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Analog Devices Inc. LTC3852IUDD#TRPBF
- Part No.:
- LTC3852IUDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3852IUDD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,264
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Product details
Overview
LTC3852IUDD#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency, current-mode synchronous step-down DC/DC controller with integrated charge pump. It operates from a low 2.7V–5.5V input to power its internal logic and gate drivers, supports up to 38V main input (VIN2), delivers ±1.25% output voltage accuracy, enables phase-lockable switching up to 750kHz, and features power-good monitoring and adjustable soft-start - ideal for lithium-ion powered systems requiring high-efficiency 1.2V/20A conversion.
For engineers reviewing the LTC3852IUDD#TRPBF datasheet, LTC3852IUDD#TRPBF pinout, LTC3852IUDD#TRPBF application, or LTC3852IUDD#TRPBF equivalent, key selection criteria include its dual-input architecture (VIN1 + VIN2), RSENSE/DCR current sensing, Burst Mode®/pulse-skipping/continuous mode selection via MODE/PLLIN, 99% duty cycle capability, and 24-lead 3mm × 5mm QFN package with exposed thermal pad.
Technical Context
The LTC3852IUDD#TRPBF implements a constant-frequency current-mode control loop with slope compensation, where peak inductor current is set by the ITH voltage and compared against sensed voltage across SENSE+/SENSE–. Its onboard charge pump doubles VIN1 (2.7V–5.5V) to generate a regulated 4.8V–5.05V VPUMP supply, enabling direct drive of logic-level N-channel MOSFETs without external bias rails.
Three operating modes are selected via MODE/PLLIN: forced continuous conduction (tied to INTVCC), pulse-skipping (tied to GND2), or Burst Mode® (resistor-biased to INTVCC). The RUN pin provides precision enable/disable with 1.1V–1.35V threshold, while TRACK/SS combines soft-start ramping (1μA internal current) and output voltage tracking functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Controller Input Range (VIN2) | 4V to 38V - supports wide-range industrial and battery-fed buck stages without pre-regulation. |
| Charge Pump Input (VIN1) | 2.7V to 5.5V - enables self-powered operation from single-cell Li-ion or 3.3V system rails. |
| Output Voltage Accuracy | ±1.25% over temperature - ensures stable regulation for sensitive digital loads like FPGAs and processors. |
| Switching Frequency Range | 250kHz to 750kHz (phase-lockable) - balances efficiency, size, and EMI in compact power designs. |
| Max Duty Cycle | 99% - allows ultra-low dropout operation, critical for high-current, low-VOUT applications. |
| Power Good Threshold | ±10% of regulated VOUT - provides reliable system sequencing and fault detection with 17μs mask timer. |
| Current Sense Threshold | 40mV to 68mV (adjustable via ITH) - supports precise current limiting and foldback during short-circuit events. |
Pinout & Package
Package: 24-lead (3mm × 5mm) plastic QFN with exposed thermal pad (Pin 25 = GND), rated for –40°C to +125°C junction temperature. Requires soldering of exposed pad to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE– (1), SENSE+ (2) | Current sense differential inputs | Kelvin connection to sense resistor or DCR network; enables accurate peak-current mode control and foldback. |
| PGOOD (3) | Open-drain power-good indicator | Asserts low when VOUT is within ±10% of target after 17μs delay - used for system enable sequencing. |
| GND2 (4) | Buck controller small-signal ground | Reference for feedback, compensation, and current sense; must be Kelvin-connected to CINTVCC (–) and layout-sensitive. |
| BG (5) | Bottom gate driver output | Drives gate of synchronous N-MOSFET between GND2 and INTVCC; 1.1Ω pull-down / 2.1Ω pull-up resistance. |
| C+ (7), C– (8) | Flying capacitor terminals | Interface with external 2.2μF ceramic flying cap; forms switched-capacitor doubler for VPUMP generation. |
| SHDN (10) | Active-low charge pump shutdown | CMOS input (VIH = 1.3V, VIL = 0.4V); disables charge pump only - does not affect buck controller if RUN is active. |
| VIN1 (12) | Charge pump input supply | Accepts 2.7V–5.5V; powers internal doubler - independent of VIN2, enabling split-rail architectures. |
| VPUMP (13) | Regulated charge pump output | Stable ~5V rail (4.8–5.05V at 1mA); powers INTVCC, TG/BG drivers, and logic - eliminates need for LDO. |
| INTVCC (14) | Internal gate drive and logic supply | Derived from VPUMP; requires ≥2.2μF low-ESR bypass to GND2; supplies up to 50mA peak current. |
| VIN2 (15) | Main controller input supply | 4V–38V input to buck stage; powers high-side switch path and sets maximum output power capability. |
| BOOST (16) | Floating bootstrap supply node | Connects to boost capacitor (+) terminal; swings from ~INTVCC–0.7V to VIN1+INTVCC - enables high-side N-MOSFET drive. |
| TG (17) | Top gate driver output | Floating driver referenced to SW node; 1.2Ω pull-down / 2.2Ω pull-up; drives gate of high-side N-MOSFET. |
| SW (18) | Switch node | Connection point between TG, BG, inductor, and high-side MOSFET drain - critical for layout EMI and efficiency. |
| MODE/PLLIN (19) | Mode select & external sync input | Selects Burst Mode® (50k–250kΩ to INTVCC), pulse-skipping (GND2), or forced CCM (INTVCC); accepts 250–750kHz external clock. |
| FREQ/PLLFLTR (20) | Oscillator frequency set / PLL filter | Resistor-to-GND2 sets nominal frequency (205–810kHz); also serves as PLL loop filter when synchronized externally. |
| RUN (21) | Precision enable input | 1.1V–1.35V rising threshold with 130mV hysteresis; internal 2μA pull-up - enables clean startup and sequencing. |
| TRACK/SS (22) | Soft-start & tracking input | 1μA internal current charges external capacitor; regulates VFB to TRACK/SS voltage during ramp - enables controlled startup or supply tracking. |
| ITH (23) | Error amplifier output & current limit control | Analog control voltage (0.4V–1.6V) setting peak inductor current threshold; also used for current foldback and mode transitions. |
| VFB (24) | Feedback input | Compares against 0.8V internal reference; connects to resistive divider on VOUT - determines regulated output voltage. |
| GND (25, Exposed Pad) | Common ground & thermal path | Must be soldered to PCB plane; serves as return for all grounds (GND1, GND2) and primary thermal dissipation path. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated charge pump | Doubles 2.7V–5.5V VIN1 to regulated 5V VPUMP - eliminates external bias supply and supports logic-level MOSFETs. |
| Triple operating mode selection | Hardware-selectable Burst Mode®, pulse-skipping, or forced continuous conduction - optimizes light-load efficiency vs. ripple trade-offs. |
| Adjustable soft-start & tracking | Single-pin TRACK/SS with 1μA internal current - enables programmable voltage ramp or ratiometric tracking of master supply. |
| Reverse current prevention | Active during normal operation and disabled only during soft-start - protects input source and improves transient response. |
| 99% maximum duty cycle | Enables ultra-low dropout operation - critical for high-current, low-VOUT applications such as core voltage regulation. |
| Phase-lockable oscillator | 250kHz–750kHz range with external synchronization via MODE/PLLIN - simplifies multi-rail EMI reduction and timing coordination. |
Applications
| Lithium-Ion Powered Devices | Distributed DC Power Systems |
|---|---|
|
Use Scenario: Portable medical monitors powered by single-cell Li-ion (3.0V–4.2V) requiring stable 1.2V/20A for FPGA processing. IC Role / Device Role / Timing Role: Primary step-down controller managing high-current core rail; charge pump enables direct use of VIN1 as battery input. Use Value: Eliminates need for intermediate 5V LDO, reduces component count, and maintains >90% efficiency across 1A–20A load range. |
Use Scenario: Telecom shelf with multiple 12V/48V backplane inputs feeding isolated point-of-load converters. IC Role / Device Role / Timing Role: Intermediate bus converter stepping 12V down to 3.3V/15A for downstream POL modules. Use Value: 38V VIN2 rating and 99% duty cycle support high-efficiency conversion even under brownout conditions. |
| General Purpose 3.3V Systems | Industrial Embedded Controllers |
|
Use Scenario: Industrial PLC CPU board with 3.3V system rail powering ARM Cortex-A series SoC and DDR memory. IC Role / Device Role / Timing Role: Main 3.3V regulator using VIN1=3.3V and VIN2 tied to same rail - self-powered configuration per Figure 1a. Use Value: Integrated charge pump removes dependency on external 5V supply, simplifying BOM and improving reliability. |
Use Scenario: Harsh-environment motor drive control board requiring –40°C to +125°C operation and robust start-up sequencing. IC Role / Device Role / Timing Role: High-reliability buck controller with precision RUN threshold, PGOOD monitoring, and thermal-aware design. Use Value: Guaranteed –40°C to +125°C operation, 130mV RUN hysteresis, and exposed-pad thermal management ensure long-term field stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8640S | Monolithic 42V input, 6A buck regulator with integrated MOSFETs; no external charge pump needed but lower current capability. | Best for space-constrained designs where 6A suffices and integration outweighs flexibility of discrete FET selection. | Choose LT8640S when board area is critical and 6A output meets requirements; LTC3852IUDD#TRPBF preferred for >10A or custom FET optimization. |
| MP2918 | 36V input, current-mode controller with integrated gate drivers but no charge pump - requires external 5V/12V bias for logic-level FETs. | Suitable for systems with existing auxiliary bias rails; lacks VIN1-doubling capability for true single-supply operation. | Choose MP2918 when auxiliary 5V is available and cost sensitivity favors competitive pricing; LTC3852IUDD#TRPBF enables true low-VIN autonomy. |
Compared with LT8640S and MP2918, the LTC3852IUDD#TRPBF uniquely combines low-input charge pump autonomy, 38V VIN2 capability, and 20A scalability - making it optimal for high-current, battery-fed, or split-rail industrial buck designs where flexibility and efficiency across wide input ranges are essential.
Availability
LTC3852IUDD#TRPBF is available at Aetrix Electronics and suitable for lithium-ion powered devices, distributed DC power systems, and industrial embedded controllers requiring stable component supply, extended temperature operation, and long-term production continuity.
Supply support for LTC3852IUDD#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC3852IUDD#TRPBF belongs to Linear's high-performance power controller family, designed specifically for efficient, flexible, and robust DC/DC conversion in battery-powered, industrial, and telecom applications demanding precision regulation and wide input range operation.
FAQ
What is the operating temperature range for the LTC3852IUDD#TRPBF?
The LTC3852IUDD#TRPBF is specified for –40°C to +125°C junction temperature operation and is guaranteed across this full range. Its 24-lead QFN package with exposed thermal pad enables effective heat dissipation in high-power-density applications, and the device includes thermal protection circuitry to prevent damage under overload conditions. This makes the LTC3852IUDD#TRPBF suitable for automotive under-hood, industrial motor control, and outdoor telecom equipment deployments.
How does the charge pump in the LTC3852IUDD#TRPBF function and what input voltage does it require?
The LTC3852IUDD#TRPBF integrates a switched-capacitor charge pump that doubles VIN1 (2.7V–5.5V) to generate a regulated ~5V VPUMP supply. It uses an internal 1.2MHz oscillator and external flying capacitor (CFLY) to achieve this, eliminating the need for an external bias rail. The charge pump is independent of VIN2, allowing split-rail configurations - for example, VIN1 = 3.3V (battery) and VIN2 = 24V (main bus) - while still driving logic-level MOSFETs efficiently.
Can the LTC3852IUDD#TRPBF operate without an external current sense resistor?
Yes, the LTC3852IUDD#TRPBF supports both RSENSE and DCR current sensing. When using DCR sensing, the SENSE+ and SENSE– pins interface with a resistor-capacitor network across the inductor winding to derive a voltage proportional to inductor current. This eliminates power loss and board space associated with a discrete sense resistor, while maintaining accurate current-mode control and foldback protection - provided the DCR network is properly compensated per the datasheet guidelines.
What are the key differences between Burst Mode®, pulse-skipping, and forced continuous conduction modes on the LTC3852IUDD#TRPBF?
The LTC3852IUDD#TRPBF offers three distinct light-load efficiency strategies: Burst Mode® minimizes quiescent current by disabling switching until output droop triggers restart (best for ultra-low IQ); pulse-skipping skips cycles while maintaining fixed frequency (lower noise than Burst Mode®); forced continuous conduction maintains switching regardless of load (lowest output ripple, highest light-load loss). Selection is made via MODE/PLLIN pin configuration - each mode is hardware-selectable with no firmware required.
Is the LTC3852IUDD#TRPBF pin-compatible with other members of the LTC385x family?
No, the LTC3852IUDD#TRPBF is not pin-compatible with LTC3851 or LTC3853. While sharing functional similarities, the LTC3852 has a unique 24-pin QFN layout optimized for dual-input operation and integrated charge pump control - including dedicated C+, C–, VIN1, and VPUMP pins absent in earlier variants. Pinouts differ significantly; migration requires PCB redesign. Always verify pin mapping and reference design schematics before substitution.
LTC3852IUDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- 235kHz ~ 750kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (3x5)
LTC3852IUDD#TRPBF FAQ
1.How can I place an order for LTC3852IUDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3852IUDD#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 LTC3852IUDD#TRPBF reliable?
The price and inventory of LTC3852IUDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3852IUDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3852IUDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3852IUDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3852IUDD#TRPBF?
LTC3852IUDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3852IUDD#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 LTC3852IUDD#TRPBF?
For technical support, including LTC3852IUDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3852IUDD#TRPBF requirements.
6.How does Aetrix verify that LTC3852IUDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3852IUDD#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 LTC3852IUDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3852IUDD#TRPBF?
All LTC3852IUDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3852IUDD#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 LTC3852IUDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3852IUDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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