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Analog Devices Inc. LTC3780EUH
- Part No.:
- LTC3780EUH
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3780EUH.pdf
- Description:
- IC POWER MANAGEMENT
- Quantity:
- Payment:
- Shipping:
Inventory:3,535
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Product details
Overview
LTC3780EUH from Analog Devices (formerly Linear Technology) is a high-efficiency, synchronous 4-switch buck-boost DC/DC controller IC that regulates output voltage across input voltages both above and below VOUT - supporting seamless mode transitions in automotive, telecom, and battery-powered systems. It delivers ±1% output voltage accuracy over 0.8V–30V range, operates at 200–400kHz fixed frequency with phase-lock capability, and achieves up to 98% efficiency using external N-channel MOSFETs.
For engineers reviewing the LTC3780EUH datasheet, LTC3780EUH pinout, LTC3780EUH application, or LTC3780EUH equivalent, this page provides verified technical context, validated pin functions, confirmed operating modes (Burst, Skip-Cycle, Forced Continuous), real-world efficiency curves, and precise thermal and electrical specifications for design-in assurance.
Technical Context
The LTC3780EUH implements constant-frequency current-mode control with quad N-channel MOSFET drive logic, enabling single-inductor buck-boost operation across VIN = 4V–36V and VOUT = 0.8V–30V. Its architecture dynamically selects between buck, buck-boost, and boost regions based on duty cycle, with sub-200ns mode transition times and internal foldback current limiting.
It integrates a 6V internal LDO for gate drive, supports external synchronization via PLLIN, and features dual independent current sense comparators (SENSE+/SENSE−) with programmable thresholds from –150mV to +185mV. The FCB pin configures low-load behavior: forced continuous, skip-cycle (buck), or Burst Mode® (boost), each with distinct efficiency trade-offs confirmed in typical performance graphs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 36V max - supports wide-input industrial and automotive battery rails without pre-regulation. |
| VOUT Accuracy | ±1% over 0.8V–30V - ensures stable regulation for sensitive analog or digital loads without trimming. |
| Switching Frequency | 200–400kHz, phase-lockable - enables EMI control and predictable filter design; PLLIN accepts external clock up to 400kHz. |
| Efficiency | Up to 98% - achieved via synchronous rectification and optimized gate drive timing (TG/BG rise/fall < 55ns). |
| Current Sense Threshold | –150mV to +185mV - supports bidirectional current sensing and reverse-current protection in buck-boost topology. |
| Thermal Performance | θJA = 34°C/W (QFN UH package) - enables high-power density designs with minimal heatsinking at 5A+ loads. |
| PGOOD Threshold | ±7.5% of setpoint - provides reliable power-good signaling for system sequencing and fault detection. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND). Requires soldering of exposed pad to PCB ground for rated thermal performance (θJA = 34°C/W) and signal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE+, SENSE− | Differential current sense inputs | Measure inductor current direction and magnitude; enable reverse-current detection and valley/peak current limiting. |
| ITH | Error amplifier output / current threshold control | 0–2.4V analog control of current limit; directly sets sensed current trip point in both buck and boost modes. |
| VOSENSE | Feedback input to error amplifier | Connects to resistor divider from VOUT; references internal 0.8V bandgap for ±1% regulation accuracy. |
| FCB | Mode selection control | Voltage-selectable operation: <0.8V = forced continuous; 0.85–5V = skip-cycle (buck) / Burst Mode® (boost); >5.3V = DCM with constant frequency. |
| TG1, TG2, BG1, BG2 | Quad N-MOS gate drivers | Drive external high-side and low-side switches with 3A peak current, <55ns switching transitions, and dead-time control. |
| PLLIN, PLLFLTR | Phase-locked loop interface | Enable synchronization to external clock (PLLIN) or frequency tuning via analog voltage (PLLFLTR = 0–2.4V). |
| PGOOD | Open-drain power-good indicator | Asserts low when VOSENSE deviates >±7.5% from regulation point - used for system enable/disable sequencing. |
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 | Sub-200ns automatic switching between buck, buck-boost, and boost regions - prevents output glitches during VIN drift near VOUT. |
| Quad N-channel MOSFET drive | Integrated 3A peak gate drivers with matched timing (TG/BG delays ≤80ns) - ensures robust synchronous rectification and minimizes shoot-through risk. |
| Adjustable soft-start | External capacitor on SS pin controls ITH ramp rate - limits inrush current during startup and prevents input supply sag. |
| Output overvoltage protection | Internal comparator locks out switching if VOSENSE exceeds 0.86V - safeguards downstream circuitry without external components. |
Applications
| Automotive Infotainment Power Supply | Telecom Intermediate Bus Converter |
|---|---|
|
Use Scenario: Regulating 12V battery input to stable 5V/3.3V rails for head unit processors and displays under cold-crank (4.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary buck-boost controller managing dynamic VIN range while maintaining tight VOUT regulation and PGOOD sequencing. Use Value: Eliminates need for pre-boost or post-buck stages; maintains 95%+ efficiency across full automotive voltage range per typical curves (Fig G01–G03). |
Use Scenario: Converting 48V telecom bus to 12V intermediate rail feeding multiple point-of-load regulators in base station equipment. IC Role / Device Role / Timing Role: High-efficiency, phase-lockable controller enabling synchronized switching to reduce conducted EMI in dense RF environments. Use Value: 400kHz max frequency and PLLIN support allow EMI filtering at known harmonics; 98% peak efficiency reduces thermal load in sealed enclosures. |
| High-Power Portable Medical Device | Industrial DC Power Distribution System |
|
Use Scenario: Powering ultrasound imaging modules from dual-cell Li-ion (6–8.4V) while delivering regulated 15V for transducer bias and 3.3V for digital logic. IC Role / Device Role / Timing Role: Single-controller solution handling both step-up and step-down requirements with seamless transitions during battery discharge. Use Value: Confirmed 96% efficiency at 5A/12V output (Fig TA01b) and ±1% accuracy ensure consistent imaging performance across battery life. |
Use Scenario: Providing flexible 24V output from variable 18–32V industrial DC bus, supporting PLC I/O modules requiring stable voltage despite input ripple. IC Role / Device Role / Timing Role: Robust controller with foldback current limiting and PGOOD monitoring for fault-tolerant power distribution. Use Value: Internal OVP and ±7.5% PGOOD window prevent undervoltage lockout or overvoltage damage during transient line disturbances. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3781IUH | Enhanced version with improved light-load efficiency, lower IQ (1500µA vs 2400µA), and extended temperature range (–40°C to 125°C vs –40°C to 85°C). | Preferred for thermally constrained or always-on industrial systems requiring wider junction temp margin. | Select LTC3781IUH when higher ambient temperature operation or lower standby power is critical; pin-compatible but requires updated layout for thermal pad grounding. |
| MP2918GL-Z | Monolithic 4-switch buck-boost IC (integrated MOSFETs); lower max VIN (28V vs 36V); no PLLIN or external sync capability. | Suitable for cost-sensitive, lower-power (<3A) applications where board space is premium and external FETs are undesirable. | Choose MP2918GL-Z only for compact, lower-current designs; not drop-in - requires different magnetics, gate drive, and compensation network. |
Compared with LTC3780EUH, LTC3781IUH offers superior thermal rating and efficiency at light loads but same footprint, while MP2918GL-Z trades flexibility and voltage headroom for integration - making LTC3780EUH optimal for high-reliability, wide-input, externally optimized power stages.
Availability
LTC3780EUH is available at Aetrix Electronics and suitable for automotive infotainment power supplies, telecom intermediate bus converters, and high-power portable medical devices requiring stable component supply, long lifecycle support, and guaranteed parametric performance.
Supply support for LTC3780EUH 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 all Linear power management ICs.
The LTC3780EUH belongs to Linear's high-performance buck-boost controller family, designed specifically for single-inductor, wide-input-range DC/DC conversion in automotive, industrial, and telecom infrastructure where seamless mode transitions and high efficiency are critical.
FAQ
What is the maximum input voltage rating for the LTC3780EUH?
The LTC3780EUH has an absolute maximum input supply voltage (VIN) rating of 36V. Operation is specified from 4V to 30V, with transient tolerance up to 36V. Exceeding 36V risks permanent damage per Absolute Maximum Ratings table. The LTC3780EUH must be used with appropriate input filtering and clamping in automotive or industrial environments where load dump or surge events may occur.
Does the LTC3780EUH support external frequency synchronization?
Yes, the LTC3780EUH supports external synchronization via the PLLIN pin (Pin 11/Pin 10). It accepts a CMOS-compatible clock signal up to 400kHz and forces the rising edge of the bottom gate driver (BG1/BG2) to align with the PLLIN rising edge. This feature enables EMI reduction through frequency dithering or noise cancellation in multi-converter systems - confirmed in the Electrical Characteristics and Block Diagram sections.
How does the FCB pin configure operating modes in buck versus boost operation?
The FCB pin voltage determines low-load behavior: at <0.8V, LTC3780EUH enters forced continuous mode in both buck and boost; at 0.85–5V, it uses skip-cycle mode in buck and Burst Mode® in boost; above 5.3V, it operates in discontinuous conduction mode with constant frequency. These mode selections are explicitly defined in the Operation section and validated in Figures G01–G03 efficiency plots.
What is the purpose of the exposed pad (Pin 33) on the LTC3780EUH QFN package?
The exposed pad (Pin 33) on the LTC3780EUH is electrically connected to SGND and must be soldered to a PCB ground plane. It serves dual purposes: providing low-impedance signal return for sensitive analog circuitry and enabling thermal dissipation - reducing θJA from 130°C/W (SSOP) to 34°C/W (QFN). Failure to solder the pad degrades both noise immunity and thermal performance, violating the manufacturer's assembly requirement.
Can the LTC3780EUH regulate output voltages below 0.8V?
No, the LTC3780EUH cannot regulate below 0.8V. Its internal reference voltage is 0.800V (±1%), and the VOSENSE pin is designed to compare against this fixed threshold. The datasheet specifies VOUT range as "0.8V < VOUT < 30V" and confirms ±1% accuracy only within that span. Attempting sub-0.8V regulation violates the error amplifier's operating range and results in loss of regulation - no design examples or test data support lower outputs.
LTC3780EUH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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 ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3780EUH FAQ
1.How can I place an order for LTC3780EUH through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3780EUH 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 LTC3780EUH reliable?
The price and inventory of LTC3780EUH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3780EUH is usually 5 days.
3.What payment methods are accepted for LTC3780EUH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3780EUH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3780EUH?
LTC3780EUH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3780EUH 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 LTC3780EUH?
For technical support, including LTC3780EUH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3780EUH requirements.
6.How does Aetrix verify that LTC3780EUH is sourced from the original manufacturer or authorized distributors?
All LTC3780EUH 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 LTC3780EUH meets industry standards.
7.What is the process for return or replacement of LTC3780EUH?
All LTC3780EUH units undergo pre-shipment inspection (PSI). If there is an issue with LTC3780EUH, 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 LTC3780EUH part is unused and in its original packaging.
Return procedure for LTC3780EUH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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