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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > DC DC Switching Controllers

Analog Devices Inc. LTC3785EUF#TRPBF

Name: LTC3785EUF#TRPBF
Brand: Analog Devices Inc.
SKU: LTC3785EUF#TRPBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LTC3785EUF#TRPBF

Manufacturer:: Analog Devices Inc.

Category:: DC DC Switching Controllers

Package:: 24-WFQFN Exposed Pad

Datasheet:: LTC3785EUF#TRPBF.pdf

Description:: IC REG CTRLR BUCK-BOOST 24QFN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

LTC3785EUF#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, synchronous, No RSENSE™ buck-boost DC/DC controller IC that regulates output voltage across input voltages both above and below VOUT using a single inductor and four N-channel MOSFETs. It operates from 2.7V to 10V input, delivers up to 10A output current, achieves up to 96% efficiency, and supports programmable switching frequency from 100kHz to 1MHz - ideal for Li-ion-powered portable electronics requiring seamless VIN-to-VOUT transition.

For engineers reviewing the LTC3785EUF#TRPBF datasheet, LTC3785EUF#TRPBF pinout, LTC3785EUF#TRPBF application, or LTC3785EUF#TRPBF equivalent, key selection considerations include its single-inductor buck-boost topology, true output disconnect during shutdown, programmable foldback current limit, Burst Mode® operation for light-load efficiency, and integrated gate drivers with nonoverlap timing control.

Technical Context

The LTC3785EUF#TRPBF implements a voltage-mode, four-switch buck-boost architecture with drain-to-source current sensing (No RSENSE™) for both forward and reverse current limiting. Its control loop uses a 1.225V internal reference and error amplifier output (VC) to modulate duty cycles across three operating regions: buck (VIN > VOUT), buck-boost (VIN ≈ VOUT), and boost (VIN < VOUT), with seamless mode transitions governed by VC voltage thresholds.

It integrates dual floating gate drivers (VBST1/VBST2) for top-side N-MOSFETs A and D, ground-referenced drivers (VDRV) for bottom switches B and C, and independent current sense comparators (ISVIN/ISSW1 for input, ISVOUT/ISSW2 for output) with programmable thresholds via ILSET and CCM pins. Protection includes overvoltage (10% above FB), undervoltage (–6.5% below FB), thermal shutdown, and fault latching with soft-start capacitor-based timing.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	2.7V to 10V - supports single/dual-cell Li-ion, alkaline, or NiMH battery inputs without external level shifting.
Output Current	Up to 10A - enables high-power portable rail generation with proper MOSFET selection and thermal layout.
Switching Frequency	100kHz to 1MHz - set by RT resistor; higher frequencies allow smaller magnetics but increase switching losses.
Efficiency	Up to 96% - achieved with synchronous rectification, low-loss gate drive, and optimized driver impedance (2Ω typical).
Feedback Reference	1.225V ±25mV - sets output voltage via external resistor divider; stable over –40°C to 85°C junction temperature.
Current Limit Threshold	Programmable 20–155mV - via ILSET resistor; enables precise input current limiting with foldback during short-circuit.
Operating Temperature	–40°C to 85°C - specified for industrial-grade performance; junction max 125°C with θJA = 30°C/W on 4-layer board.

Pinout & Package

Package: 24-lead (4mm × 4mm) plastic QFN with exposed pad (Pin 25), RoHS-compliant, lead-free finish. Exposed pad must be soldered to PCB ground for thermal and electrical integrity.

Pin/Terminal	Circuit Role	Design Meaning
RUN/SS (1)	Enable & Soft-Start Control	Internal 1µA charge source; clamps VC during startup; discharges on fault to trigger latch-off or recycle after 32× soft-start time.
VC (2)	Error Amplifier Output	Compensation node for feedback loop; clamped by RUN/SS during soft-start; determines switch duty cycle.
FB (3)	Feedback Input	Connects to resistor divider midpoint; referenced to 1.225V internal reference for output voltage regulation.
VSENSE (4)	OV/UV Sense Input	Monitors output for overvoltage (+10%) and undervoltage (–6.5%) relative to FB; allows external threshold tuning.
ILSET (5)	Current Limit Programming	Resistor to GND sets forward current limit threshold (20–155mV); enables accurate input current regulation.
CCM (6)	Continuous Conduction Mode Select	Low = –15mV reverse limit (ideal diode); high = symmetric forward/reverse limit for full bidirectional operation.
RT (7)	Oscillator Frequency Set	Resistor to GND programs f_OSC ≈ 25 MHz / R_T(kΩ); supports 100kHz–1MHz range with ±15% accuracy.
MODE (8)	Burst Mode Enable	High = variable-frequency Burst Mode (86µA quiescent); low = fixed-frequency operation for low-noise applications.
NC (9)	No Connect	No internal connection; leave unconnected or tie to GND per layout best practice.
ISVOUT (10)	Reverse Current Sense +	Connects to drain of top boost MOSFET (D); used with ISSW2 to detect reverse current flow at output.
VBST2 (11)	Boost Supply for TG2	Floating supply for top boost switch gate driver; swings up to VOUT + VCC – V_diode during operation.
TG2 (12)	Top Gate Driver for Switch D	Drives gate of N-MOSFET D (boost top switch); referenced to SW2; includes 100ns nonoverlap with BG2.
SW2 (13)	Switch Node for Boost Path	Common node of switches C and D; serves as ground reference for TG2/BG2 drivers and ISSW2 sensing.
ISSW2 (14)	Reverse Current Sense –	Connects to source of top boost MOSFET (D); differential pair with ISVOUT detects reverse conduction.
BG2 (15)	Bottom Gate Driver for Switch C	Drives gate of N-MOSFET C (boost bottom switch); referenced to SW2; includes 100ns nonoverlap with TG2.
VDRV (16)	Driver Supply for Grounded Switches	Supplies gate drive for BG1 and BG2; connect directly to VCC; bypass with ≥1µF ceramic near pin.
BG1 (17)	Bottom Gate Driver for Switch B	Drives gate of N-MOSFET B (buck bottom switch); referenced to SW1; includes 100ns nonoverlap with TG1.
ISSW1 (18)	Forward Current Sense –	Connects to source of top buck MOSFET (A); differential pair with ISVIN detects input current during TG1 on-time.
SW1 (19)	Switch Node for Buck Path	Common node of switches A and B; serves as ground reference for TG1/BG1 drivers and ISSW1 sensing.
TG1 (20)	Top Gate Driver for Switch A	Drives gate of N-MOSFET A (buck top switch); referenced to SW1; includes 100ns nonoverlap with BG1.
VBST1 (21)	Boost Supply for TG1	Floating supply for top buck switch gate driver; swings up to VIN + VCC – V_diode during operation.
ISVIN (22)	Forward Current Sense +	Connects to drain of top buck MOSFET (A); used with ISSW1 to detect input current during conduction.
VCC (23)	Internal LDO Output	4.35V regulated supply for logic and drivers; requires ≥4.7µF ceramic bypass to GND; can be bootstrapped from VOUT.
VIN (24)	Main Input Supply	Input to VCC LDO; requires ≥10µF ceramic decoupling close to pin; powers internal regulator and bootstrap circuits.
GND (25)	Ground / Exposed Pad	Electrical and thermal ground connection; exposed pad must be soldered to PCB ground plane for θJA = 30°C/W.

Key Features

Feature	Design Value
Single-inductor buck-boost topology	Enables VIN > VOUT, VIN = VOUT, and VIN < VOUT operation without external power path reconfiguration.
No RSENSE™ current sensing	Eliminates power loss and board space of external sense resistors by using MOSFET R_DS(ON) for current monitoring.
True output disconnect	Shuts off all four switches during shutdown, preventing backfeed and enabling safe hot-swap or battery isolation.
Programmable burst mode	Reduces quiescent current to 86µA at light loads while maintaining regulation; disabled via MODE pin for noise-sensitive systems.
Dual independent current limits	Separate forward (input) and reverse (output) current limiting with foldback during short-circuit or low-VOUT conditions.
Integrated gate drivers with nonoverlap	Prevents shoot-through with 100ns dead time between TG/BG pairs; 2Ω driver impedance ensures fast MOSFET switching.

Applications

Palmtop Computers	Handheld Instruments
Use Scenario: Power management in compact, battery-operated palmtop PCs requiring stable 3.3V or 5V rails from varying Li-ion cell voltages (3.0V–4.2V). IC Role / Device Role / Timing Role: Primary buck-boost controller managing single-inductor conversion with seamless transition between buck and boost modes as battery discharges. Use Value: Eliminates need for separate buck and boost ICs, reducing BOM count and PCB area while maintaining >94% efficiency across full battery range.	Use Scenario: Portable test equipment (e.g., multimeters, oscilloscope probes) needing isolated, low-noise 7V or 9V rails from 2-cell alkaline batteries (1.8V–3.2V). IC Role / Device Role / Timing Role: High-efficiency synchronous buck-boost regulator delivering regulated output despite wide input variation and transient load steps. Use Value: Achieves up to 96% peak efficiency and <50mV load transient response (10mA→2A) without external compensation components.
Wireless Modems	Cellular Telephones
Use Scenario: LTE/5G modem modules in IoT gateways requiring 3.3V or 5V output from USB-powered (5V) or battery-backed (3.6V nominal) sources. IC Role / Device Role / Timing Role: Input-flexible DC/DC controller supporting both step-down (USB) and step-up (battery brownout) operation with programmable frequency to avoid RF band interference. Use Value: Programmable 100kHz–1MHz switching frequency avoids critical 2.4GHz/5GHz bands; Burst Mode reduces standby current to sub-100µA.	Use Scenario: Smartphone auxiliary power rails (e.g., camera flash, RF front-end) powered from main Li-ion battery (2.7V–4.4V) with tight output tolerance. IC Role / Device Role / Timing Role: Precision-regulated buck-boost controller with 1.225V ±25mV reference and overvoltage protection to safeguard sensitive analog/RF circuitry. Use Value: Integrated OV/UV protection triggers immediate shutdown at +10%/–6.5% of VOUT, preventing damage during load dump or cold-junction events.

Palmtop Computers

Handheld Instruments

Use Scenario: Power management in compact, battery-operated palmtop PCs requiring stable 3.3V or 5V rails from varying Li-ion cell voltages (3.0V–4.2V).

IC Role / Device Role / Timing Role: Primary buck-boost controller managing single-inductor conversion with seamless transition between buck and boost modes as battery discharges.

Use Value: Eliminates need for separate buck and boost ICs, reducing BOM count and PCB area while maintaining >94% efficiency across full battery range.

Use Scenario: Portable test equipment (e.g., multimeters, oscilloscope probes) needing isolated, low-noise 7V or 9V rails from 2-cell alkaline batteries (1.8V–3.2V).

IC Role / Device Role / Timing Role: High-efficiency synchronous buck-boost regulator delivering regulated output despite wide input variation and transient load steps.

Use Value: Achieves up to 96% peak efficiency and <50mV load transient response (10mA→2A) without external compensation components.

Wireless Modems

Cellular Telephones

Use Scenario: LTE/5G modem modules in IoT gateways requiring 3.3V or 5V output from USB-powered (5V) or battery-backed (3.6V nominal) sources.

IC Role / Device Role / Timing Role: Input-flexible DC/DC controller supporting both step-down (USB) and step-up (battery brownout) operation with programmable frequency to avoid RF band interference.

Use Value: Programmable 100kHz–1MHz switching frequency avoids critical 2.4GHz/5GHz bands; Burst Mode reduces standby current to sub-100µA.

Use Scenario: Smartphone auxiliary power rails (e.g., camera flash, RF front-end) powered from main Li-ion battery (2.7V–4.4V) with tight output tolerance.

IC Role / Device Role / Timing Role: Precision-regulated buck-boost controller with 1.225V ±25mV reference and overvoltage protection to safeguard sensitive analog/RF circuitry.

Use Value: Integrated OV/UV protection triggers immediate shutdown at +10%/–6.5% of VOUT, preventing damage during load dump or cold-junction events.

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LTC3786EUF#TRPBF	Pin-compatible upgrade with improved current limit accuracy (±3% vs ±10%), lower quiescent current in Burst Mode (45µA), and enhanced thermal performance (θJA = 25°C/W).	Preferred for new designs requiring tighter current regulation or extended battery life in ultra-low-power modes.	Select LTC3786EUF#TRPBF when higher precision current limiting and lower IQ are critical; not drop-in for legacy layouts requiring exact thermal footprint match.
MP2918GL-Z	Monolithic 4-switch buck-boost IC (integrated MOSFETs); 2.8V–22V input; fixed 500kHz frequency; no ILSET or CCM programming; lower max output current (6A).	Suitable for cost-sensitive, space-constrained designs where external MOSFETs are undesirable and 6A output suffices.	Choose MP2918GL-Z only if integrated power stage and simplified layout outweigh need for programmability and 10A capability.

Compared with LTC3786EUF#TRPBF, the LTC3785EUF#TRPBF offers broader frequency tuning and proven field reliability but trades off current limit accuracy and quiescent current; versus MP2918GL-Z, it provides higher output current and full external MOSFET control at the cost of greater design complexity and component count.

Availability

LTC3785EUF#TRPBF is available at Aetrix Electronics and suitable for palmtop computers, handheld instruments, and wireless modems requiring stable component supply, long-term manufacturability, and industrial-temperature grade performance.

Supply support for LTC3785EUF#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 its high-performance power management portfolio with rigorous qualification and long-term product support.

The LTC3785EUF#TRPBF belongs to Linear's No RSENSE™ synchronous controller family, designed specifically for high-efficiency, wide-input-range DC/DC conversion in portable and battery-powered systems where size, efficiency, and seamless VIN-to-VOUT transition are critical.

FAQ

What is the maximum output current supported by the LTC3785EUF#TRPBF?

The LTC3785EUF#TRPBF supports up to 10A of continuous output current when paired with appropriately rated external N-channel MOSFETs, inductors, and thermal management. Actual achievable current depends on layout, ambient temperature, and MOSFET R_DS(ON); the IC itself does not integrate power switches and relies on external components to deliver this current level. Efficiency remains above 90% at 5A with typical Li-ion input conditions.

Does the LTC3785EUF#TRPBF require external current sense resistors?

No, the LTC3785EUF#TRPBF implements No RSENSE™ technology, using the R_DS(ON) of external N-channel MOSFETs for current sensing - eliminating external sense resistors and associated power loss. Forward current is sensed across switch A (ISVIN–ISSW1), and reverse current across switch D (ISVOUT–ISSW2). An optional external resistor may be added for higher accuracy, but is not required for basic operation.

How does the LTC3785EUF#TRPBF handle input voltages both above and below the output voltage?

The LTC3785EUF#TRPBF uses a four-switch synchronous buck-boost topology with automatic mode transition: buck mode (VIN > VOUT) activates switches A/B; boost mode (VIN < VOUT) activates switches C/D; and buck-boost mode (VIN ≈ VOUT) phases in all four switches. The error amplifier output (VC) controls duty cycles across all regions, ensuring continuous regulation without discontinuities or output glitches during transitions.

What protection features are integrated into the LTC3785EUF#TRPBF?

The LTC3785EUF#TRPBF integrates overvoltage protection (10% above FB), undervoltage protection (–6.5% below FB), foldback current limiting, thermal shutdown, and programmable fault latching. During overvoltage, all switching halts until fault clears; during undervoltage, Burst Mode is disabled to maintain regulation. Current limit faults discharge the RUN/SS capacitor to trigger either latch-off or auto-recycle after 32× soft-start time.

Can the LTC3785EUF#TRPBF operate with a 2.7V input supply?

Yes, the LTC3785EUF#TRPBF is fully specified to operate down to 2.7V input voltage across its –40°C to 85°C junction temperature range. At 2.7V input, it can still regulate outputs such as 3.3V or 5V in boost mode, provided external components (MOSFETs, inductor, capacitors) are selected for low-V_GS drive and low R_DS(ON). The internal VCC LDO maintains 4.35V regulation even at minimum VIN, ensuring robust gate drive performance.

LTC3785EUF#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-Up/Step-Down

Output Configuration:: Positive

Topology:: Buck-Boost

Number of Outputs:: 2

Output Phases:: 1

Voltage - Supply (Vcc/Vdd):: 2.7V ~ 10V

Frequency - Switching:: 100kHz ~ 1MHz

Duty Cycle (Max):: 99%

Synchronous Rectifier:: Yes

Clock Sync:: No

Serial Interfaces:: -

Control Features:: Current Limit, Enable, Soft Start

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-QFN (4x4)

LTC3785EUF#TRPBF FAQ

1.How can I place an order for LTC3785EUF#TRPBF through Aetrix?

Please submit a Request for Quotation (RFQ) for LTC3785EUF#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 LTC3785EUF#TRPBF reliable?

The price and inventory of LTC3785EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3785EUF#TRPBF is usually 5 days.

3.What payment methods are accepted for LTC3785EUF#TRPBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3785EUF#TRPBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LTC3785EUF#TRPBF?

LTC3785EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LTC3785EUF#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 LTC3785EUF#TRPBF?

For technical support, including LTC3785EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3785EUF#TRPBF requirements.

6.How does Aetrix verify that LTC3785EUF#TRPBF is sourced from the original manufacturer or authorized distributors?

All LTC3785EUF#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 LTC3785EUF#TRPBF meets industry standards.

7.What is the process for return or replacement of LTC3785EUF#TRPBF?

All LTC3785EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3785EUF#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 LTC3785EUF#TRPBF part is unused and in its original packaging.

Return procedure for LTC3785EUF#TRPBF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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