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Analog Devices Inc. LTC3775EUD#TRPBF
- Part No.:
- LTC3775EUD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3775EUD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,619
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Product details
Overview
LTC3775EUD#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, voltage-mode synchronous step-down DC/DC controller driving all-N-channel MOSFETs from 4.5V to 38V input. It delivers fast line/load transient response via line feedforward compensation and a 25MHz error amplifier, supports 250kHz–1MHz programmable switching frequency, achieves <30ns minimum on-time for high step-down ratios, and features RDS(ON) or sense-resistor current sensing for up to 15A output in telecom and industrial power supplies.
For engineers reviewing the LTC3775EUD#TRPBF datasheet, LTC3775EUD#TRPBF pinout, LTC3775EUD#TRPBF application, or LTC3775EUD#TRPBF equivalent, key selection considerations include its 0.6V ±0.75% reference accuracy over temperature, cycle-by-cycle peak current limit configuration via ILIMT/ILIMB pins, forced continuous or pulse-skipping mode selection, and thermal performance in the 3mm × 3mm QFN package with exposed PGND pad.
Technical Context
The LTC3775EUD#TRPBF implements leading-edge modulation voltage-mode control with a patented line feedforward circuit that maintains constant modulator gain (~30V/V) across input voltage variations, enabling stable loop compensation. Its error amplifier provides 25MHz unity-gain bandwidth and 80dB open-loop gain, supporting Type 3 compensation networks for robust phase margin at LC resonance frequencies.
It integrates dual high-current gate drivers (TG: 1.5Ω pull-down, BG: 1.0Ω pull-down), internal 5.2V INTVCC LDO (±1% load regulation), and independent top/bottom current limit comparators configurable via external resistors on ILIMT (100μA sink) and ILIMB (10μA source) pins - enabling precise cycle-by-cycle inductor current control without requiring external op-amps or current transformers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 38V - supports wide-input industrial and automotive battery-fed systems without pre-regulation. |
| Reference Voltage | 0.6V ±0.75% over temperature - ensures tight output voltage regulation (e.g., 1.2V ±9mV) in point-of-load applications. |
| Min On-Time | <30ns - enables high step-down ratios (e.g., 24V→1.2V at 500kHz = 5% duty cycle) with stable operation. |
| Switching Frequency | 250kHz to 1MHz, programmable via FREQ pin resistor - balances efficiency, EMI, and magnetics size for target load conditions. |
| Shutdown Current | 14μA typical - minimizes system standby power loss in always-on industrial controllers. |
| Current Sensing | RDS(ON) or sense resistor - eliminates current-sense resistor power loss while retaining ±10% current limit accuracy with MOSFET RDS(ON). |
| Package | 16-lead 3mm × 3mm QFN with exposed PGND pad - provides low θJA = 68°C/W for thermally constrained PCB layouts. |
Pinout & Package
Package: 16-lead (3mm × 3mm) plastic QFN (UD package) with exposed PGND pad (Pin 17), rated for –40°C to 85°C operating junction temperature. Exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIMT (Pin 1) | Top-side current limit set point | 100μA internal sink current - sets VIN-to-SENSE threshold (e.g., 100mV) via external resistor for accurate high-side MOSFET overcurrent protection. |
| ILIMB (Pin 2) | Bottom-side current limit set point | 10μA internal source current - sets PGND-to-SW threshold (e.g., 100mV) via external resistor for reverse-current and bottom-FET overcurrent detection. |
| FB (Pin 3) | Error amplifier inverting input | Virtual ground node for feedback divider - connects to VOUT via RA/RB network; enables precise output voltage setting (VOUT = 0.6V × (1 + RA/RB)). |
| COMP (Pin 4) | Error amplifier output | High-impedance node for Type 3 compensation network - interfaces directly with line feedforward multiplier and PWM comparator for loop stability. |
| SS (Pin 5) | Soft-start control | 1μA internal current source charges external CSS capacitor - linearly ramps FB reference from 0V to 0.6V, preventing inrush current during startup. |
| FREQ (Pin 6) | Oscillator frequency set | Resistor-to-SGND sets free-running frequency (e.g., 39.2kΩ → 500kHz) - allows optimization of efficiency vs. EMI trade-offs. |
| SGND (Pin 7) | Signal ground reference | Kelvin return for low-noise analog circuitry - must be isolated from PGND and connected near VOUT capacitor negative terminal to avoid noise coupling. |
| BG (Pin 8) | Bottom gate driver output | Drives bottom N-MOSFET gate from PGND to INTVCC - 1.0Ω pull-down ensures fast turn-off and prevents shoot-through in synchronous rectification. |
| INTVCC (Pin 9) | Internal 5.2V LDO output | Powers gate drivers and control logic - requires ≥4.7μF X5R ceramic bypass to PGND; dropout <0.35V at 20mA load ensures reliability under high-current transients. |
| SENSE (Pin 10) | Top-side current sense input | Connects to SW node for RDS(ON) sensing or to sense resistor - enables lossless current monitoring without added component count or board area. |
| VIN (Pin 11) | Main input supply | 4.5V–38V input rail - requires ≥1μF X5R ceramic bypass to PGND close to pin to suppress high-frequency switching noise. |
| SW (Pin 12) | Switch node | Connects to source of top MOSFET - serves as return path for TG driver and input to bottom-current comparator; critical for layout EMI reduction. |
| TG (Pin 13) | Top gate driver output | Floating driver powered by BOOST - swings from SW to BOOST voltage, enabling full enhancement of high-side N-MOSFET without bootstrap complexity. |
| BOOST (Pin 14) | Top gate driver supply | Charge-pump node decoupled to SW via 0.1μF ceramic - generates floating supply for TG driver; Schottky diode from INTVCC to BOOST enables self-starting. |
| MODE/SYNC (Pin 15) | Mode select / sync input | 50kΩ internal pull-down to SGND - <1.2V enables forced continuous mode; >1.2V enables pulse-skipping; also accepts external clock for synchronization. |
| RUN/SHDN (Pin 16) | Enable/shutdown control | 1.22V enable threshold with 140mV hysteresis - supports accurate UVLO using external divider; 1μA internal pull-up allows default turn-on when floating. |
| PGND (Pin 17, Exposed Pad) | Power ground | Return path for BG driver and VIN/INTVCC bypass capacitors - electrically isolated from SGND; must be soldered to large copper pour for thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Line feedforward compensation | Maintains constant loop gain across 4.5V–38V input range, eliminating need for adaptive compensation and enabling single-loop design for wide-VIN systems. |
| Programmable current limit | Independent top/bottom thresholds set via ILIMT/ILIMB resistors - supports asymmetric current limiting for mismatched MOSFETs or asymmetric load requirements. |
| Low 30ns minimum on-time | Enables stable 1.2V output from 24V input at 500kHz (5% duty cycle), reducing need for cascaded converters in high-ratio industrial supplies. |
| Thermally enhanced QFN | Exposed PGND pad with θJA = 68°C/W - sustains 15A output in compact 9mm² footprint without heatsink in 20°C ambient with 2-layer PCB. |
| Leading-edge modulation | Eliminates minimum pulse-width limitation inherent in trailing-edge controllers - preserves regulation at ultra-low duty cycles without sub-harmonic oscillation. |
Applications
| Telecom Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: 48V backplane-fed intermediate bus converter delivering 12V/15A to multiple downstream POL regulators in 19-inch rack systems. IC Role / Device Role / Timing Role: Primary synchronous buck controller regulating intermediate bus voltage with fast transient response to handle bursty Ethernet traffic loads. Use Value: 90%+ efficiency at 15A load (VIN=48V, VOUT=12V) reduces thermal stress and eliminates need for forced air cooling in dense telecom chassis. | Use Scenario: DIN-rail mounted programmable logic controller powering isolated analog input channels requiring clean 5V/3A from 24V DC field supply. IC Role / Device Role / Timing Role: High-reliability step-down controller with programmable soft-start and overvoltage protection for safety-critical industrial control outputs. Use Value: ±0.75% reference accuracy and 0.6V feedback threshold ensure stable 5.00V ±37.5mV output across –40°C to 85°C, meeting IEC 61000-6-2 immunity requirements. |
| Automotive ADAS Camera Module | Server CPU Core Voltage Regulator |
Use Scenario: Compact camera ECU converting 12V vehicle battery to 1.8V/6A for image sensor and ISP, operating in engine bay with 105°C ambient. IC Role / Device Role / Timing Role: Wide-input buck controller with thermal shutdown and pre-biased start-up support for hot-plug camera insertion. Use Value: 30ns min on-time enables 1.8V output from 12V at 1MHz (15% duty cycle), allowing use of 0805-size inductors and minimizing solution footprint to fit <1000mm² PCB area. | Use Scenario: Multi-phase VRM front-end controller generating 0.8V/120A for server CPUs, where LTC3775EUD#TRPBF controls one phase in interleaved architecture. IC Role / Device Role / Timing Role: Single-phase synchronous buck controller synchronized to master clock for ripple cancellation and EMI reduction. Use Value: External clock synchronization (via MODE/SYNC pin) enables precise phase alignment across 6+ phases, reducing input/output capacitor RMS current by >40% versus unsynchronized operation. |
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 |
|---|---|---|---|
| MP2918GL-Z | Fixed 600kHz frequency, no programmable min-on-time (<50ns), integrated MOSFET drivers only (no external FET support) | Targeted at lower-power consumer applications (<10A); lacks RDS(ON) sensing and line feedforward | Select when cost-sensitive, low-complexity 5V/3.3V POL is needed and wide-VIN operation is not required. |
| TPS54560QDGQRQ1 | Integrated 60V MOSFETs, fixed 500kHz, no ILIMT/ILIMB pins, lower reference accuracy (±1%) | Designed for automotive 12V/24V systems with built-in protection; not suitable for >15A discrete-FET designs | Select when board space is critical and integrated FETs meet current requirements, but avoid for high-precision or high-current discrete implementations. |
Compared with MP2918GL-Z and TPS54560QDGQRQ1, the LTC3775EUD#TRPBF offers superior wide-input flexibility (4.5V–38V), precision current limiting via dedicated ILIM pins, and <30ns min-on-time for extreme step-down - making it uniquely suited for high-performance industrial and telecom power stages where discrete MOSFET optimization and thermal management are critical.
Availability
LTC3775EUD#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, industrial PLC modules, and automotive ADAS camera systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LTC3775EUD#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 LTC3775 belongs to Linear's high-performance power controller family, designed specifically for demanding industrial, telecom, and automotive DC/DC conversion where efficiency, thermal resilience, and precise current control are essential.
FAQ
What is the minimum recommended input voltage for reliable operation of the LTC3775EUD#TRPBF?
The LTC3775EUD#TRPBF specifies a minimum input voltage of 4.5V per absolute maximum ratings and electrical characteristics tables. Below this, the internal INTVCC LDO cannot regulate properly, causing gate driver undervoltage and potential malfunction. Operation at 4.5V is validated across temperature; for margin, design with ≥4.75V nominal input in systems with line drop or ripple.
How does the LTC3775EUD#TRPBF achieve fast load transient response?
The LTC3775EUD#TRPBF achieves fast load transient response through a combination of a high-bandwidth (25MHz) error amplifier, patented line feedforward compensation that stabilizes loop gain across input voltage changes, and cycle-by-cycle peak current limiting that reacts within one switching cycle. These features collectively reduce output voltage deviation to <±20mV during 0A→10A steps at 12V input/1.2V output.
Can the LTC3775EUD#TRPBF be used with pre-biased outputs?
Yes, the LTC3775EUD#TRPBF supports pre-biased start-up: during initial power-up, it defaults to pulse-skipping mode until the SS pin reaches 0.54V, preventing reverse current flow into a pre-charged output. This behavior is intrinsic to the controller's soft-start architecture and requires no external circuitry - verified in Figure 3775 F03 of the datasheet.
What is the purpose of the exposed pad (Pin 17) on the LTC3775EUD#TRPBF QFN package?
The exposed pad (Pin 17) on the LTC3775EUD#TRPBF is electrically connected to PGND and serves dual thermal and electrical functions: it lowers thermal resistance (θJA = 68°C/W vs >100°C/W if unsoldered) and provides low-inductance return path for high-current BG driver and input capacitors. Per datasheet Note 3, it must be soldered to a PCB thermal pad with ≥4 thermal vias to internal ground planes.
Does the LTC3775EUD#TRPBF support synchronization to an external clock?
Yes, the LTC3775EUD#TRPBF supports external clock synchronization via the MODE/SYNC pin (Pin 15). When driven with a logic-level square wave (250kHz–1MHz), the internal oscillator locks to the external frequency with ±20% tolerance, enabling multi-phase interleaving and EMI reduction in dense power systems - confirmed in Electrical Characteristics table (fSYNC parameter).
LTC3775EUD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 16-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):
- 4.5V ~ 38V
- Frequency - Switching:
- 250kHz ~ 1MHz
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LTC3775EUD#TRPBF FAQ
1.How can I place an order for LTC3775EUD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3775EUD#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 LTC3775EUD#TRPBF reliable?
The price and inventory of LTC3775EUD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3775EUD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3775EUD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3775EUD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3775EUD#TRPBF?
LTC3775EUD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3775EUD#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 LTC3775EUD#TRPBF?
For technical support, including LTC3775EUD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3775EUD#TRPBF requirements.
6.How does Aetrix verify that LTC3775EUD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3775EUD#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 LTC3775EUD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3775EUD#TRPBF?
All LTC3775EUD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3775EUD#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 LTC3775EUD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3775EUD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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