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Analog Devices Inc. LT3506IDHD#PBF
- Part No.:
- LT3506IDHD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-WFDFN Exposed Pad
- Datasheet:
-
LT3506IDHD#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.6A DL 16DFN
- Quantity:
- Payment:
- Shipping:
Inventory:141
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Product details
Overview
LT3506IDHD#PBF 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 3.6V–25V input and 575kHz fixed switching frequency. It features independent shutdown/soft-start pins, anti-phase operation to reduce input ripple, and accurate 0.8V ±1% feedback reference - used in DSP power supplies, DSL/cable modems, and distributed power regulation.
For engineers reviewing the LT3506IDHD#PBF datasheet, LT3506IDHD#PBF pinout, LT3506IDHD#PBF application, or LT3506IDHD#PBF equivalent, key selection considerations include its –40°C to 125°C industrial temperature grade, thermally enhanced 5mm × 4mm DFN-16 package with exposed GND pad, dual-channel sequencing via independent PGOOD outputs, and compatibility with ceramic output capacitors for low-ripple 1.6A solutions.
Technical Context
The LT3506IDHD#PBF implements constant-frequency current-mode control with shared master oscillator and independent slave oscillators per channel, enabling precise duty-cycle regulation and cycle-by-cycle current limiting. Its bipolar NPN internal switches require external BOOST capacitors and Schottky catch diodes for saturation drive, and feature frequency foldback under overload to limit peak switch current.
Each channel operates with independent error amplifiers (VC pins), soft-start ramp generators (2μA current sources), and open-collector PGOOD comparators triggered at 90% of regulated FB voltage (720mV threshold). Anti-phase switching reduces input RMS ripple by canceling harmonic components between channels, while shared VIN1 bias rail powers internal reference and oscillator circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 25V - supports 4-cell Li-ion, unregulated wall adapters, lead-acid, and distributed 5V/12V rails without pre-regulation. |
| Switching Frequency | 575kHz - enables use of sub-3mm height inductors (e.g., 6.4μH Sumida CR54-6R4) and compact ceramic input/output caps. |
| Output Current per Channel | 1.6A continuous - sustained across full temperature range with thermal shutdown and frequency foldback protection. |
| Feedback Reference Voltage | 0.8V ±1% - sets output voltage via external resistor divider; enables precise 1.2V, 1.8V, 3.3V, or 5V regulation with <±2% total error. |
| Power Good Threshold | 720mV on FB pin - triggers open-collector PGOOD output when output reaches 90% of target, enabling reliable supply sequencing with microcontrollers. |
| Junction Temperature Range | –40°C to 125°C - validated I-grade operation ensures reliability in industrial motor drives, base station power, and automotive infotainment subsystems. |
| Thermal Resistance θJA | 43°C/W - achieved via exposed pad soldered to PCB ground plane; allows 1.6A/channel operation at ≤70°C ambient without forced airflow. |
Pinout & Package
LT3506IDHD#PBF uses a 16-lead, 5mm × 4mm plastic DFN package with exposed thermal pad (Pin 17 = GND). The package is RoHS-compliant, lead-free, and requires soldering of the exposed pad to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1 (16), FB2 (9) | Feedback input | Regulates output to 0.8V; connects to resistor divider tap - determines VOUT with ±1% reference accuracy. |
| VC1 (15), VC2 (10) | Error amplifier output | Controls peak switch current; used for loop compensation or override shutdown by pulling to GND. |
| PGOOD1 (14), PGOOD2 (11) | Open-collector power-good indicator | Asserts high (via external pull-up) when FB ≥ 720mV; enables safe sequencing of downstream logic/DSPs. |
| RUN/SS1 (13), RUN/SS2 (12) | Enable & soft-start control | Pull low to disable channel; capacitor to GND ramps voltage to limit inrush current during startup. |
| BOOST1 (1), BOOST2 (8) | Bootstrap drive supply | Requires external diode + capacitor to generate >VIN voltage for full NPN switch saturation and low VCE(SAT). |
| SW1 (2), SW2 (7) | Switch node output | Connects to inductor, catch diode anode, and BOOST capacitor - carries high di/dt switching current. |
| VIN1 (3,4), VIN2 (5,6) | Input power supply | VIN1 powers internal bias circuits; VIN2 supplies only channel 2 switch - both require local 4.7μF ceramic bypass. |
| GND (17) | Ground reference & thermal path | Exposed pad must be soldered to large PCB copper area for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Anti-phase dual-channel operation | Reduces input ripple current magnitude by >50% vs. in-phase converters - lowers required input capacitance and EMI filter size. |
| Independent shutdown and soft-start | Enables staggered power-up of two rails (e.g., core + I/O) without external timing circuitry - simplifies system-level sequencing. |
| Accurate 0.8V ±1% feedback reference | Supports tight output regulation (±2% total) across line, load, and temperature - critical for DSP, FPGA, and ASIC core supplies. |
| Frequency foldback under overload | Reduces switching frequency to ~170kHz during short-circuit or heavy overload - limits power dissipation and prevents thermal runaway. |
| Integrated 2A bipolar NPN power switches | Eliminates need for external MOSFETs and gate drivers - reduces BOM count and layout area while maintaining 85–90% efficiency at 1.6A. |
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. IC Role / Device Role / Timing Role: Primary DC/DC regulator providing tightly regulated, sequenced, low-noise supplies with PGOOD signaling to processor reset controller. Use Value: Independent RUN/SS and PGOOD pins enable deterministic boot timing; anti-phase operation minimizes conducted EMI into sensitive analog front-end circuits. |
Use Scenario: Compact dual-output power for Broadcom BCM338x-based DSL modems with 1.8V PHY and 3.3V interface rails. IC Role / Device Role / Timing Role: Integrated buck converter replacing discrete controllers + MOSFETs - delivers 1.6A per rail in <200mm² footprint. Use Value: 575kHz switching allows use of 2.2μH/4.7μH shielded inductors and 22μF X7R ceramics - meets FCC Class B emissions without shielding cans. |
| Distributed Power Regulation | Industrial Disk Drive Power |
Use Scenario: Local point-of-load regulation from 12V or 24V backplane in programmable logic controllers (PLCs) and I/O modules. IC Role / Device Role / Timing Role: High-input-voltage buck regulator converting unregulated 24V to 5V/3.3V for microcontroller, ADC, and communication ICs. Use Value: 25V absolute max VIN rating and –40°C to 125°C operation ensure robustness in harsh factory-floor environments with wide ambient swings. |
Use Scenario: Dual 1.6A supplies for 2.5" SATA HDD actuator coil driver (5V) and spindle motor controller (12V derived via secondary stage). IC Role / Device Role / Timing Role: Primary regulator powering servo control logic and buffer memory - must survive cold-cranking and load-dump transients. Use Value: Input undervoltage lockout at 3.4V and thermal shutdown prevent malfunction during brownouts; exposed pad ensures stable junction temp under burst write loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EFE#PBF | Single-channel, 3A, 4MHz sync buck; no PGOOD, no soft-start, different pinout. | Not suitable for dual-rail sequencing; requires external timing for multi-rail systems. | Choose only if single 3A output suffices and board space allows redesign. |
| TPS54290PWPR | Dual-channel, 2A/channel, 300–2000kHz adjustable freq; 2.95–18V input; no BOOST pins (MOSFET-based). | Lower input voltage range excludes 24V industrial rails; lacks anti-phase reduction of input ripple. | Prefer for cost-sensitive consumer apps with <18V input; avoid where 24V tolerance or EMI reduction is critical. |
Compared with LTC3631EFE#PBF and TPS54290PWPR, the LT3506IDHD#PBF uniquely combines dual 1.6A channels, 25V input capability, anti-phase ripple cancellation, and guaranteed –40°C to 125°C operation - making it optimal for industrial and telecom infrastructure where reliability, input range, and EMI control are non-negotiable.
Availability
LT3506IDHD#PBF is available at Aetrix Electronics and suitable for DSP power supplies, DSL/cable modem designs, and distributed power regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3506IDHD#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3506 series belongs to Linear Technology's monolithic DC/DC regulator product line, designed specifically for compact, high-efficiency dual-output power conversion in space-constrained industrial and telecom equipment where input voltage flexibility and thermal robustness are essential.
FAQ
What is the maximum operating junction temperature for the LT3506IDHD#PBF?
The LT3506IDHD#PBF has a maximum junction temperature of 125°C and is specified for continuous operation across –40°C to 125°C ambient. Its DFN-16 package achieves θJA = 43°C/W when the exposed pad is properly soldered to a 4-layer PCB with ≥2 in² copper pour - enabling full 1.6A/channel output at 70°C ambient without derating. Thermal shutdown activates above 165°C to protect the device.
Does the LT3506IDHD#PBF support synchronization to an external clock?
No, the LT3506IDHD#PBF does not support external clock synchronization. It uses an internal master oscillator fixed at 575kHz, with slave oscillators locked to it in anti-phase configuration. There is no SYNC pin or frequency adjustment capability - unlike later-generation parts such as the LT8640S. For synchronized multi-rail systems, external timing must be managed via RUN/SS pin control or downstream sequencing ICs.
Can the LT3506IDHD#PBF operate with only one channel enabled?
Yes, the LT3506IDHD#PBF supports independent channel operation: pulling RUN/SS1 low disables Channel 1 while Channel 2 remains fully functional, and vice versa. Both channels share the same VIN1 bias rail and oscillator, but have separate FB, VC, PGOOD, and BOOST paths - allowing asymmetric configurations (e.g., 1.2V/1.6A + 3.3V/0.8A) without performance penalty or cross-talk.
What is the minimum recommended output capacitance for stable operation of the LT3506IDHD#PBF?
The LT3506IDHD#PBF requires ≥22μF ceramic output capacitance (X5R/X7R, 6.3V rating) for 3.3V/5V outputs delivering ≥1A. This ensures loop stability, limits output ripple to <10mVpp, and provides adequate energy storage for transient load steps. For 1.2V or 1.8V outputs, 22μF remains valid; reducing below 10μF risks instability and excessive overshoot during load transients - especially with low-ESR tantalum alternatives.
Is the LT3506IDHD#PBF pin-compatible with the LT3506AIDHD#PBF?
Yes, the LT3506IDHD#PBF is pin-compatible and footprint-compatible with the LT3506AIDHD#PBF - both use identical 16-lead 5mm × 4mm DFN packages and share identical pin functions and electrical connections. The sole difference is switching frequency: 575kHz (LT3506) vs. 1.1MHz (LT3506A), which affects inductor and capacitor selection but requires no PCB changes.
LT3506IDHD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFDFN Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LT3506IDHD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3506IDHD#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 LT3506IDHD#PBF reliable?
The price and inventory of LT3506IDHD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3506IDHD#PBF is usually 5 days.
3.What payment methods are accepted for LT3506IDHD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3506IDHD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3506IDHD#PBF?
LT3506IDHD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3506IDHD#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 LT3506IDHD#PBF?
For technical support, including LT3506IDHD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3506IDHD#PBF requirements.
6.How does Aetrix verify that LT3506IDHD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3506IDHD#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 LT3506IDHD#PBF meets industry standards.
7.What is the process for return or replacement of LT3506IDHD#PBF?
All LT3506IDHD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3506IDHD#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 LT3506IDHD#PBF part is unused and in its original packaging.
Return procedure for LT3506IDHD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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