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Analog Devices Inc. LTC3546EFE
- Part No.:
- LTC3546EFE
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3546EFE.pdf
- Description:
- IC REG BCK ADJ 1A/2A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,347
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Product details
Overview
LTC3546EFE from Analog Devices is a dual synchronous step-down DC/DC regulator 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 SW2A/B; 0.19Ω/0.18Ω for SW1), supports 2.25MHz fixed or 0.75–4MHz adjustable switching frequency, and delivers up to 96% efficiency in Burst Mode operation - used in ultra-mobile PCs and point-of-load power delivery.
For engineers reviewing the LTC3546EFE datasheet, LTC3546EFE pinout, LTC3546EFE application, or LTC3546EFE equivalent, key selection criteria include dual-channel current-mode control, external SW1D configuration flexibility, independent PGOOD outputs, programmable Burst Mode clamp via BMC pins, and thermal performance in the 28-lead TSSOP package with exposed pad.
Technical Context
The LTC3546EFE employs a constant-frequency current-mode architecture with shared oscillator and phase-selectable (in-phase or 180° out-of-phase) dual regulators. Each channel uses an error amplifier with 2.5MHz bandwidth comparing VFB to a 0.6V reference, controlling peak inductor current via ITH voltage (0–1.5V range).
SW1D auto-detection logic identifies whether the dependent switch is connected to SW1 (enabling 2A/2A mode) or SW2A/B (enabling 3A/1A mode), dynamically configuring current limits (ILIM1+1D = 2.5–3.2A; ILIM2+1D = 3.75–4.8A). Burst Mode operation is triggered when ITH falls below 0.24V and resumes when ITH exceeds 0.31V, minimizing gate-charge losses at light loads.
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 optimization of size (small inductors/caps) vs. EMI/efficiency trade-offs. |
| Peak Efficiency | Up to 96% - achieved using synchronous rectification and low RDS(ON) internal MOSFETs, eliminating Schottky diode losses. |
| Light-Load IQ | 160µA in Burst Mode - extends battery life in always-on subsystems of portable electronics. |
| Shutdown Current | <1µA - ensures minimal leakage during system sleep or standby states. |
| Power Good Threshold | –8% deviation from regulated VFB - provides reliable rail monitoring for sequenced power-up in multi-rail systems. |
Pinout & Package
The LTC3546EFE is housed in a thermally enhanced 28-lead plastic TSSOP package (FE) with exposed pad (Pin 29 = GNDD), rated for –40°C to +85°C operation and θJA = 25°C/W. Soldering the exposed pad to PCB ground is mandatory for rated thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 / VIN2 / VIN1D | Independent input supply pins | Enable separate input sourcing for each regulator stage - VIN1 powers SW1 (1A), VIN2 powers SW2A/B (2A), VIN1D powers SW1D (1A dependent switch). |
| SW1 / SW2A / SW2B / SW1D | Switch node terminals | SW1 connects to Channel 1 inductor; SW2A/SW2B must be shorted externally as dual-phase node for Channel 2; SW1D auto-detected for 2A/2A or 3A/1A reconfiguration. |
| VFB1 / VFB2 | Feedback inputs | Monitor output voltage via resistive dividers; nominal 0.6V reference sets regulation point - enables precise output programming. |
| BMC1 / BMC2 | Burst Mode clamp control | Set Burst Mode activation threshold externally (0–0.6V) or use internal clamp (tie to VCCA); tie to GND to disable Burst Mode. |
| TRACK/SS1 / TRACK/SS2 | Tracking/soft-start inputs | Enable output voltage ramp control: floating = internal 1.2ms soft-start; capacitor = programmable ramp; external voltage = tracking of another supply. |
| PGOOD1 / PGOOD2 | Open-drain power-good indicators | Pull low when respective output deviates >–8% from target - used for sequencing, fault reporting, and system enable logic. |
| RUN1 / RUN2 | Channel enable inputs | Active-high logic enables/disables each regulator independently; both low = full shutdown (<1µA IQ). |
| SYNC/MODE | Mode selection & synchronization | Selects Burst Mode (>VIN–0.5V), pulse-skipping (<0.5V), or forced continuous (≈VIN/2); also accepts external clock for synchronization. |
| FREQ | Oscillator frequency control | Tie to VCCA for 2.25MHz; connect resistor to GNDA for 0.75–4MHz adjustment; used with RC network for PLL sync compensation. |
| PHASE | Channel phase alignment | High = in-phase switching (reduces input ripple); low = 180° out-of-phase (reduces output capacitor RMS current). |
| ITH1 / ITH2 | Error amplifier outputs | Control peak inductor current (0–1.5V range); voltage increase raises current limit - used for loop compensation and current limiting. |
| GNDA / GNDD / PGND1 / PGND2 / PGND1D | Analog/digital/power grounds | Separate ground paths minimize noise coupling: GNDA (analog ref), GNDD (digital substrate), PGNDx (switch node return for each channel). |
Key Features
| Feature | Design Value |
|---|---|
| Dual configurable output topology | Supports 3A/1A (SW1D→SW2A/B) or 2A/2A (SW1D→SW1) via external connection - eliminates need for multiple discrete regulators in space-constrained designs. |
| Three selectable light-load modes | Burst Mode (30mVP-P ripple, 160µA IQ), pulse-skipping (low ripple), or forced continuous (lowest noise) - user-selectable per system noise/efficiency requirements. |
| Auto-detect SW1D configuration | Internal logic identifies SW1D connection target and configures current limits and control timing accordingly - no firmware or external logic required. |
| Independent tracking & soft-start | Each channel has dedicated TRACK/SS pin enabling independent ramp control, supply tracking, or coordinated power-up with other rails - critical for FPGA/CPU sequencing. |
| 100% duty-cycle low-dropout operation | Enables VOUT ≥ VIN operation (e.g., 3.3V input → 3.3V output) by holding high-side switch on continuously - useful for post-regulation or battery backup paths. |
| Short-circuit protected with current-mode control | Fast overcurrent response via cycle-by-cycle peak current limiting (ILIM1 = 1.4–1.6A; ILIM2 = 2.8–3.2A) - prevents damage during load faults without external sensing. |
Applications
| Netbooks & Ultra-Mobile PCs | PC Cards & ExpressCard Modules |
|---|---|
Use Scenario: Powering CPU core, memory, and I/O rails in fanless, compact mobile computing platforms with strict thermal and size constraints. IC Role / Device Role / Timing Role: Dual-channel point-of-load regulator providing 1.2V@1A (core) and 2.5V@3A (I/O) with synchronized 180° phase to reduce input capacitor stress. Use Value: Eliminates need for two separate regulators; 96% efficiency extends battery runtime; Burst Mode maintains >85% efficiency down to 1mA load. |
Use Scenario: Generating multiple isolated power rails for hot-pluggable peripheral cards requiring strict sequencing and fast transient response. IC Role / Device Role / Timing Role: Configured as 2A/2A dual regulator with TRACK/SS1 and TRACK/SS2 tied to enable controlled, matched voltage ramp-up across VCCIO and VCCCLK. Use Value: Independent PGOOD1/PGOOD2 signals ensure safe card insertion detection; 1.2ms internal soft-start meets PC Card specification timing windows. |
| DSL & Wireless Modems | Point-of-Load DC/DC Conversion |
Use Scenario: Supplying RF transceiver, baseband processor, and analog front-end in broadband access equipment with variable line input (3.3–5.5V). IC Role / Device Role / Timing Role: Operated in 3A/1A mode: 3A channel powers RF PA (2.5V), 1A channel powers digital baseband (1.2V); SYNC/MODE pin tied to external clock for EMI reduction. Use Value: Adjustable 0.75–4MHz frequency avoids sensitive RF bands; low 30mVP-P Burst Mode ripple prevents interference with receive sensitivity. |
Use Scenario: Replacing discrete buck controllers + MOSFETs in industrial embedded systems where board space and BOM count are critical. IC Role / Device Role / Timing Role: Integrated solution with internal switches, compensation, and protection - reduces component count by ≥12 parts versus controller-based design. Use Value: Exposed-pad TSSOP package achieves 25°C/W θJA, enabling 3A continuous output without heatsink; RDS(ON) specs guarantee <1.2W conduction loss at full load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65286RGER | Fixed 1.8V/3.3V dual outputs; no adjustable VOUT or SW1D reconfiguration; lower max IOUT (2A/2A only); integrated LDOs. | Suitable for fixed-rail applications like set-top boxes; lacks flexibility for custom voltage sequencing or dynamic load sharing. | Choose when standard voltages suffice and LDO integration is needed; avoid when programmable outputs or 3A/1A mode is required. |
| ISL95831IRZ | Higher input range (1.5–24V); supports Intel VR12.5/VR12.6; no SW1D reconfiguration; requires external MOSFETs. | Targeted at CPU VR applications with complex VID protocols; not suitable for low-voltage portable systems with 2.3–5.5V input. | Choose for server/desktop CPU power delivery; avoid for battery-powered devices due to higher minimum VIN and external FET requirement. |
Compared with TPS65286RGER and ISL95831IRZ, the LTC3546EFE uniquely supports field-reconfigurable 3A/1A or 2A/2A operation via SW1D routing, offers wider VOUT adjustability (0.6–5V), and delivers superior light-load efficiency (160µA IQ) - making it optimal for compact, battery-sensitive, multi-rail embedded systems.
Availability
LTC3546EFE 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 consistent parametric performance across production batches.
Supply support for LTC3546EFE 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 ICs, serving industrial, automotive, communications, and consumer markets.
The LTC3546EFE belongs to Linear's high-efficiency monolithic DC/DC converter product line, designed specifically for space-constrained, battery-powered applications demanding flexible multi-rail power delivery with minimal external components.
FAQ
What is the maximum output current configuration supported by the LTC3546EFE?
The LTC3546EFE supports two primary configurations: 3A/1A (when SW1D is connected to SW2A/B) and 2A/2A (when SW1D is connected to SW1). In 3A/1A mode, the combined SW2A/B + SW1D path delivers up to 3.75–4.8A peak current depending on BMC2 voltage; the standalone SW1 channel delivers 1.4–1.6A peak. The LTC3546EFE maintains regulation under these loads with proper thermal design and layout.
How does the LTC3546EFE achieve 96% peak efficiency?
The LTC3546EFE achieves up to 96% peak efficiency through synchronous rectification using low RDS(ON) internal MOSFETs (0.096Ω top / 0.085Ω bottom for SW2A/B; 0.19Ω / 0.18Ω for SW1), eliminating Schottky diode forward voltage losses. Combined with optimized gate drive and current-mode control minimizing switching transition losses, this enables high efficiency across 0.1–3A load range at 3.6VIN/2.5VOUT.
Can the LTC3546EFE operate with input voltage equal to output voltage?
Yes, the LTC3546EFE supports 100% duty-cycle operation, allowing VOUT ≥ VIN - for example, delivering 3.3V output from a 3.3V input. This low-dropout capability is enabled by holding the high-side P-channel MOSFET fully on, making the LTC3546EFE suitable for post-regulation, battery backup, or voltage-following applications where input and output rails are closely matched.
What is the function of the PHASE pin on the LTC3546EFE?
The PHASE pin on the LTC3546EFE selects relative switching timing between Channel 1 and Channel 2: logic high enables in-phase operation (reducing input capacitor RMS current), while logic low enables 180° out-of-phase operation (reducing output capacitor RMS current and improving transient response). This flexibility allows designers to optimize either input or output filtering based on system-level EMI and thermal constraints.
Is the LTC3546EFE pin-compatible with other packages in the LTC3546 family?
No, the LTC3546EFE (28-lead TSSOP, FE package) is not pin-compatible with the LTC3546EUFD (28-lead 4mm × 5mm QFN, UFD package), despite identical pin functions and numbering. The FE package has different mechanical dimensions, thermal pad configuration, and soldering requirements. PCB layout must be specific to the FE footprint; migration requires board redesign.
LTC3546EFE 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
LTC3546EFE FAQ
1.How can I place an order for LTC3546EFE through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3546EFE 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 LTC3546EFE reliable?
The price and inventory of LTC3546EFE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3546EFE is usually 5 days.
3.What payment methods are accepted for LTC3546EFE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3546EFE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3546EFE?
LTC3546EFE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3546EFE 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 LTC3546EFE?
For technical support, including LTC3546EFE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3546EFE requirements.
6.How does Aetrix verify that LTC3546EFE is sourced from the original manufacturer or authorized distributors?
All LTC3546EFE 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 LTC3546EFE meets industry standards.
7.What is the process for return or replacement of LTC3546EFE?
All LTC3546EFE units undergo pre-shipment inspection (PSI). If there is an issue with LTC3546EFE, 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 LTC3546EFE part is unused and in its original packaging.
Return procedure for LTC3546EFE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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