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Analog Devices Inc. LTC3549EDCB#TRMPBF
- Part No.:
- LTC3549EDCB#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 6-WFDFN Exposed Pad
- Datasheet:
-
LTC3549EDCB#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
LTC3549EDCB#TRMPBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous buck regulator optimized for low-input-voltage, high-efficiency power conversion in portable battery-powered systems. It delivers up to 250mA output current at 1.2V from 1.8V input, operates with 2.25MHz fixed-frequency current-mode control, features 100% duty cycle capability for ultra-low dropout, and integrates both P-channel and N-channel MOSFETs - eliminating the need for an external Schottky diode. It is used in compact Li-ion–powered devices such as MP3 players and digital cameras.
For engineers reviewing the LTC3549EDCB#TRMPBF datasheet, LTC3549EDCB#TRMPBF pinout, LTC3549EDCB#TRMPBF application, or LTC3549EDCB#TRMPBF equivalent, key selection criteria include its 1.6V–5.5V input range, 50µA quiescent current in Burst Mode, 0.611V feedback reference, 6-lead 2mm × 3mm DFN package with exposed thermal pad, and compatibility with ceramic output capacitors without ESR dependency.
Technical Context
The LTC3549EDCB#TRMPBF employs a constant-frequency, current-mode architecture with internal slope compensation active above 40% duty cycle to prevent subharmonic oscillation. Its dual-MOSFET synchronous rectification uses a P-channel main switch (RDS(ON) = 0.56Ω typical in DFN) and N-channel synchronous switch (RDS(ON) = 0.4Ω typical), enabling high efficiency across load range without external diode.
Burst Mode operation is controlled via the MODE pin (logic-low enables), reducing supply current to 50µA at light loads while maintaining <20mVP-P output ripple; Pulse Skip mode (MODE pin high) provides lower-noise regulation above ~50mA load. Internal soft-start ramps the 0.611V reference over 1ms, ensuring controlled VOUT rise without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.6V to 5.5V - supports single-cell Li-ion (2.7–4.2V), Li-metal, or two-cell alkaline/NiMH batteries without external LDO pre-regulation. |
| Output Current | 250mA at VIN = 1.8V, VOUT = 1.2V - sufficient for core logic rails in handheld audio/video devices. |
| Switching Frequency | 2.25MHz (±0.45MHz) - enables use of small 2.2–4.7µH shielded inductors and 4.7µF ceramic output capacitors. |
| Quiescent Current | 50µA in Burst Mode, <1µA in shutdown - extends battery runtime in standby/sleep states. |
| Feedback Reference | 0.611V (±12mV over –40°C to 85°C) - sets output voltage via external resistor divider; enables precise 0.85V–1.8V programmable outputs. |
| Efficiency Peak | 93% at VIN = 2.5V, VOUT = 1.5V, ILOAD = 100mA - minimizes thermal stress in space-constrained DFN package. |
| Duty Cycle Range | 0% to 100% - maintains regulation down to VIN ≈ VOUT + ILOAD × RDS(ON), critical for end-of-battery-life operation. |
Pinout & Package
The LTC3549EDCB#TRMPBF is housed in a thermally enhanced 6-lead (2mm × 3mm) plastic DFN package (DCB) with 0.75mm profile and exposed GND pad (Pin 7) that must be soldered to PCB ground for electrical integrity and thermal performance (θJA = 64°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 1.6–5.5V; requires ≥4.7µF ceramic decoupling directly to GND pins 2 and 7. |
| GND (Pin 2) | Signal ground reference | Internal circuit ground node; must be connected to system ground plane. |
| SW (Pin 3) | Switch node | Connects to inductor; carries high di/dt square-wave current; layout requires short, wide trace. |
| MODE (Pin 4) | Operating mode select | Logic-low (<0.3V) enables Burst Mode; logic-high (>1.1V) enables Pulse Skip; floating prohibited. |
| RUN (Pin 5) | Enable/shutdown control | Logic-high (>1.1V) enables regulation; logic-low (<0.3V) disables all circuitry, drawing <1µA. |
| VFB (Pin 6) | Feedback input | Monitors resistive divider output; regulates VOUT to 0.611V; ±30nA bias current enables high-resistor-divider designs. |
| GND (Pin 7) | Exposed thermal pad | Internally connected to GND; mandatory solder connection to PCB ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated P- and N-channel MOSFETs eliminate external Schottky diode, reducing BOM count and improving light-load efficiency by >5%. |
| Burst Mode operation | Reduces quiescent current to 50µA while maintaining <20mVP-P output ripple - ideal for intermittent sensor or RF subsystems. |
| 100% duty cycle capability | Enables dropout operation down to VIN = VOUT, extending usable battery life in Li-ion applications from 4.2V to <1.8V. |
| Ceramic capacitor stability | Control loop independent of output capacitor ESR - allows use of low-ESR, high-density X5R/X7R ceramics for minimal board area and ripple. |
| Internal soft-start | 1ms linear ramp of 0.611V reference ensures monotonic VOUT rise without external timing components or overshoot. |
Applications
| Portable Audio Devices | Digital Cameras |
|---|---|
Use Scenario: Powering DSP, ADC, and flash memory in battery-operated MP3 players and voice recorders. IC Role / Device Role / Timing Role: Primary step-down regulator generating 1.2V/1.5V core voltage from single Li-ion cell. Use Value: 93% peak efficiency and 50µA Burst Mode current maximize playback time; 2.25MHz switching avoids audible noise in audio band. |
Use Scenario: Supplying image sensor interface and microcontroller in compact digital still/video cameras. IC Role / Device Role / Timing Role: High-efficiency DC-DC converter delivering stable 1.8V rail during burst capture sequences. Use Value: 100% duty cycle operation sustains regulation as battery discharges from 4.2V to 2.8V; low ripple prevents image sensor noise coupling. |
| Cellular Handsets | Wearable Electronics |
Use Scenario: Providing always-on logic supply for baseband processors and PMIC subsystems in feature phones. IC Role / Device Role / Timing Role: Standby power regulator operating in Burst Mode between cellular transmission bursts. Use Value: <1µA shutdown current and 50µA light-load current minimize battery drain during idle periods; 2mm × 3mm DFN fits tight RF module layouts. |
Use Scenario: Generating regulated voltage for Bluetooth LE SoCs and environmental sensors in smart bands and hearables. IC Role / Device Role / Timing Role: Ultra-compact synchronous buck supplying 1.2V to low-power MCU from coin-cell or thin-film battery. Use Value: 1.6V minimum input enables direct use of 1.8V alkaline cells; exposed thermal pad aids heat dissipation in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRVR | 3MHz switching frequency, 300mA IOUT, 0.6V reference, 2.05–6.0V input range | Higher input voltage ceiling and output current; less suitable for sub-2V Li-metal cells | Choose when higher IOUT or wider VIN is required; requires re-optimization of inductor/capacitor values. |
| MAX17222ELT+T | 1.2MHz frequency, 500mA IOUT, 0.6V reference, 0.7–5.5V input, integrated compensation | Lower quiescent current (1.5µA) but reduced efficiency below 1VIN; no 100% duty cycle | Prefer for ultra-low-IQ applications where dropout is not critical; verify thermal performance at 250mA in DFN. |
Compared with TPS62231DRVR and MAX17222ELT+T, the LTC3549EDCB#TRMPBF offers superior low-input-voltage operation (1.6V min), guaranteed 100% duty cycle, and tighter reference tolerance (±12mV vs ±20mV), making it uniquely suited for deep-discharge Li-ion and Li-metal battery systems where sustained regulation at end-of-life voltage is essential.
Availability
LTC3549EDCB#TRMPBF is available at Aetrix Electronics and suitable for portable audio devices, digital cameras, and wearable electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3549EDCB#TRMPBF 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. (including former Linear Technology products) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial automation, and communications markets.
The LTC3549EDCB#TRMPBF belongs to Linear's µPower synchronous buck regulator family, designed specifically for energy-constrained, battery-powered portable electronics where efficiency at light loads and ultra-low dropout are critical system requirements.
FAQ
What is the minimum input voltage supported by the LTC3549EDCB#TRMPBF?
The LTC3549EDCB#TRMPBF supports a minimum input voltage of 1.6V, verified across the full –40°C to 85°C operating temperature range. This enables direct regulation from partially discharged Li-metal or two-cell alkaline batteries. Operation below 1.6V is not guaranteed and may result in loss of regulation or increased dropout voltage due to rising RDS(ON) of the internal P-channel MOSFET.
How does the MODE pin affect efficiency and output ripple in the LTC3549EDCB#TRMPBF?
The MODE pin selects between Burst Mode (low) and Pulse Skip mode (high) in the LTC3549EDCB#TRMPBF. In Burst Mode, efficiency exceeds 85% at 1mA load with <20mVP-P ripple; in Pulse Skip mode, ripple drops to <5mVP-P but efficiency falls to ~70% at same load. The trade-off is noise-sensitive applications (e.g., audio codecs) versus ultra-low-power standby.
Can the LTC3549EDCB#TRMPBF operate with ceramic output capacitors only?
Yes, the LTC3549EDCB#TRMPBF is fully stable with ceramic output capacitors - including X5R and X7R dielectrics - due to its ESR-independent control loop. A 4.7µF to 10µF ceramic capacitor is recommended for optimal transient response and minimal footprint. No tantalum or electrolytic capacitor is required for stability.
What is the purpose of the exposed pad (Pin 7) on the LTC3549EDCB#TRMPBF DFN package?
The exposed pad (Pin 7) on the LTC3549EDCB#TRMPBF is electrically and thermally connected to GND. It must be soldered to a dedicated PCB ground plane to ensure proper thermal dissipation (θJA = 64°C/W) and low-impedance grounding for noise-sensitive analog circuits. Omitting this connection risks thermal shutdown and degraded load transient response.
Does the LTC3549EDCB#TRMPBF include overtemperature protection?
Yes, the LTC3549EDCB#TRMPBF incorporates thermal shutdown that activates when junction temperature exceeds approximately 150°C. At that point, both internal MOSFETs turn off and the SW pin becomes high-impedance. Recovery occurs automatically once TJ falls below ~140°C. This protection is independent of the –40°C to 85°C specified operating range and safeguards against sustained overload or poor PCB thermal design.
LTC3549EDCB#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 6-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.611V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 250mA
- Frequency - Switching:
- 2.25MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-DFN (2x3)
LTC3549EDCB#TRMPBF FAQ
1.How can I place an order for LTC3549EDCB#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3549EDCB#TRMPBF 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 LTC3549EDCB#TRMPBF reliable?
The price and inventory of LTC3549EDCB#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3549EDCB#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3549EDCB#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3549EDCB#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3549EDCB#TRMPBF?
LTC3549EDCB#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3549EDCB#TRMPBF 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 LTC3549EDCB#TRMPBF?
For technical support, including LTC3549EDCB#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3549EDCB#TRMPBF requirements.
6.How does Aetrix verify that LTC3549EDCB#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3549EDCB#TRMPBF 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 LTC3549EDCB#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3549EDCB#TRMPBF?
All LTC3549EDCB#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3549EDCB#TRMPBF, 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 LTC3549EDCB#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3549EDCB#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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