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Analog Devices Inc. LTC3612IUDC#PBF
- Part No.:
- LTC3612IUDC#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3612IUDC#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:656
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Product details
Overview
LTC3612IUDC#PBF from Analog Devices (formerly Linear Technology) is a 3A, 4MHz monolithic synchronous step-down DC/DC converter in a 20-pin 3mm × 4mm QFN package. It operates from 2.25V to 5.5V input, delivers output down to 0.6V with ±1% accuracy, and supports Burst Mode® operation with 70µA quiescent current-ideal for Li-ion-powered portable systems requiring high efficiency at light loads.
For engineers reviewing the LTC3612IUDC#PBF datasheet, LTC3612IUDC#PBF pinout, LTC3612IUDC#PBF application, or LTC3612IUDC#PBF equivalent, key selection considerations include its programmable switching frequency up to 4MHz, 100% duty cycle low-dropout capability, selectable operating modes (Burst/Pulse-Skipping/Forced Continuous), DDR memory termination support, and thermal performance in the UDC QFN package.
Technical Context
The LTC3612IUDC#PBF uses a constant-frequency current-mode control architecture with internal slope compensation. Its dual MOSFET power stage integrates a P-channel high-side switch (70mΩ typical RDS(ON)) and N-channel synchronous rectifier (45mΩ typical), eliminating external diode requirements.
It features three distinct operating modes selected via the MODE pin: Burst Mode® (70µA IQ), Pulse-Skipping (moderate ripple, higher IQ), and Forced Continuous (lowest output ripple, mandatory for sink-current applications like DDR termination). Frequency is set by RT/SYNC pin-via resistor, external clock (≤4MHz), or internal 2.25MHz oscillator.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A continuous; supports ±1.5A bidirectional current in DDR mode for memory VTT termination. |
| Input Voltage Range | 2.25V to 5.5V; compatible with single-cell Li-ion (2.7–4.2V) and fixed 3.3V/5V rails. |
| Quiescent Current | 70µA in Burst Mode® at no load; ≤1µA in shutdown-enables multi-week battery standby. |
| Feedback Accuracy | ±1% over –40°C to 125°C; ensures stable regulation across industrial temperature range. |
| Switching Frequency | Programmable 300kHz–4MHz; enables use of sub-1µH inductors and minimizes EMI in noise-sensitive systems. |
| Duty Cycle | 100% capability; maintains regulation down to VIN – VOUT ≈ 0.15V at 3A, extending runtime in battery discharge tail. |
| Package Thermal Resistance | θJA = 43°C/W (QFN UDC); exposed PGND pad must be soldered for rated thermal performance. |
Pinout & Package
The LTC3612IUDC#PBF is housed in a thermally enhanced 20-pin 3mm × 4mm plastic QFN (UDC) package with exposed PGND pad (Pin 21) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DDR (Pin 1) | DDR Mode Select | Tying to SVIN enables DDR termination mode; TRACK/SS becomes external reference input. |
| RT/SYNC (Pin 2) | Oscillator Control | Sets frequency via resistor-to-GND, external clock (≤4MHz), or internal 2.25MHz when tied to SVIN. |
| SGND (Pin 3) | Signal Ground | Reference for feedback, compensation, and small-signal circuitry; must connect to PGND at single point. |
| SW (Pins 5,6,11,12) | Switch Node | Connection point for inductor; carries high dv/dt switching waveform-requires tight layout and ground plane. |
| PVIN (Pins 8,9) | Power Input | Supplies P-channel MOSFET source; may be lower than SVIN to reduce gate drive losses. |
| PVIN_DRV (Pin 13) | Gate Driver Supply | Must tie directly to PVIN; powers internal high-side gate driver. |
| SVIN (Pin 14) | Signal Supply | Powers control logic and UVLO comparator; monitored for input undervoltage lockout (1.7V–2.25V threshold). |
| RUN (Pin 15) | Enable Input | Active-high; <0.4V disables regulator and reduces supply current to ≤1µA. |
| PGOOD (Pin 16) | Power Good Output | Open-drain signal indicating VOUT within ±7.5% window; actively pulls down in shutdown to discharge output caps. |
| MODE (Pin 17) | Operating Mode Select | Voltage-controlled: SGND = Burst Mode®, SVIN = Pulse-Skipping, 1.1V–0.58×SVIN = Forced Continuous. |
| VFB (Pin 18) | Feedback Input | Compares resistive divider output against 0.6V internal reference; ±1% accuracy over full temp range. |
| ITH (Pin 19) | Error Amplifier Output | Controls peak inductor current; tie to SVIN to enable internal AVP compensation and simplify loop design. |
| TRACK/SS (Pin 20) | Soft-Start/Tracking/Ref | Enables internal soft-start (tie to SVIN), external timing (RC), or supply tracking; also serves as external reference in DDR mode. |
| PGND (Pin 21) | Power Ground | Exposed pad; connects to N-channel MOSFET source and must be soldered to PCB ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Power Stage | Eliminates external catch diode, reduces conduction loss, and improves efficiency up to 95% at 3A. |
| 100% Duty Cycle Operation | Extends usable battery voltage range by maintaining regulation even when VIN ≈ VOUT, critical for portable system runtime. |
| Three Selectable Operating Modes | Engineers choose trade-off between light-load efficiency (Burst), ripple/noise (Forced Continuous), or transient response (Pulse-Skipping). |
| DDR Memory Termination Support | Provides ±1.5A bidirectional current capability and tracking functionality for DDR2/DDR3 VTT rails with matched slew rates. |
| Adjustable Compensation via ITH Pin | Allows optimization of transient response across wide output capacitor types (ceramic, polymer, tantalum) and load ranges (1mA–3A). |
| Programmable Soft-Start & Tracking | Prevents inrush current and enables coordinated power-up with other rails using external RC or master supply reference. |
Applications
| Point-of-Load Regulation | Portable Computer Systems |
|---|---|
Use Scenario: Local 1.8V/1.2V rail generation for FPGA I/O banks or ASIC cores on dense PCBs with tight space constraints. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated voltage with fast transient response and minimal board area. Use Value: 3A output and 4MHz switching enable sub-1µH inductors and compact 3mm × 4mm footprint-reducing total solution size by >30% vs. legacy 500kHz converters. | Use Scenario: Main system rail (e.g., 1.5V CPU core) and auxiliary rails (e.g., 1.05V GPU) in ultrabooks and 2-in-1 devices powered by single-cell Li-ion. IC Role / Device Role / Timing Role: High-efficiency step-down converter operating in Burst Mode® during sleep states to extend battery life. Use Value: 70µA quiescent current and 100% duty cycle operation maintain regulation down to 2.5V input-extending usable battery capacity by ~12% in discharge tail. |
| DDR Memory Termination | Handheld Devices |
Use Scenario: Active VTT termination for DDR2/DDR3 memory interfaces requiring bidirectional ±1.5A current sourcing/sinking. IC Role / Device Role / Timing Role: DDR-specific buck regulator with TRACK/SS pin enabling precise voltage tracking and fast transient response to memory bus activity. Use Value: Internal DDR mode configures error amplifier for symmetric sourcing/sinking, reducing VTT ripple to <15mVpp under 1.5A step loads-meeting JEDEC DDR3 spec. | Use Scenario: Power management in smartphones, tablets, and medical handhelds where size, efficiency, and thermal performance are critical. IC Role / Device Role / Timing Role: Primary PMIC buck stage supplying application processor, display backlight driver, or RF transceiver subsystem. Use Value: QFN UDC package with exposed PGND pad achieves θJA = 43°C/W-enabling 3A operation without heatsink in 40mm² footprint, meeting IPC-2221 Class 2 thermal limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS543320RHLR | 4A output, 2.95–16V input, integrated FETs, but requires external compensation and lacks DDR mode. | Higher input range suits 12V intermediate bus; no native DDR tracking or bidirectional current capability. | Select when input exceeds 5.5V or >3A output is required; avoid if DDR termination or ultra-low IQ (<100µA) is critical. |
| MP2332HG-P | 3A, 4.5–21V input, 500kHz–2.2MHz freq, 30µA IQ in skip mode-but no Burst Mode®, no DDR mode, no 100% duty cycle. | Better suited for industrial 12V/24V inputs; lacks low-VIN support and battery-friendly features. | Choose for cost-sensitive 12V systems where 2.25V start-up and DDR compliance are unnecessary. |
Compared with TPS543320RHLR and MP2332HG-P, the LTC3612IUDC#PBF uniquely combines single-cell Li-ion compatibility (2.25V min), 70µA Burst Mode® IQ, DDR termination support, and 100% duty cycle-making it optimal for space-constrained, battery-powered applications demanding precision rail control.
Availability
LTC3612IUDC#PBF is available at Aetrix Electronics and suitable for portable computer systems, DDR memory termination, and handheld device power supplies requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature range (–40°C to 125°C).
Supply support for LTC3612IUDC#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 high-performance analog and power management portfolio. Linear's legacy designs emphasize precision, efficiency, and robustness in demanding applications.
The LTC3612IUDC#PBF belongs to Linear's monolithic synchronous buck regulator family, engineered specifically for high-density, battery-operated systems requiring ultra-low quiescent current, wide input range, and advanced mode flexibility-including DDR termination and tracking.
FAQ
What is the maximum switching frequency supported by the LTC3612IUDC#PBF?
The LTC3612IUDC#PBF supports a maximum switching frequency of 4MHz, achievable either by applying an external clock signal to the RT/SYNC pin or by selecting an appropriate resistor value (e.g., ~100kΩ to ground). At 4MHz, the device enables use of very small inductors (e.g., 0.33µH) and ceramic capacitors, minimizing solution footprint while maintaining stability across load and line variations. The internal oscillator defaults to 2.25MHz when RT/SYNC is tied to SVIN.
Does the LTC3612IUDC#PBF support DDR memory termination, and how is it configured?
Yes, the LTC3612IUDC#PBF supports DDR memory termination. To enable DDR mode, tie the DDR pin (Pin 1) to SVIN. This reconfigures the error amplifier for bidirectional current capability (±1.5A) and repurposes the TRACK/SS pin as an external reference input for precise voltage tracking. In this mode, the regulator maintains tight regulation during both sourcing and sinking transients-critical for DDR2/DDR3 VTT compliance-and eliminates need for external op-amps or discrete termination networks.
What is the quiescent current of the LTC3612IUDC#PBF in Burst Mode® operation?
The LTC3612IUDC#PBF draws 70µA typical quiescent current in Burst Mode® operation at no load, with a maximum of 100µA over temperature. This ultra-low IQ is achieved by disabling non-essential internal circuitry during idle periods while maintaining output voltage regulation via periodic switching bursts. In shutdown (RUN = low), supply current drops further to ≤1µA-making the LTC3612IUDC#PBF suitable for battery-powered applications requiring multi-week standby time.
Can the LTC3612IUDC#PBF operate with input voltage as low as 2.25V, and what happens near dropout?
Yes, the LTC3612IUDC#PBF is fully specified to operate from 2.25V to 5.5V input. As input voltage approaches the output voltage, the controller increases duty cycle toward 100%, enabling low-dropout operation. At 100% duty cycle, regulation is maintained by the P-channel MOSFET's RDS(ON) (70mΩ typical) and inductor DCR-allowing continued operation even when VIN – VOUT is as low as ~0.15V at 3A. This extends usable battery life in Li-ion discharge tail without requiring a separate LDO.
What package type and thermal characteristics does the LTC3612IUDC#PBF use?
The LTC3612IUDC#PBF uses a 20-pin 3mm × 4mm plastic QFN package (UDC) with exposed PGND pad (Pin 21). Its thermal resistance is θJA = 43°C/W under standard JEDEC 2-layer board conditions. For rated performance, the exposed pad must be soldered to a minimum 100mm² copper area connected to internal ground planes. This package enables high-power density (3A in 12mm²) while maintaining junction temperature below 125°C at 3A load with 200LFM airflow.
LTC3612IUDC#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN 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):
- 2.25V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 3A
- Frequency - Switching:
- 300kHz ~ 4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LTC3612IUDC#PBF FAQ
1.How can I place an order for LTC3612IUDC#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3612IUDC#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 LTC3612IUDC#PBF reliable?
The price and inventory of LTC3612IUDC#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3612IUDC#PBF is usually 5 days.
3.What payment methods are accepted for LTC3612IUDC#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3612IUDC#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3612IUDC#PBF?
LTC3612IUDC#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3612IUDC#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 LTC3612IUDC#PBF?
For technical support, including LTC3612IUDC#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3612IUDC#PBF requirements.
6.How does Aetrix verify that LTC3612IUDC#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3612IUDC#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 LTC3612IUDC#PBF meets industry standards.
7.What is the process for return or replacement of LTC3612IUDC#PBF?
All LTC3612IUDC#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3612IUDC#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 LTC3612IUDC#PBF part is unused and in its original packaging.
Return procedure for LTC3612IUDC#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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