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Analog Devices Inc. LT3506IDHD#TRPBF
- Part No.:
- LT3506IDHD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-WFDFN Exposed Pad
- Datasheet:
-
LT3506IDHD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.6A DL 16DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,946
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Product details
Overview
LT3506IDHD#TRPBF from Analog Devices (formerly Linear Technology) is a dual monolithic current-mode PWM step-down DC/DC converter with integrated 2A bipolar NPN power switches, 3.6V–25V input range, 575kHz fixed switching frequency, and independent shutdown/soft-start/power-good functions for 1.6A per channel regulation. It enables compact dual-rail power supplies in disk drives, DSL modems, and distributed power systems.
For engineers reviewing the LT3506IDHD#TRPBF datasheet, LT3506IDHD#TRPBF pinout, LT3506IDHD#TRPBF application, or LT3506IDHD#TRPBF equivalent, key selection considerations include its –40°C to 125°C industrial temperature grade, anti-phase switching for reduced input ripple, 0.8V ±1% feedback reference, thermal shutdown protection, and compatibility with ceramic output capacitors for low-ripple 1.6A dual outputs.
Technical Context
The LT3506IDHD#TRPBF implements constant-frequency current-mode control with shared master oscillator and independent slave oscillators per channel, enabling precise duty-cycle modulation via VC pin voltage and cycle-by-cycle peak-current limiting. Its bipolar NPN internal switches require external BOOST capacitor-diode networks to achieve full saturation.
Anti-phase operation (180° phase shift between channels) minimizes input capacitor RMS current and reduces EMI; frequency foldback activates below 0.4V FB to limit switch current during overload or short-circuit conditions. The device uses an 800mV precision bandgap reference and features independent PGOOD open-collector outputs valid only when VIN > 3.4V and RUN/SS > 0.8V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 25V - supports 4-cell Li-ion, 5V logic rails, unregulated wall adapters, and lead-acid batteries without external pre-regulation |
| Switching Frequency | 575kHz - enables use of sub-3mm-height inductors (e.g., 6.4μH) and small ceramic input/output caps for high-density layouts |
| Output Current per Channel | 1.6A continuous - sustained at VOUT = 1.8V/3.3V with proper inductor selection (e.g., Sumida CR54-6R4) and thermal management |
| Feedback Reference Voltage | 0.8V ±1% - sets output accuracy across –40°C to 125°C; enables precise resistor-divider programming of any VOUT ≥ 0.8V |
| Operating Temperature Range | –40°C to 125°C - qualified for industrial environments; junction temperature limited to 125°C with θJC = 4.3°C/W (DFN package) |
| Power Good Threshold | FB = 720mV rising - asserts PGOOD when output reaches 90% of target, easing sequencing with microcontrollers and DSPs |
| Shutdown Quiescent Current | 30μA - ultra-low standby draw when both RUN/SS pins pulled low, critical for battery-backed systems |
Pinout & Package
LT3506IDHD#TRPBF is housed in a thermally enhanced 16-lead (5mm × 4mm) plastic DFN package with exposed pad (Pin 17) that must be soldered to PCB ground for electrical integrity and thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1 / FB2 (Pins 16, 9) | Feedback input | Regulates output to 0.8V; connects to resistor divider tap - determines VOUT with ±1% accuracy over temperature |
| RUN/SS1 / RUN/SS2 (Pins 13, 12) | Enable & soft-start control | Pull low to disable regulator; capacitor to ground controls startup dI/dt and prevents inrush - independent per channel |
| PGOOD1 / PGOOD2 (Pins 14, 11) | Open-collector power-good indicator | Sinks current when output is out-of-regulation; requires external pull-up - enables safe supply sequencing |
| VC1 / VC2 (Pins 15, 10) | Error amplifier output | Controls peak switch current; clamped at 0.75V (turn-on) and 1.9V (current limit) - used for loop compensation or override |
| BOOST1 / BOOST2 (Pins 1, 8) | Bootstrap drive supply | Must be ≥1.5V above SW pin; generated via external diode + capacitor - ensures full saturation of internal NPN switches |
| SW1 / SW2 (Pins 2, 7) | Switch node | Connects to inductor, catch diode, and BOOST capacitor - carries high di/dt switching current; layout critical for EMI |
| VIN1 (Pins 3, 4) / VIN2 (Pins 5, 6) | Input power inputs | VIN1 powers internal bias circuitry and Channel 1 switch; VIN2 powers Channel 2 switch - local 4.7μF ceramic bypass required |
| Exposed Pad (Pin 17) | Thermal & electrical ground | Mandatory solder connection to PCB ground plane - primary path for heat dissipation and noise return |
Key Features
| Feature | Design Value |
|---|---|
| Anti-phase dual-channel operation | Reduces input ripple current by up to 50% vs. in-phase converters - allows smaller input capacitors and lower EMI filter cost |
| Independent soft-start and shutdown | Enables staggered power-up of multiple rails - eliminates bus droop and prevents brown-out in multi-voltage systems |
| Integrated 2A bipolar NPN switches | Eliminates need for external MOSFETs and gate drivers - simplifies BOM and improves reliability in space-constrained designs |
| Frequency foldback under fault | Reduces switching frequency to ~170kHz when FB < 0.4V - limits power dissipation and peak switch current during overload or short-circuit |
| Thermal shutdown with hysteresis | Protects against sustained overloads or poor heatsinking - resumes operation automatically after junction cools by ≥15°C |
| Ceramic-capacitor optimized design | Stable with zero-ESR ceramics due to current-mode control - achieves <10mVpp output ripple without electrolytic bulk caps |
Applications
| Disk Drive Power Supply | DSP Core & I/O Rail Generation |
|---|---|
Use Scenario: Dual-rail power for 2.5" HDD servo controller (1.2V core) and spindle motor driver (3.3V interface). IC Role / Device Role / Timing Role: Primary dual-output buck regulator delivering regulated 1.2V/1.6A and 3.3V/1.6A from 12V adapter input. Use Value: Anti-phase operation cuts input ripple by 40%, reducing 12V rail filtering requirements; PGOOD signals coordinate spin-up sequence with host controller. |
Use Scenario: Powering TI C6000 DSP with separate 1.4V core and 3.3V I/O supplies in telecom baseband unit. IC Role / Device Role / Timing Role: Single-package dual buck solution replacing two discrete regulators - simplifies layout and improves cross-regulator transient response. Use Value: Independent RUN/SS pins enable controlled core-power-first sequencing; 125°C rating supports convection-cooled outdoor enclosures. |
| DSL/Cable Modem Power Management | Distributed Power Regulation |
Use Scenario: Generating 1.8V PHY and 3.3V analog front-end rails from 5V or 12V PoE-derived input in residential gateway. IC Role / Device Role / Timing Role: High-efficiency dual buck regulator operating across wide input range (5V–25V) with minimal external components. Use Value: 575kHz switching enables 2.2μH inductors and 22μF ceramic outputs - achieves >85% efficiency at full load while fitting <1 cm² PCB area. |
Use Scenario: Local point-of-load regulation for FPGA I/O banks and transceiver banks in industrial PLC backplane system. IC Role / Device Role / Timing Role: Distributed dual-buck IC mounted near load to minimize IR drop and noise coupling on long PCB traces. Use Value: Exposed-pad DFN package provides low thermal resistance (θJC = 4.3°C/W) - maintains <100°C junction temp at 1.6A/channel with 200 LFM airflow. |
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 |
|---|---|---|---|
| LTC3631EMSE#PBF | Single 3A buck with external sync capability; no dual independent outputs or anti-phase operation | Requires two ICs for dual-rail generation; lacks independent PGOOD and RUN/SS per channel | Choose only if single-rail >2A output suffices and board area permits two separate regulators |
| TPS54290PWPR | 2.2MHz switching, 2A per channel, but uses external MOSFETs; no integrated switches or BOOST pins | Higher BOM count and layout complexity; requires gate drivers, bootstrap circuits, and discrete FETs | Select when higher frequency (2.2MHz) and adjustable frequency are mandatory, and thermal design accommodates discrete FETs |
Compared with LTC3631EMSE#PBF and TPS54290PWPR, the LT3506IDHD#TRPBF delivers true dual-channel integration with anti-phase operation, internal bipolar switches, and seamless sequencing - reducing component count by ≥6 and PCB area by >35% in dual-rail applications requiring ≤1.6A per rail.
Availability
LT3506IDHD#TRPBF is available at Aetrix Electronics and suitable for disk drive power supplies, DSP power management, DSL/cable modem regulation, distributed power systems, and industrial embedded controllers requiring stable component supply across extended temperature ranges.
Supply support for LT3506IDHD#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 (including legacy Linear Technology products) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and aerospace markets.
The LT3506 series belongs to Linear Technology's monolithic DC/DC regulator product line, designed specifically for space-constrained, high-reliability dual-rail power conversion in industrial and networking equipment where thermal robustness and sequencing control are critical.
FAQ
What is the maximum output current per channel for LT3506IDHD#TRPBF?
The LT3506IDHD#TRPBF delivers up to 1.6A per channel continuously under typical conditions (e.g., VOUT = 1.8V or 3.3V, VIN = 5V–12V, 200 LFM airflow). This assumes proper inductor selection (e.g., Sumida CR54-6R4), adequate PCB copper for thermal dissipation, and operation within the –40°C to 125°C ambient range. Peak switch current limit is 2.0A minimum at low duty cycle, decreasing linearly to ~1.7A at 89% duty cycle.
Does LT3506IDHD#TRPBF support ceramic output capacitors?
Yes, the LT3506IDHD#TRPBF is fully compatible with ceramic output capacitors due to its current-mode control architecture, which does not rely on capacitor ESR for loop stability. A 22μF X5R/X7R ceramic capacitor is recommended for 3.3V/5V outputs delivering >1A, achieving <10mVpp ripple. For 1.8V outputs, 22μF remains suitable; increasing capacitance improves transient response without stability risk.
How does anti-phase switching benefit LT3506IDHD#TRPBF designs?
Anti-phase switching (180° phase shift between channels) in the LT3506IDHD#TRPBF reduces input capacitor RMS current by up to 50% compared to in-phase operation. This allows smaller input capacitors (e.g., 4.7μF ceramic instead of 22μF), lowers EMI filter requirements, and decreases board-level conducted emissions - particularly valuable in compact, multi-rail systems like DSL modems and disk drives.
What is the function of the BOOST pins on LT3506IDHD#TRPBF?
The BOOST1 and BOOST2 pins on the LT3506IDHD#TRPBF provide elevated gate drive voltage for the internal bipolar NPN power switches. Each BOOST pin must be biased ≥1.5V above its corresponding SW pin using an external diode and capacitor. This ensures full saturation of the NPN transistors, minimizing VCE(SAT) (~210mV at 1A) and maximizing efficiency - a key distinction from MOSFET-based buck controllers.
Can LT3506IDHD#TRPBF operate with input voltage below 3.6V?
No, the LT3506IDHD#TRPBF has a guaranteed minimum input voltage of 3.6V (undervoltage lockout threshold is 3.4V min). Operation below this level disables regulation and may cause erratic behavior or failure to start. For sub-3.6V inputs, consider alternative regulators such as the LTC3630A (2.25V–5.5V input) or redesign the front-end to meet LT3506IDHD#TRPBF's specified input range.
LT3506IDHD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFDFN 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):
- 23.25V
- Current - Output:
- 1.6A
- Frequency - Switching:
- 575kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-DFN (5x4)
LT3506IDHD#TRPBF FAQ
1.How can I place an order for LT3506IDHD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3506IDHD#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 LT3506IDHD#TRPBF reliable?
The price and inventory of LT3506IDHD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3506IDHD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3506IDHD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3506IDHD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3506IDHD#TRPBF?
LT3506IDHD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3506IDHD#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 LT3506IDHD#TRPBF?
For technical support, including LT3506IDHD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3506IDHD#TRPBF requirements.
6.How does Aetrix verify that LT3506IDHD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3506IDHD#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 LT3506IDHD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3506IDHD#TRPBF?
All LT3506IDHD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3506IDHD#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 LT3506IDHD#TRPBF part is unused and in its original packaging.
Return procedure for LT3506IDHD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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