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Analog Devices Inc. LTC3854EDDB#TRMPBF
- Part No.:
- LTC3854EDDB#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LTC3854EDDB#TRMPBF.pdf
- Description:
- IC REG CTRLR BUCK 12DFN
- Quantity:
- Payment:
- Shipping:
Inventory:642
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Product details
Overview
LTC3854EDDB#TRMPBF from Analog Devices (formerly Linear Technology) is a high-performance synchronous step-down DC/DC controller driving all-N-channel MOSFET stages. It operates from 4.5V to 38V input, regulates output from 0.8V to 5.5V, features 400kHz fixed-frequency current-mode control, 75ns minimum on-time, and delivers up to 20A output current in telecom power supplies.
For engineers reviewing the LTC3854EDDB#TRMPBF datasheet, LTC3854EDDB#TRMPBF pinout, LTC3854EDDB#TRMPBF application, or LTC3854EDDB#TRMPBF equivalent, key selection considerations include RSENSE/DCR current sensing flexibility, OPTI-LOOP® compensation for wide output capacitance tolerance, 97% duty cycle dropout operation, ±1% 0.8V reference accuracy over temperature, and thermal performance in the 2mm × 3mm DFN package.
Technical Context
The LTC3854EDDB#TRMPBF implements constant-frequency peak current-mode control with internal slope compensation that preserves maximum inductor peak current across all duty cycles. Its transconductance error amplifier (gm = 2.0 mmho, GBW = 3 MHz) interfaces with the ITH pin to set current comparator trip level, while the 0.8V feedback reference maintains ±1% accuracy from –40°C to 85°C.
It integrates dual N-channel MOSFET drivers with 2.5Ω TG pull-up, 2.1Ω TG pull-down, 2.5Ω BG pull-up, and 1.2Ω BG pull-down resistances, enabling fast 25ns rise/fall times into 3300pF loads. The 5V INTVCC LDO supplies up to 40mA and powers gate drivers and internal circuitry, with shutdown quiescent current of 15µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide industrial and telecom input rails without external pre-regulation |
| Output Voltage Range | 0.8V to 5.5V - enables direct regulation of core voltages (e.g., 1.2V, 1.8V, 3.3V, 5V) with ±1% reference accuracy |
| Switching Frequency | 400kHz (±10%) - balances efficiency, size, and EMI; fixed frequency simplifies filter design |
| Minimum On-Time | 75ns - allows high step-down ratios (e.g., 24V→1.2V at 400kHz) without pulse-skipping instability |
| Current Sensing | RSENSE or DCR - selectable architecture enables trade-offs between accuracy (shunt) and efficiency (inductor DCR) |
| Duty Cycle Limit | 97% - supports ultra-low dropout operation (e.g., 5.5V→5V at VIN = 5.8V), critical for battery backup systems |
| Soft-Start Control | Adjustable via RUN/SS pin capacitor - provides controlled VOUT ramp with disabled current foldback during startup |
| Thermal Package | 12-pin 2mm × 3mm DFN with exposed pad - θJA = 76°C/W enables 20A operation with moderate PCB copper area |
Pinout & Package
Package: 12-lead (3mm × 2mm) plastic DFN with exposed GND pad (Pin 13), rated for –40°C to 85°C operating temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Error amplifier feedback input | Connects to resistor divider across VOUT; sets regulated output voltage with 0.8V internal reference |
| ITH (Pin 2) | Error amplifier output & compensation node | Controls peak current limit; connects to Type II/III compensation network for loop stability |
| RUN/SS (Pin 3) | Enable and soft-start control | Pull below 0.4V for shutdown; internal 1.25µA current charges external capacitor for linear VOUT ramp |
| BOOST (Pin 4) | Bootstrap supply for top-side driver | Connects to SW via low-ESR capacitor; enables floating gate drive for high-side N-MOSFET |
| TG (Pin 5) | Top-gate driver output | Drives high-side N-MOSFET gate with 5V swing referenced to SW node; 2.5Ω pull-up / 2.1Ω pull-down |
| SW (Pin 6) | Switch node connection | Connects to inductor and BOOST capacitor; voltage swings from ground to VIN during operation |
| GND (Pin 7) | Signal and power ground | Kelvin-connected internal ground; must be tied to low-impedance PCB ground plane |
| BG (Pin 8) | Bottom-gate driver output | Drives synchronous N-MOSFET gate with 0–5V swing referenced to GND; 2.5Ω pull-up / 1.2Ω pull-down |
| INTVCC (Pin 9) | Internal 5V LDO output | Supplies gate drivers and internal circuitry; requires ≥2.2µF X5R ceramic bypass to GND |
| VIN (Pin 10) | Main input supply | Accepts 4.5V–38V; must be bypassed with low-ESR capacitor near pin |
| SENSE– (Pin 11) | Current sense negative input | Differential input for RSENSE or DCR sensing network; common-mode range 0V–5.5V |
| SENSE+ (Pin 12) | Current sense positive input | Differential input paired with SENSE–; enables accurate peak current detection with <1µA bias current |
| SGND (Pin 13) | Exposed thermal pad | Must be soldered to PCB GND for thermal conduction and electrical grounding; integral to θJC = 10°C/W rating |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance by optimizing transient response across wide COUT and ESR ranges |
| Current Foldback Limiting | Reduces MOSFET dissipation during short-circuit by lowering peak current limit; disabled during soft-start |
| Pre-biased Output Startup | Allows safe start-up into already-powered outputs without reverse current flow or latch-up |
| Output Overvoltage Protection | Disables top MOSFET and turns on bottom MOSFET if FB exceeds 0.88V, preventing load damage |
| Low Shutdown IQ | 15µA shutdown current enables long battery life in always-on systems requiring periodic wake-up |
| DCR or RSENSE Sensing | Eliminates power loss from shunt resistors in high-current designs while retaining accuracy via calibrated RC filter |
Applications
| Telecom Power Supply | Industrial 24V Distribution |
|---|---|
|
Use Scenario: Regulating 48V intermediate bus down to 3.3V/5V for base station FPGAs and DSPs. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-efficiency, high-reliability power conversion with remote sensing. Use Value: 97% efficiency at 10A load (VIN=24V, VOUT=5V) reduces thermal stress in dense telecom modules. |
Use Scenario: Converting 24V factory floor supply to 12V for PLC I/O modules and sensors. IC Role / Device Role / Timing Role: Wide-input DC/DC controller supporting brownout resilience and 97% dropout operation during line sag. Use Value: 4.5V–38V input range accommodates 24V ±20% industrial tolerances without derating. |
| Automotive Infotainment | Distributed Data Center PSU |
|
Use Scenario: Generating 1.2V core voltage for automotive SoCs from 9V–16V battery rail. IC Role / Device Role / Timing Role: High-step-down ratio controller using 75ns min-on-time to achieve 1.2V from 12V at 400kHz. Use Value: Pre-biased startup prevents glitching when hot-plugging infotainment modules into live 12V bus. |
Use Scenario: Point-of-load regulation in server racks converting 12V backplane to 0.8V CPU core rails. IC Role / Device Role / Timing Role: Precision 0.8V reference (±1%) and OPTI-LOOP® enable stable regulation under dynamic CPU load transients. Use Value: ±1% reference accuracy ensures compliance with Intel VR13/VR14 specifications for processor power delivery. |
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 |
|---|---|---|---|
| LTC3855EDDB#TRMPBF | Includes phase-locking capability and dual-output tracking; same pinout but adds PLLIN/CLKOUT pins | Required for multi-phase or synchronized clocking in high-density power systems | Select LTC3855EDDB#TRMPBF only when interleaved operation or clock synchronization is needed |
| TPS54360BDDAR | Lower max input (60V vs 38V), no DCR sensing, 500kHz default freq, integrated high-side FET (not controller-only) | Suitable for lower-power (<6A), cost-sensitive designs where integration outweighs flexibility | LTC3854EDDB#TRMPBF retains external MOSFET control and DCR sensing for higher efficiency and thermal scalability |
Compared with LTC3855EDDB#TRMPBF, the LTC3854EDDB#TRMPBF offers identical controller functionality without phase-lock overhead; versus TPS54360BDDAR, it provides superior current-sensing flexibility and higher output current capability via discrete MOSFETs.
Availability
LTC3854EDDB#TRMPBF is available at Aetrix Electronics and suitable for telecom power supplies, industrial 24V distribution systems, and automotive infotainment electronics requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3854EDDB#TRMPBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3854EDDB#TRMPBF belongs to Linear's high-efficiency synchronous buck controller product line, designed specifically for wide-input industrial and telecom power conversion where precision, thermal robustness, and flexible current sensing are critical.
FAQ
What is the operating temperature range for the LTC3854EDDB#TRMPBF?
The LTC3854EDDB#TRMPBF is specified for operation from –40°C to +85°C ambient temperature. Its DFN package has a junction-to-ambient thermal resistance (θJA) of 76°C/W, and maximum junction temperature is 125°C. Derating is required above 70°C ambient for full 20A output capability.
Does the LTC3854EDDB#TRMPBF support DCR current sensing?
Yes, the LTC3854EDDB#TRMPBF fully supports DCR current sensing via its differential SENSE+ and SENSE– inputs. The device's high-impedance current comparator (input bias <1µA) and wide common-mode range (0V–5.5V) enable accurate inductor DCR measurement when paired with an RC filter matching the L/DCR time constant.
What is the purpose of the OPTI-LOOP® compensation in the LTC3854EDDB#TRMPBF?
OPTI-LOOP® compensation in the LTC3854EDDB#TRMPBF dynamically optimizes the control loop's transient response across a wide range of output capacitance values and ESR, reducing sensitivity to capacitor aging and temperature drift. This eliminates the need for iterative compensation tuning when using different capacitor types or quantities.
Can the LTC3854EDDB#TRMPBF start up into a pre-biased output?
Yes, the LTC3854EDDB#TRMPBF supports pre-biased output startup. During start-up, its synchronous MOSFET drivers remain inactive until the feedback voltage rises above the reference, preventing reverse current flow through the output capacitors and avoiding potential damage to downstream circuitry.
What is the function of the RUN/SS pin on the LTC3854EDDB#TRMPBF?
The RUN/SS pin on the LTC3854EDDB#TRMPBF serves dual functions: pulling it below 0.4V places the IC in shutdown mode (IQ = 15µA), while releasing it allows an internal 1.25µA current to charge an external capacitor, generating a linear voltage ramp that controls soft-start timing and output voltage slew rate.
LTC3854EDDB#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-WFDFN 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:
- 400kHz
- Duty Cycle (Max):
- 98%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-DFN (3x2)
LTC3854EDDB#TRMPBF FAQ
1.How can I place an order for LTC3854EDDB#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3854EDDB#TRMPBF 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 LTC3854EDDB#TRMPBF reliable?
The price and inventory of LTC3854EDDB#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3854EDDB#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3854EDDB#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3854EDDB#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3854EDDB#TRMPBF?
LTC3854EDDB#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3854EDDB#TRMPBF 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 LTC3854EDDB#TRMPBF?
For technical support, including LTC3854EDDB#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3854EDDB#TRMPBF requirements.
6.How does Aetrix verify that LTC3854EDDB#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3854EDDB#TRMPBF 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 LTC3854EDDB#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3854EDDB#TRMPBF?
All LTC3854EDDB#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3854EDDB#TRMPBF, 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 LTC3854EDDB#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3854EDDB#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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