My Inquiry
My Account
Analog Devices Inc. LTC3775EUD#PBF
- Part No.:
- LTC3775EUD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3775EUD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,637
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3775EUD#PBF 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 features 30ns minimum on-time, ±0.75% 0.6V reference accuracy over temperature, programmable 250kHz–1MHz switching frequency, and RDS(ON)/sense-resistor current sensing for telecom power supplies delivering 1.2V/15A output.
For engineers reviewing the LTC3775EUD#PBF datasheet, LTC3775EUD#PBF pinout, LTC3775EUD#PBF application, or LTC3775EUD#PBF equivalent, key selection criteria include minimum on-time capability for high step-down ratios, line feedforward compensation for fast transient response, cycle-by-cycle peak current limit configuration, and thermal performance in the 3mm × 3mm QFN package with exposed PGND pad.
Technical Context
The LTC3775EUD#PBF implements leading-edge modulation voltage mode control with patented line feedforward compensation, enabling stable operation across wide input ranges while maintaining fast line and load transient response. Its error amplifier delivers 25MHz unity-gain bandwidth and 80dB open-loop gain, supporting Type 3 compensation networks for robust loop stability.
Cycle-by-cycle current limiting is configurable via external resistors on ILIMT (100μA sink) and ILIMB (10μA source) pins, allowing independent adjustment of topside and bottom-side current thresholds. The controller supports both pulse-skipping and forced continuous conduction modes, selected via the MODE/SYNC pin with 1.2V threshold and 430mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 38V input supply - enables direct regulation from 12V/24V/28V industrial and telecom rails without pre-regulation. |
| tON(MIN) | <30ns - supports ultra-low duty cycles (e.g., 1.2V out from 12V in = 10%) without pulse skipping, critical for high step-down ratio designs. |
| VFB Accuracy | ±0.75% at 0.6V over temperature - ensures tight output voltage regulation across –40°C to 85°C junction range. |
| fOSC | 250kHz to 1MHz programmable - balances efficiency, component size, and EMI; 500kHz typical for 15A point-of-load applications. |
| IQ(SHDN) | 14μA typical shutdown current - minimizes system standby power in always-on infrastructure equipment. |
| INTVCC Regulator | 5.2V ±0.3V LDO with 0.35V dropout at 20mA - powers gate drivers and internal circuitry independently of VIN, improving noise immunity. |
| Driver RON | TG/BG pull-down: 1.5Ω/1.0Ω - delivers high peak gate drive current for fast MOSFET switching and low conduction losses. |
Pinout & Package
The LTC3775EUD#PBF is housed in a thermally enhanced 16-lead (3mm × 3mm) plastic QFN package with exposed PGND pad (Pin 17), requiring soldering to PCB for θJA = 68°C/W thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIMT (Pin 1) | Topside current limit set point | 100μA internal sink current - resistor to VIN programs VILIMT(MAX) = 90–110mV for precise high-side MOSFET overcurrent protection. |
| ILIMB (Pin 2) | Bottom-side current limit set point | 10μA internal source current - resistor to SGND programs VILIMB(MAX) = 80–120mV for accurate low-side current sensing. |
| FB (Pin 3) | Error amplifier inverting input | Virtual ground node for feedback divider - connects to VOUT via RA/RB network; enables Type 3 compensation with COMP pin. |
| COMP (Pin 4) | Error amplifier output | Drives line feedforward multiplier and PWM comparator - requires RC network to FB for loop stability with LC output filter. |
| SS (Pin 5) | Soft-start control | 1μA internal current source charges external CSS capacitor - linearly ramps VOUT from 0V to final value, preventing inrush current. |
| FREQ (Pin 6) | Oscillator frequency set | Resistor to SGND sets fOSC = 250kHz–1MHz - 39.2kΩ yields 500kHz typical for balanced efficiency and size. |
| SGND (Pin 7) | Signal ground reference | Kelvin return for FB, SS, COMP, MODE/SYNC - must be isolated from PGND to avoid noise coupling into control loop. |
| BG (Pin 8) | Bottom gate driver output | Swings PGND to INTVCC - drives low-side N-MOSFET gate with 1.0Ω pull-down for fast turn-off and shoot-through prevention. |
| INTVCC (Pin 9) | Internal 5.2V regulator output | Powers gate drivers and analog circuitry - requires ≥4.7μF X5R ceramic bypass to PGND for stable operation. |
| SENSE (Pin 10) | Top MOSFET current sense input | Connects to SW node for RDS(ON) sensing or to sense resistor - enables lossless current monitoring with <100mV threshold. |
| VIN (Pin 11) | Main input supply | 4.5V–38V input rail - bypassed to PGND with ≥1μF X5R capacitor to suppress high-frequency switching noise. |
| SW (Pin 12) | Switch node connection | Connects to source of top N-MOSFET - serves as input to bottom current limit comparator and reverse current detection. |
| TG (Pin 13) | Top gate driver output | Floating driver powered by BOOST - swings above VIN to fully enhance top N-MOSFET; requires BOOST-SW 0.1μF charge pump cap. |
| BOOST (Pin 14) | Top gate driver supply | Charge pump output referenced to SW - decoupled to SW with 0.1μF ceramic cap; Schottky diode from INTVCC enables bootstrapping. |
| MODE/SYNC (Pin 15) | Operation mode select / sync input | 1.2V threshold with 430mV hysteresis - DC logic level selects pulse-skipping vs continuous mode; AC signal synchronizes oscillator. |
| RUN/SHDN (Pin 16) | Enable/shutdown control | 1.22V enable threshold, 0.74V shutdown threshold - internal 1μA pull-up allows default startup; supports external UVLO with R4/R5 divider. |
| PGND (Pin 17) | Power ground | Exposed pad connected to BG driver return and bottom MOSFET source - must be soldered to PCB thermal plane for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Line feedforward compensation | Compensates modulator gain variation with VIN, delivering constant loop gain and >10× improvement in line transient response vs standard voltage-mode controllers. |
| 30ns minimum on-time | Enables 1.2V output from 24V input (5% duty cycle) without pulse skipping, eliminating low-load efficiency cliffs and output ripple modulation. |
| MOSFET RDS(ON) current sensing | Eliminates sense resistor losses and board space - achieves >95% efficiency at 15A with discrete N-MOSFETs while maintaining ±5% current limit accuracy. |
| Programmable cycle-by-cycle current limit | Independent ILIMT/ILIMB resistors allow asymmetric current limiting - protects high-side MOSFET during short-circuit while optimizing low-side conduction losses. |
| Thermally enhanced QFN package | 3mm × 3mm footprint with exposed PGND pad reduces θJA to 68°C/W - sustains 15A continuous output in compact 1-in² PCB area without heatsink. |
Applications
| Telecom Point-of-Load | Industrial 24V-to-12V Conversion |
|---|---|
Use Scenario: Regulating 1.2V/15A for FPGA core power in 48V-powered base station equipment with strict EMI limits. IC Role / Device Role / Timing Role: Voltage-mode synchronous buck controller managing dual N-MOSFET power stage with 500kHz fixed frequency and line feedforward for rapid 48V line transients. Use Value: 30ns tON(MIN) enables direct 48V-to-1.2V conversion (2.5% duty cycle), avoiding cascaded regulation and reducing BOM count by 30%. | Use Scenario: Generating 12V/10A from 24V factory automation PLC power rail with high reliability and thermal margin. IC Role / Device Role / Timing Role: High-efficiency step-down controller operating in forced continuous mode with programmable 400kHz switching to balance efficiency and inductor size. Use Value: ±0.75% VFB accuracy and 25MHz error amplifier bandwidth maintain ±1% output regulation under ±10% input variation and 0–10A load steps. |
| Automotive Infotainment Power | Server VR13-Compatible Supply |
Use Scenario: Providing 1.8V/8A for automotive infotainment SoC with cold-crank tolerance down to 4.5V battery input. IC Role / Device Role / Timing Role: Wide-VIN synchronous controller using RDS(ON) current sensing and soft-start to prevent inrush during engine start. Use Value: 14μA shutdown current and 4.5V minimum VIN ensure reliable operation during automotive stop-start cycles without auxiliary bias supply. | Use Scenario: Delivering 1.0V/30A to server CPU with VR13 compliance, requiring precise current reporting and fast load transient response. IC Role / Device Role / Timing Role: Primary buck controller with cycle-by-cycle current limit and programmable frequency synchronization to system clock. Use Value: Independent ILIMT/ILIMB programming enables accurate current sharing in multiphase configurations while maintaining <500ns current limit response time. |
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 |
|---|---|---|---|
| MP2918GQ-Z | Integrated MOSFETs (40V/12A), fixed 600kHz frequency, no RDS(ON) sensing, lower IQ (10μA) | Targeted at space-constrained consumer applications; lacks programmable frequency and independent current limit configuration | Select when board area is critical and 12A max output suffices; avoid for >15A or high step-down ratio designs. |
| TPS546D24RSAR | Dual-output, PMBus interface, 1.5V to 16V VIN, integrated current sensing, 400kHz–2MHz programmable frequency | Designed for digital power systems requiring telemetry and dynamic voltage scaling; higher cost and complexity | Select when digital control, multi-rail sequencing, or real-time current monitoring are required; not drop-in for analog-only designs. |
Compared with MP2918GQ-Z and TPS546D24RSAR, the LTC3775EUD#PBF provides superior flexibility in high-current (>15A), high step-down ratio (VIN/VOUT > 10), and thermally constrained applications due to its 30ns minimum on-time, discrete MOSFET support, and thermally optimized QFN package - making it ideal for industrial and telecom power where efficiency and reliability outweigh integration convenience.
Availability
LTC3775EUD#PBF is available at Aetrix Electronics and suitable for telecom power supplies, industrial 24V-to-12V conversion, and automotive infotainment systems requiring stable component supply with guaranteed long-term availability.
Supply support for LTC3775EUD#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 acquired Linear Technology in 2017, inheriting its precision analog and power management portfolio. Linear Technology was renowned for high-performance DC/DC controllers and regulators targeting demanding industrial and communications applications.
The LTC3775EUD#PBF belongs to Linear's high-efficiency synchronous buck controller product line, designed specifically for high-current, wide-input-voltage point-of-load power conversion in telecom infrastructure, industrial automation, and automotive electronics where thermal performance and transient response are critical.
FAQ
What is the minimum on-time specification for the LTC3775EUD#PBF and why does it matter?
The LTC3775EUD#PBF has a guaranteed minimum on-time of less than 30ns. This parameter determines the lowest achievable duty cycle, enabling high step-down ratios such as converting 24V input to 1.2V output (5% duty cycle) without entering pulse-skipping mode. Maintaining fixed-frequency operation at light loads improves EMI predictability and avoids audible noise, which is essential in sensitive telecom and industrial applications where the LTC3775EUD#PBF is commonly deployed.
How does the LTC3775EUD#PBF implement current sensing and what are the trade-offs between methods?
The LTC3775EUD#PBF supports two current sensing methods: RDS(ON) sensing via the SENSE pin connected to the switch node, or external sense resistor sensing. RDS(ON) eliminates power loss and board space but trades off accuracy (±15% typical) due to MOSFET parameter variation. Sense resistor sensing provides ±1% current limit accuracy but adds conduction loss and component count. The LTC3775EUD#PBF allows seamless selection via external component choice without changing IC configuration.
Can the LTC3775EUD#PBF operate with input voltages below 4.5V?
No, the LTC3775EUD#PBF has an absolute minimum input voltage of 4.5V per its Absolute Maximum Ratings and Electrical Characteristics tables. Operation below this threshold risks improper startup, unstable regulation, or failure to enable the INTVCC LDO regulator. For sub-4.5V applications, alternative controllers such as the LTC3891 (2.5V–60V range) should be considered, as the LTC3775EUD#PBF is specifically optimized for industrial and telecom rails starting at 4.5V.
What thermal considerations apply to the LTC3775EUD#PBF's QFN package?
The LTC3775EUD#PBF uses a 16-lead 3mm × 3mm QFN with exposed PGND pad (Pin 17). To achieve the specified θJA = 68°C/W, the exposed pad must be soldered to a PCB thermal plane with ≥4 thermal vias. Failure to do so increases thermal resistance significantly, risking junction temperature exceedance at 15A output. The datasheet mandates soldering the pad - unlike MSOP variants - making thermal layout non-negotiable for reliable LTC3775EUD#PBF operation.
How does the RUN/SHDN pin function beyond simple enable/disable control?
The RUN/SHDN pin on the LTC3775EUD#PBF provides three-level control: >1.22V enables normal operation, <1.22V disables gate drivers (outputs pulled low), and <0.74V forces full shutdown with <14μA quiescent current. Its internal 1μA pull-up allows default startup when floating, and external resistor dividers enable precise undervoltage lockout (UVLO) with hysteresis calculated as 4μA × R4. This makes the LTC3775EUD#PBF suitable for brown-out protection in industrial systems without additional supervisor ICs.
LTC3775EUD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LTC3775EUD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3775EUD#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 LTC3775EUD#PBF reliable?
The price and inventory of LTC3775EUD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3775EUD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3775EUD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3775EUD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3775EUD#PBF?
LTC3775EUD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3775EUD#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 LTC3775EUD#PBF?
For technical support, including LTC3775EUD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3775EUD#PBF requirements.
6.How does Aetrix verify that LTC3775EUD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3775EUD#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 LTC3775EUD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3775EUD#PBF?
All LTC3775EUD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3775EUD#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 LTC3775EUD#PBF part is unused and in its original packaging.
Return procedure for LTC3775EUD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3775EUD#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
