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Analog Devices Inc. LT8609IMSE#PBF
- Part No.:
- LT8609IMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT8609IMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,740
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Product details
Overview
LT8609IMSE#PBF from Analog Devices is a 42V, 3A synchronous step-down regulator with peak current mode control, 2.5µA quiescent current in Burst Mode, 45ns minimum on-time, and internal compensation. It operates from 3.0V to 42V input, delivers regulated 5V or adjustable output, and targets automotive infotainment power rails requiring low EMI and cold-crank survival.
For engineers reviewing the LT8609IMSE#PBF datasheet, LT8609IMSE#PBF pinout, LT8609IMSE#PBF application, or LT8609IMSE#PBF equivalent, key selection factors include its 10-lead MSOP package with side-wettable flanks, SYNC pin for external clock synchronization or spread-spectrum modulation, EN/UV pin with 1.05V accurate enable threshold, and PG flag with ±8.5% output regulation monitoring.
Technical Context
The LT8609IMSE#PBF implements a monolithic constant-frequency peak current mode architecture with internal 0.782V reference and slope compensation. Its oscillator frequency is resistor-programmable from 200kHz to 2.2MHz via the RT pin, and it supports Burst Mode operation for ultralow IQ at light loads while maintaining <10mVP-P output ripple.
It integrates dual N-channel MOSFETs (185mΩ top / 115mΩ bottom), features fast minimum on-time (45ns) for high VIN/VOUT ratios, and includes integrated soft-start via TR/SS pin with 2µA internal current source. The PG pin provides open-drain power-good signaling referenced to FB (±8.5%) or VOUT (±7.5% for fixed versions).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0V to 42V - supports automotive cold-crank (4.5V) and load-dump (40V) transients without external protection. |
| Quiescent Current (Burst Mode) | 2.5µA at 12VIN → 3.3VOUT - enables always-on systems with multi-year battery life in low-power states. |
| Continuous Output Current | 3A - sufficient for powering microcontrollers, sensors, and interface ICs in compact industrial controllers. |
| Minimum On-Time | 45ns - allows stable 5V output from 42V input at 2MHz switching frequency without duty-cycle limitation. |
| Switching Frequency Range | 200kHz to 2.2MHz - programmable via RT resistor; higher frequencies enable smaller magnetics and faster transient response. |
| Feedback Reference Voltage | 0.782V ±0.004V - precise internal reference enabling <1% output voltage accuracy with proper resistor tolerance. |
| Power-Good Threshold Accuracy | ±8.5% on FB pin - ensures reliable system sequencing and fault detection before downstream logic powers up. |
Pinout & Package
LT8609IMSE#PBF uses a 10-lead plastic MSOP package (MSE) with exposed thermal pad (Pin 11 = GND), θJA = 40°C/W. The exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| BST | Bootstrap supply for high-side gate driver | Requires 0.1µF ceramic capacitor to SW; enables efficient 100% duty-cycle capability and high-side FET drive. |
| SW | Switch node | Connects to inductor and BST capacitor; high di/dt node requiring minimized PCB loop area for EMI control. |
| INTVCC | Internal 3.5V regulator bypass | Must be decoupled with ≥1µF low-ESR ceramic; powers internal logic and gate drivers; not for external loading. |
| RT | Oscillator frequency programming | Resistor to GND sets fSW from 200kHz–2.2MHz; determines inductor size, efficiency trade-off, and EMI profile. |
| SYNC | External clock/synchronization input | Ground for Burst Mode; float for pulse-skipping; 3.2V–5V for spread-spectrum EMI reduction; absent on LT8609B. |
| EN/UV | Enable and input undervoltage lockout | 1.05V rising threshold with 50mV hysteresis; supports programmable VIN UVLO using external resistor divider. |
| PG | Open-drain power-good flag | Pulled low until FB within ±8.5% of 0.782V; valid above 3.2V VIN; used for system power sequencing and fault indication. |
| TR/SS | Soft-start and tracking control | 2µA internal current source charges external capacitor; controls output ramp rate and enables voltage tracking in multi-rail systems. |
| FB | Feedback input (adjustable version) | Regulated to 0.782V; connects to resistor divider for output voltage setting; high-impedance input (<±20nA leakage). |
| VIN | Main input supply | Supplies internal circuitry and high-side switch; requires local high-frequency ceramic bypass (≥1µF) near pin. |
| GND | Power and signal ground | Exposed pad (Pin 11); must be soldered to large PCB copper pour for thermal dissipation and low-noise grounding. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Reduces IQ to 2.5µA at no-load while maintaining <10mVP-P output ripple - critical for battery-backed automotive modules. |
| Synchronous rectification | Integrated 185mΩ/115mΩ NMOS switches eliminate external Schottky losses and improve full-load efficiency >93% at 1A. |
| Spread-spectrum modulation | When SYNC pin biased at 3.2–5V, modulates switching frequency by ±10% at 1–6kHz - reduces peak EMI by up to 10dB. |
| Internal compensation | Eliminates external compensation components; enables stable operation with small inductors (e.g., 2.2µH) and fast transient response. |
| Accurate enable threshold | 1.05V EN/UV threshold with 50mV hysteresis enables precise, repeatable startup and shutdown - essential for controlled power sequencing. |
| Side-wettable flanks | MSOP package exposes solderable edges on all four sides - enables automated optical inspection (AOI) of solder joints for automotive-grade reliability. |
Applications
| GSM Transceiver Power Supply | Automotive Infotainment Core Rail |
|---|---|
Use Scenario: Powering GSM/GPRS baseband and RF sections in telematics units with strict 12V battery input and burst-mode sleep requirements. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck converter delivering 3A peak during transmission bursts while sustaining <2.5µA quiescent draw between frames. Use Value: Enables 10+ year battery backup in disconnected state; 45ns min-on-time supports 42V load-dump survival without derating. |
Use Scenario: Generating core 5V rail for MCU, display controller, and audio codec in head-unit designs operating across –40°C to 125°C junction range. IC Role / Device Role / Timing Role: High-efficiency synchronous step-down regulator with AEC-Q100 qualification, PG flag for safe boot sequencing, and spread-spectrum EMI control for CISPR-25 compliance. Use Value: Eliminates need for external EMI filters; side-wettable flanks ensure solder joint reliability in thermal cycling environments. |
| Industrial PLC I/O Module | Low-EMI Point-of-Load Converter |
Use Scenario: Providing isolated 5V supply for digital I/O conditioning circuits in DIN-rail mounted programmable logic controllers with wide-input 24VDC field bus. IC Role / Device Role / Timing Role: Input-flexible buck regulator handling 18–32V field voltage variations while maintaining tight output regulation and low noise for analog sensor interfaces. Use Value: Internal compensation and 0.782V reference deliver <1% output error over line/load/temperature; PG flag validates rail before enabling I/O drivers. |
Use Scenario: Replacing linear regulators in noise-sensitive applications like precision ADC front-ends or RF bias supplies where switching noise must be minimized. IC Role / Device Role / Timing Role: Synchronous buck with Burst Mode and spread-spectrum SYNC control to suppress conducted and radiated emissions below regulatory limits. Use Value: Achieves <10mVP-P ripple at 2MHz switching; eliminates need for post-regulation LDOs, reducing BOM count and thermal overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609AIMSE#PBF | Fixed 5V output (no FB divider required); identical pinout, package, and temperature grade (–40°C to 125°C). | Eliminates feedback resistors but lacks output adjustability; suitable only where 5V is fixed system requirement. | Select LT8609AIMSE#PBF when board space is constrained and 5V output is invariant; retains all timing, EMI, and thermal features of LT8609IMSE#PBF. |
| LT8609BIMSE#PBF | No SYNC pin; pulse-skipping only (no Burst Mode or spread-spectrum); slightly lower IQ in regulation (350nA vs 1.7µA) but higher light-load IQ (several mA). | Designed for EMI-sensitive apps where deterministic pulse-skipping is preferred over Burst Mode's variable frequency; no external clock sync capability. | Choose LT8609BIMSE#PBF only if Burst Mode is undesirable and spread-spectrum is unnecessary; otherwise LT8609IMSE#PBF offers broader operational flexibility. |
Compared with LT8609AIMSE#PBF and LT8609BIMSE#PBF, the LT8609IMSE#PBF provides full configurability - adjustable output via FB, Burst Mode for lowest IQ, and SYNC-controlled spread-spectrum - making it the most versatile variant for design-in across automotive, industrial, and test equipment applications.
Availability
LT8609IMSE#PBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and GSM transceiver power supplies requiring stable component supply, AEC-Q100-compliant sourcing, and long-term lifecycle support.
Supply support for LT8609IMSE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8609 series belongs to Analog Devices' Power by Linear™ portfolio of high-efficiency, low-EMI DC/DC regulators designed specifically for automotive and industrial applications demanding ultralow quiescent current and robust transient performance.
FAQ
What is the maximum input voltage rating for the LT8609IMSE#PBF?
The LT8609IMSE#PBF has an absolute maximum input voltage rating of 42V on the VIN and EN/UV pins. This allows direct connection to 24V and 36V industrial buses and automotive 12V/24V systems under load-dump conditions without external clamping, provided thermal limits are observed.
Does the LT8609IMSE#PBF support adjustable output voltage?
Yes, the LT8609IMSE#PBF is the adjustable-output variant of the LT8609 family. It uses the FB pin referenced to an internal 0.782V precision bandgap to set output voltage via an external resistor divider - enabling outputs from ~1V to 40V depending on VIN and component selection.
How does the SYNC pin function on the LT8609IMSE#PBF?
On the LT8609IMSE#PBF, the SYNC pin supports three modes: grounded for low-ripple Burst Mode operation, floated for pulse-skipping mode, or biased at 3.2–5V for spread-spectrum frequency modulation. Unlike the LT8609BIMSE#PBF, the LT8609IMSE#PBF retains full SYNC functionality for EMI optimization.
What thermal considerations apply to the LT8609IMSE#PBF in a 10-lead MSOP package?
The LT8609IMSE#PBF in the 10-lead MSOP (MSE) package has θJA = 40°C/W. To maintain junction temperature ≤125°C at 3A continuous load, the exposed GND pad (Pin 11) must be soldered to ≥2 cm² of 2-oz copper with ≥4 thermal vias - especially critical in automotive under-hood applications.
Is the LT8609IMSE#PBF qualified for automotive use?
Yes, the LT8609IMSE#PBF is rated for –40°C to 125°C operating junction temperature and is AEC-Q100 qualified for automotive applications. Its side-wettable flanks, robust UVLO, and built-in PG flag meet functional safety requirements for infotainment and body electronics subsystems.
LT8609IMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.782V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 3A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT8609IMSE#PBF FAQ
1.How can I place an order for LT8609IMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8609IMSE#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 LT8609IMSE#PBF reliable?
The price and inventory of LT8609IMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8609IMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT8609IMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8609IMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8609IMSE#PBF?
LT8609IMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8609IMSE#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 LT8609IMSE#PBF?
For technical support, including LT8609IMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8609IMSE#PBF requirements.
6.How does Aetrix verify that LT8609IMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT8609IMSE#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 LT8609IMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT8609IMSE#PBF?
All LT8609IMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8609IMSE#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 LT8609IMSE#PBF part is unused and in its original packaging.
Return procedure for LT8609IMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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