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Analog Devices Inc. LTC3780IG#PBF
- Part No.:
- LTC3780IG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 24-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC3780IG#PBF.pdf
- Description:
- IC REG CTRLR BUCK-BOOST 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:418
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Product details
Overview
LTC3780IG#PBF from Analog Devices is a high-efficiency, synchronous 4-switch buck-boost controller IC that regulates output voltage across input voltages both above and below VOUT (4V–36V input, 0.8V–30V output), operates in continuous current mode up to 400kHz, delivers ±1% output voltage accuracy, and supports seamless buck/boost/buck-boost transitions-ideal for automotive power systems with wide battery voltage variation.
For engineers reviewing the LTC3780IG#PBF datasheet, LTC3780IG#PBF pinout, LTC3780IG#PBF application, or LTC3780IG#PBF equivalent, key selection criteria include its quad N-channel MOSFET drive capability, FCB-selectable low-current modes (Burst Mode® in boost, skip-cycle in buck), internal 6V LDO for gate drive, and phase-lockable oscillator-critical for EMI-sensitive automotive and telecom DC distribution designs.
Technical Context
The LTC3780IG#PBF implements a constant-frequency current-mode control architecture with dual independent gate drivers (TG1/BG1 for switch A/B; TG2/BG2 for switch C/D), enabling precise inductor current sensing via external RSENSE and real-time ITH-based current limit adjustment. Its mode logic automatically selects buck, boost, or buck-boost operation based on VIN–VOUT relationship and duty cycle boundaries.
Operation is governed by three critical analog control paths: VOSENSE feedback referenced to 0.800V internal bandgap, ITH-controlled current comparator threshold (0–2.4V range), and FCB pin voltage (0–5.5V) that directly configures low-power operating mode-no digital configuration or firmware required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports full automotive cold-crank (4.5V) to load-dump (36V) transients without external protection. |
| Output Voltage Range | 0.8V to 30V - adjustable via external resistor divider; ±1% accuracy ensures stable rail generation for MCU, FPGA, or RF subsystems. |
| Switching Frequency | 200kHz to 400kHz - phase-lockable via PLLIN; enables synchronized multi-rail systems and EMI frequency planning. |
| Efficiency | Up to 98% - achieved via synchronous rectification and optimized gate drive timing (TG/BG rise/fall times ≤55ns). |
| Current Sense Threshold | Buck min: –6mV; Boost max: +185mV - supports accurate peak/valley current limiting across wide load and duty ranges. |
| Operating Temperature | –40°C to +125°C junction - qualified for under-hood automotive applications per AEC-Q100 stress test requirements. |
| Power Good Accuracy | ±7.5% window on VOSENSE - provides reliable system-level power sequencing and fault detection without external comparators. |
Pinout & Package
Package: 24-Lead Plastic SSOP (G package), 5.0mm × 7.5mm body, exposed pad not present. Thermal resistance θJA = 130°C/W. Pin 1 = PGOOD (open-drain), Pin 7 = SGND (signal ground reference), Pin 17 = PGND (power ground), Pin 24 = BOOST2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGOOD (Pin 1) | Open-drain status output | Asserts low when VOSENSE deviates >±7.5% from 0.8V reference-enables safe microcontroller boot sequencing. |
| FCB (Pin 9) | Mode selection input | Voltage <0.8V forces continuous conduction; 0.85–5V enables skip-cycle (buck) or Burst Mode® (boost); >5.3V selects DCM. |
| ITH (Pin 5) | Error amplifier output / current limit control | 0–2.4V analog voltage sets instantaneous current trip point-used for soft-start ramping and foldback limiting. |
| TG1, BG1, TG2, BG2 (Pins 14,16,18,23) | Quad N-channel MOSFET gate drivers | Drive high-side (TGx) and low-side (BGx) switches with 3A peak current, 50–80ns timing delays-ensures shoot-through prevention. |
| SENSE+, SENSE– (Pins 3,4) | Differential current sense inputs | Measure voltage across external RSENSE to monitor inductor current in both buck and boost directions-supports bidirectional regulation. |
| RUN (Pin 8) | Enable/disable control | Pull <1.5V to shut down all switching and gate drivers; internal 100kΩ pull-down enables simple ON/OFF control with single resistor. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor 4-switch topology | Eliminates need for separate buck and boost converters-reduces BOM count, PCB area, and magnetic component cost in wide-input-range systems. |
| Seamless mode transition | Automatic buck → buck-boost → boost handoff with <200ns transition time-prevents output voltage glitch during VIN crossing VOUT (e.g., 12V battery sag). |
| Internal 6V LDO (INTVCC) | Supplies gate drivers and control circuitry; switchover to EXTVCC at 5.7V reduces power loss and thermal stress in high-current designs. |
| Adjustable soft-start | SS pin accepts external capacitor to linearly ramp ITH voltage-limits inrush current into bulk output capacitors during startup. |
| Output overvoltage lockout | VOSENSE >0.86V triggers immediate shutdown-protects downstream loads from catastrophic failure due to feedback divider fault. |
| VOUT disconnection during shutdown | Internal switches isolate output from input when RUN = low-prevents backfeed and enables true zero-load standby in battery-powered systems. |
Applications
| Automotive Infotainment Power Supply | Telecom DC-DC Intermediate Bus Converter |
|---|---|
Use Scenario: Regulating 12V vehicle battery to stable 5V/3.3V rails for head unit MCU, display driver, and audio codec under cold-crank (4.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary buck-boost controller managing four external N-MOSFETs; handles seamless VIN–VOUT crossover during engine start-stop cycles. Use Value: Maintains uninterrupted operation without brownout or reset-enabled by ±1% VOUT accuracy, 400kHz switching, and 125°C junction rating. |
Use Scenario: Converting –48V telecom supply to +12V intermediate bus feeding multiple POL converters in base station equipment. IC Role / Device Role / Timing Role: High-efficiency (98%) synchronous controller driving discrete MOSFETs; PLLIN synchronization eliminates beat frequencies in multi-rail systems. Use Value: Reduces heat sink size and improves system MTBF via low conduction/switching losses and robust overvoltage/foldback protection. |
| Industrial Battery-Operated Test Equipment | High-Power Portable Medical Device PSU |
Use Scenario: Powering 24V motor drivers and 5V data acquisition circuits from 18–30V Li-ion pack with minimal voltage droop during high-current pulses. IC Role / Device Role / Timing Role: Bidirectional current-mode controller supporting both sourcing and sinking; FCB pin configures skip-cycle mode for >90% light-load efficiency. Use Value: Extends runtime by >35% vs fixed-frequency operation at 10% load-verified by efficiency curves at 0.1A output current. |
Use Scenario: Providing isolated 15V/2A and 5V/3A outputs from 24V medical-grade battery in portable ultrasound or infusion pump. IC Role / Device Role / Timing Role: Primary non-isolated buck-boost stage preceding isolated flyback; VOUT disconnect during shutdown prevents battery drain during standby. Use Value: Meets IEC 60601 leakage and creepage requirements via clean shutdown behavior and low quiescent current (55µA in shutdown). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8705IUFD#PBF | Wider VIN range (2.8V–80V); includes integrated MOSFET drivers but no internal LDO; requires external VCC bias. | Better suited for industrial HVDC systems; lacks FCB-selectable Burst Mode®-light-load efficiency lower than LTC3780IG#PBF in automotive use cases. | Select LT8705 when input exceeds 36V or when higher integration (no external bootstrap diodes) is prioritized over temperature grade. |
| MPQ4316AGL-A-Z | Integrated 4-switch buck-boost converter (not controller); 3.3V–40V input; fixed 500kHz frequency; no PLL or FCB mode selection. | Targeted at space-constrained consumer electronics; lacks programmable soft-start, PGOOD accuracy, and automotive temp grade. | Choose MPQ4316 for cost-sensitive, low-complexity designs where full feature set of LTC3780IG#PBF is unnecessary. |
Compared with LT8705IUFD#PBF and MPQ4316AGL-A-Z, the LTC3780IG#PBF uniquely combines automotive-grade temperature range (–40°C to +125°C), FCB-configurable low-power modes, and internal 6V LDO-making it optimal for mission-critical automotive and telecom power systems requiring reliability, flexibility, and thermal robustness.
Availability
LTC3780IG#PBF is available at Aetrix Electronics and suitable for automotive infotainment, telecom intermediate bus, and industrial battery-powered systems requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned qualification.
Supply support for LTC3780IG#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 precision instrumentation, industrial automation, communications, and automotive markets.
The LTC3780IG#PBF belongs to Analog Devices' Power by Linear™ controller family, engineered specifically for high-efficiency, wide-input-range DC-DC conversion in harsh environments where reliability, thermal resilience, and seamless mode transitions are mandatory.
FAQ
What is the maximum operating junction temperature for the LTC3780IG#PBF?
The LTC3780IG#PBF is rated for an operating junction temperature range of –40°C to +125°C, as specified in the Absolute Maximum Ratings table. This I-grade qualification makes it suitable for under-hood automotive applications and high-ambient industrial environments where thermal derating must be minimized. The SSOP package has θJA = 130°C/W, so proper PCB copper pour and airflow are essential to maintain TJ ≤ 125°C at full load.
How does the FCB pin configure low-power operation in the LTC3780IG#PBF?
The FCB pin on the LTC3780IG#PBF selects among three distinct low-current modes: voltage <0.8V forces continuous conduction; 0.85–5V enables skip-cycle mode in buck operation or Burst Mode® in boost operation; >5.3V activates discontinuous conduction mode with constant frequency. This analog control eliminates need for digital configuration and allows dynamic mode switching based on system load profile.
Can the LTC3780IG#PBF drive external MOSFETs without external bootstrap diodes?
No-the LTC3780IG#PBF requires external Schottky bootstrap diodes (e.g., 1N5817) connected between INTVCC and BOOST1/BOOST2 pins to recharge the floating gate drive supplies during dead time. While synchronous rectification eliminates external catch diodes, the bootstrap diodes remain mandatory for high-side gate drive integrity and are explicitly shown in all application schematics in the datasheet.
What is the purpose of the STBYMD pin on the LTC3780IG#PBF?
The STBYMD pin on the LTC3780IG#PBF controls whether the internal 6V LDO remains active during RUN-pin shutdown. When pulled to ground, it disables the LDO and pulls SS low-providing single-pin system disable. When biased to 2–5V (e.g., via resistor divider from VIN), it keeps INTVCC alive to power external wake-up circuitry, enabling controlled restart without full re-initialization of the LTC3780IG#PBF.
Does the LTC3780IG#PBF support output voltage tracking during startup?
The LTC3780IG#PBF does not include dedicated voltage tracking circuitry, but output voltage ramp rate is fully controllable via the SS (soft-start) pin. Connecting an external capacitor to SS linearly ramps the ITH voltage, which directly modulates current limit and thus output voltage slew rate-enabling coordinated startup with other rails using simple RC networks or DAC-controlled voltage sources.
LTC3780IG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SSOP (0.209", 5.30mm Width)
- 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:
- 24-SSOP
LTC3780IG#PBF FAQ
1.How can I place an order for LTC3780IG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3780IG#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 LTC3780IG#PBF reliable?
The price and inventory of LTC3780IG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3780IG#PBF is usually 5 days.
3.What payment methods are accepted for LTC3780IG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3780IG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3780IG#PBF?
LTC3780IG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3780IG#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 LTC3780IG#PBF?
For technical support, including LTC3780IG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3780IG#PBF requirements.
6.How does Aetrix verify that LTC3780IG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3780IG#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 LTC3780IG#PBF meets industry standards.
7.What is the process for return or replacement of LTC3780IG#PBF?
All LTC3780IG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3780IG#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 LTC3780IG#PBF part is unused and in its original packaging.
Return procedure for LTC3780IG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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