My Inquiry
My Account
Analog Devices Inc. LT3581EMSE#PBF
- Part No.:
- LT3581EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3581EMSE#PBF.pdf
- Description:
- IC REG BST CHARG PUMP ADJ 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:661
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3581EMSE#PBF from Analog Devices (formerly Linear Technology) is a 3.3A, 42V combined master/slave PWM DC/DC converter IC for boost, inverting, SEPIC, and flyback topologies. It delivers 12V at 830mA or –12V at 625mA from a 5V input, features output short-circuit protection, 200kHz–2.5MHz programmable switching frequency, and integrated fault detection for overvoltage, overtemperature, and overcurrent conditions - used in TFT-LCD bias supplies and automotive ECU power rails.
For engineers reviewing the LT3581EMSE#PBF datasheet, LT3581EMSE#PBF pinout, LT3581EMSE#PBF application, or LT3581EMSE#PBF equivalent, key selection considerations include its dual-switch current sharing (1.9A/1.4A), 250mV VCE(SAT) at 2.75A, 16-lead MSOP package with exposed thermal pad, and configurable undervoltage lockout via SHDN pin.
Technical Context
The LT3581EMSE#PBF implements constant-frequency current-mode control with internal 1.215V positive feedback reference and 9mV negative feedback threshold. Its master/slave NPN switch architecture enables flexible topology configuration while maintaining precise peak-current regulation via external sense resistor and ramp compensation.
Fault management uses dual-path detection: FAULT1 (internal - SW overcurrent, VIN >22V, SWx >42V, TJ >165°C) and FAULT2 (external pull-down). During fault, it disables switches, asserts active-low FAULT, disables CLKOUT, and executes SS pin charge/discharge timeout sequence to isolate downstream circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Configuration | Dual NPN: 1.9A master + 1.4A slave, tied for 3.3A total current limit |
| Input Voltage Range | 2.5V to 22V operating; 40V transient tolerance - supports wide automotive and industrial supply rails |
| Switching Frequency | 200kHz to 2.5MHz, set by RT resistor or external SYNC clock - enables compact magnetics and EMI optimization |
| VCE(SAT) | 250mV at 2.75A with both switches tied - minimizes conduction loss in high-current boost/inverting designs |
| Feedback Reference | 1.215V (boost/SEPIC) or 9mV (inverting) - enables precise output voltage regulation across topologies |
| Quiescent Current | 2.3mA typical (active), 1µA max (shutdown) - suitable for low-power always-on subsystems |
| Thermal Protection | Internal overtemperature shutdown at 165°C junction - prevents permanent damage during sustained overload |
Pinout & Package
LT3581EMSE#PBF is housed in a 16-lead plastic MSOP package (3mm × 4.9mm) with exposed thermal pad (Pin 17 = GND), optimized for thermal dissipation in high-power DC/DC applications. Pin count and layout match industry-standard MSOP footprint for compatibility with existing PCB tooling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Positive/Negative Feedback Input | Accepts 1.215V reference for boost or 9mV for inverting mode - sets output voltage via single resistor divider |
| VC (Pin 2) | Error Amplifier Output | Drives external compensation network (capacitor + resistor + capacitor) to stabilize loop response |
| GATE (Pin 3) | PMOS Gate Drive Output | Sinks up to 933µA to control external PMOS for output disconnect during fault - soft-start ramped with SS voltage |
| FAULT (Pin 4) | Bidirectional Fault Indicator | Active-low open-drain output; pulled low internally on fault or externally to force shutdown - requires 100kΩ pull-up |
| VIN (Pin 5) | Main Input Supply | 2.5V–22V input rail; must be locally bypassed with ≥4.7µF ceramic capacitor near pin |
| SW1 (Pins 6,7,8) | Master Switch Collector | 1.9A rated NPN collector; connects to inductor/transformer primary - minimize trace area to reduce EMI |
| SW2 (Pins 9,10,11) | Slave Switch Collector | 1.4A rated NPN collector; paralleled with SW1 for 3.3A operation or used independently in multi-rail designs |
| CLKOUT (Pin 12) | Buffered Oscillator Output | Drives ≤50pF load at same frequency as internal oscillator/SYNC - used for multi-regulator synchronization or temperature monitoring |
| SHDN (Pin 13) | Shutdown Control Input | High-impedance input with 1.33V turn-on threshold and 30mV hysteresis - accepts slow-ramping signals for UVLO implementation |
| RT (Pin 14) | Frequency Setting Input | Connects to ground via resistor (e.g., 43.2kΩ for 2MHz); sets free-running oscillator frequency |
| SS (Pin 15) | Soft-Start Timing Node | Charged by internal 250kΩ resistor; controls ramp rate of switch current and GATE drive - 100nF–1µF capacitor typical |
| SYNC (Pin 16) | External Clock Input | Accepts 0.4V–1.3V logic-level clock; overrides internal oscillator when driven - enables system-wide switching frequency alignment |
| GND (Exposed Pad) | Power Ground / Thermal Path | Must be soldered to PCB ground plane; provides primary thermal conduction path (θJC = 10°C/W) |
Key Features
| Feature | Design Value |
|---|---|
| Output Short-Circuit Protection | Automatic shutdown and isolation via GATE-driven PMOS when FB detects out-of-regulation condition |
| Configurable Undervoltage Lockout | SHDN pin accepts resistor divider from VIN to set custom turn-on threshold (e.g., 8V UVLO using RUVLO1/RUVLO2) |
| Frequency Foldback | Reduces switching frequency to 1/6 nominal when FB enters 350mV–900mV range - improves start-up current control |
| Sample Mode Fault Detection | Forces Q1/Q2 on every cycle when |FB – VREF| >3.7% to sample inductor current and detect output shorts |
| CLKOUT Temperature Monitoring | CLKOUT duty cycle varies linearly with junction temperature - enables passive thermal sensing without external sensor |
Applications
| TFT-LCD Bias Supply | Automotive ECU Power |
|---|---|
Use Scenario: Generating ±15V and +24V rails for LCD panel gate/source drivers in infotainment displays. IC Role / Device Role / Timing Role: Dual-output inverting/boost converter providing isolated high-voltage bias with fault containment. Use Value: Integrated master/slave switches eliminate need for discrete current-sharing components; 42V rating supports 24V automotive input transients. | Use Scenario: Local 5V-to-12V boost supply for engine control unit microcontrollers and sensors in 12V vehicle systems. IC Role / Device Role / Timing Role: High-efficiency, fault-protected DC/DC converter powering safety-critical subsystems. Use Value: 165°C overtemperature shutdown and VIN OVLO (22V) prevent latch-up during load-dump events; MSOP package fits constrained ECU layouts. |
| Vacuum Fluorescent Display (VFD) Bias | Industrial Sensor Interface Power |
Use Scenario: Providing 30V–60V anode supply and –10V grid bias for VFD modules in HVAC and instrumentation panels. IC Role / Device Role / Timing Role: High-voltage inverting/charge-pump capable converter delivering stable bias under variable load. Use Value: 42V switch rating and adjustable frequency allow efficient high-VOUT generation; fault protection avoids display burn-in during filament surge. | Use Scenario: Isolated 3.3V-to-15V boost for analog front-end amplifiers and ADC references in 4–20mA loop-powered sensors. IC Role / Device Role / Timing Role: Compact, low-noise local regulator with precise feedback and soft-start for signal integrity. Use Value: 1.215V reference and 83.3µA FB bias current enable <1% output accuracy; SS-controlled ramp prevents sensor offset drift at power-up. |
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 buck, boost, LDOs; no integrated high-voltage switches - requires external FETs for >20V output | Targeted at portable SoC power, not high-voltage bias generation | Select when multi-rail sequencing and ultra-low quiescent current (<10µA) are required over high-voltage capability |
| TPS61088RHLR | Single-switch 10A boost IC with 12.6V max VSW; lacks slave switch, fault protection, and inverting mode support | Optimized for USB PD and battery-powered 5V–20V boost, not industrial bias supplies | Select when highest efficiency at 3–5A and minimal BOM count are priorities, and 42V switch rating is unnecessary |
Compared with LTC3589EUF#PBF and TPS61088RHLR, the LT3581EMSE#PBF uniquely combines dual 42V NPN switches, inverting topology support, and comprehensive fault protection - making it irreplaceable for high-reliability TFT-LCD and automotive bias applications requiring >20V outputs and robust short-circuit handling.
Availability
LT3581EMSE#PBF is available at Aetrix Electronics and suitable for TFT-LCD bias supplies, automotive ECU power rails, vacuum fluorescent display (VFD) drivers, and industrial sensor interface power requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT3581EMSE#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 digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3581 belongs to ADI's high-voltage monolithic DC/DC converter product line, designed specifically for space-constrained, fault-critical applications demanding robust protection, flexible topology support, and wide input/output voltage ranges - including automotive, industrial, and display power systems.
FAQ
What is the maximum output voltage achievable with LT3581EMSE#PBF in boost configuration?
The LT3581EMSE#PBF supports output voltages up to 40V in standard boost mode using internal feedback. For higher outputs (e.g., 60V), external charge-pump aided regulation is recommended per the datasheet's "Charge Pump Aided Regulators" section. The 42V switch rating ensures safe operation with margin against transients, but output voltage is limited by external component selection and stability constraints - not by the IC's intrinsic capability.
Does LT3581EMSE#PBF support true inverting operation with negative output regulation?
Yes, LT3581EMSE#PBF supports true inverting operation with regulated negative output. It uses a dedicated 9mV negative feedback reference (vs. 1.215V for boost) and adjusts error amplifier behavior accordingly. The FB pin interprets voltage polarity relative to GND, enabling stable –12V at 625mA from 5V input as verified in the Typical Application schematic. No external level-shifting circuitry is required.
How does the LT3581EMSE#PBF implement output short-circuit protection without external current sense resistors?
The LT3581EMSE#PBF implements output short-circuit protection using Sample Mode: when FB deviates >3.7% from its reference (e.g., <45mV in inverting mode), the IC forces both SW1 and SW2 fully on each cycle to directly measure inductor current. If sampled current exceeds 1.9A (SW1) or 3.3A (combined), it triggers FAULT1 and disables switching. This eliminates need for external sense resistors while maintaining fast, accurate short detection.
Can LT3581EMSE#PBF synchronize to an external clock while maintaining frequency foldback functionality?
Yes, LT3581EMSE#PBF retains full frequency foldback behavior when synchronized to an external clock. Foldback activates based on FB pin voltage (350mV–900mV range), independent of clock source. When SYNC is driven, the internal oscillator is disabled and foldback modulates the external clock's effective duty cycle - preserving inrush current limiting and start-up stability even in synchronized multi-regulator systems.
What is the thermal performance difference between LT3581EMSE#PBF (MSOP) and LT3581EDE#PBF (DFN)?
LT3581EMSE#PBF in 16-lead MSOP has θJA = 45°C/W and θJC = 10°C/W, while LT3581EDE#PBF in 14-lead DFN has θJA = 43°C/W and θJC = 4.3°C/W. The DFN offers superior junction-to-case thermal resistance due to larger exposed pad area, but the MSOP's longer leads provide better mechanical reliability in high-vibration environments like automotive ECUs - making LT3581EMSE#PBF preferred where board-level shock resistance outweighs marginal thermal advantage.
LT3581EMSE#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
LT3581EMSE#PBF FAQ
1.How can I place an order for LT3581EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3581EMSE#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 LT3581EMSE#PBF reliable?
The price and inventory of LT3581EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3581EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3581EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3581EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3581EMSE#PBF?
LT3581EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3581EMSE#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 LT3581EMSE#PBF?
For technical support, including LT3581EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3581EMSE#PBF requirements.
6.How does Aetrix verify that LT3581EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3581EMSE#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 LT3581EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3581EMSE#PBF?
All LT3581EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3581EMSE#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 LT3581EMSE#PBF part is unused and in its original packaging.
Return procedure for LT3581EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3581EMSE#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
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…
