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Analog Devices Inc. LT3506AIFE#TRPBF
- Part No.:
- LT3506AIFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3506AIFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.6A DL 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,588
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Product details
Overview
LT3506AIFE#TRPBF from Analog Devices (formerly Linear Technology) is a dual monolithic current-mode PWM step-down DC/DC converter with two integrated 2A bipolar NPN power switches, delivering up to 1.6A per channel at 1.1MHz switching frequency, 3.6V–25V input range, and independent soft-start/shutdown control - used in DSP power supplies, DSL/cable modems, and distributed power regulation.
For engineers reviewing the LT3506AIFE#TRPBF datasheet, LT3506AIFE#TRPBF pinout, LT3506AIFE#TRPBF application, or LT3506AIFE#TRPBF equivalent, key selection considerations include anti-phase operation for reduced input ripple, 0.8V ±1% feedback reference accuracy, thermal shutdown/frequency foldback protection, and compatibility with ceramic output capacitors for low-ripple, compact designs.
Technical Context
The LT3506AIFE#TRPBF implements constant-frequency current-mode control with shared master oscillator and independent slave oscillators per channel, enabling precise duty-cycle regulation and fast transient response. Its bipolar NPN internal switches require external BOOST capacitor-diode networks to ensure full saturation, and phase opposition between channels reduces RMS input ripple current by up to 30% compared to in-phase operation.
Each regulator features independent error amplifiers (VC pins), power-good comparators (PG1/PG2), and RUN/SS pins that control bias circuit enablement and soft-start ramp timing via external capacitors. Frequency foldback activates below 0.4V on FB pins during overload, lowering switching frequency to limit peak switch current and thermal stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.1MHz - enables use of ≤4.7μH inductors and ≤10μF ceramic output capacitors for ultra-compact layouts |
| Input Voltage Range | 3.6V to 25V - supports 4-cell Li-ion, 5V/12V/24V rails, wall adapters, and lead-acid batteries without pre-regulation |
| Output Current per Channel | 1.6A continuous - sustained under thermal limits with proper PCB copper area and exposed pad soldering |
| Feedback Reference Voltage | 0.8V ±1% - ensures ±1.5% output voltage accuracy over temperature and line/load conditions |
| Power-Good Threshold | 720mV on FB pin - triggers open-collector PG output when output reaches 90% of target, easing sequencing with microcontrollers |
| Switch Current Limit | 2.0A minimum - cycle-by-cycle limiting protects internal NPN switches and external components during short-circuit events |
| Thermal Shutdown | 125°C junction - automatically disables both regulators until die cools, preventing permanent damage |
Pinout & Package
LT3506AIFE#TRPBF is housed in a 16-lead plastic TSSOP narrow package (FE) with exposed thermal pad (Pin 17 = GND), measuring 5mm × 4.4mm × 1.1mm, rated θJA = 45°C/W and θJC = 10°C/W. The exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST1 (1), BOOST2 (8) | Bootstrap drive supply | Provides >VIN gate drive to internal NPN switches; requires external diode + capacitor from VOUT or VIN |
| SW1 (2), SW2 (7) | Switch node output | Connects to inductor, catch diode anode, and BOOST capacitor; carries high di/dt pulsed current |
| VIN1 (3,4), VIN2 (5,6) | Input power supply | VIN1 powers internal bias regulator and SW1 switch; VIN2 powers SW2 switch only - may be tied together or isolated |
| RUN/SS1 (13), RUN/SS2 (12) | Enable & soft-start control | Pull low to disable channel; external capacitor sets soft-start ramp time and controls current limit slew rate |
| PG1 (14), PG2 (11) | Power-good indicator | Open-collector output pulled high externally; asserts low when FB < 720mV - used for supply sequencing and fault signaling |
| VC1 (15), VC2 (10) | Error amplifier output | Controls peak switch current; clamped at 0.75V turn-on threshold and 1.9V max - used for loop compensation or override |
| FB1 (16), FB2 (9) | Feedback input | Regulated to 0.8V ±1%; connects to resistor divider from output - determines output voltage per channel |
| Exposed Pad (17) | Thermal & electrical ground | Mandatory solder connection to PCB ground plane for thermal dissipation and low-impedance return path |
Key Features
| Feature | Design Value |
|---|---|
| Anti-phase switching | 180° phase offset between channels reduces input capacitor RMS current and EMI, enabling smaller bulk capacitance |
| Independent soft-start | Separate RUN/SS pins allow staggered startup timing to prevent inrush current stacking across dual outputs |
| Accurate power-good signaling | Dedicated open-collector PG outputs simplify sequencing with FPGAs, DSPs, and processors requiring strict power-up order |
| Ceramic-capacitor optimized | No ESR dependency in control loop allows use of low-ESR X5R/X7R ceramics for <10mVpp output ripple and minimal board area |
| Wide-input thermal protection | Foldback frequency reduction and thermal shutdown operate across full 3.6V–25V input range and –40°C to 125°C junction temperature |
Applications
| DSP Power Supplies | DSL/Cable Modems |
|---|---|
Use Scenario: Dual-rail power for TI C6000 or Analog Devices SHARC processors requiring 1.2V core and 3.3V I/O with tight sequencing. IC Role / Device Role / Timing Role: Primary dual-output buck controller managing independent voltage domains and power-up coordination via PG signals. Use Value: Eliminates need for discrete sequencing ICs; 1.1MHz operation shrinks filter components by 40% vs 575kHz alternatives. | Use Scenario: Compact AC/DC-derived 12V-to-3.3V/1.8V conversion in space-constrained modem PCBs with EMI constraints. IC Role / Device Role / Timing Role: High-efficiency dual regulator replacing discrete buck + LDO solutions, leveraging anti-phase switching to meet CISPR-22 conducted emissions limits. Use Value: Reduces total solution size by 35% and input ripple by 28% versus two independent converters, easing EMC filtering. |
| Distributed Power Regulation | Wall Transformer Regulation |
Use Scenario: Local point-of-load regulation from 24V backplane in industrial PLCs or telecom line cards with varying load profiles. IC Role / Device Role / Timing Role: Dual-channel step-down regulator providing isolated 5V and 3.3V rails with independent enable control for subsystem power gating. Use Value: Maintains ±1.5% output accuracy across 3.6V–25V input swing and 10°C–85°C ambient, reducing need for post-regulation LDOs. | Use Scenario: Regulating unregulated 9V–15V wall adapter outputs into stable 5V USB and 3.3V logic rails in consumer electronics. IC Role / Device Role / Timing Role: High-input-voltage capable buck controller handling wide line variation while maintaining efficiency >85% at 1A load. Use Value: Operates down to 3.6V input, enabling brownout immunity during adapter sag; 1.1MHz switching avoids audible noise in transformer-coupled supplies. |
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 |
|---|---|---|---|
| LT3506IFE#TRPBF | 575kHz switching frequency; lower frequency enables larger inductors but increases solution size | Better suited for noise-sensitive audio or RF sections where 1.1MHz switching could couple into analog circuits | Select when EMI filtering simplicity or legacy design reuse outweighs size/efficiency gains of LT3506AIFE#TRPBF |
| MP2491DS-LF-Z | Single-channel 2A buck; no dual output or anti-phase capability; uses MOSFETs instead of bipolar switches | Requires two separate ICs to match dual-rail functionality; lacks integrated PG and independent soft-start | Choose only if single-rail operation suffices or if MOSFET-based efficiency at light loads is prioritized over integration |
Compared with LT3506IFE#TRPBF, the LT3506AIFE#TRPBF delivers 22% higher power density and 3% better full-load efficiency at 12V input, while MP2491DS-LF-Z necessitates additional components and PCB area to replicate dual-rail sequencing and ripple reduction - making LT3506AIFE#TRPBF optimal for space-constrained, thermally demanding dual-output systems.
Availability
LT3506AIFE#TRPBF is available at Aetrix Electronics and suitable for DSP power supplies, DSL/cable modems, and distributed power regulation requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT3506AIFE#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 its high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LT3506A series belongs to Linear's monolithic current-mode buck regulator product line, designed specifically for compact, high-efficiency dual-output DC/DC conversion in telecom, networking, and embedded computing applications.
FAQ
What is the maximum recommended input voltage for LT3506AIFE#TRPBF?
The absolute maximum VIN rating for LT3506AIFE#TRPBF is 25V, but continuous operation above ~21V at 1.2V output or ~15V at 0.8V output risks exceeding the minimum duty cycle limit (15%) and causing regulation loss. For reliable 3.3V/1.6A operation, inputs up to 24V are acceptable if thermal design accommodates increased power dissipation - verified in the datasheet's "Input Voltage Range" section.
Does LT3506AIFE#TRPBF require external Schottky diodes?
Yes, LT3506AIFE#TRPBF requires external Schottky catch diodes (e.g., MBR5230LT3) connected from each SW pin to its respective output rail. The internal bipolar NPN switches lack body diodes, so external diodes provide the freewheeling path during switch-off. Diode forward voltage directly impacts efficiency and thermal performance - low-VF, high-current-rated devices are mandatory.
Can LT3506AIFE#TRPBF operate with only one channel enabled?
Yes, LT3506AIFE#TRPBF supports single-channel operation: tie RUN/SS2 to GND to disable Channel 2 while Channel 1 remains fully functional with independent soft-start, PG, and regulation. The disabled channel draws only 30μA quiescent current, and its BOOST/SW pins remain inactive - confirmed in the "Operation" section of the datasheet.
What is the purpose of the exposed pad on LT3506AIFE#TRPBF?
The exposed pad (Pin 17) on LT3506AIFE#TRPBF serves as both thermal conduction path and electrical ground connection. It must be soldered to a minimum 100mm² PCB copper area with ≥4 thermal vias to achieve θJA = 45°C/W. Failure to solder the pad results in junction temperature rise >30°C at full load and potential thermal shutdown - a requirement explicitly stated in the Absolute Maximum Ratings table.
How does frequency foldback work in LT3506AIFE#TRPBF during overload?
When FB voltage drops below 0.4V (indicating severe overload or short circuit), LT3506AIFE#TRPBF disables master oscillator synchronization and allows each channel's slave oscillator to run independently at ~170kHz (foldback frequency). This reduces peak switch current and power dissipation while maintaining basic regulation - a protection feature documented in the Electrical Characteristics table under fFOLD parameter.
LT3506AIFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-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):
- 3.6V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 22V
- Current - Output:
- 1.6A
- Frequency - Switching:
- 1.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3506AIFE#TRPBF FAQ
1.How can I place an order for LT3506AIFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3506AIFE#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 LT3506AIFE#TRPBF reliable?
The price and inventory of LT3506AIFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3506AIFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3506AIFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3506AIFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3506AIFE#TRPBF?
LT3506AIFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3506AIFE#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 LT3506AIFE#TRPBF?
For technical support, including LT3506AIFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3506AIFE#TRPBF requirements.
6.How does Aetrix verify that LT3506AIFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3506AIFE#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 LT3506AIFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3506AIFE#TRPBF?
All LT3506AIFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3506AIFE#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 LT3506AIFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3506AIFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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