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Analog Devices Inc. LTC3549EDCB#TRPBF
- Part No.:
- LTC3549EDCB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 6-WFDFN Exposed Pad
- Datasheet:
-
LTC3549EDCB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,979
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Product details
Overview
LTC3549EDCB#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous buck regulator optimized for ultra-low-input-voltage battery-powered systems. It delivers up to 250mA output current from 1.6V–5.5V input, features 2.25MHz fixed-frequency current-mode control, 0.611V reference voltage, and 100% duty-cycle capability for low-dropout operation in single-cell Li-ion or dual-alkaline applications.
For engineers reviewing the LTC3549EDCB#TRPBF datasheet, LTC3549EDCB#TRPBF pinout, LTC3549EDCB#TRPBF application, or LTC3549EDCB#TRPBF equivalent, key selection criteria include light-load efficiency in Burst Mode (50µA IQ), ceramic-capacitor stability, internal soft-start (1ms), overtemperature protection, and DFN-6 (2mm × 3mm) thermal performance with exposed GND pad.
Technical Context
The LTC3549EDCB#TRPBF employs constant-frequency current-mode control with internal P-channel main and N-channel synchronous MOSFETs - eliminating external diode requirements. Its 2.25MHz oscillator enables compact 2.2–4.7µH inductor selection and supports stable regulation with ≥4.7µF ceramic output capacitors.
Burst Mode operation reduces quiescent current to 50µA at light loads by gating switching cycles, while pulse-skip mode (enabled via MODE pin >1.1V) maintains lower output ripple (<20mVP-P) above ~50mA load. Internal soft-start ramps the 0.611V reference linearly over 1ms, and overtemperature protection disables both switches above ~150°C junction temperature.
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 2-cell alkaline/NiMH (2.4–3.2V) without external LDO pre-regulation. |
| Output Current | 250mA @ VIN=1.8V, VOUT=1.2V - sufficient for microcontrollers, sensors, and RF front-ends in portable devices. |
| Switching Frequency | 2.25MHz (±0.45MHz) - enables use of small 2–4.7µH shielded inductors and avoids AM radio band interference. |
| Quiescent Current | 50µA in Burst Mode, <1µA in shutdown - extends battery runtime in standby or intermittent wake-up systems. |
| 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% @ VOUT=1.2V, IOUT=100mA, VIN=2.5V - minimizes thermal rise in space-constrained DFN-6 package. |
| Duty Cycle Max | 100% - sustains regulation down to VIN ≈ VOUT + IOUT×RDS(ON)P, critical for end-of-battery-life operation. |
| Thermal Resistance | θJA = 64°C/W - requires PCB-exposed GND pad soldering for reliable operation at full load in 75°C ambient. |
Pinout & Package
Package: 6-lead DFN (2mm × 3mm, 0.75mm height) with exposed GND pad (Pin 7), RoHS-compliant and lead-free (#PBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 1.6–5.5V; requires local 4.7µF ceramic decoupling to GND (Pins 2 & 7) to suppress high-frequency switching noise. |
| GND (Pin 2) | Signal ground reference | Must be connected to system ground plane; forms return path for feedback and control circuitry. |
| SW (Pin 3) | Switch node | Connects to inductor; carries high dv/dt square wave; layout must minimize loop area to reduce EMI. |
| MODE (Pin 4) | Operating mode select | Ground → Burst Mode (50µA IQ); >1.1V → Pulse-Skip Mode (lower ripple, higher light-load IQ). |
| RUN (Pin 5) | Enable/disable control | >1.1V → active regulation; <0.3V → shutdown (<1µA supply current); must not float. |
| VFB (Pin 6) | Feedback input | Monitors resistive divider output; regulates VOUT to 0.611V; ±30nA bias current enables high-value resistors. |
| GND (Pin 7) | Exposed thermal pad | Electrically and thermally GND; must be soldered to ≥200mm² PCB copper pour for thermal relief and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated P- and N-channel MOSFETs eliminate Schottky diode loss and board area; RDS(ON)P = 0.56Ω, RDS(ON)N = 0.4Ω (DD package, 100mA). |
| Burst Mode® operation | Reduces average input current to 50µA at light loads while maintaining regulation; prevents audible coil whine in audio-sensitive designs. |
| Ceramic capacitor compatibility | Stable with ≥4.7µF X5R/X7R ceramics on input/output - enables ultra-compact footprint and <20mVP-P ripple without ESR dependency. |
| Internal soft-start | 1ms linear ramp of 0.611V reference ensures controlled VOUT rise without external components; prevents inrush current into large output caps. |
| Overtemperature protection | Thermal shutdown activates >125°C junction; both switches disable and SW pin floats high-impedance to prevent uncontrolled discharge. |
| Low dropout capability | 100% duty cycle allows VIN-to-VOUT differential as low as IOUT×RDS(ON)P - extends usable battery life below 1.8V. |
Applications
| Wearable Health Monitor | Bluetooth Low Energy Module |
|---|---|
Use Scenario: Continuous ECG sensing powered by coin-cell or thin-film battery with multi-day runtime. IC Role / Device Role / Timing Role: Primary step-down regulator supplying 1.2V/1.5V to ultra-low-power MCU and analog front-end. Use Value: 50µA Burst Mode IQ and 100% duty cycle sustain operation down to 1.6V input, directly enabling single-CR2032 use without boost converter. | Use Scenario: BLE SoC (e.g., nRF52832) in compact IoT sensor node with intermittent transmission bursts. IC Role / Device Role / Timing Role: Efficient 3.3V or 1.8V rail generator from 2xAA alkaline stack (2.4–3.2V). Use Value: 2.25MHz switching avoids interference with 2.4GHz RF band; ceramic-stable output ensures clean digital supply during TX/RX transitions. |
| Industrial Wireless Sensor Node | Portable Medical Diagnostic Device |
Use Scenario: LoRaWAN edge node operating in remote locations with primary alkaline batteries. IC Role / Device Role / Timing Role: Main power converter for microcontroller, LoRa transceiver, and environmental sensors. Use Value: Wide 1.6–5.5V input range accommodates fresh-to-dead battery voltage swing; overtemperature protection ensures reliability in sealed enclosures. | Use Scenario: Handheld glucose meter or pulse oximeter requiring FDA-grade reliability and long shelf life. IC Role / Device Role / Timing Role: Precision 1.2V/1.5V supply for ADC, op-amps, and display driver with minimal thermal drift. Use Value: 0.611V reference with ±0.4%/V line regulation and <0.5% load regulation ensures consistent measurement accuracy across battery discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 2.25MHz, 300mA, 1.8–6.5V input; 55µA IQ in PWM mode only; no Burst Mode; requires external compensation. | Higher input range but lacks true ultralow-IQ Burst Mode; less suitable for coin-cell multi-year applications. | Select when input exceeds 5.5V or when fixed 3.3V/1.8V outputs suffice without resistor programming. |
| MAX17222ETA+ | 1.8MHz, 500mA, 0.4–5.5V input; 300nA shutdown, 2.5µA IQ in skip mode; integrated inductor option available. | Lower minimum input enables direct supercapacitor backup; higher peak current supports larger loads. | Select for sub-1V input scenarios or when board space constraints favor module-level integration. |
Compared with TPS62231DRYR and MAX17222ETA+, the LTC3549EDCB#TRPBF uniquely combines 1.6V start-up, 50µA Burst Mode IQ, programmable output via 0.611V reference, and DFN-6 thermal performance - making it optimal for cost-sensitive, battery-limited portable medical and wearable designs where runtime and size are critical.
Availability
LTC3549EDCB#TRPBF is available at Aetrix Electronics and suitable for wearable health monitors, Bluetooth Low Energy modules, industrial wireless sensor nodes, portable medical diagnostic devices, and compact consumer electronics requiring stable component supply across extended production lifecycles.
Supply support for LTC3549EDCB#TRPBF 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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3549EDCB#TRPBF belongs to ADI's legacy Linear Technology µPower DC/DC converter family, designed specifically for energy-constrained portable and battery-operated systems demanding high efficiency at ultralow input voltages and minimal quiescent current.
FAQ
What is the minimum input voltage required for startup of the LTC3549EDCB#TRPBF?
The LTC3549EDCB#TRPBF guarantees operation down to 1.6V input, and its absolute maximum rating allows VIN as low as –0.3V. Startup is functional at 1.6V across the full –40°C to 85°C temperature range, enabling direct use with aging alkaline or deeply discharged Li-ion cells. Below 1.6V, regulation ceases but the device remains undamaged.
How does the MODE pin affect efficiency and output ripple in the LTC3549EDCB#TRPBF?
When the MODE pin is grounded, the LTC3549EDCB#TRPBF enters Burst Mode, achieving 50µA quiescent current and peak efficiency >90% at light loads (<10mA), but with higher output ripple due to gated switching. When MODE is pulled >1.1V, it operates in pulse-skip mode - increasing light-load IQ to ~95µA but reducing ripple to <20mVP-P and improving RF compatibility for sensitive analog circuits.
Can the LTC3549EDCB#TRPBF operate with ceramic capacitors on both input and output?
Yes - the LTC3549EDCB#TRPBF is explicitly characterized and stable with ceramic capacitors. A minimum 4.7µF X5R/X7R ceramic is recommended for COUT, and ≥4.7µF ceramic is required for CIN. Its current-mode architecture does not rely on output capacitor ESR for stability, unlike older voltage-mode regulators, enabling ultra-low-ripple, compact designs.
What thermal considerations apply to the LTC3549EDCB#TRPBF in high-ambient or dropout conditions?
In dropout (e.g., VIN = 1.6V, VOUT = 1.2V, IOUT = 250mA), power dissipation is dominated by P = IOUT² × RDS(ON)P. At 75°C ambient and 0.8Ω RDS(ON)P, PD ≈ 50mW. With θJA = 64°C/W, junction temperature rises to ~78°C - well below the 125°C limit. Full thermal performance requires soldering the exposed GND pad (Pin 7) to ≥200mm² PCB copper.
Is the LTC3549EDCB#TRPBF pin-compatible with other members of the LTC354x family?
No - the LTC3549EDCB#TRPBF uses a unique 6-lead DFN (DCB) package with specific pinout (VIN, GND, SW, MODE, RUN, VFB, Exposed GND). Other LTC354x variants like LTC3547 (QFN-16) or LTC3548 (QFN-16) differ in pin count, function allocation, and package dimensions; direct PCB replacement is not possible without layout revision.
LTC3549EDCB#TRPBF 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#TRPBF FAQ
1.How can I place an order for LTC3549EDCB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3549EDCB#TRPBF 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#TRPBF reliable?
The price and inventory of LTC3549EDCB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3549EDCB#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3549EDCB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3549EDCB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3549EDCB#TRPBF?
LTC3549EDCB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3549EDCB#TRPBF 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#TRPBF?
For technical support, including LTC3549EDCB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3549EDCB#TRPBF requirements.
6.How does Aetrix verify that LTC3549EDCB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3549EDCB#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3549EDCB#TRPBF?
All LTC3549EDCB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3549EDCB#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LTC3549EDCB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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