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Analog Devices Inc. LTC3809EMSE#TRPBF
- Part No.:
- LTC3809EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3809EMSE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,361
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Product details
Overview
LTC3809EMSE#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-down DC/DC controller IC that drives external complementary P- and N-channel MOSFETs without requiring a current sense resistor. It features constant-frequency current-mode control, 550kHz default switching frequency, 2.75V–9.8V input range, 0.6V ±1.5% reference, and 100% duty cycle for low-dropout operation - ideal for battery-powered portable instruments and distributed power systems.
For engineers reviewing the LTC3809EMSE#TRPBF datasheet, LTC3809EMSE#TRPBF pinout, LTC3809EMSE#TRPBF application, or LTC3809EMSE#TRPBF equivalent, key selection considerations include its No RSENSE™ architecture, selectable Burst Mode®/pulse-skipping/forced continuous operation, spread spectrum modulation for EMI reduction, true PLL synchronization (250–750kHz), and auxiliary winding regulation capability.
Technical Context
The LTC3809EMSE#TRPBF implements a constant-frequency current-mode control loop using VDS sensing across the external P-MOSFET to eliminate the need for a discrete sense resistor. Its differential current comparator monitors ΔVSENSE between VIN and SW pins, with peak threshold programmable via IPRG pin (85mV/125mV/204mV).
It integrates a true phase-locked loop (PLL) with capture range 200–1000kHz, enabling precise frequency locking to external clocks applied at SYNC/MODE. Spread spectrum modulation (460–635kHz) is activated by biasing SYNC/MODE between 1.35V and VIN–0.5V, reducing spectral peaks while maintaining PWM pulse-skipping light-load behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.75V to 9.8V - supports single/dual Li-ion, USB, and intermediate bus rails without level-shifting. |
| Output Voltage Range | 0.6V to VIN - enables wide output flexibility including sub-1V core supplies and adjustable point-of-load regulation. |
| Reference Voltage | 0.6V ±1.5% - high-accuracy feedback reference enabling tight output voltage tolerance over temperature and line/load. |
| Switching Frequency | Up to 750kHz (programmable) - allows use of compact 2.2μH inductors and ceramic output capacitors in space-constrained designs. |
| Quiescent Current | 9μA in shutdown - minimizes battery drain during system sleep states in portable applications. |
| Peak Gate Drive Current | 1A (TG/BG) - ensures fast MOSFET turn-on/off for high-efficiency operation at high frequencies and heavy loads. |
| UVLO Threshold | 2.25V (rising), 2.15V (falling) - prevents unstable startup or operation near battery depletion voltage. |
Pinout & Package
Package: 10-lead plastic MSOP (3mm × 3mm), thermally enhanced with exposed pad (Pin 11 = GND, must be soldered to PCB ground plane).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PLLLPF (1) | Frequency set / PLL filter node | Selects unsynchronized oscillator frequency (GND=300kHz, float=550kHz, VIN=750kHz); serves as PLL loop filter when synchronized. |
| SYNC/MODE (2) | Multi-function control input | Enables external clock sync (250–750kHz), selects Burst Mode® (VIN), forced continuous (GND), pulse-skipping (VFB), or spread spectrum (1.35–VIN–0.5V). |
| VFB (3) | Feedback input | Compares output voltage (via resistor divider) against 0.6V internal reference to regulate VOUT. |
| ITH (4) | Error amplifier output / current threshold | Sets peak inductor current limit (0.7–2.0V range); determines load transient response and current limit accuracy. |
| RUN (5) | Enable/shutdown control | Logic-high (>1.1V) enables soft-start; <0.8V forces shutdown with 9μA quiescent current. |
| IPRG (6) | Current sense threshold select | Three-state pin (GND/VIN/float) sets ΔVSENSE(MAX) to 85mV/204mV/125mV for optimized MOSFET RDS(ON) selection. |
| BG (7) | N-channel MOSFET gate driver | Drives bottom switch with rail-to-rail swing (PGND to VIN) and 1A peak current capability. |
| TG (8) | P-channel MOSFET gate driver | Drives top switch with rail-to-rail swing (PGND to VIN) and 1A peak current; supports low-VGS logic-level FETs. |
| VIN (9) | Power supply input | Supplies entire IC, gate drivers, and current comparator; also serves as positive input to differential current sense amplifier. |
| SW (10) | Switch node connection | Connects to drains of both external MOSFETs and inductor; serves as negative input to current comparator and reverse-current detector. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE™ architecture | Eliminates power loss and board area associated with external current sense resistors; improves efficiency by up to 2% at full load. |
| Selectable spread spectrum modulation | Reduces EMI peak amplitudes by spreading 550kHz fundamental across 460–635kHz band - simplifies compliance with CISPR 22/32 Class B limits. |
| True PLL synchronization | Locks internal oscillator to external clock (250–750kHz) with ±0.1% frequency accuracy - enables deterministic noise placement in multi-rail systems. |
| 100% duty cycle operation | Extends battery runtime by maintaining regulation down to VOUT – VDS(ON) – ILOAD×RINDUCTOR - critical for Li-ion discharge curves. |
| Auxiliary winding regulation | Uses SYNC/MODE pin as secondary-side feedback input - enables isolated flyback or forward converter topologies with ±2% cross-regulation. |
Applications
| 1-Cell Li-ion Portable Instruments | Distributed DC Power Systems |
|---|---|
Use Scenario: Handheld test equipment powered by single-cell Li-ion (2.7–4.2V) requiring stable 1.8V/3.3V rails under variable load and temperature. IC Role / Device Role / Timing Role: Synchronous buck controller regulating output voltage via VDS-based current sensing and internal 0.6V reference. Use Value: No RSENSE™ eliminates sense resistor losses, extending battery life by >15 minutes at 500mA load; 100% duty cycle maintains regulation until battery reaches 2.8V. | Use Scenario: Intermediate bus converter in telecom or industrial backplane supplying multiple downstream POL converters. IC Role / Device Role / Timing Role: Primary step-down controller delivering tightly regulated 5V or 3.3V from 12V or 24V input with low EMI and high efficiency. Use Value: Spread spectrum modulation reduces conducted emissions by 12dBµV at 150kHz–30MHz; PLL sync enables coherent switching across multiple rails to suppress beat frequencies. |
| Low-Noise Medical Sensors | USB-Powered Embedded Systems |
Use Scenario: Battery-operated wearable sensor node with analog front-end requiring ultra-low-noise 2.5V supply for ADC reference. IC Role / Device Role / Timing Role: Low-EMI buck controller operating in Burst Mode® at light loads (<10mA) and forced continuous mode during signal acquisition. Use Value: Burst Mode® reduces no-load quiescent current to 25μA; spread spectrum + constant-frequency operation lowers RMS noise floor by 8dB below 1MHz. | Use Scenario: USB-C powered IoT gateway requiring 3.3V/1.2V rails from 5V input with strict inrush and thermal constraints. IC Role / Device Role / Timing Role: High-efficiency synchronous buck controller with programmable soft-start and output overvoltage protection. Use Value: Internal soft-start (0.74ms typical) limits inrush current to <1.2A; OVP triggers at 0.68V on VFB (13.3% above 0.6V) to protect downstream logic from USB overvoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3850EMSE#TRPBF | Higher 1MHz max frequency; integrated LDO bias supply; no IPRG pin; requires external sense resistor. | Designed for higher-density, higher-frequency POL applications where board space is constrained but sense resistor loss is acceptable. | Choose LTC3850EMSE#TRPBF only if 1MHz operation and integrated bias supply are required - not a drop-in replacement due to different current sensing method and pinout. |
| MP2315DJ-LF-Z | Integrated power MOSFETs (no external FETs); fixed 500kHz frequency; no PLL sync; no spread spectrum; lower VIN min (4.5V). | Targeted at cost-sensitive, low-power applications (<3A) where simplicity and BOM count outweigh EMI and efficiency optimization. | Choose MP2315DJ-LF-Z only for non-battery, fixed-input applications where external FET drive and advanced noise control are unnecessary. |
Compared with LTC3850EMSE#TRPBF and MP2315DJ-LF-Z, the LTC3809EMSE#TRPBF uniquely combines No RSENSE™ operation, true PLL synchronization, and selectable spread spectrum - making it optimal for battery-powered, low-EMI, and multi-rail-coordinated designs where external MOSFET flexibility and efficiency are prioritized over integration or maximum frequency.
Availability
LTC3809EMSE#TRPBF is available at Aetrix Electronics and suitable for 1-cell lithium-ion portable instruments, distributed DC power systems, low-noise medical sensors, and USB-powered embedded systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3809EMSE#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. (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 LTC3809EMSE#TRPBF belongs to ADI's Power by Linear™ synchronous controller product line, engineered specifically for high-efficiency, low-EMI, and flexible external-FET DC/DC conversion in battery-powered and noise-sensitive applications.
FAQ
What is the primary function of the LTC3809EMSE#TRPBF in a power supply design?
The LTC3809EMSE#TRPBF is a synchronous step-down DC/DC controller IC that regulates output voltage by driving external complementary P- and N-channel MOSFETs. It uses VDS sensing instead of a current sense resistor (No RSENSE™), supports programmable switching frequency up to 750kHz, and provides three light-load modes (Burst Mode®, pulse-skipping, forced continuous). The LTC3809EMSE#TRPBF enables high-efficiency, low-EMI, and compact power conversion in battery-powered and distributed systems.
Does the LTC3809EMSE#TRPBF require an external current sense resistor?
No, the LTC3809EMSE#TRPBF does not require an external current sense resistor. It implements No RSENSE™ technology by measuring the voltage drop (ΔVSENSE) across the external P-channel MOSFET between VIN and SW pins. This eliminates power loss and board area associated with traditional sense resistors. The LTC3809EMSE#TRPBF uses this sensed voltage - programmable via the IPRG pin (85mV/125mV/204mV) - to set the peak inductor current limit.
How does the SYNC/MODE pin configure operating modes on the LTC3809EMSE#TRPBF?
The SYNC/MODE pin on the LTC3809EMSE#TRPBF serves four functions: (1) auxiliary winding feedback input, (2) external clock synchronization input for PLL, (3) light-load mode selector, and (4) spread spectrum enable. Tying SYNC/MODE to VIN selects Burst Mode®, to GND selects forced continuous mode, to VFB selects pulse-skipping mode, and to a DC voltage between 1.35V and VIN–0.5V enables spread spectrum modulation. When driven by an external clock (250–750kHz), the LTC3809EMSE#TRPBF locks its oscillator via PLL and disables Burst Mode®.
What package type and thermal characteristics does the LTC3809EMSE#TRPBF use?
The LTC3809EMSE#TRPBF is housed in a 10-lead plastic MSOP package (3mm × 3mm) with an exposed pad (Pin 11) that must be soldered to the PCB ground plane for electrical integrity and thermal performance. Its thermal resistance is θJA = 40°C/W. The device operates across –40°C to +85°C ambient temperature and has a maximum junction temperature of 125°C. The exposed pad significantly improves heat dissipation compared to standard MSOP packages without thermal pads.
Can the LTC3809EMSE#TRPBF support low-dropout operation, and how is it implemented?
Yes, the LTC3809EMSE#TRPBF supports low-dropout operation via 100% duty cycle capability. When input voltage approaches output voltage, the controller extends the top P-channel MOSFET on-time beyond one switching cycle until it remains continuously on (DC conduction). In this state, VOUT ≈ VIN – VDS(ON) – ILOAD×RINDUCTOR, enabling extended battery runtime in Li-ion systems. This behavior is automatic and requires no external configuration - the LTC3809EMSE#TRPBF maintains regulation down to ~2.8V input for a 2.5V output.
LTC3809EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.75V ~ 9.8V
- Frequency - Switching:
- 460kHz ~ 635kHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LTC3809EMSE#TRPBF FAQ
1.How can I place an order for LTC3809EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3809EMSE#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 LTC3809EMSE#TRPBF reliable?
The price and inventory of LTC3809EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3809EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3809EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3809EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3809EMSE#TRPBF?
LTC3809EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3809EMSE#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 LTC3809EMSE#TRPBF?
For technical support, including LTC3809EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3809EMSE#TRPBF requirements.
6.How does Aetrix verify that LTC3809EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3809EMSE#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 LTC3809EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3809EMSE#TRPBF?
All LTC3809EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3809EMSE#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 LTC3809EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3809EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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