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Analog Devices Inc. LTC3546EUFD#PBF
- Part No.:
- LTC3546EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3546EUFD#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A/2A DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,287
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Product details
Overview
LTC3546EUFD#PBF from Analog Devices (formerly Linear Technology) is a dual synchronous step-down DC/DC regulator IC supporting configurable 3A/1A or 2A/2A output configurations. It operates from 2.3V to 5.5V input, delivers adjustable outputs from 0.6V to 5V per channel, and achieves up to 96% efficiency in Burst Mode. It is used in point-of-load power delivery for ultra-mobile PCs and DSL modems.
For engineers reviewing the LTC3546EUFD#PBF datasheet, LTC3546EUFD#PBF pinout, LTC3546EUFD#PBF application, or LTC3546EUFD#PBF equivalent, key selection criteria include its dual-channel current-mode architecture, programmable switching frequency (0.75–4 MHz), independent tracking/soft-start, and thermal performance in the 4mm × 5mm QFN package with exposed pad.
Technical Context
The LTC3546EUFD#PBF implements a constant-frequency current-mode control architecture with shared oscillator and phase-selectable operation (in-phase or 180° out-of-phase). Each channel features independent error amplifiers, peak-current limiting via ITH pins, and auto-detecting dependent switch control for SW1D connection to either SW1 or SW2A/B.
It supports three low-load operating modes-Burst Mode (30mVP-P ripple, 160µA IQ), pulse-skipping, and forced continuous-selected via SYNC/MODE voltage levels. Internal 0.6V reference, ±0.1µA feedback bias, and ±8% PGOOD thresholds enable precise regulation and system-level power sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.3V to 5.5V - supports single-cell Li-ion, USB, and 3.3V/5V rail inputs without external LDO pre-regulation. |
| VOUT Range | 0.6V to 5V per channel - enables core voltage scaling for processors, FPGAs, and memory interfaces. |
| Switching Frequency | 0.75MHz to 4MHz (adjustable) or fixed 2.25MHz - allows optimization of inductor size vs. EMI in space-constrained designs. |
| Peak Output Current | Configurable: 3A/1A or 2A/2A - achieved by externally connecting SW1D to SW2A/B or SW1, respectively. |
| Efficiency | Up to 96% - enabled by integrated low-RDS(ON) MOSFETs (0.096Ω top / 0.085Ω bottom for SW2) eliminating need for Schottky diodes. |
| Shutdown Current | <1µA - ensures battery-powered systems maintain long shelf life during storage or deep sleep. |
| Power Good Accuracy | ±8% threshold deviation - provides reliable sequencing signal for downstream logic and processors. |
Pinout & Package
The LTC3546EUFD#PBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29 = GNDD), rated for –40°C to +85°C operation. The exposed pad must be soldered to PCB for thermal performance (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW1 | Channel 1 switch node | Connects to inductor for 1A primary output; swing range: VIN1 to PGND1. |
| SW1D | Dependent switch node | Auto-detected connection to SW1 (enables 2A/2A) or SW2A/B (enables 3A/1A); must never tie to VIN or GND. |
| SW2A/SW2B | Channel 2 switch nodes | Must be externally shorted; drive 2A output stage; swing range: VIN2 to PGND2. |
| VFB1/VFB2 | Feedback inputs | Monitor regulated outputs via resistive dividers; nominal 0.6V reference enables precise voltage setting. |
| BMC1/BMC2 | Burst Mode clamp controls | Set Burst Mode threshold externally (0–0.6V) or use internal clamp (tie to VCCA); tie to GND to disable Burst Mode. |
| TRACK/SS1/SS2 | Tracking/soft-start inputs | Enable output voltage ramp control or supply tracking; floating = internal 1.2ms soft-start; capacitor = programmable ramp. |
| PGOOD1/PGOOD2 | Power-good open-drain outputs | Pull low when respective output deviates >8% from regulation - used for system power sequencing and fault indication. |
| FREQ | Frequency set/sync input | Tie to VIN for 2.25MHz; connect resistor to GNDA for 0.75–4MHz; apply external clock for synchronization. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-channel current-mode control | Ensures fast transient response and stable parallel operation with minimal output capacitance. |
| Configurable output current sharing | SW1D auto-detection enables flexible 3A/1A or 2A/2A partitioning without redesigning PCB layout. |
| Three selectable light-load modes | Burst Mode (low IQ), pulse-skipping (low ripple), or forced continuous (lowest noise) - selected via SYNC/MODE voltage. |
| Independent tracking and soft-start | Each channel supports external voltage tracking or programmable capacitor-based soft-start for controlled power-up sequencing. |
| Integrated low-RDS(ON) MOSFETs | Eliminates external Schottky diodes and reduces BOM count while maintaining high efficiency across load range. |
| 100% duty-cycle capability | Enables low-dropout operation near input rail - critical for battery-powered systems under brownout conditions. |
Applications
| Ultra-Mobile PC Power Rails | DSL Modem Core Supply |
|---|---|
Use Scenario: Dual-rail power for CPU core (1.2V @ 2A) and I/O (2.5V @ 3A) in fanless netbook designs. IC Role / Device Role / Timing Role: Primary point-of-load regulator delivering tightly regulated, sequenced outputs with low quiescent current. Use Value: Configurable 3A/1A mode supplies high-current core rail; Burst Mode extends battery runtime at light loads. |
Use Scenario: Generating 3.3V @ 2A and 1.8V @ 1A for ADSL line driver and PHY ICs in residential gateways. IC Role / Device Role / Timing Role: Dual-output DC/DC converter providing isolated, tracked startup for analog and digital subsystems. Use Value: TRACK/SS1 and TRACK/SS2 enable synchronized ramp-up, preventing latch-up in mixed-signal ICs. |
| PC Card (PCMCIA) Power Management | Industrial IoT Sensor Hub |
Use Scenario: Compact 28-pin QFN fits tight PC Card form factor; powers FPGA (1.2V) and transceiver (2.5V) from 3.3V bus. IC Role / Device Role / Timing Role: Space-optimized dual buck regulator with integrated switches and thermal pad for convection-cooled cards. Use Value: 4mm × 5mm footprint and 34°C/W θJA allow full 3A output without heatsink in confined card slots. |
Use Scenario: Powering ARM Cortex-M7 MCU (1.1V @ 1A), RF transceiver (3.3V @ 0.5A), and analog front-end (2.5V @ 0.3A) in battery-backed edge node. IC Role / Device Role / Timing Role: Highly integrated dual regulator enabling single-chip power solution with shutdown IQ <1µA. Use Value: Ultralow shutdown current preserves battery charge during multi-week sleep cycles between sensor readings. |
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 |
|---|---|---|---|
| TPS65270RGET | Fixed 1.2V/3.3V outputs; no SW1D configurability; 2.2MHz fixed frequency; lower max IOUT (2A/2A only) | Best for cost-sensitive, non-adjustable dual-rail systems where flexibility is secondary to BOM simplicity. | Select when fixed voltages suffice and board area is constrained - lacks LTC3546EUFD#PBF's wide VOUT adjustability and 3A capability. |
| ISL95210IRZ | Supports 3-phase interleaving; higher max fSW (1.5MHz); no Burst Mode; requires external MOSFETs | Suitable for high-efficiency server VRMs requiring phase interleaving and dynamic voltage scaling. | Choose for high-power (>10A) applications needing interleaved control - not drop-in; requires external power stages and more complex loop compensation. |
Compared with TPS65270RGET and ISL95210IRZ, the LTC3546EUFD#PBF uniquely combines adjustable dual outputs, SW1D-based current reconfiguration, Burst Mode efficiency at microamp loads, and integrated MOSFETs in a compact QFN - making it optimal for portable, battery-aware, and space-limited embedded systems.
Availability
LTC3546EUFD#PBF is available at Aetrix Electronics and suitable for ultra-mobile PCs, DSL modems, and PC Card power management requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature grade (–40°C to +85°C).
Supply support for LTC3546EUFD#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, communications, and industrial markets.
The LTC3546EUFD#PBF belongs to Linear's high-efficiency monolithic DC/DC regulator product line, designed specifically for space-constrained, battery-powered, and thermally demanding embedded systems requiring dual-output flexibility and low-noise operation.
FAQ
What output configurations does the LTC3546EUFD#PBF support?
The LTC3546EUFD#PBF supports two primary configurations: 3A/1A (SW1D connected to SW2A/B) and 2A/2A (SW1D connected to SW1). This is achieved through internal auto-detection of the SW1D connection, enabling flexible current allocation without changing the IC or PCB layout. Both configurations retain independent voltage adjustment, tracking, and mode control per channel.
How does the LTC3546EUFD#PBF achieve up to 96% efficiency?
The LTC3546EUFD#PBF achieves up to 96% efficiency using integrated low-RDS(ON) synchronous MOSFETs - 0.096Ω/0.085Ω for SW2 and 0.19Ω/0.18Ω for SW1 - eliminating external Schottky diode losses. Combined with optimized gate drive, current-mode control, and selectable light-load modes (especially Burst Mode), it minimizes conduction and switching losses across the full load range.
Can the LTC3546EUFD#PBF operate with 100% duty cycle?
Yes, the LTC3546EUFD#PBF supports 100% duty-cycle operation on both channels, enabling dropout-free regulation when VIN approaches VOUT. This is critical for battery-powered systems during brownout conditions, ensuring uninterrupted power to sensitive loads like microcontrollers and sensors without requiring additional LDO post-regulation.
What is the function of the SYNC/MODE pin on the LTC3546EUFD#PBF?
The SYNC/MODE pin on the LTC3546EUFD#PBF serves dual functions: (1) selecting operating mode - Burst Mode (>VIN–0.5V), pulse-skipping (<0.5V), or forced continuous (~VIN/2); and (2) accepting an external clock for frequency synchronization. When used for sync, pulse-skipping mode is automatically engaged, ensuring deterministic timing alignment with system clocks.
Does the LTC3546EUFD#PBF require external compensation components?
Yes, the LTC3546EUFD#PBF requires external compensation via the ITH1 and ITH2 pins - typically a series RC network from each ITH pin to ground - to stabilize the current-mode control loop. The values depend on output voltage, inductance, and desired phase margin; typical designs use 1–10nF capacitors and 1–10kΩ resistors, as detailed in the datasheet's compensation guidelines.
LTC3546EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN 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):
- 2.3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5V
- Current - Output:
- 1A, 2A
- Frequency - Switching:
- 2.25MHz, 750kHz ~ 4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3546EUFD#PBF FAQ
1.How can I place an order for LTC3546EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3546EUFD#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 LTC3546EUFD#PBF reliable?
The price and inventory of LTC3546EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3546EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3546EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3546EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3546EUFD#PBF?
LTC3546EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3546EUFD#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 LTC3546EUFD#PBF?
For technical support, including LTC3546EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3546EUFD#PBF requirements.
6.How does Aetrix verify that LTC3546EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3546EUFD#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 LTC3546EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3546EUFD#PBF?
All LTC3546EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3546EUFD#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 LTC3546EUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3546EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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