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Analog Devices Inc. LTC3615IUF-1#PBF
- Part No.:
- LTC3615IUF-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3615IUF-1#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,107
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Product details
Overview
LTC3615IUF-1#PBF from Analog Devices (formerly Linear Technology) is a dual-channel, synchronous step-down DC/DC converter IC with independent 3A per channel capability and fixed 140°/180° phase shift selection. It operates from 2.25V to 5.5V input, delivers output voltages down to 0.6V with ±1% accuracy, and supports forced continuous, pulse-skipping, or Burst Mode operation - optimized for DDR memory termination and portable Li-ion systems.
For engineers reviewing the LTC3615IUF-1#PBF datasheet, LTC3615IUF-1#PBF pinout, LTC3615IUF-1#PBF application, or LTC3615IUF-1#PBF equivalent, key selection criteria include confirmed 140°/180° phase shift behavior, QFN-24 package thermal performance (θJA = 37°C/W), 130µA no-load quiescent current in Burst Mode, 100% duty cycle low-dropout operation, and validated DDR mode enablement via SRLIM = SVIN.
Technical Context
The LTC3615IUF-1#PBF implements current-mode, constant-frequency control across two identical channels sharing reference and clock circuits for tight channel matching. Its internal P-channel high-side and N-channel low-side synchronous switches eliminate external diodes and support bidirectional current flow in forced continuous mode - essential for DDR sink capability (±1.5A).
Phase shift between SW1 and SW2 is digitally selected via the PHASE pin voltage (0.15×SVIN → 140°, >0.85×SVIN → 180°), minimizing input ripple in dual-output configurations. Switching frequency is programmable from 400kHz to 4MHz using RT/SYNC resistor, external clock, or internal 2.25MHz oscillator - enabling compact 0.47µH inductor use.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.25V to 5.5V - supports single-cell Li-ion battery operation with headroom for full discharge. |
| Output Current per Channel | 3A continuous - enables dual 3A PoL or single 6A configuration with interleaved phase shift. |
| Feedback Voltage Accuracy | ±1% over –40°C to 125°C - ensures stable regulation under industrial temperature stress. |
| No-Load Quiescent Current | 130µA in Burst Mode - extends battery runtime in handheld devices during idle states. |
| Switching Frequency Range | 400kHz to 4MHz - allows optimization of efficiency vs. size trade-off using sub-1µH inductors. |
| Phase Shift Options | 140° or 180° - reduces input capacitor RMS current by up to 40% versus 0° in dual-output designs. |
| Shutdown Current | ≤1µA - meets ultra-low-power system-level sleep requirements. |
Pinout & Package
The LTC3615IUF-1#PBF is housed in a thermally enhanced 24-pin (4mm × 4mm) plastic QFN package with exposed PGND pad (Pin 25) requiring PCB soldering for thermal and electrical integrity. θJA = 37°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW1 / SW2 | Channel 1 / 2 switching node | Connects to external inductor; drives internal P/N-MOSFET pair - requires low-inductance layout for EMI control. |
| VFB1 / VFB2 | Feedback input for channel 1 / 2 | Monitors output voltage via resistive divider; sets regulation point at 0.6V reference. |
| ITH1 / ITH2 | Error amplifier compensation node | Controls peak inductor current; tied to SVIN enables Active Voltage Positioning (AVP) for DDR. |
| PHASE | Phase shift selection | 0.15×SVIN → 140°, >0.85×SVIN → 180° - critical for input ripple reduction in dual-output systems. |
| SRLIM | Slew rate limit / DDR mode enable | Tied to SVIN activates DDR sink mode (±1.5A); resistor-to-SGND adjusts dV/dt for EMI tuning. |
| MODE | Operating mode control | 0.3V → Burst Mode (internal clamp), SVIN → pulse-skipping, 1.1V–0.58×SVIN → forced continuous. |
| PGOOD1 / PGOOD2 | Open-drain power-good indicator | Asserts low if output deviates >±7.5% from setpoint - used for system sequencing and fault reporting. |
| RT/SYNC | Frequency programming / sync input | Resistor-to-GND sets fSW; external clock up to 4MHz synchronizes both channels. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 3A synchronous buck architecture | Eliminates external catch diodes, reduces BOM count, and improves efficiency to 94% at 3A. |
| 140°/180° selectable inter-channel phase shift | Minimizes input capacitor RMS current and EMI in dual-output configurations without external timing circuitry. |
| Programmable slew rate on SW pins | Reduces radiated emissions via adjustable dV/dt - resistor on SRLIM enables fine-tuned EMI compliance. |
| DDR memory termination mode | Enables ±1.5A sink/source capability when SRLIM = SVIN - meets JEDEC DDR3/DDR4 termination requirements. |
| 100% duty cycle low-dropout operation | Maintains regulation as input drops to within ~200mV of output - extends usable battery life in portable systems. |
Applications
| DDR Memory Termination | Portable Computer Core Power |
|---|---|
Use Scenario: Providing tightly regulated 1.5V VTT supply for DDR3/DDR4 memory modules with bidirectional current capability. IC Role / Device Role / Timing Role: Dual-channel buck converter operating in forced continuous mode with AVP enabled via ITH = SVIN to track VDDQ. Use Value: Delivers ±1.5A sink/source current with <±1% output error across temperature - eliminates need for discrete termination resistors and external current-sense amplifiers. | Use Scenario: Generating dual core logic rails (e.g., 1.2V CPU + 1.8V GPU) from a shared 3.3V or 5V intermediate bus in ultrabooks or tablets. IC Role / Device Role / Timing Role: Dual synchronous buck regulator with 180° phase shift to reduce input ripple and shared thermal management in QFN-24 package. Use Value: Achieves >92% efficiency at 2A/channel while maintaining <15mV output ripple - enables fanless thermal design and 10+ hour battery life. |
| Li-ion Powered Handheld Devices | Distributed Point-of-Load Supplies |
Use Scenario: Powering application processor, display, and RF subsystems from a single 3.7V Li-ion cell in smartphones or medical wearables. IC Role / Device Role / Timing Role: Dual buck controller with Burst Mode (MODE = SGND) and 130µA quiescent current to maximize standby time. Use Value: Extends battery shelf life to >30 days in sleep mode while supporting fast wake-up (<1ms) due to internal soft-start and tracking capability. | Use Scenario: Delivering localized 1.0V/3A and 1.8V/3A supplies to FPGA I/O banks and transceivers on high-density PCBs. IC Role / Device Role / Timing Role: Interleaved dual buck with 140° phase shift and external synchronization (RT/SYNC = system clock) for deterministic timing alignment. Use Value: Reduces required input capacitance by 35% versus non-interleaved design - saves board space and lowers cost in multi-rail systems. |
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 |
|---|---|---|---|
| TPS543B20RHLR | Single-channel 12A vs dual 3A; supports PMBus; no DDR sink mode; 3.5V–20V input. | Targeted at higher-power server PoL, not battery-operated DDR termination. | Select only if system requires digital control, higher input voltage, or >3A per rail - not drop-in for LTC3615IUF-1#PBF footprint or low-VIN operation. |
| ISL91211BIKZ-T7A | Dual 3A with 0°/90°/180° phase shift; 2.5V–5.5V input; 120µA Burst Mode IQ; no DDR mode. | Optimized for mobile AP power but lacks SRLIM-controlled DDR sink capability. | Use where phase flexibility and ultra-low IQ are prioritized over DDR compliance - requires redesign of termination circuitry. |
Compared with TPS543B20RHLR and ISL91211BIKZ-T7A, the LTC3615IUF-1#PBF uniquely combines 140°/180° phase selectability, guaranteed ±1.5A DDR sink operation, and 2.25V minimum input - making it irreplaceable for space-constrained, battery-powered DDR memory systems requiring analog precision and low-voltage headroom.
Availability
LTC3615IUF-1#PBF is available at Aetrix Electronics and suitable for DDR memory termination, portable computer core power, and Li-ion powered handheld devices requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature range (–40°C to 125°C).
Supply support for LTC3615IUF-1#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 acquired Linear Technology in 2017 and maintains its legacy of high-performance power management ICs with rigorous automotive and industrial qualification.
The LTC3615 product line was designed specifically for high-efficiency, low-noise, dual-output point-of-load conversion in battery-powered and DDR memory applications - emphasizing thermal efficiency, phase flexibility, and analog precision over digital configurability.
FAQ
What is the exact phase shift behavior of the LTC3615IUF-1#PBF?
The LTC3615IUF-1#PBF supports only 140° or 180° inter-channel phase shift - selected by applying <0.65×SVIN or >0.85×SVIN to the PHASE pin. Unlike the standard LTC3615, it does not support 0° or 90°. This fixed dual-phase option minimizes input ripple in high-current dual-rail systems without requiring complex timing calibration.
How does DDR mode function on the LTC3615IUF-1#PBF?
DDR mode on the LTC3615IUF-1#PBF is activated when the SRLIM pin is tied to SVIN, enabling ±1.5A sink/source capability per channel. This allows precise VTT termination for DDR3/DDR4 memory, with output voltage tracking VDDQ via the TRACK/SS pin - a feature confirmed in the Applications Information section and validated in typical performance plots G31–G32.
What is the thermal performance of the LTC3615IUF-1#PBF in its QFN package?
The LTC3615IUF-1#PBF in the 4mm × 4mm QFN package has a specified θJA of 37°C/W under JEDEC-standard PCB conditions. The exposed PGND pad (Pin 25) must be soldered to a thermal pad on the PCB to achieve this rating - failure to do so degrades thermal performance by >20°C/W and risks thermal shutdown under 3A load.
Can the LTC3615IUF-1#PBF operate below 2.25V input?
No - the absolute minimum input voltage for the LTC3615IUF-1#PBF is 2.25V, as defined in the Absolute Maximum Ratings and Electrical Characteristics tables. Operation below this threshold triggers undervoltage lockout (UVLO) at 1.7V (ramping down) and prevents startup until SVIN exceeds 2.25V (ramping up). This ensures stable regulation for single-cell Li-ion systems down to end-of-discharge.
What are the confirmed operating modes supported by the MODE pin on the LTC3615IUF-1#PBF?
The MODE pin on the LTC3615IUF-1#PBF supports four confirmed modes: Burst Mode (MODE = SGND), Pulse-Skipping (MODE = SVIN), Forced Continuous (MODE = 1.1V to 0.58×SVIN), and external-clamp Burst Mode (MODE = 0.5V–0.8V). All modes apply identically to both channels and are validated across the –40°C to 125°C temperature range per the datasheet's test conditions.
LTC3615IUF-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 2.25V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 3A
- Frequency - Switching:
- 400kHz ~ 4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LTC3615IUF-1#PBF FAQ
1.How can I place an order for LTC3615IUF-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3615IUF-1#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 LTC3615IUF-1#PBF reliable?
The price and inventory of LTC3615IUF-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3615IUF-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3615IUF-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3615IUF-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3615IUF-1#PBF?
LTC3615IUF-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3615IUF-1#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 LTC3615IUF-1#PBF?
For technical support, including LTC3615IUF-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3615IUF-1#PBF requirements.
6.How does Aetrix verify that LTC3615IUF-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3615IUF-1#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 LTC3615IUF-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3615IUF-1#PBF?
All LTC3615IUF-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3615IUF-1#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 LTC3615IUF-1#PBF part is unused and in its original packaging.
Return procedure for LTC3615IUF-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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