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Analog Devices Inc. LTC3311SEV#TRMPBF
- Part No.:
- LTC3311SEV#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 18-TFQFN Exposed Pad
- Datasheet:
-
LTC3311SEV#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 12.5A 18LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:573
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Product details
Overview
LTC3311SEV#TRMPBF from Analog Devices is a monolithic, Silent Switcher 2 synchronous step-down DC/DC converter delivering up to 12.5A output current from 2.25V–5.5V input, featuring 500mV feedback reference, 35ns minimum on-time, and ±1% VOUT accuracy with remote sense. It serves as a high-density POL regulator for FPGA core supplies in space-constrained telecom and automotive systems.
For engineers reviewing the LTC3311SEV#TRMPBF datasheet, LTC3311SEV#TRMPBF pinout, LTC3311SEV#TRMPBF application, or LTC3311SEV#TRMPBF equivalent, key selection criteria include its AEC-Q100 qualification, 3mm × 3mm LQFN thermal performance (θJCbottom = 9°C/W), programmable 0.5–5MHz switching frequency, and integrated power good, soft-start, and die temperature monitoring functions.
Technical Context
The LTC3311SEV#TRMPBF employs constant-frequency peak current mode control with internal hot-loop bypass capacitors to achieve ultralow EMI emissions per CISPR25 Class 5 while maintaining high efficiency-enabled by 4.5mΩ NMOS and 16mΩ PMOS switches. Its architecture supports forced continuous or pulse-skip operation via MODE/SYNC pin configuration.
It integrates a precision 400mV enable threshold with hysteresis, 100% duty cycle dropout capability, and dual overcurrent protection: top-switch peak limit (15–21A) and bottom-switch valley limit (12–16A). The SSTT pin provides combined soft-start, voltage tracking, and die temperature monitoring (4mV/°C slope) without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.25V to 5.5V - supports single-cell Li-ion, 3.3V/5V intermediate bus, and automotive cold-crank conditions down to 2.25V. |
| VOUT Range | 0.5V to VIN - enables sub-1V FPGA/ASIC core rails with ±1% regulation accuracy using remote sense. |
| Max Output Current | 12.5A - sustained delivery enabled by thermally enhanced 3mm × 3mm LQFN package with exposed PGND pad. |
| Switching Frequency | Programmable 0.5–5MHz via RT resistor - allows optimization of inductor size (e.g., 100nH at 2MHz) vs. efficiency trade-off. |
| Min On-Time | 35ns - supports high VIN/VOUT ratios (e.g., 5V→1.2V at 2MHz) without pulse skipping or instability. |
| Shutdown Current | 1µA - enables ultra-low-power system standby states in battery-backed industrial controllers. |
| Thermal Rating | Junction range –40°C to +125°C - qualified per AEC-Q100 Grade 1 for under-hood automotive applications. |
Pinout & Package
Package: 18-lead 3mm × 3mm LQFN with exposed PGND pad (Pin 19), θJCbottom = 9°C/W, requiring soldering of exposed pad to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN (1) | Enable control input | Precision 400mV threshold with hysteresis; direct tie-to-VIN enables operation; <0.4V disables regulator with 1µA shutdown current. |
| AGND (2) | Remote sense ground reference | Kelvin connection point for FB divider low-side; rejects up to ±100mV PCB ground offset for accurate remote VOUT regulation. |
| VIN (3,4,11,12) | Main power input | Four parallel pins reduce IR drop and inductance; must be short-traced and locally bypassed to PGND with low-ESR ceramics. |
| PGND (5,10,19) | Power ground return | Three dedicated pins + exposed pad form primary thermal path; requires multiple large vias to inner ground planes. |
| SW (6–9) | Switch node output | Four paralleled SW pins drive external inductor; low-inductance routing critical to minimize EMI and voltage spikes. |
| MODE/SYNC (13) | Multi-phase sync & mode control | Configures pulse-skip/forced-continuous mode or accepts/synchronizes to external 0.5–2.25MHz clock signal. |
| PGOOD (14) | Power status indicator | Open-drain output asserts low when VOUT deviates >3% from setpoint or during fault; includes 125µs delay to reject transients. |
| RT (15) | Oscillator frequency programming | Resistor to AGND sets fSW from 0.5–5MHz; e.g., 274kΩ yields 2MHz default for Wurth 100nH inductor selection. |
| SSTT (16) | Soft-start/track/temp monitor | 10µA internal current charges external capacitor for controlled VOUT ramp; post-startup voltage = 4mV × Tj for die temp readout. |
| ITH (17) | Loop compensation node | Connects Type II/III compensation network (RC + C) referenced to AGND; sets bandwidth and phase margin for transient response. |
| FB (18) | Feedback voltage input | Regulated to 500mV ±5mV; connects to resistive divider from VOUT; phase-lead cap from FB to VOUT improves load-step response. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 Architecture | Integrated VIN bypass capacitors and balanced SW layout reduce radiated EMI to meet CISPR25 Class 5 limits without shielding. |
| Thermally Enhanced LQFN | 3mm × 3mm footprint with θJCbottom = 9°C/W enables 12.5A operation at <125°C junction without heatsink in 1-layer PCB designs. |
| Robust Overcurrent Protection | Dual-level current limiting: peak NMOS switch limit (15–21A) and valley PMOS limit (12–16A) prevent inductor saturation during overload. |
| Configurable Multi-Phase Support | MODE/SYNC pin enables precise phase alignment across parallel LTC3311S units for >12.5A scalable power stages. |
| Integrated Temperature Monitoring | SSTT pin outputs 4mV/°C analog voltage post-soft-start - enables real-time die temperature readback without external sensor. |
Applications
| Automotive ADAS Power Supply | Telecom Baseband Processor Rail |
|---|---|
Use Scenario: Powers 1.2V core of radar SoC in engine compartment with ambient temperatures up to 105°C and cold-crank VIN dips to 2.5V. IC Role / Device Role / Timing Role: Primary POL regulator delivering 12.5A with AEC-Q100 qualification, PGOOD sequencing, and thermal derating via SSTT monitoring. Use Value: Maintains ±1% output accuracy despite ±100mV ground shift between module and SoC; Silent Switcher 2 eliminates need for EMI filters in compact radar housing. |
Use Scenario: Supplies 1.8V/10A rail to 5G baseband processor in densely packed macro cell radio unit with strict conducted/radiated EMI limits. IC Role / Device Role / Timing Role: High-efficiency, low-noise buck converter synchronized to system clock via MODE/SYNC pin for deterministic noise placement. Use Value: 2MHz operation enables 100nH inductor and 22µF ceramic output caps; 4.5mΩ RDS(ON) achieves >92% efficiency at full load, reducing thermal load in sealed enclosure. |
| FPGA Core Voltage Regulation | Industrial PLC I/O Module Supply |
Use Scenario: Generates 0.85V/8A core voltage for Xilinx Kintex Ultrascale+ FPGA in factory automation controller with tight board area constraints. IC Role / Device Role / Timing Role: Compact 3mm × 3mm step-down regulator with remote sense (AGND) and programmable soft-start for safe FPGA configuration sequencing. Use Value: 35ns min-on-time supports 5V→0.85V conversion at 2MHz; FB accuracy ±1% ensures reliable FPGA startup across –40°C to 85°C operating range. |
Use Scenario: Provides isolated 3.3V/3A auxiliary supply for digital I/O banks in DIN-rail mounted PLC with wide input range (2.25–5.5V) and surge immunity. IC Role / Device Role / Timing Role: Robust DC/DC converter with UVLO hysteresis (150mV), output short-circuit recovery, and thermal shutdown for unattended industrial deployment. Use Value: 100% duty cycle operation sustains regulation during brownouts; valley-current limiting prevents latch-up during I/O short events without external circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3310SEV#TRMPBF | Lower max output current (8A), no SSTT temperature monitor, identical pinout and Silent Switcher 2 EMI performance. | Suitable for lower-power FPGA or microcontroller cores where thermal monitoring is not required. | Select when 8A suffices and die temperature telemetry is unnecessary - reduces BOM cost while retaining layout compatibility. |
| TPS546B24RVFT | 6V–18V input range, 40A capability, PMBus interface, larger 5mm × 5mm QFN package, no integrated temperature sensing. | Targets higher-input industrial or server applications requiring digital control and telemetry beyond analog monitoring. | Choose for systems needing PMBus configuration, input voltages above 5.5V, or >12.5A output - not pin-compatible; requires new layout. |
Compared with LTC3311SEV#TRMPBF, LTC33110SEV#TRMPBF offers reduced current capacity but identical footprint and EMI behavior, while TPS546B24RVFT provides digital control and higher voltage/current at the cost of larger size and no analog temperature output.
Availability
LTC3311SEV#TRMPBF is available at Aetrix Electronics and suitable for automotive ADAS modules, 5G telecom baseband supplies, and FPGA core power applications requiring stable component supply, AEC-Q100 compliance, and high-density POL integration.
Supply support for LTC3311SEV#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and automotive markets since 1965.
The LTC3311S product line delivers ultra-low-noise, high-current monolithic DC/DC converters for space-constrained, EMI-sensitive applications including automotive radar, 5G infrastructure, and high-end computing - emphasizing Silent Switcher 2 integration and thermal efficiency.
FAQ
What is the maximum output current capability of the LTC3311SEV#TRMPBF?
The LTC3311SEV#TRMPBF delivers up to 12.5A of continuous output current under typical thermal conditions using the 3mm × 3mm LQFN package with proper PCB copper area and airflow. Its 4.5mΩ NMOS and 16mΩ PMOS switches, combined with θJCbottom = 9°C/W, enable this rating while maintaining junction temperature below 125°C in most 2-layer board implementations. Derating is required above 85°C ambient.
Does the LTC3311SEV#TRMPBF support synchronization to an external clock source?
Yes, the LTC3311SEV#TRMPBF supports external clock synchronization via the MODE/SYNC pin, accepting square-wave inputs from 0.5MHz to 2.25MHz. During synchronization, it operates in forced continuous mode, locks top-switch turn-on to the rising edge of the external clock, and automatically adapts slope compensation. The internal PLL detects clock removal within ~20µs and reverts to the default 2MHz frequency.
How does the SSTT pin function across different operating modes of the LTC3311SEV#TRMPBF?
The SSTT pin on the LTC3311SEV#TRMPBF serves three distinct roles: during startup, it sources 10µA to charge an external capacitor for controlled soft-start; once regulation is achieved, it transitions to outputting a 4mV/°C analog voltage proportional to die temperature; during output short-circuit recovery, it is pulled low to initiate a new soft-start cycle, ensuring safe re-enabling after fault clearance.
What is the significance of the AGND pin in the LTC3311SEV#TRMPBF design?
The AGND pin on the LTC3311SEV#TRMPBF is the dedicated remote ground sense reference for the feedback divider, enabling Kelvin sensing to reject up to ±100mV of PCB ground potential difference between the IC and load. It must be connected directly to the negative terminal of the output capacitor at the load point-not to local PGND-to maintain ±1% VOUT accuracy in high-current, multi-ground-plane systems.
Is the LTC3311SEV#TRMPBF qualified for automotive applications?
Yes, the LTC3311SEV#TRMPBF is AEC-Q100 qualified for automotive applications (Grade 1, –40°C to +125°C junction temperature) and features built-in protections essential for under-hood use: input undervoltage lockout with hysteresis, output overvoltage protection, thermal shutdown, and robust short-circuit recovery. Its Silent Switcher 2 architecture meets stringent CISPR25 Class 5 EMI requirements common in ADAS systems.
LTC3311SEV#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 18-TFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.25V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.5V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 12.5A
- Frequency - Switching:
- 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 18-LQFN (3x3)
LTC3311SEV#TRMPBF FAQ
1.How can I place an order for LTC3311SEV#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3311SEV#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 LTC3311SEV#TRMPBF reliable?
The price and inventory of LTC3311SEV#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3311SEV#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3311SEV#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3311SEV#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3311SEV#TRMPBF?
LTC3311SEV#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3311SEV#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 LTC3311SEV#TRMPBF?
For technical support, including LTC3311SEV#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3311SEV#TRMPBF requirements.
6.How does Aetrix verify that LTC3311SEV#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3311SEV#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 LTC3311SEV#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3311SEV#TRMPBF?
All LTC3311SEV#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3311SEV#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 LTC3311SEV#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3311SEV#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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