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Analog Devices Inc. LT3501IFE#TRPBF
- Part No.:
- LT3501IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3501IFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,910
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Product details
Overview
LT3501IFE#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic dual-channel current-mode PWM step-down DC/DC converter with two integrated 3.5A NPN power switches, wide 3.1V–25V input range, independent feedback and soft-start control per channel, and antiphase 180° switching at 250kHz–1.5MHz for reduced input ripple. It enables precise output tracking in DSP power supplies and disc drive applications.
For engineers reviewing the LT3501IFE#TRPBF datasheet, LT3501IFE#TRPBF pinout, LT3501IFE#TRPBF application, or LT3501IFE#TRPBF equivalent, key selection considerations include its dual 3A output capability with independent sequencing, 95% max duty cycle for low-dropout operation, exposed-pad 20-lead TSSOP thermal performance, and antiphase synchronization for EMI-sensitive designs.
Technical Context
The LT3501IFE#TRPBF implements dual independent current-mode control loops, each with transconductance error amplifiers (275 µmho typ), internal 0.8V reference (±2% over temp), and cycle-by-cycle peak current limiting via IND/VOUT sense resistors. Its oscillator supports resistor-programmed (15.4k–133kΩ) or external clock synchronization with automatic slope compensation adjustment.
Each channel features dedicated soft-start (3.25 µA source current), power-good open-collector outputs (90% threshold, 30 mV hysteresis), and shutdown logic with 1.28V threshold and <10 µA quiescent current. The BST1/BST2 pins enable bootstrapped base drive for high-efficiency NPN saturation and support 100% duty cycle when boost voltage remains above 2.0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.1V to 25V - supports wide-range wall adapters, distributed power rails, and industrial inputs without pre-regulation. |
| Output Current per Channel | 3A continuous - delivers sufficient power for core logic and I/O rails in DSPs and modems without external MOSFETs. |
| Switching Frequency Range | 250kHz to 1.5MHz - programmable via RT/SYNC resistor or external clock; enables optimization of size vs. efficiency. |
| Max Duty Cycle | ~95% - allows operation with VIN as low as VOUT + 0.5V under light load, critical for dropout-limited systems. |
| Feedback Reference Voltage | 0.800V ±2% (–40°C to 125°C) - stable regulation point enabling accurate 1.8V, 3.3V, and 5V outputs with standard resistor dividers. |
| Channel Phase Relationship | 180° antiphase - reduces input capacitor RMS current by ~30% and eases EMI filtering requirements. |
| Shutdown Quiescent Current | 9 µA (Ch1), <1 µA (Ch2) - enables ultra-low-power system standby without auxiliary LDOs. |
Pinout & Package
LT3501IFE#TRPBF is housed in a 20-lead plastic TSSOP package with exposed leadframe (Pin 21 = GND) for low thermal resistance (θJC(PAD) = 10°C/W). The exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 (1) | Channel 1 input supply & bias rail | Powers internal circuitry and connects to collector of Ch1 NPN switch; requires local 0.47µF decoupling. |
| SW1 (2) | Channel 1 switch emitter | High dI/dt node requiring Schottky catch diode to ground; drives inductor directly. |
| IND1 (3) | Channel 1 current sense input | Connects to inductor side of internal sense resistor; used for cycle-by-cycle current limiting. |
| VOUT1 (4) | Channel 1 current sense return | Connects to output side of internal sense resistor; bias current flows out if VOUT1 < 1.6V. |
| PG1 (5) | Channel 1 power-good indicator | Open-collector NPN sinks current when FB1 falls below 90% of 0.8V; 30mV hysteresis ensures clean sequencing. |
| PG2 (6) | Channel 2 power-good indicator | Independent open-collector output identical to PG1; can be wire-OR'd for system-level power status. |
| VOUT2 (7) | Channel 2 current sense return | Same function as VOUT1 but for Ch2; enables independent current monitoring per rail. |
| IND2 (8) | Channel 2 current sense input | Same function as IND1 but for Ch2; supports independent overload protection per channel. |
| SW2 (9) | Channel 2 switch emitter | Identical to SW1; antiphase switching reduces input ripple when both channels active. |
| VIN2 (10) | Channel 2 input supply | Independent collector supply for Ch2 NPN; may tie to VIN1 or separate source for isolation. |
| BST2 (11) | Channel 2 bootstrap drive | Provides >VIN base drive to Ch2 NPN; requires 100nF ceramic capacitor to SW2 for saturation. |
| SS/TRACK2 (12) | Channel 2 soft-start & tracking control | 3.25µA constant-current source; capacitor sets ramp rate; enables ratiometric or absolute tracking with SS1. |
| VC2 (13) | Channel 2 error amplifier output | Drives peak current comparator; used for loop compensation, current clamping, or override control. |
| FB2 (14) | Channel 2 feedback input | Inverting input of transconductance amplifier; regulated to 0.8V; bias current ±250nA affects divider accuracy. |
| SHDN (15) | Global shutdown control | 1.28V threshold with hysteresis; pulls both channels into <10µA shutdown; doubles as UVLO for system start-up. |
| RT/SYNC (16) | Frequency programming & sync input | 0.975V-regulated node; resistor sets frequency (250kHz–1.5MHz); accepts external clock on rising edge. |
| FB1 (17) | Channel 1 feedback input | Identical to FB2; independent regulation enables different output voltages per channel (e.g., 3.3V/1.8V). |
| VC1 (18) | Channel 1 error amplifier output | Same function as VC2; allows individual loop compensation per channel for asymmetric loads. |
| SS/TRACK1 (19) | Channel 1 soft-start & tracking control | Identical to SS/TRACK2; enables independent or coordinated startup with SS/TRACK2. |
| BST1 (20) | Channel 1 bootstrap drive | Same function as BST2; requires dedicated 100nF capacitor to SW1 for reliable 100% duty cycle. |
| Exposed Pad (21) | Power & signal ground | Only GND connection; must be soldered to large PCB copper area for thermal management and noise control. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 3.5A NPN switches | Eliminates need for external high-current MOSFETs or discrete drivers in compact dual-rail designs. |
| Antiphase 180° channel synchronization | Reduces input capacitor RMS current and peak EMI, enabling smaller bulk capacitance and simpler filtering. |
| Programmable 250kHz–1.5MHz switching | Allows trade-off between inductor size (higher f = smaller L) and conduction vs. switching loss (lower f = higher efficiency). |
| 95% maximum duty cycle with dropout enhancement | Supports operation with VIN as low as VOUT + 0.4V at light load, extending usable input range in battery-powered systems. |
| Independent soft-start, power-good, and tracking pins | Enables flexible power sequencing (ratiometric, sequential, absolute) without external timers or supervisors. |
| Exposed-pad TSSOP-20 package | Provides θJC(PAD) = 10°C/W for high-power density; requires direct soldering to PCB ground plane for thermal integrity. |
Applications
| DSP Power Supplies | Disc Drives |
|---|---|
Use Scenario: Dual-core digital signal processors requiring tightly regulated 1.8V core and 3.3V I/O rails with controlled power-up sequencing. IC Role / Device Role / Timing Role: Primary dual-output DC/DC regulator providing independent, ratiometric tracking and antiphase switching. Use Value: Eliminates external sequencing ICs; 180° phase shift cuts input ripple by 40%, reducing bulk capacitor count and board area. |
Use Scenario: Spindle motor and servo controller boards needing isolated 5V analog and 3.3V digital supplies from a 12V bus. IC Role / Device Role / Timing Role: Dual buck converter delivering independent, independently disabled outputs with fast transient response. Use Value: Independent VIN1/VIN2 pins allow separation of noisy motor supply from sensitive analog rail; PG1/PG2 enable fault-isolated power monitoring. |
| DSL/Cable Modems | Wall Transformer Regulation |
Use Scenario: Residential gateway devices with multiple SoC domains (CPU, PHY, RF) requiring 1.2V, 1.8V, and 3.3V rails from 12V AC/DC adapter. IC Role / Device Role / Timing Role: High-efficiency dual regulator supporting parallel output configuration for increased current capacity. Use Value: Outputs can be paralleled for up to 6A total; 83.9% efficiency at 250kHz enables thermally constrained plastic enclosures. |
Use Scenario: Universal-input wall adapters delivering regulated 5V/3.3V USB-C PD accessory rails from unregulated 9–24V DC input. IC Role / Device Role / Timing Role: Wide-input dual buck converter enabling single-board solution for multi-voltage legacy adapter replacement. Use Value: 3.1V–25V input range accommodates varying rectified AC waveforms; 9µA shutdown current meets Energy Star standby requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3776EUF#PBF | MOSFET driver (external FETs), 4.5V–38V input, no integrated switches; supports 2-phase interleaving up to 60A. | Requires external high-current MOSFETs and gate drivers; suited for >10A systems where thermal management is critical. | Select LTC3776EUF#PBF when output current exceeds 3A per rail or when custom FET selection is needed for efficiency optimization. |
| TPS54290PWPR | Single-channel 2.5A synchronous buck; 4.5V–28V input; no tracking/sequencing pins; 100% duty cycle not supported. | Requires two separate ICs for dual-rail design; lacks independent soft-start, PG, or antiphase capability. | Select TPS54290PWPR only for cost-sensitive, non-sequenced dual-rail systems where board space and EMI are secondary concerns. |
Compared with LT3501IFE#TRPBF, LTC3776EUF#PBF offers higher scalability but adds layout complexity and BOM count, while TPS54290PWPR reduces integration and eliminates tracking-making LT3501IFE#TRPBF optimal for compact, sequenced dual-rail designs up to 3A/channel.
Availability
LT3501IFE#TRPBF is available at Aetrix Electronics and suitable for DSP power supplies, disc drive controllers, and DSL/cable modem designs requiring stable component supply, long-term production continuity, and guaranteed –40°C to 125°C operation.
Supply support for LT3501IFE#TRPBF 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 full product support, datasheets, and application engineering for all Linear-branded ICs including the LT3501 series.
The LT3501 belongs to Linear's high-performance power management portfolio, designed specifically for space-constrained, multi-rail embedded systems requiring precision tracking, low-noise operation, and robust thermal performance.
FAQ
What is the operating temperature range for the LT3501IFE#TRPBF?
The LT3501IFE#TRPBF is specified and tested over the full –40°C to +125°C junction temperature range. This industrial-grade rating ensures reliable operation in demanding environments such as network equipment, automotive infotainment head units, and industrial PLC modules where ambient temperatures exceed commercial limits.
Can the LT3501IFE#TRPBF outputs be configured for ratiometric tracking?
Yes, the LT3501IFE#TRPBF supports ratiometric tracking using the SS/TRACK1 and SS/TRACK2 pins. By connecting matching RC networks to both pins and tying the FB2 divider top to VOUT1, the second output follows the first in fixed ratio-enabling coordinated startup for CPU core/I/O pairs without external circuitry.
Does the LT3501IFE#TRPBF support external clock synchronization?
Yes, the LT3501IFE#TRPBF supports external synchronization via the RT/SYNC pin. A clean CMOS/TTL clock applied to this pin locks both channels to the incoming frequency with 180° phase separation, preserving slope compensation and enabling deterministic EMI reduction in noise-sensitive systems like medical imaging or audio processing.
What is the minimum input voltage required for the LT3501IFE#TRPBF to regulate a 1.8V output?
The LT3501IFE#TRPBF can regulate a 1.8V output down to approximately 2.2V input under light load due to its ~95% maximum duty cycle and dropout enhancement circuitry. At full 3A load, minimum VIN rises to ~3.1V per datasheet specifications-verified across –40°C to 125°C.
How does the LT3501IFE#TRPBF handle overcurrent conditions?
The LT3501IFE#TRPBF uses cycle-by-cycle peak current limiting via internal sense resistors on IND/VOUT pins. When sensed current exceeds the VC-set threshold, the switch disables immediately. Under sustained overload, the SS pin discharges to lower the regulation point-providing hiccup-mode-like foldback without latch-up or thermal shutdown.
LT3501IFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3.1V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 23.75V
- Current - Output:
- 3A
- Frequency - Switching:
- 250kHz ~ 1.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT3501IFE#TRPBF FAQ
1.How can I place an order for LT3501IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3501IFE#TRPBF 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 LT3501IFE#TRPBF reliable?
The price and inventory of LT3501IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3501IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3501IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3501IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3501IFE#TRPBF?
LT3501IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3501IFE#TRPBF 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 LT3501IFE#TRPBF?
For technical support, including LT3501IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3501IFE#TRPBF requirements.
6.How does Aetrix verify that LT3501IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3501IFE#TRPBF 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 LT3501IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3501IFE#TRPBF?
All LT3501IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3501IFE#TRPBF, 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 LT3501IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3501IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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