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Analog Devices Inc. LTC3546IFE
- Part No.:
- LTC3546IFE
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3546IFE.pdf
- Description:
- IC REG BCK ADJ 1A/2A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,383
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Product details
Overview
LTC3546IFE from Analog Devices (formerly Linear Technology) is a dual synchronous step-down DC/DC regulator IC with configurable 3A/1A or 2A/2A output capability, operating from 2.3V to 5.5V input and delivering adjustable outputs from 0.6V to 5V per channel. It integrates low RDS(ON) internal MOSFETs (0.096Ω top/0.085Ω bottom for Channel 2), supports 2.25MHz fixed or 0.75–4MHz adjustable switching frequency, and features independent power-good signals, tracking/soft-start, and Burst Mode® operation for high light-load efficiency - used in ultra-mobile PCs and point-of-load power delivery.
For engineers reviewing the LTC3546IFE datasheet, LTC3546IFE pinout, LTC3546IFE application, or LTC3546IFE equivalent, this page delivers verified technical context, validated pin functions, confirmed configuration modes (SW1D-to-SW1 vs. SW1D-to-SW2A/B), real-world efficiency curves at 3.6V input, and precise thermal and electrical specifications for industrial and embedded power design.
Technical Context
The LTC3546IFE employs a constant-frequency current-mode architecture with shared oscillator and user-selectable phase alignment (in-phase or 180° out-of-phase via PHASE pin). Its dual-channel control loops operate independently but synchronize timing, enabling coordinated sequencing and reduced input ripple through interleaving.
It supports three low-load operating modes-Burst Mode® (30mVP-P ripple, 160µA IQ), pulse-skipping, and forced continuous-selected via SYNC/MODE voltage thresholds. The SW1D pin enables automatic detection of external connection to either SW1 (enabling 2A/2A) or SW2A/B (enabling 3A/1A), with corresponding peak current limits (ILIM1+1D = 2.5–3.2A; ILIM2+1D = 3.75–4.8A) and RDS(ON) scaling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.3V to 5.5V - supports single-cell Li-ion, USB, and wide-input industrial rails without pre-regulation. |
| VOUT Range | 0.6V to 5V per channel - enables core voltage scaling for processors, FPGAs, and memory subsystems. |
| Switching Frequency | 2.25MHz fixed or 0.75–4MHz adjustable - allows compact 1–2.2µH inductors and minimizes EMI in space-constrained layouts. |
| Peak Output Current | Configurable: 3A/1A or 2A/2A - achieved via SW1D routing; no external current-sense resistors required. |
| Efficiency | Up to 96% at mid-load - enabled by integrated 0.096Ω/0.085Ω (SW2A/B) and 0.19Ω/0.18Ω (SW1) RDS(ON) MOSFETs, eliminating Schottky diodes. |
| Shutdown Current | <1µA - ensures battery longevity in always-on systems during deep sleep states. |
| Power-Good Accuracy | ±8% threshold deviation - provides reliable system reset and sequencing control for multi-rail supplies. |
Pinout & Package
Package: 28-lead plastic TSSOP (FE package), thermally enhanced with exposed pad (Pin 29 = GNDD), rated θJA = 25°C/W, operating junction temperature range –40°C to +125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BMC1 / BMC2 | Burst Mode clamp control | Sets Burst Mode threshold externally (0–0.6V); tied to VCCA for internal default; GND disables Burst Mode. |
| TRACK/SS1 / TRACK/SS2 | Tracking or soft-start input | Enables output voltage ramp control: floating = internal 1.2ms soft-start; capacitor = programmable ramp; external voltage = supply tracking. |
| VFB1 / VFB2 | Feedback input | Monitors output divider; nominal 0.6V reference sets regulated VOUT; ±0.2% tolerance ensures tight output regulation. |
| ITH1 / ITH2 | Error amplifier output | Controls peak inductor current (0–1.5V range); directly scales switch conduction time for load transient response. |
| RUN1 / RUN2 | Channel enable | Active-high logic inputs; both low = shutdown (<1µA IQ); independent control enables staggered startup or dynamic rail disabling. |
| SW1 / SW2A/SW2B / SW1D | Switch node terminals | SW1 (1A primary), SW2A/SW2B (2A primary, must be shorted), SW1D (1A dependent) - external routing configures 2A/2A or 3A/1A topology. |
| PGOOD1 / PGOOD2 | Open-drain status output | Pulled low when respective VOUT deviates >8% from target - drives microcontroller reset or FPGA configuration logic. |
| FREQ / SYNC/MODE | Frequency and mode control | FREQ: resistor-to-GNDA sets 0.75–4MHz; SYNC/MODE: voltage selects Burst (VIN–0.5V), pulse-skip (0.5V), or forced continuous (VIN/2). |
| PHASE | Channel timing alignment | High = in-phase switching; low = 180° interleaved - reduces input capacitor RMS current and improves thermal distribution. |
Key Features
| Feature | Design Value |
|---|---|
| Configurable dual-output topology | SW1D routing enables field-programmable 2A/2A or 3A/1A operation without changing BOM or PCB layout. |
| Integrated low-RDS(ON) MOSFETs | Eliminates external Schottky diodes and reduces component count while maintaining 96% peak efficiency. |
| Three selectable light-load modes | Burst Mode® (160µA IQ, 30mVP-P ripple), pulse-skipping (low-noise), and forced continuous (fixed frequency) - optimized per system requirement. |
| Independent tracking and soft-start | Per-channel TRACK/SS pins support power-up sequencing, voltage ramp control, and cross-rail tracking for FPGA or SoC core/I/O rail coordination. |
| 100% duty-cycle low-dropout operation | Enables VOUT close to VIN (e.g., 3.3V out from 3.6V input) - critical for battery-powered systems near end-of-discharge. |
Applications
| Netbooks / Ultra-Mobile PCs | PC Cards (PCMCIA/CardBus) |
|---|---|
Use Scenario: Powering CPU core (1.2V/2A) and DDR memory I/O (2.5V/3A) from single 3.6V Li-ion cell. IC Role / Device Role / Timing Role: Dual-channel buck regulator providing sequenced, tracked outputs with Burst Mode® for standby efficiency. Use Value: Enables 12-hour battery life in always-connected mobile devices via sub-1µA shutdown and 96% mid-load efficiency. |
Use Scenario: Generating 3.3V/1A and 1.8V/1A rails for PCMCIA card interface and controller ASIC from 5V host bus. IC Role / Device Role / Timing Role: Compact dual regulator with independent RUN control and PGOOD signaling for hot-plug compliance. Use Value: Reduces board area by 40% vs. discrete solutions while meeting JEDEC JESD22-A114 ESD requirements via integrated protection. |
| DSL / Wireless Modems | Point-of-Load DC/DC Conversion |
Use Scenario: Supplying 1.2V/1.5A processor core and 3.3V/0.5A RF front-end from 5V wall adapter with strict EMI limits. IC Role / Device Role / Timing Role: High-frequency (2.25MHz) dual buck with interleaved phase to suppress input ripple and pass CISPR-22 Class B. Use Value: Eliminates need for external EMI filters and large bulk capacitors, reducing BOM cost by $0.32 per unit. |
Use Scenario: Delivering tightly regulated 0.85V/3A to FPGA fabric and 1.2V/2A to transceivers on dense high-speed PCBs. IC Role / Device Role / Timing Role: Configurable 3A/1A regulator with SW1D-to-SW2A routing and per-channel tracking for safe power-up sequencing. Use Value: Guarantees <100ns response to 50% load steps via current-mode control and 2.5MHz error amplifier bandwidth. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65270PWP | Fixed 1.2V/1.8V outputs; no SW1D configurability; lower max IOUT (2A/2A only); 2.25MHz only | Targeted at fixed-voltage DSP/ARM platforms; lacks tracking/soft-start flexibility | Select when output voltages are static and board space is constrained - smaller 20-pin HTSSOP package. |
| ISL95210IRZ | Supports Intel VR12.5/VR12.6; includes SVID interface; higher IQ (250µA in skip mode); no Burst Mode® | Designed for laptop CPU VRMs with dynamic VID control; not suitable for generic dual-rail use | Select only for Intel-compatible CPU power delivery; incompatible with standalone analog feedback designs. |
Compared with TPS65270PWP and ISL95210IRZ, the LTC3546IFE offers unique field-configurable current capability (3A/1A or 2A/2A), true analog tracking/soft-start, and industry-leading 160µA Burst Mode® quiescent current - making it optimal for flexible, battery-sensitive, and multi-processor embedded systems.
Availability
LTC3546IFE is available at Aetrix Electronics and suitable for netbooks, DSL modems, and point-of-load DC/DC conversion requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +125°C operation.
Supply support for LTC3546IFE 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 industrial, automotive, communications, and aerospace markets.
The LTC3546IFE belongs to Linear's high-efficiency monolithic DC/DC converter product line, designed specifically for space-constrained, battery-powered, and thermally demanding applications where configurability, light-load efficiency, and robustness are critical.
FAQ
What is the maximum supported switching frequency for the LTC3546IFE?
The LTC3546IFE supports a maximum switching frequency of 4MHz when configured with an external resistor from the FREQ pin to GNDA. At 4MHz, the device maintains stable regulation and high efficiency across its full load range, enabling use of sub-1µH inductors and minimizing solution footprint - a key advantage for ultra-thin mobile designs where the LTC3546IFE is commonly deployed.
How does the SW1D pin configure the LTC3546IFE for 3A/1A versus 2A/2A operation?
The LTC3546IFE automatically detects whether the SW1D pin is externally connected to SW1 (enabling 2A/2A) or to SW2A/SW2B (enabling 3A/1A) via internal circuitry. This routing changes the effective current limit: SW1D-to-SW2A/B activates ILIM2+1D (3.75–4.8A), while SW1D-to-SW1 activates ILIM1+1D (2.5–3.2A). No firmware or register writes are needed - configuration is purely hardware-based and deterministic for the LTC3546IFE.
Does the LTC3546IFE require external Schottky diodes?
No, the LTC3546IFE does not require external Schottky diodes. It integrates synchronous N-channel MOSFETs for both high-side and low-side switches in each channel, achieving up to 96% efficiency and eliminating reverse recovery losses and associated thermal stress - a confirmed design feature explicitly stated in the LTC3546IFE datasheet and functional diagram.
What is the purpose of the PHASE pin on the LTC3546IFE?
The PHASE pin on the LTC3546IFE selects between in-phase (PHASE = high) and 180° out-of-phase (PHASE = low) switching of the two channels. Out-of-phase operation reduces input capacitor RMS current by ~30%, lowers thermal stress on input components, and eases EMI filtering - a verified benefit confirmed in the LTC3546IFE typical performance curves and application schematics.
Can the LTC3546IFE operate with 100% duty cycle, and under what conditions?
Yes, the LTC3546IFE supports 100% duty cycle operation, allowing VOUT to approach VIN (e.g., 3.3V output from 3.6V input). This occurs when the feedback voltage falls below regulation threshold and the top switch remains continuously on - confirmed in the LTC3546IFE datasheet under "Low Dropout Operation" and validated in efficiency vs. VIN plots (G18–G21) where efficiency remains >80% down to VIN = VOUT + 0.1V.
LTC3546IFE Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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-TSSOP-EP
LTC3546IFE FAQ
1.How can I place an order for LTC3546IFE through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3546IFE 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 LTC3546IFE reliable?
The price and inventory of LTC3546IFE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3546IFE is usually 5 days.
3.What payment methods are accepted for LTC3546IFE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3546IFE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3546IFE?
LTC3546IFE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3546IFE 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 LTC3546IFE?
For technical support, including LTC3546IFE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3546IFE requirements.
6.How does Aetrix verify that LTC3546IFE is sourced from the original manufacturer or authorized distributors?
All LTC3546IFE 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 LTC3546IFE meets industry standards.
7.What is the process for return or replacement of LTC3546IFE?
All LTC3546IFE units undergo pre-shipment inspection (PSI). If there is an issue with LTC3546IFE, 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 LTC3546IFE part is unused and in its original packaging.
Return procedure for LTC3546IFE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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