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Analog Devices Inc. LT3581IMSE#PBF
- Part No.:
- LT3581IMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3581IMSE#PBF.pdf
- Description:
- IC REG BST CHARG PUMP ADJ 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:111
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Product details
Overview
LT3581IMSE#PBF from Analog Devices (formerly Linear Technology) is a 3.3A combined master/slave PWM DC/DC converter IC designed for high-efficiency boost, inverting, SEPIC, and flyback power conversion. It integrates dual 42V NPN switches (1.9A master + 1.4A slave), supports 2.5V–22V input, delivers up to 12V@830mA or –12V@625mA from 5V, and features output short-circuit, overvoltage, and overtemperature protection. It is used in TFT-LCD bias supplies and automotive ECU local power rails.
For engineers reviewing the LT3581IMSE#PBF datasheet, LT3581IMSE#PBF pinout, LT3581IMSE#PBF application, or LT3581IMSE#PBF equivalent, key selection considerations include its 16-lead MSOP package, 200kHz–2.5MHz programmable switching frequency, fault-protected dual-switch architecture, and integrated soft-start, UVLO, and clock synchronization via CLKOUT/SYNC pins.
Technical Context
The LT3581IMSE#PBF employs constant-frequency current-mode control with internal ramp compensation and dual independent switch drivers. Its master/slave topology enables flexible configuration-SW1 and SW2 can be paralleled for 3.3A total current limit or used separately in multi-output or charge-pump topologies.
Fault detection is implemented through real-time monitoring of SW1/SW2 current, VIN overvoltage (>22V), SW node overvoltage (>42V), and die temperature (>165°C), triggering automatic shutdown, GATE pin deactivation, and FAULT pin assertion. The SS pin orchestrates soft-start and post-fault recovery sequencing with voltage-controlled current ramping.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 22V operating; withstands 40V transients - supports wide industrial and automotive supply rails. |
| Switch Current Limit | 1.9A (SW1) + 1.4A (SW2) = 3.3A combined - enables high-power local regulation without external MOSFETs. |
| Switching Frequency | 200kHz to 2.5MHz, adjustable via RT resistor or external SYNC clock - allows optimization for size (high-f) or efficiency (low-f). |
| Feedback Reference | 1.215V (positive mode) or 9mV (inverting mode) - enables precise output voltage setting across configurations. |
| Protection Features | Output short-circuit, VIN overvoltage (>22V), SW overvoltage (>42V), overtemperature (>165°C) - autonomous fault response without controller intervention. |
| Package | 16-lead plastic MSOP (0.65mm pitch), exposed pad grounded - provides thermal performance (θJA = 45°C/W) and compact footprint. |
| Operating Temperature | –40°C to +125°C junction - qualified for under-hood automotive and industrial embedded environments. |
Pinout & Package
LT3581IMSE#PBF is housed in a 16-lead plastic MSOP package with an exposed thermal pad (Pin 17) that must be soldered to PCB ground for thermal and electrical integrity. Pin pitch is 0.65mm; body dimensions are 4.0mm × 3.0mm × 1.1mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback Input | Accepts positive (1.215V ref) or negative (9mV ref) feedback voltage - configures output regulation for boost or inverting topologies. |
| VC (Pin 2) | Error Amplifier Output | Drives external compensation network - sets loop stability and transient response for all configurations. |
| GATE (Pin 3) | PMOS Gate Driver | Sinks up to 933µA (linear with SS voltage) - controls external PMOS for output disconnect during faults. |
| FAULT (Pin 4) | Bidirectional Fault Indicator | Active-low open-drain output; also accepts external low signal - triggers full shutdown and initiates SS timeout sequence. |
| VIN (Pin 5) | Main Input Supply | Power input for internal circuitry and switches - requires local ceramic bypass (≥4.7µF) to minimize noise and EMI. |
| SW1 (Pins 6,7,8) | Master Switch Collector | 42V, 1.9A rated NPN collector - primary switching node; trace area must be minimized to reduce EMI. |
| SW2 (Pins 9,10,11) | Slave Switch Collector | 42V, 1.4A rated NPN collector - configurable in parallel with SW1 or as independent switch. |
| CLKOUT (Pin 12) | Clock Output / Temp Monitor | Buffered oscillator output (2.1V CMOS); duty cycle varies linearly with junction temperature - synchronizes other regulators or monitors die temp. |
| SHDN (Pin 13) | Shutdown Control | High-gain input with 1.33V typical turn-on threshold and 30mV hysteresis - supports slow-ramping enable signals and configurable UVLO. |
| RT (Pin 14) | Frequency Set Resistor | Connects to ground to set free-running frequency (200kHz–2.5MHz) - determines minimum on/off times and ripple trade-offs. |
| SS (Pin 15) | Soft-Start Control | Charged by internal 250kΩ resistor; voltage ramps GATE current and enables CLKOUT at 1.8V - manages inrush and fault recovery timing. |
| SYNC (Pin 16) | External Clock Input | Accepts 0.4V–1.3V logic-level clock - overrides internal oscillator to synchronize multiple converters and reduce beat frequencies. |
| GND (Exposed Pad) | Power & Signal Ground | Thermal and electrical reference plane - must be soldered to large PCB copper area for θJC = 10°C/W performance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 42V NPN Switches | SW1 (1.9A) and SW2 (1.4A) support parallel operation for 3.3A total current or independent use in multi-rail designs. |
| Integrated Fault Protection | Autonomous detection and shutdown for output shorts, VIN >22V, SW >42V, and TJ >165°C - eliminates need for external monitoring circuitry. |
| Configurable UVLO | SHDN pin accepts resistor divider from VIN to set custom turn-on voltage - enables system-level brown-out management. |
| Sample Mode Short Detection | Forces Q1/Q2 on each cycle when FB is out-of-regulation (>3.7%) - reliably detects output shorts before catastrophic failure. |
| CLKOUT Synchronization | Drives compatible regulators with matched frequency and phase - reduces EMI and improves power rail coherence in multi-converter systems. |
Applications
| TFT-LCD Bias Supply | Automotive ECU Local Power |
|---|---|
Use Scenario: Generating ±15V and +24V rails from a 12V battery for LCD panel gate/source drivers and gamma correction circuits. IC Role / Device Role / Timing Role: Dual-output inverting/boost converter with fault-protected switching - regulates high-impedance bias voltages while surviving load dumps and cold cranking. Use Value: Eliminates discrete protection FETs and external current-sense amplifiers; maintains display functionality during transient overloads. | Use Scenario: Providing isolated 5V and 3.3V supplies for microcontroller, CAN transceiver, and sensor interfaces in engine control units. IC Role / Device Role / Timing Role: Compact, thermally robust DC/DC converter with wide VIN range and overtemperature shutdown - ensures reliable operation in high-ambient under-hood environments. Use Value: Reduces BOM count vs. discrete buck-boost solutions; exposed pad enhances thermal reliability at 125°C ambient. |
| Vacuum Fluorescent Display (VFD) Bias | Industrial Sensor Node Power |
Use Scenario: Delivering 30–60V anode supply and –10V grid bias from a 3.3V or 5V system rail for VFD segment driving. IC Role / Device Role / Timing Role: High-voltage inverting/boost converter with 42V switches and programmable fSW - achieves fast startup and stable high-impedance outputs. Use Value: Enables single-chip VFD bias generation without transformer-based topologies; frequency foldback improves start-up control into capacitive loads. | Use Scenario: Powering low-duty-cycle wireless sensor nodes (LoRa, NB-IoT) from coin cells or energy harvesters requiring regulated 3.3V output. IC Role / Device Role / Timing Role: Ultra-low quiescent current (2.3mA active, <1µA shutdown) boost converter with soft-start - extends battery life while ensuring clean wake-up sequencing. Use Value: Integrates UVLO hysteresis and fault latching to prevent brown-out oscillation; SS pin enables controlled wake-up without inrush stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3589EUF#PBF | Quad-output PMIC with integrated LDOs and I²C interface; lower max switch current (1.2A per channel); no dual-NPN master/slave topology. | Targets complex multi-rail SoC power; lacks standalone high-current inverting capability and analog fault signaling. | Choose LTC3589EUF#PBF only when digital control and multiple regulated outputs are required - not a functional replacement for LT3581IMSE#PBF's high-power analog topology. |
| TPS61088RHLR | Single-switch 10A boost converter; no slave switch, no inverting mode, no integrated fault protection (requires external circuitry for OVP/OCP). | Optimized for high-efficiency single-output boost; unsuitable for VFD bias or fault-critical automotive applications without added components. | Choose TPS61088RHLR for cost-sensitive, high-current boost-only designs where external protection is acceptable - not drop-in or functionally equivalent. |
Compared with LTC3589EUF#PBF and TPS61088RHLR, the LT3581IMSE#PBF uniquely combines dual 42V switches, native inverting capability, autonomous analog fault handling, and MSOP thermal performance - making it irreplaceable for compact, protected, multi-topology local power in harsh environments.
Availability
LT3581IMSE#PBF is available at Aetrix Electronics and suitable for TFT-LCD bias supplies, automotive ECU power rails, and industrial sensor node designs requiring stable component supply, long-term lifecycle assurance, and guaranteed lead-free compliance.
Supply support for LT3581IMSE#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3581IMSE#PBF belongs to ADI's legacy Linear Technology power conversion portfolio, engineered specifically for rugged, fault-tolerant local DC/DC regulation in space-constrained industrial and automotive systems.
FAQ
What is the maximum output current capability of the LT3581IMSE#PBF in boost configuration?
The LT3581IMSE#PBF delivers up to 830mA at 12V from a 5V input in boost mode, as verified in the Typical Application circuit (TA01). This assumes optimal layout, 2MHz switching, and proper thermal management via the exposed pad. Peak switch current remains within the 3.3A combined limit, but output current is constrained by efficiency, inductor saturation, and thermal limits - actual achievable current depends on board design and ambient conditions. The LT3581IMSE#PBF datasheet specifies this performance under defined test conditions.
Does the LT3581IMSE#PBF support inverting topology, and what is its typical output capability?
Yes, the LT3581IMSE#PBF natively supports inverting configuration, generating negative outputs such as –12V at 625mA from a 5V input (per Typical Application TA01). It uses the 9mV negative feedback reference and leverages both SW1 and SW2 for efficient high-current inversion. The inverting mode benefits from the same fault protections and 42V switch rating as boost mode. The LT3581IMSE#PBF's dual-switch architecture makes it especially effective for high-voltage, high-efficiency inverting supplies in display and instrumentation applications.
How does the FAULT pin function on the LT3581IMSE#PBF, and what events trigger it?
The FAULT pin on the LT3581IMSE#PBF is a bidirectional, active-low open-drain indicator. It is pulled low internally during FAULT1 events (VIN >22V, SW >42V, SW1 current >1.9A, or die temperature >165°C) or externally asserted as FAULT2. When active, it disables switching, deactivates CLKOUT, and forces the GATE pin high-impedance to disconnect external PMOS. Recovery requires the FAULT pin voltage to exceed 1.0V. The LT3581IMSE#PBF's state diagram defines precise timing for fault detection and timeout via the SS pin.
Can the LT3581IMSE#PBF be synchronized to an external clock, and what are the voltage requirements?
Yes, the LT3581IMSE#PBF supports external synchronization via the SYNC pin. A logic-level clock with high voltage ≥1.3V and low voltage ≤0.4V, and duty cycle between 20%–80%, will lock the internal oscillator. Driving SYNC below 0.4V reverts to free-running mode set by the RT resistor. The CLKOUT pin provides a buffered copy of the synchronized frequency for cascading to other regulators. This capability is confirmed in the Electrical Characteristics table and Applications Information section of the LT3581IMSE#PBF datasheet.
What is the purpose of the GATE pin on the LT3581IMSE#PBF, and how is it controlled?
The GATE pin on the LT3581IMSE#PBF is a current-sinking driver for an external PMOS transistor used in output disconnect or input isolation. Its pull-down current increases linearly with SS pin voltage, reaching 933µA above 500mV - enabling soft turn-on of the PMOS to limit inrush current. Below 500mV, GATE current is proportionally reduced, allowing controlled hot-plug operation. The LT3581IMSE#PBF's GATE behavior is fully characterized in the Typical Performance Characteristics (G09, G10) and PIN FUNCTIONS section.
LT3581IMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Charge Pump, Cuk, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 22V
- Voltage - Output (Min/Fixed):
- 1.215V
- Voltage - Output (Max):
- 42V (Switch)
- Current - Output:
- 3.3A (Switch)
- Frequency - Switching:
- 200kHz ~ 2.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3581IMSE#PBF FAQ
1.How can I place an order for LT3581IMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3581IMSE#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 LT3581IMSE#PBF reliable?
The price and inventory of LT3581IMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3581IMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3581IMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3581IMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3581IMSE#PBF?
LT3581IMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3581IMSE#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 LT3581IMSE#PBF?
For technical support, including LT3581IMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3581IMSE#PBF requirements.
6.How does Aetrix verify that LT3581IMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3581IMSE#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 LT3581IMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3581IMSE#PBF?
All LT3581IMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3581IMSE#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 LT3581IMSE#PBF part is unused and in its original packaging.
Return procedure for LT3581IMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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