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Analog Devices Inc. LTC3612IUDC
- Part No.:
- LTC3612IUDC
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3612IUDC.pdf
- Description:
- IC REG BUCK ADJ 3A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,304
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Product details
Overview
LTC3612IUDC 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 datasheet, LTC3612IUDC pinout, LTC3612IUDC application, or LTC3612IUDC equivalent, this page provides verified functional identity, validated thermal and electrical specs, confirmed pin roles for UDC-package layout, and two rigorously cross-checked alternative parts for point-of-load and DDR termination designs.
Technical Context
The LTC3612IUDC implements a constant-frequency, current-mode control architecture with programmable switching frequency up to 4MHz via RT/SYNC pin. Its dual MOSFET power stage features 70mΩ P-channel top switch and 45mΩ N-channel synchronous bottom switch, enabling 100% duty cycle low-dropout operation and ±1.5A bidirectional current capability in DDR mode.
It supports four selectable operating modes - Burst Mode® (internal/external clamp), pulse-skipping, and forced continuous - controlled by the MODE pin voltage. Internal compensation and Active Voltage Positioning (AVP) are enabled when ITH is tied to SVIN, while TRACK/SS enables soft-start, tracking, or external reference functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A continuous; supports ±1.5A sinking in DDR mode for memory termination compliance. |
| 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® sleep; ≤1µA in shutdown - extends battery runtime in standby. |
| Feedback Accuracy | ±1% over –40°C to 125°C - ensures stable regulation across industrial temperature range. |
| Switching Frequency | Programmable 300kHz–4MHz; internal default 2.25MHz - enables use of sub-1µH inductors. |
| Output Voltage Range | 0.6V to VIN - supports core logic, DDR, and low-voltage ASIC supplies. |
| Package | 20-pin 3mm × 4mm QFN (UDC); exposed PGND pad requires PCB soldering for θJA = 43°C/W. |
Pinout & Package
Package: 20-lead (3mm × 4mm) plastic QFN (UDC), thermally enhanced with exposed PGND pad (Pin 21) that must be soldered to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DDR (Pin 1) | DDR mode select | Tie to SVIN to enable DDR termination mode; enables TRACK/SS as external reference input. |
| RT/SYNC (Pin 2) | Oscillator control | Set frequency via resistor-to-GND, synchronize to external clock ≤4MHz, or tie to SVIN for 2.25MHz internal oscillator. |
| SGND (Pin 3) | Signal ground reference | Return for feedback divider, compensation network, and small-signal circuitry; connect to PGND at single point. |
| SW (Pins 5,6,11,12) | Switch node | Connection point for inductor; ties to drains of internal P- and N-channel MOSFETs - high dv/dt node requiring tight layout. |
| PVIN (Pins 8,9) | Main power input | Supplies P-channel top switch; may be lower than SVIN to reduce gate drive loss in dropout conditions. |
| PVIN_DRV (Pin 13) | Gate driver supply | Must be connected directly to PVIN - powers internal level-shifting drivers for top MOSFET. |
| SVIN (Pin 14) | Control circuit supply | Powers bias, error amplifier, and logic; monitored by UVLO (2.25V threshold) - defines minimum system start-up voltage. |
| RUN (Pin 15) | Enable control | Active-high; pull low to enter shutdown (<1µA IQ); open or tie to SVIN for normal operation. |
| PGOOD (Pin 16) | Power-good indicator | Open-drain output asserting when VFB is within ±7.5% of setpoint for >105µs - used for sequencing and fault reporting. |
| 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; ±30nA input bias minimizes divider error. |
| ITH (Pin 19) | Error amplifier output | Controls peak inductor current; tie to SVIN to enable internal compensation and AVP for dynamic load response. |
| TRACK/SS (Pin 20) | Soft-start/tracking/reference | Enables internal soft-start (tie to SVIN), external timing (RC network), or supply tracking - also functions as external reference in DDR mode. |
| PGND (Pin 21) | Power ground | Source connection for N-channel bottom switch; exposed pad must be soldered for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous buck topology | Eliminates external catch diode; achieves up to 95% efficiency and reduces board area vs. asynchronous designs. |
| Burst Mode® operation | 70µA IQ at no load with regulated output - preserves battery life in always-on portable devices without sacrificing regulation. |
| 100% duty cycle capability | Enables ultra-low dropout operation down to VIN – (RDS(ON)_top × IOUT), extending runtime in deep discharge states. |
| DDR memory termination support | ±1.5A bidirectional current delivery with dedicated DDR pin and tracking - meets JEDEC SSTL-15/18 requirements. |
| Adjustable compensation via ITH | External RC network on ITH allows transient response optimization across wide output capacitor types and load ranges. |
| Four selectable operating modes | Mode pin voltage selects optimal trade-off between light-load efficiency (Burst), EMI control (forced continuous), or ripple performance (pulse-skipping). |
Applications
| Point-of-Load Regulation | DDR Memory Termination |
|---|---|
|
Use Scenario: Regulating 1.2V/1.8V core voltage for FPGA or SoC in compact handheld device with single Li-Ion cell. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering 3A continuous current with fast transient response to dynamic processor loads. Use Value: 95% peak efficiency and 70µA Burst Mode® IQ extend battery life; 4MHz switching enables <1µH inductor for minimal footprint. |
Use Scenario: Providing bidirectional ±1.5A termination for DDR3/DDR4 memory bus in laptop mainboard. IC Role / Device Role / Timing Role: DDR-compliant termination regulator using dedicated DDR pin and TRACK/SS for VTT tracking. Use Value: Eliminates need for discrete op-amp + MOSFET termination circuit; supports active-high/low VTT with precise 0.6V reference. |
| Portable Computer Systems | Handheld Medical Devices |
|
Use Scenario: Powering display backlight LED driver IC and USB PHY from shared 3.3V rail in ultrabook design. IC Role / Device Role / Timing Role: Secondary buck converter generating clean, low-noise 1.8V supply with forced continuous mode to avoid RF interference. Use Value: Switching noise suppressed via synchronization to system clock; PGOOD enables safe power sequencing with other rails. |
Use Scenario: Supplying 0.9V analog sensor front-end and 1.2V microcontroller core in battery-operated glucose meter. IC Role / Device Role / Timing Role: Low-quiescent, high-accuracy regulator ensuring stable ADC reference and MCU operation during intermittent use. Use Value: ±1% VFB accuracy maintains measurement integrity; shutdown current <1µA prevents battery drain during long idle periods. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54332DR | 3A, 5.5V max input, fixed 500kHz–2.5MHz sync range; no DDR mode or Burst Mode®; higher 120µA IQ. | Lacks bidirectional current and DDR-specific tracking; suitable for general-purpose POL but not memory termination. | Select when cost sensitivity outweighs DDR support and ultra-low IQ is unnecessary. |
| MP2315GJ-Z | 3A, 6V max input, 2.2MHz fixed frequency; no MODE-selectable operation modes; 350µA typical IQ in skip mode. | No programmable frequency, no external soft-start, no AVP or DDR features; simpler control but less flexible. | Choose for space-constrained consumer applications where full feature set is unused and BOM cost is critical. |
Compared with TPS54332DR and MP2315GJ-Z, the LTC3612IUDC uniquely combines DDR termination capability, 70µA Burst Mode® IQ, and 4MHz programmability - making it the only option among the three qualified for high-efficiency, low-noise, bidirectional memory supply designs across –40°C to 125°C.
Availability
LTC3612IUDC is available at Aetrix Electronics and suitable for point-of-load regulation, DDR memory termination, and portable computer systems requiring stable component supply, extended temperature operation, and long-term industrial availability.
Supply support for LTC3612IUDC 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 power management portfolio with rigorous automotive and industrial qualification standards.
The LTC3612IUDC belongs to Linear's monolithic synchronous buck regulator family, designed specifically for high-efficiency, low-noise, and thermally constrained point-of-load applications in portable and embedded systems.
FAQ
What is the maximum supported switching frequency for the LTC3612IUDC?
The LTC3612IUDC supports an externally programmable switching frequency up to 4MHz via the RT/SYNC pin - either through a resistor-to-ground, synchronization to an external clock signal, or by tying RT/SYNC to SVIN for the internal 2.25MHz oscillator. This high-frequency capability enables use of compact sub-1µH inductors and reduces output ripple in space-constrained designs.
Does the LTC3612IUDC support DDR memory termination, and how is it configured?
Yes, the LTC3612IUDC supports DDR memory termination with ±1.5A bidirectional current capability. To enable DDR mode, tie the DDR pin (Pin 1) to SVIN; this reconfigures TRACK/SS (Pin 20) as an external reference input for VTT tracking. The device then regulates VTT to half the TRACK/SS voltage, meeting JEDEC SSTL-15/18 specifications without external components.
What is the guaranteed operating temperature range for the LTC3612IUDC part number?
The LTC3612IUDC is specified and guaranteed over the industrial temperature range of –40°C to +125°C. This is confirmed in the order information table, where LTC3612IUDC#TRPBF is explicitly listed with "–40°C to 125°C" under Temperature Range - distinct from the E-grade (0°C to 85°C) and H-grade (–40°C to 150°C) variants.
How does Burst Mode® operation reduce quiescent current in the LTC3612IUDC?
In Burst Mode® operation, the LTC3612IUDC disables internal circuits between switching bursts at light loads, reducing quiescent current to just 70µA while maintaining regulated output voltage. The MODE pin tied to SGND activates internal clamping; the burst comparator monitors the ITH pin voltage and triggers sleep mode when average inductor current exceeds load demand - minimizing switching losses without compromising regulation.
Can the LTC3612IUDC operate in 100% duty cycle mode, and what is its practical benefit?
Yes, the LTC3612IUDC supports true 100% duty cycle operation, allowing the top P-channel MOSFET to remain continuously on when VIN approaches VOUT. This low-dropout behavior extends usable battery life in deeply discharged states - for example, sustaining 1.8V output down to ~2.0V input - by minimizing conduction loss through the RDS(ON) of the internal switch rather than relying on inefficient linear regulation.
LTC3612IUDC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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 (3x3)
LTC3612IUDC FAQ
1.How can I place an order for LTC3612IUDC through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3612IUDC 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 reliable?
The price and inventory of LTC3612IUDC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3612IUDC is usually 5 days.
3.What payment methods are accepted for LTC3612IUDC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3612IUDC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3612IUDC?
LTC3612IUDC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3612IUDC 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?
For technical support, including LTC3612IUDC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3612IUDC requirements.
6.How does Aetrix verify that LTC3612IUDC is sourced from the original manufacturer or authorized distributors?
All LTC3612IUDC 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 meets industry standards.
7.What is the process for return or replacement of LTC3612IUDC?
All LTC3612IUDC units undergo pre-shipment inspection (PSI). If there is an issue with LTC3612IUDC, 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 part is unused and in its original packaging.
Return procedure for LTC3612IUDC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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