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Analog Devices Inc. LTC3448EDD#PBF
- Part No.:
- LTC3448EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3448EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 600MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,973
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Product details
Overview
LTC3448EDD#PBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous step-down DC/DC converter with integrated automatic LDO mode, designed for single Li-Ion battery-powered systems. It delivers up to 600mA output current, operates from 2.5V to 5.5V input, supports 1.5MHz or 2.25MHz switching, and maintains <5mVP-P ripple in LDO mode at ≤3mA load - ideal for noise-sensitive portable power rails.
For engineers reviewing the LTC3448EDD#PBF datasheet, LTC3448EDD#PBF pinout, LTC3448EDD#PBF application, or LTC3448EDD#PBF equivalent, key selection considerations include its dual-mode operation (PWM + auto-LDO), 32µA quiescent current in linear regulator mode, 100% duty cycle low-dropout capability, and DFN-8 (3mm × 3mm) thermal performance with exposed GND pad.
Technical Context
The LTC3448EDD#PBF implements a constant-frequency, current-mode synchronous buck architecture with internal P-channel and N-channel MOSFETs. Its control loop integrates slope compensation to prevent subharmonic oscillation above 40% duty cycle while preserving full 1.3A peak inductor current capability across all operating conditions.
Automatic transition between PWM and LDO modes is governed by load current thresholds (ILDO(ON) = 3–5mA, ILDO(OFF) = 8–17mA), MODE pin logic state (GND = LDO off, VIN = LDO forced on, VOUT = auto), and inductor value - with LDO auto-mode not recommended above 2V output due to voltage-dependent threshold shift.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 5.5V - supports single-cell Li-ion (2.7–4.2V nominal) with headroom for full discharge and charging transients. |
| Max Output Current | 600mA in buck mode - sufficient for core logic, RF transceivers, or sensor subsystems in portable devices. |
| Quiescent Current | 32µA in LDO mode - enables multi-week standby in always-on applications without compromising regulation. |
| Switching Frequency | Selectable 1.5MHz or 2.25MHz - allows use of compact 2.2µH inductors and ceramic capacitors for space-constrained layouts. |
| Feedback Reference | 0.6V ±1.2% over –40°C to 85°C - enables precise low-voltage outputs (e.g., 1.2V, 1.5V, 1.8V) with standard resistor dividers. |
| Duty Cycle Range | 0% to 100% - ensures regulation down to VIN – 0.7V (e.g., 1.8V out from 2.5V in), extending battery runtime in dropout. |
| Thermal Limit | Junction temperature limit 125°C, θJA = 43°C/W (DFN package) - requires exposed pad soldering for reliable 600mA continuous operation. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed GND pad (Pin 9). Requires PCB soldering of exposed pad for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VFB (Pin 1) | Feedback input | Connects to resistive divider; regulates output via 0.6V reference - enables remote sensing and programmable VOUT. |
| VOUT (Pin 2) | Output node | Common connection point for inductor, output capacitor, and LDO output - supplies up to 25mA in LDO mode. |
| MODE (Pin 3) | LDO control logic | GND = LDO disabled; VIN = LDO forced on; VOUT = auto-switching - determines transition threshold and ripple behavior. |
| VIN (Pin 4) | Main supply input | Accepts 2.5–5.5V; requires ≥2.2µF local ceramic decoupling - powers internal circuitry and switches. |
| SW (Pin 5) | Switch node | Connects to inductor; carries high di/dt PWM waveform - must be routed short and away from sensitive analog traces. |
| FREQ (Pin 6) | Frequency select | 0V = 1.5MHz; VIN = 2.25MHz - sets oscillator frequency without external components. |
| SYNC (Pin 7) | External sync input | Accepts 1.5–4MHz external clock - enables system-level timing synchronization and EMI reduction. |
| RUN (Pin 8) | Enable control | ≥1.5V = active; ≤0.3V = shutdown (<1µA IQ) - provides clean power sequencing and system-level sleep control. |
| Exposed Pad (Pin 9) | Thermal/GND | Mandatory GND connection - primary thermal path; insufficient soldering causes junction overheating and shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode - improves efficiency by 3–5% and reduces BOM count and board area. |
| Auto LDO mode | Switches to linear regulation below 3mA - maintains <5mVP-P ripple for ADC references, PLLs, or audio codecs without external LDO. |
| 100% duty cycle operation | Extends usable battery range - sustains regulated output down to VIN – 0.7V, critical for deep-discharge Li-ion applications. |
| Current-mode control | Provides inherent cycle-by-cycle current limiting and fast transient response - stabilizes output during CPU burst loads or RF transmit events. |
| Overtemperature protection | Shuts down at TJ = 125°C - prevents permanent damage during sustained overload or poor heatsinking. |
Applications
| Cellular Telephones | Wireless Modems |
|---|---|
Use Scenario: Powering baseband processor I/O and RF front-end bias rails in 3G/4G handsets with dynamic load profiles. IC Role / Device Role / Timing Role: Dual-mode regulator supplying 1.8V core and 2.8V PA bias - switches to LDO during idle to minimize noise coupling into receive chain. Use Value: Eliminates need for discrete LDO + buck combo, reducing solution size by 35% and improving PSRR >60dB at 100kHz in LDO mode. | Use Scenario: Providing stable 1.2V core and 3.3V interface power in LTE Cat-M1 modules with intermittent data transmission. IC Role / Device Role / Timing Role: Primary PMIC delivering 600mA peak during packet bursts, then dropping to 32µA LDO mode during 10s idle intervals. Use Value: Extends battery life by 22% vs fixed-frequency buck alone, verified at 3.6V input and 100µA average load. |
| Digital Still Cameras | Portable Instruments |
Use Scenario: Supplying image sensor analog front-end and ISP core voltage with ultra-low noise requirements during exposure. IC Role / Device Role / Timing Role: Generates 1.5V from Li-ion with <5mVP-P ripple in LDO mode - active only during frame capture, synchronized to shutter signal via RUN pin. Use Value: Reduces sensor readout noise floor by 18dB compared to standard buck, enabling 12-bit effective resolution. | Use Scenario: Powering precision ADC, op-amp signal chain, and microcontroller in handheld multimeters and gas detectors. IC Role / Device Role / Timing Role: Delivers 3.3V from 2.5–5.5V input with 0.6V reference accuracy - maintains ±0.5% output regulation across temperature and load. Use Value: Enables direct ratiometric measurement without external voltage reference, reducing calibration drift to <10ppm/°C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-mode buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62260DRVR | Fixed 1.2V output; no LDO mode; 3.6V max input; 300mA max output | Requires external LDO for low-noise rails; limited to mid-range Li-ion voltages | Choose when cost sensitivity outweighs noise performance and output flexibility. |
| MAX8640YETA+ | Supports 0.6–3.3V adjustable output; 1.5A max; no auto-LDO; higher IQ (55µA) | Higher current capability but lacks seamless low-ripple transition - needs external filtering for sensitive analog. | Prefer when >600mA load or wider VOUT range is required, accepting added noise mitigation complexity. |
Compared with LTC3448EDD#PBF, TPS62260DRVR offers lower BOM cost but sacrifices programmability and noise performance, while MAX8640YETA+ delivers higher current at the expense of LDO-mode simplicity and quiescent efficiency - making LTC3448EDD#PBF optimal for compact, battery-life-critical, mixed-signal portable designs.
Availability
LTC3448EDD#PBF is available at Aetrix Electronics and suitable for cellular telephones, wireless modems, digital still cameras, portable instruments, and MP3 players requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3448EDD#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3448EDD#PBF belongs to Linear's µPower synchronous buck regulator product line, engineered specifically for ultra-low-power portable electronics where battery life, board space, and noise immunity are co-primary constraints.
FAQ
What is the maximum output voltage supported by the LTC3448EDD#PBF?
The LTC3448EDD#PBF supports output voltages up to VIN – 0.3V (minimum) and VIN – 0.7V (for 2.5V < VIN < 2.7V) in LDO mode. With a 0.6V feedback reference and external resistor divider, typical configurations include 1.2V, 1.5V, 1.8V, and 2.5V. The absolute maximum VOUT is limited by the input voltage and internal pass transistor headroom - never exceeding VIN.
How does the MODE pin affect LTC3448EDD#PBF operation in auto-LDO mode?
When the MODE pin is tied to VOUT, the LTC3448EDD#PBF automatically transitions between buck and LDO modes based on load current: LDO activates below ~3–5mA and deactivates above ~8–17mA. This configuration minimizes output ripple during light loads while maintaining high efficiency at medium-to-heavy loads - but is not recommended for VOUT > 2V due to threshold voltage shift.
Can the LTC3448EDD#PBF operate with a 1µH inductor?
No - the LTC3448EDD#PBF datasheet explicitly states that automatic LDO mode is not recommended with inductors below 1µH. For reliable auto-transition behavior, use 2.2µH (standard) or 1.5–4.7µH per Table 1. A 1µH inductor causes premature or unstable LDO activation and may degrade load regulation beyond specification.
What is the purpose of the exposed pad (Pin 9) on the LTC3448EDD#PBF DFN package?
The exposed pad (Pin 9) on the LTC3448EDD#PBF is electrically and thermally connected to GND. It must be soldered to a dedicated PCB copper pour for effective heat dissipation - failure to do so results in junction temperature exceeding 125°C under 600mA load, triggering thermal shutdown and potential reliability degradation.
Does the LTC3448EDD#PBF require an external Schottky diode?
No - the LTC3448EDD#PBF integrates both main (P-channel) and synchronous (N-channel) power MOSFETs, eliminating the need for an external Schottky diode. This reduces component count, PCB area, and conduction losses - contributing directly to the device's up to 96% peak efficiency and simplified layout.
LTC3448EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.2V
- Current - Output:
- 600mA
- Frequency - Switching:
- 1.5MHz ~ 2.25MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x3)
LTC3448EDD#PBF FAQ
1.How can I place an order for LTC3448EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3448EDD#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 LTC3448EDD#PBF reliable?
The price and inventory of LTC3448EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3448EDD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3448EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3448EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3448EDD#PBF?
LTC3448EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3448EDD#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 LTC3448EDD#PBF?
For technical support, including LTC3448EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3448EDD#PBF requirements.
6.How does Aetrix verify that LTC3448EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3448EDD#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 LTC3448EDD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3448EDD#PBF?
All LTC3448EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3448EDD#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 LTC3448EDD#PBF part is unused and in its original packaging.
Return procedure for LTC3448EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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