTT-ADJ be used without external resistors?
Yes - UC285TDKTTT-ADJ defaults to 1.2 V output when the ADJ pin is connected directly to VOUT, eliminating the need for external resistors. This matches the standard GTL bus voltage and simplifies designs where fixed 1.2 V is sufficient. For other voltages, two precision (0.1%) resistors are required between ADJ, VOUT, and GND per the feedback equation in the datasheet.
What package type and thermal characteristics apply to UC285TDKTTT-ADJ?
UC285TDKTTT-ADJ uses the 5-pin TO-263 (TD) package with flange-mount construction (drawing KTT). The metal tab and center lead are internally connected to GND, providing low thermal resistance to heatsink and low-inductance grounding. Its RθJA is specified in context of PCB copper area per JEDEC standards, and thermal shutdown activates at ~150°C junction temperature.
Does UC285TDKTTT-ADJ support Kelvin sensing, and how is it implemented?
Yes - UC285TDKTTT-ADJ supports true Kelvin sensing via its 5-pin configuration: ADJ serves as the feedback reference point, while VOUT carries the load current. By routing the ADJ trace directly to the load ground (not the regulator ground), voltage drops across PCB traces are excluded from regulation, maintaining accuracy even with >100-mΩ path resistance - a key advantage for backplane and modular system designs.
UC285TDKTTT-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable (Fixed)
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 7.5V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 6V
- Voltage Dropout (Max):
- 2.2V @ 5A
- Current - Output:
- 5A
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- -
- Protection Features:
- Over Temperature, Reverse Polarity, Short Circuit
- Operating Temperature:
- -40°C ~ 100°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
UC285TDKTTT-ADJ FAQ
1.How can I place an order for UC285TDKTTT-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for UC285TDKTTT-ADJ 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 UC285TDKTTT-ADJ reliable?
The price and inventory of UC285TDKTTT-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC285TDKTTT-ADJ is usually 5 days.
3.What payment methods are accepted for UC285TDKTTT-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC285TDKTTT-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC285TDKTTT-ADJ?
UC285TDKTTT-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC285TDKTTT-ADJ 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 UC285TDKTTT-ADJ?
For technical support, including UC285TDKTTT-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC285TDKTTT-ADJ requirements.
6.How does Aetrix verify that UC285TDKTTT-ADJ is sourced from the original manufacturer or authorized distributors?
All UC285TDKTTT-ADJ 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 UC285TDKTTT-ADJ meets industry standards.
7.What is the process for return or replacement of UC285TDKTTT-ADJ?
All UC285TDKTTT-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with UC285TDKTTT-ADJ, 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 UC285TDKTTT-ADJ part is unused and in its original packaging.
Return procedure for UC285TDKTTT-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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