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Analog Devices Inc. LTC3815EUFE#TRPBF
- Part No.:
- LTC3815EUFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC3815EUFE#TRPBF.pdf
- Description:
- IC REG BUCK PROG 6A 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,222
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Product details
Overview
LTC3815EUFE#TRPBF from Analog Devices is a 6A monolithic synchronous step-down DC/DC converter with PMBus interface, operating from 2.25V to 5.5V input and delivering programmable output voltage from 0.4V to 72% of VIN. It features ±1% total output voltage accuracy over temperature, integrated 13-bit ADC for telemetry, and phase-lockable switching frequency up to 3MHz-used in high-density point-of-load power for FPGAs and ASICs.
For engineers reviewing the LTC3815EUFE#TRPBF datasheet, LTC3815EUFE#TRPBF pinout, LTC3815EUFE#TRPBF application, or LTC3815EUFE#TRPBF equivalent, key selection criteria include PMBus margining resolution (0.1%), fast transient response enabled by controlled-on-time current-mode architecture, differential remote sensing capability, and thermal performance in the 4mm × 6mm QFN package with exposed PGND pad.
Technical Context
The LTC3815EUFE#TRPBF implements a phase-lockable controlled-on-time current-mode architecture with valley current sensing via internal NMOS RDS(ON) (20 mΩ typical). Its error amplifier delivers 80 dB open-loop gain and 20 MHz gain-bandwidth product, enabling stable loop compensation through ITH pin RC networks.
It integrates a 13-bit ADC supporting time-averaged (~4 ms) and peak readback of input/output voltage, current, and die temperature at 25 Hz refresh rate. The PMBus interface complies with SMBus 2.0, supports 10–400 kHz clock frequency, and enables full configuration including MFR_VOUT_COMMAND (±25% margining), fault status reporting, and peak value capture/reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.25V to 5.5V - supports direct operation from 2.5V, 3.3V, 5V rails or single-cell Li-ion batteries. |
| Output Current | 6A continuous - delivered via integrated 35 mΩ PMOS and 20 mΩ NMOS power switches. |
| Output Voltage Range | 0.4V to 72% of VIN - set by single external resistor on REF pin or external reference voltage. |
| Margining Resolution | 0.1% per LSB - enables precise ±25% VOUT adjustment via PMBus MFR_VOUT_COMMAND register. |
| Switching Frequency | 400kHz to 3MHz - programmable with RT resistor or synchronized to external clock on MODE/SYNC pin. |
| Accuracy | ±1% total VOUT error over temperature at VIN = 3.3V or 5V - includes offset, line regulation, and reference drift contributions. |
| ADC Resolution | 13-bit for VOUT/IOUT/VIN/IIN; 9-bit for temperature - enables telemetry with 0.5 mV, 10 mA, and 1°C LSB steps. |
Pinout & Package
The LTC3815EUFE#TRPBF is housed in a thermally enhanced 38-lead 4mm × 6mm plastic QFN package (UFE) with exposed PGND pad (Pin 39) requiring PCB soldering for electrical integrity and thermal performance (θJA = 38°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RT (1) | Oscillator frequency programming | Resistor-to-ground sets switching frequency from 400kHz to 3MHz; tie to VIN for fixed 1MHz. |
| ASEL (2) | PMBus address LSB selection | ±1% resistor to ground configures 3 LSBs of 7-bit SMBus address per Table 7. |
| MARGIN (3) | Fast margining trigger | Floating: margining via PMBus; pulled high/low: immediate ramp to pre-stored HIGH/LOW register values. |
| WP (4) | Write protection control | Pulled high: disables writes to MFR_VOUT_COMMAND, MFR_VOUT_MARGIN_HIGH/LOW registers. |
| ALERT (5) | Open-drain SMBus alert | Active-low interrupt signal indicating PMBus faults, PGOOD loss, or thermal/voltage violations. |
| CLKOUT (6) | Two-phase clock output | 180° out-of-phase with internal clock; enables 12A two-phase operation when paired with second LTC3815. |
| SDA/SCL (7,8) | PMBus bidirectional data/clock | Compliant with SMBus 2.0; 10–400 kHz operation; requires external pull-up resistors. |
| MODE/SYNC (9) | Mode selection & sync input | Tied to VIN: discontinuous mode; grounded: forced continuous mode; driven externally: frequency synchronization. |
| SW (10,11,13,14,18,19,21,22,23) | Internal switch node | Connects to drains of integrated PMOS/NMOS power switches; requires low-inductance layout. |
| PVIN (15–17) | Power MOSFET source supply | Independent of VIN; may be connected to same or lower voltage rail to optimize efficiency. |
| PGOOD (29) | Power-good status flag | Open-drain output asserting only after VOUT remains within programmed window for delay set by PGFD pin. |
| VIN (24) | Signal circuitry supply | Powers internal logic, ADC, and PMBus interface; decoupled separately from PVIN. |
| PGFD (25) | PGOOD filter delay select | Voltage sets one of seven discrete delays (200μs × 2N, N = 0–5,7) before PGOOD assertion. |
| RUN_MSTR (26) | Master shutdown control | Below 0.4V: full shutdown (<1 μA IQ); above 1V: normal operation; hysteresis ensures clean turn-on. |
| RUN_STBY (27) | Standby mode control | Below 0.4V: regulator off but ADC/PMBus active at 1Hz refresh and 120 μA IQ. |
| CSLEW (28) | VOUT slew rate control | Capacitor value sets margining transition rate: 0.1%/ms per nF (e.g., 1nF → 0.1%/ms). |
| TRACK/SS (30) | Soft-start & tracking input | Capacitor-to-ground sets soft-start ramp (~5V/sec/μF); resistive divider enables voltage tracking. |
| VSS_SENSE / VCC_SENSE (31,32) | Differential output voltage sense | Enables Kelvin sensing for accurate regulation; VSS_SENSE tied to VIN configures slave mode. |
| REF (36) | Reference voltage input | 100 μA internal current source times external resistor sets base VOUT; margining applied around this value. |
| PGLIM (37) | PGOOD threshold programming | Voltage vs SGND sets ±0.4×ΔV window around VREF; tie to VIN for default ±10%. |
| SGND (38) | Signal ground reference | Kelvin-connected to negative output capacitor terminals; separate from PGND plane for load regulation. |
| PGND (39) | Power ground & thermal pad | Exposed pad must be soldered to PCB for electrical return path and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated power MOSFETs | 35 mΩ PMOS + 20 mΩ NMOS enable high-efficiency 6A conversion without external switches. |
| PMBus telemetry engine | Simultaneous readback of time-averaged and peak VIN, VOUT, IIN, IOUT, and temperature at 25 Hz. |
| Differential remote sensing | VCC_SENSE/VSS_SENSE pins support Kelvin connections to minimize IR drop errors in high-current designs. |
| Programmable PGOOD window | PGLIM pin allows custom over/undervoltage thresholds from ±6% to ±30% around VREF. |
| Master/standby shutdown modes | RUN_MSTR < 0.4V cuts IQ to <1 μA; RUN_STBY < 0.4V retains PMBus/ADC at 120 μA and 1 Hz refresh. |
| Two-phase clock output | CLKOUT provides 180° phase-shifted signal enabling seamless 12A dual-phase operation with matched timing. |
Applications
| ASIC/FPGA Core Power | Intelligent POL Systems |
|---|---|
Use Scenario: Delivering tightly regulated 0.8V–1.2V core voltage to Xilinx Kintex or Intel Stratix FPGA under dynamic load transients up to 4A/μs. IC Role / Device Role / Timing Role: Primary synchronous buck controller with PMBus-configurable VOUT, margining, and real-time telemetry. Use Value: ±1% output accuracy and fast transient response maintain core voltage within spec during burst-mode processing. | Use Scenario: Distributed 12V-to-3.3V/5V conversion in telecom line cards with centralized PMBus monitoring and fault logging. IC Role / Device Role / Timing Role: Digitally configurable point-of-load regulator with integrated ADC and SMBus alert signaling. Use Value: Eliminates external ADC and digital isolators by providing native voltage/current/temperature telemetry over shared bus. |
| Server VR13-Compatible Supplies | Battery-Powered Industrial Controllers |
Use Scenario: Implementing VR13-compliant 1.8V DDR memory rail with programmable slew rate and ±25% margining for validation testing. IC Role / Device Role / Timing Role: PMBus-enabled buck converter supporting MFR_VOUT_COMMAND, MFR_VOUT_PEAK, and fault status registers. Use Value: 0.1% margining resolution and peak-capture registers enable automated production margin testing without external equipment. | Use Scenario: Powering ARM Cortex-M7-based edge controllers from 3.7V Li-ion battery with ultra-low standby current during sleep cycles. IC Role / Device Role / Timing Role: Efficient step-down regulator with RUN_STBY pin enabling 120 μA standby mode while retaining bus accessibility. Use Value: Standby current reduction from 5 mA to 120 μA extends battery life >10× versus always-on PMBus monitoring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3880IUHF#PBF | Dual-output, 2-phase capable, higher integration (dual 25A channels), supports 4.5V–24V input | Suitable for multi-rail systems requiring coordinated sequencing and tighter cross-regulation | Select when needing dual independent outputs or >6A per rail with digital control. |
| TPS546D24RQFT | Single-output, 6A, 4.5V–18V input, PMBus 1.3 compliant, no integrated CLKOUT for 2-phase | Optimized for higher-input industrial supplies; lacks differential sensing and fast-margining pin | Select for 12V-input systems where extended VIN range and TI ecosystem support are priorities. |
Compared with LTC3815EUFE#TRPBF, the LTC3880 offers dual-rail coordination and higher current scalability but requires larger board area, while the TPS546D24 supports wider input range and newer PMBus features but omits differential sensing and hardware margining triggers critical for precision validation.
Availability
LTC3815EUFE#TRPBF is available at Aetrix Electronics and suitable for ASIC/FPGA power delivery, intelligent point-of-load systems, and battery-powered industrial controllers requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3815EUFE#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3815EUFE#TRPBF belongs to Analog Devices' Power by Linear™ monolithic DC/DC controller family, designed specifically for digitally programmable, high-accuracy point-of-load power in space-constrained computing and infrastructure applications.
FAQ
What is the minimum input voltage required for LTC3815EUFE#TRPBF to deliver 6A at 1.2V output?
The minimum input voltage depends on load, output voltage, and switching frequency. For LTC3815EUFE#TRPBF delivering 6A at 1.2V with 1MHz switching, the minimum VIN is approximately 2.3V per Figure 36 (G36) in the datasheet. At 2MHz, it rises to ~2.6V due to reduced minimum on-time. Operation below 2.25V violates absolute maximum ratings and is not guaranteed.
How does the LTC3815EUFE#TRPBF achieve ±1% total output voltage accuracy over temperature?
The LTC3815EUFE#TRPBF achieves ±1% total output voltage accuracy through a combination of factors: a precision 100 µA reference current source (±0.5% typical), low-offset differential amplifier (±0.5% ΔVOUT,OFFSET), and tight line regulation (0.05%/V). These are summed per Note 10 in the Electrical Characteristics table, with all contributors specified over –40°C to 125°C junction temperature.
Can LTC3815EUFE#TRPBF operate in forced continuous conduction mode (FCCM), and how is it enabled?
Yes, LTC3815EUFE#TRPBF supports forced continuous conduction mode. It is enabled by grounding the MODE/SYNC pin (Pin 9). In FCCM, the bottom MOSFET remains active even at light loads, preventing inductor current reversal and eliminating audible noise or output ripple associated with discontinuous mode-critical for sensitive analog or RF circuits.
What is the function of the CSLEW pin on LTC3815EUFE#TRPBF, and how does it affect margining transitions?
The CSLEW pin (Pin 28) on LTC3815EUFE#TRPBF controls the slew rate of VOUT during PMBus margining transitions. A capacitor connected to CSLEW sets the rate: 0.1%/ms per nF (e.g., 1 nF = 0.1%/ms). With CSLEW open or shorted to VIN, two fixed slew rates are selected. This prevents abrupt voltage steps that could disrupt downstream logic or violate dV/dt limits in system-level testing.
Does LTC3815EUFE#TRPBF support two-phase interleaved operation, and what is required to implement it?
Yes, LTC3815EUFE#TRPBF supports two-phase interleaved operation via its CLKOUT pin (Pin 6), which provides a 180° phase-shifted clock signal. To implement, connect CLKOUT of the master LTC3815EUFE#TRPBF to the MODE/SYNC pin of a second LTC3815EUFE#TRPBF configured as slave (VSS_SENSE tied to VIN). This enables synchronized 12A output with reduced input/output ripple and improved thermal distribution.
LTC3815EUFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.25V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.4V
- Voltage - Output (Max):
- 3.96V
- Current - Output:
- 6A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (4x6)
LTC3815EUFE#TRPBF FAQ
1.How can I place an order for LTC3815EUFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3815EUFE#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 LTC3815EUFE#TRPBF reliable?
The price and inventory of LTC3815EUFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3815EUFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3815EUFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3815EUFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3815EUFE#TRPBF?
LTC3815EUFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3815EUFE#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 LTC3815EUFE#TRPBF?
For technical support, including LTC3815EUFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3815EUFE#TRPBF requirements.
6.How does Aetrix verify that LTC3815EUFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3815EUFE#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 LTC3815EUFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3815EUFE#TRPBF?
All LTC3815EUFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3815EUFE#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 LTC3815EUFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3815EUFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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