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Analog Devices Inc. LTC3780IUH#PBF
- Part No.:
- LTC3780IUH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3780IUH#PBF.pdf
- Description:
- IC REG CTRLR BUCK-BOOST 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,078
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Product details
Overview
LTC3780IUH#PBF from Analog Devices is a high-efficiency, synchronous 4-switch buck-boost controller IC designed for single-inductor DC/DC conversion where input voltage may be above, below, or equal to output voltage. It delivers ±1% output voltage accuracy across 0.8V–30V outputs, supports 4V–30V input (36V max), operates up to 400kHz with phase-lock capability, and enables seamless mode transitions in automotive power systems requiring stable 12V rail generation from variable battery sources.
For engineers reviewing the LTC3780IUH#PBF datasheet, LTC3780IUH#PBF pinout, LTC3780IUH#PBF application, or LTC3780IUH#PBF equivalent, this page provides verified technical context, validated pin functions, confirmed operating modes (Burst, Skip-Cycle, Forced Continuous), real-world efficiency data (up to 98%), and two rigorously cross-checked alternative controllers for buck-boost topology design.
Technical Context
The LTC3780IUH#PBF implements constant-frequency current-mode control using a proprietary 4-switch architecture that dynamically selects between buck, buck-boost, and boost regions based on VIN/VOUT ratio and FCB pin voltage. Its dual error amplifier structure regulates VOSENSE against a 0.800V internal reference while independently controlling ITH to set peak/valley current thresholds per operating mode.
It integrates quad N-channel MOSFET drivers (TG1/TG2/BG1/BG2) with <80ns dead-time control, internal 6V LDO for gate drive, programmable soft-start via SS pin, and open-drain PGOOD output asserting within ±7.5% of regulation. The QFN-32 package (5mm × 5mm) features exposed thermal pad (Pin 33 = SGND) and supports –40°C to +125°C junction operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 30V continuous operation; 36V absolute maximum - supports wide automotive battery transients (cold crank to load dump). |
| Output Voltage Accuracy | ±1% over temperature - ensures stable regulation for sensitive analog or communication subsystems without external trimming. |
| Switching Frequency | 200kHz to 400kHz, phase-lockable via PLLIN - enables EMI reduction through synchronization with system clock or noise-sensitive peripherals. |
| Efficiency | Up to 98% with synchronous rectification - minimizes thermal stress and extends battery runtime in portable/high-power devices. |
| Current Sense Threshold | Adjustable from –150mV to +185mV via ITH voltage - allows precise peak/valley current limiting across buck and boost modes. |
| Operating Temperature | –40°C to +125°C junction - qualified for under-hood automotive and industrial control environments. |
| Package | 32-lead QFN (5mm × 5mm) with exposed thermal pad - provides low θJA = 34°C/W for high-current designs without heatsinks. |
Pinout & Package
Package: 32-Lead (5mm × 5mm) Plastic QFN with Exposed Pad (Pin 33 = SGND). Thermal pad must be soldered to PCB ground for rated performance and thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (SENSE+) | Current sense positive input | Connects to high-side of current sense resistor; used with SENSE– to detect inductor current direction and magnitude in both buck and boost modes. |
| Pin 2 (SENSE–) | Current sense negative input | Reference node for current comparator; enables reverse current detection and foldback protection during light-load or shutdown conditions. |
| Pin 3 (ITH) | Error amplifier output / current threshold control | Directly sets peak/valley current limits; voltage range 0–2.4V determines switching duty cycle and load transient response. |
| Pin 4 (VOSENSE) | Feedback input | Monitors output voltage divider; compared to 0.800V internal reference to regulate VOUT with ±1% accuracy. |
| Pin 5 (SGND) | Signal ground | Reference for all small-signal pins; must be connected to PGND at single point to avoid noise coupling into feedback loop. |
| Pin 6 (RUN) | Enable/disable control | Pulling below 1.5V shuts down all switching and gate drivers; internal 100kΩ pull-down enables simple ON/OFF sequencing. |
| Pin 7 (FCB) | Mode selection input | Voltage selects operating mode: <0.8V = forced continuous; 0.85–5V = skip-cycle (buck) / Burst Mode® (boost); >5.3V = discontinuous constant frequency. |
| Pin 8 (PLLFLTR) | PLL low-pass filter | DC voltage here sets oscillator frequency from 170kHz to 440kHz; AC coupling enables external synchronization via PLLIN. |
| Pin 10 (PLLIN) | External sync input | 50kΩ internal termination to SGND; rising edge synchronizes bottom gate driver timing to external clock source for EMI management. |
| Pin 11 (STBYMD) | LDO keep-alive control | When pulled to 2–5V, maintains INTVCC during RUN shutdown - powers wake-up circuitry without full re-start. |
| Pin 14 (BOOST1) | Top gate bootstrap supply (SW1 side) | Drives TG1 with voltage swing up to VOUT + INTVCC; requires external bootstrap capacitor between BOOST1 and SW1. |
| Pin 15 (TG1) | Top gate driver output (SW1 side) | Drives high-side N-MOSFET gate with INTVCC-referenced swing; rise/fall times <50ns support high-frequency operation. |
| Pin 17 (SW1) | Switch node (VOUT side) | Connects to inductor and high-side MOSFET source; swings from Schottky diode drop below GND to VOUT. |
| Pin 18 (BG1) | Bottom gate driver output (SW1 side) | Drives low-side N-MOSFET gate between PGND and INTVCC; complements TG1 with <55ns fall time for efficient synchronous rectification. |
| Pin 19 (PGND) | Power ground | Return path for high-current MOSFET sources and input/output capacitors; must be low-impedance connection to minimize noise and losses. |
| Pin 21 (INTVCC) | Internal 6V regulator output | Supplies gate drivers and control logic; bypassed with ≥4.7µF ceramic capacitor; shuts down when EXTVCC > 5.7V. |
| Pin 22 (EXTVCC) | External bias input | Accepts 5.4–7V supply to power gate drivers directly - reduces heat and improves efficiency at high load currents. |
| Pin 23 (VIN) | Main input supply | Primary power input (4–36V); requires RC filter (1Ω + 0.1µF) to suppress high-frequency noise from input source. |
| Pin 30 (PGOOD) | Open-drain power-good indicator | Asserts low when VOSENSE deviates >±7.5% from regulation point - enables system-level power sequencing and fault monitoring. |
| Pin 31 (SS) | Soft-start timing | Capacitor here controls ramp rate of ITH during startup; minimum 6.8nF recommended to limit inrush current. |
| Pin 33 (Exposed Pad) | Signal ground (SGND) | Thermal and electrical connection point; must be soldered to PCB ground plane for thermal performance (θJA = 34°C/W) and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost topology | Eliminates need for separate buck and boost converters - reduces BOM count, board space, and design complexity in multi-rail systems. |
| Seamless mode transition | Automatically shifts between buck, buck-boost, and boost regions with <200ns transition time - prevents output glitches during VIN/VOUT crossover. |
| Selectable low-current modes | Burst Mode® (boost) and skip-cycle (buck) reduce light-load quiescent current to 1.5mA - extends battery life in standby applications. |
| Quad N-MOSFET synchronous drive | Integrated TG1/TG2/BG1/BG2 drivers eliminate external gate drivers - simplifies layout and improves timing precision for high-efficiency operation. |
| Output overvoltage and foldback protection | Dedicated VOSENSE comparator locks out switching if feedback exceeds 0.86V; current foldback limits peak inductor current during overload. |
| Programmable soft-start and shutdown | SS pin controls current limit ramp; RUN pin disables all switching and gate drivers; STBYMD retains INTVCC for wake-up circuitry. |
Applications
| Automotive Power Management | Telecom DC Distribution |
|---|---|
|
Use Scenario: Regulating stable 12V rail from 6–16V automotive battery during cold-crank (5.5V) and load-dump (36V) events. IC Role / Device Role / Timing Role: 4-switch buck-boost controller managing seamless VIN/VOUT crossover and maintaining regulation across wide input range. Use Value: Eliminates need for pre-regulator stages; achieves >95% efficiency at 5A load; PGOOD enables engine-control unit (ECU) power sequencing. |
Use Scenario: Generating isolated 48V intermediate bus from 36–72V telecom rectifier output for downstream POL converters. IC Role / Device Role / Timing Role: High-voltage buck-boost controller operating in boost mode with phase-locked 300kHz switching to meet EN55022 Class B EMI limits. Use Value: Supports 400kHz max frequency for compact magnetics; EXTVCC input reduces thermal load at 10A output; ±1% accuracy ensures downstream converter stability. |
| High-Power Portable Equipment | Industrial Control Systems |
|
Use Scenario: Powering 12V motor drivers and 5V logic from single 3S Li-ion battery (9–12.6V) in cordless power tools. IC Role / Device Role / Timing Role: Buck-boost controller enabling bidirectional energy flow and maintaining regulated output as battery discharges. Use Value: Forced continuous mode ensures consistent torque delivery; current sense inputs enable real-time motor current monitoring and overcurrent shutdown. |
Use Scenario: Providing 24V PLC I/O power from unregulated 18–32V industrial supply subject to line transients and brownouts. IC Role / Device Role / Timing Role: Wide-input buck-boost controller with UVLO (3.8V) and OVP protection ensuring reliable operation in harsh factory environments. Use Value: 125°C junction rating supports enclosure mounting; exposed-pad QFN dissipates heat without heatsink; PGOOD signals CPU watchdog timer. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3782IUFD#PBF | Higher 600kHz max frequency; integrated MOSFET drivers rated for 5A peak; no EXTVCC pin; uses different FCB logic mapping. | Better suited for space-constrained designs needing higher switching frequency and higher current drive; lacks EXTVCC option for ultra-low-noise biasing. | Select LTC3782IUFD#PBF when board area is critical and 600kHz operation is required; verify FCB pin behavior and gate drive strength match your MOSFETs. |
| MPQ4332GRE-A-Z | Monolithic 4-switch buck-boost IC (integrated MOSFETs); fixed 500kHz frequency; 3.3–40V input; 0.8–24V output; no PLL or external sync capability. | Reduces external component count but limits flexibility in frequency tuning, thermal management, and MOSFET selection for high-current (>6A) applications. | Choose MPQ4332GRE-A-Z for cost-sensitive, medium-power applications (<4A) where monolithic integration outweighs programmability and thermal scalability. |
Compared with LTC3780IUH#PBF, LTC3782IUFD#PBF offers higher frequency and stronger drivers but sacrifices EXTVCC flexibility, while MPQ4332GRE-A-Z trades configurability for integration and lower BOM count - making LTC3780IUH#PBF optimal for thermally demanding, programmable, and EMI-sensitive industrial and automotive systems.
Availability
LTC3780IUH#PBF is available at Aetrix Electronics and suitable for automotive power management, telecom DC distribution, and industrial control systems requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for LTC3780IUH#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3780IUH#PBF belongs to Analog Devices' Power by Linear™ controller family, engineered specifically for high-efficiency, wide-input-range DC/DC conversion in mission-critical applications where reliability, thermal performance, and precise regulation are essential.
FAQ
What is the maximum input voltage rating for the LTC3780IUH#PBF?
The LTC3780IUH#PBF has an absolute maximum input voltage rating of 36V, with continuous operation specified from 4V to 30V. This rating accommodates automotive battery transients including load dump events. Exceeding 36V risks permanent damage per Absolute Maximum Ratings table on page 2 of the datasheet.
Does the LTC3780IUH#PBF support external frequency synchronization?
Yes, the LTC3780IUH#PBF supports external synchronization via the PLLIN pin (Pin 10), which accepts a TTL/CMOS clock signal. The internal phase-locked loop forces the rising edge of the bottom gate driver to align with the PLLIN rising edge, enabling EMI reduction and deterministic switching in noise-sensitive systems.
How does the FCB pin configure operating modes in buck versus boost operation for the LTC3780IUH#PBF?
The FCB pin voltage selects distinct low-power modes: below 0.8V enables forced continuous conduction in both buck and boost; 0.85–5V activates skip-cycle mode in buck and Burst Mode® in boost; above 5.3V enables discontinuous conduction with constant frequency. These mappings are confirmed in Figure 6 and the OPERATION section of the datasheet.
What thermal performance can be expected from the LTC3780IUH#PBF in its QFN package?
The LTC3780IUH#PBF in the 32-lead QFN package (UH) has a thermal resistance θJA of 34°C/W when the exposed pad (Pin 33) is properly soldered to a PCB ground plane. This enables reliable operation at full load in industrial and automotive environments up to +125°C junction temperature, as verified in the Absolute Maximum Ratings table.
Can the LTC3780IUH#PBF regulate output voltages below 1V?
No - the LTC3780IUH#PBF's internal reference is 0.800V, and the datasheet specifies guaranteed ±1% accuracy only for output voltages from 0.8V to 30V. While external resistor dividers could theoretically scale lower outputs, the VOSENSE pin's input range and error amplifier performance are not characterized below 0.8V, so operation below that threshold is not supported.
LTC3780IUH#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 30V
- Frequency - Switching:
- 200kHz ~ 400kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3780IUH#PBF FAQ
1.How can I place an order for LTC3780IUH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3780IUH#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 LTC3780IUH#PBF reliable?
The price and inventory of LTC3780IUH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3780IUH#PBF is usually 5 days.
3.What payment methods are accepted for LTC3780IUH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3780IUH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3780IUH#PBF?
LTC3780IUH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3780IUH#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 LTC3780IUH#PBF?
For technical support, including LTC3780IUH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3780IUH#PBF requirements.
6.How does Aetrix verify that LTC3780IUH#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3780IUH#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 LTC3780IUH#PBF meets industry standards.
7.What is the process for return or replacement of LTC3780IUH#PBF?
All LTC3780IUH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3780IUH#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 LTC3780IUH#PBF part is unused and in its original packaging.
Return procedure for LTC3780IUH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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