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Analog Devices Inc. LTC3809EDD#TRPBF
- Part No.:
- LTC3809EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LTC3809EDD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,196
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Product details
Overview
LTC3809EDD#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, 0.6V ±1.5% reference, and supports 2.75V–9.8V input to 0.6V–VIN output in battery-powered portable instruments.
For engineers reviewing the LTC3809EDD#TRPBF datasheet, LTC3809EDD#TRPBF pinout, LTC3809EDD#TRPBF application, or LTC3809EDD#TRPBF equivalent, key selection considerations include No RSENSE™ operation, selectable Burst Mode®/pulse-skipping/forced continuous modes, PLL-based synchronization (250–750kHz), spread spectrum modulation, and 100% duty cycle low-dropout capability.
Technical Context
The LTC3809EDD#TRPBF implements a constant-frequency current-mode architecture 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 PLL for external synchronization, a dedicated PLLLPF pin for loop filtering or frequency selection, and dual-mode light-load control: Burst Mode® (for ultra-low IQ) or PWM pulse-skipping (enabled during spread spectrum or sync). The RUN pin enables micropower shutdown (IQ = 9μA), and internal soft-start ramps VFB from 0.05V to 0.55V over 0.74ms.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Synchronous buck controller - requires external P- and N-channel MOSFETs; no integrated power switches. |
| Input Voltage Range | 2.75V to 9.8V - supports single/dual Li-ion, USB, and distributed 3.3V/5V rails. |
| Output Voltage Range | 0.6V to VIN - adjustable via external resistor divider; 0.6V ±1.5% precision reference enables tight regulation. |
| Switching Frequency | Up to 750kHz (programmable via PLLLPF pin); 550kHz default - enables compact 2.2μH inductors and ceramic output caps. |
| Current Sensing Method | No RSENSE™ - senses VDS of external P-MOSFET; eliminates sense resistor losses and PCB area. |
| Light-Load Modes | Selectable Burst Mode®, pulse-skipping, or forced continuous - optimizes efficiency vs. noise/ripple trade-off per application. |
| Protection Features | Output overvoltage protection (0.66V at VFB), undervoltage lockout (2.25V rising), short-circuit current limit, reverse-current prevention. |
| Package | 10-lead (3mm × 3mm) DFN with exposed pad - thermally enhanced for high-current applications; RoHS-compliant, lead-free. |
Pinout & Package
Package: 10-lead (3mm × 3mm) plastic DFN with exposed thermal pad (Pin 11 = GND, must be soldered to PCB ground).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PLLLPF (1) | Frequency select / PLL filter | Configures oscillator frequency (300/550/750kHz) when unsynchronized; serves as PLL loop filter node when synchronized to external clock. |
| SYNC/MODE (2) | Multi-function control | Accepts external sync clock (250–750kHz); selects Burst Mode® (tied to VIN), pulse-skipping (tied to VFB), or forced continuous (tied to GND); enables spread spectrum. |
| VFB (3) | Feedback input | Compares output voltage (via resistor divider) against 0.6V reference; error amplifier output drives ITH to regulate output. |
| ITH (4) | Current threshold / compensation | Sets peak inductor current threshold; also serves as error amplifier compensation node (0.7–2V operating range). |
| RUN (5) | Enable control | Logic-high (>1.1V) enables operation with internal soft-start; <0.8V forces shutdown (IQ = 9μA). |
| IPRG (6) | Peak sense voltage select | Three-state pin (float/GND/VIN) sets max ΔVSENSE = 125/85/204mV - adjusts current limit for different P-MOSFET RDS(ON). |
| BG (7) | N-MOSFET gate driver | Drives bottom N-channel MOSFET gate from PGND to VIN; fast rise/fall times (<50ns) minimize switching losses. |
| TG (8) | P-MOSFET gate driver | Drives top P-channel MOSFET gate from PGND to VIN; complements BG for synchronous rectification. |
| VIN (9) | Supply input | Powers internal circuitry and gate drivers; also positive input to differential current comparator. |
| SW (10) | Switch node | Connects to drains of both MOSFETs and inductor; serves as negative input to current comparator and reverse-current detector. |
| GND (11) | Thermal & signal ground | Exposed pad - mandatory solder connection to PCB ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE™ operation | Eliminates external current sense resistor - reduces BOM cost, board space, and conduction losses in high-current paths. |
| True PLL synchronization | Locks internal oscillator to external clock (250–750kHz) - enables deterministic EMI reduction and multi-rail timing alignment. |
| Selectable spread spectrum modulation | Spreads 550kHz fundamental across 460–635kHz band - lowers peak radiated emissions without affecting regulation performance. |
| 100% duty cycle dropout mode | Maintains regulation as VIN approaches VOUT - extends runtime in Li-ion systems where input drops below nominal voltage. |
| Auxiliary winding regulation | Uses SYNC/MODE pin as secondary-side feedback input - enables isolated flyback or forward converter designs with tight cross-regulation. |
| Micropower shutdown | Draws only 9μA in shutdown - preserves battery life in always-on portable devices with periodic wake-up cycles. |
Applications
| Portable Medical Sensors | Industrial Handheld Meters |
|---|---|
Use Scenario: Battery-powered glucose monitor with 3.3V system rail and 1.8V sensor core, operating 72 hours on single 3.7V Li-ion cell. IC Role / Device Role / Timing Role: Synchronous buck controller regulating 3.3V from declining 4.2V–2.8V input; provides stable supply while maximizing energy extraction via 100% duty cycle. Use Value: No RSENSE™ eliminates sense resistor loss; Burst Mode® maintains >85% efficiency at 1mA load; micropower shutdown extends shelf life. | Use Scenario: Ruggedized multimeter with LCD backlight, microcontroller, and analog front-end powered from dual 1.5V alkaline cells (3V total). IC Role / Device Role / Timing Role: Step-down controller generating 2.5V for MCU and 1.2V for ADC from 3V–4.5V input; operates down to 2.75V VIN with low dropout. Use Value: Wide 2.75V–9.8V input range accommodates fresh-to-dead battery; 0.6V reference ensures accurate low-voltage regulation; small DFN saves space in compact enclosure. |
| Distributed Power Systems | Low-EMI Test Equipment |
Use Scenario: 12V intermediate bus powering multiple point-of-load converters in automated test equipment rack. IC Role / Device Role / Timing Role: Primary buck controller stepping 12V to 5V intermediate rail; synchronized to system clock to avoid beat frequencies. Use Value: PLL synchronization eliminates subharmonic interference; spread spectrum further suppresses narrowband EMI peaks; robust overvoltage protection safeguards downstream loads. | Use Scenario: Precision oscilloscope front-end requiring ultra-low-noise 3.3V analog supply with minimal conducted/radiated emissions. IC Role / Device Role / Timing Role: Low-EMI buck controller supplying ADC reference and analog signal chain; configured in spread spectrum + pulse-skipping mode. Use Value: Spread spectrum reduces spectral peaks by >10dB; pulse-skipping avoids audio-band ripple; VDS sensing eliminates resistor-induced noise coupling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3850EDD#TRPBF | Higher 1MHz max frequency; includes power-good flag and margining; requires external bootstrap capacitor for high-side N-MOSFET drive. | Targeted at higher-density, higher-efficiency designs needing PGOOD monitoring and tighter output tolerance. | Choose LTC3850EDD#TRPBF when 1MHz operation, power-good signaling, or N-MOSFET top switch is required - not drop-in compatible due to different gate drive architecture. |
| TPS54202DDCR | Integrated FETs (2A); fixed 500kHz frequency; no PLL sync or spread spectrum; lower quiescent current (25μA in Eco-mode). | Optimized for cost-sensitive, medium-current applications where board space and component count outweigh EMI flexibility. | Choose TPS54202DDCR for simpler, lower-BOM designs up to 2A; not suitable for >2A or low-EMI critical systems requiring sync/spread spectrum. |
Compared with LTC3850EDD#TRPBF and TPS54202DDCR, the LTC3809EDD#TRPBF uniquely combines No RSENSE™ operation, true PLL synchronization, and spread spectrum modulation in a compact DFN - making it optimal for noise-sensitive, battery-constrained, or multi-rail synchronized systems where external MOSFETs provide design flexibility.
Availability
LTC3809EDD#TRPBF is available at Aetrix Electronics and suitable for portable medical sensors, industrial handheld meters, distributed power systems, and low-EMI test equipment requiring stable component supply, long-term lifecycle support, and consistent parametric performance.
Supply support for LTC3809EDD#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 technologies, formed through the acquisition of Linear Technology in 2017.
The LTC3809EDD#TRPBF belongs to ADI's Power by Linear™ synchronous controller product line, designed specifically for high-efficiency, low-EMI, and battery-optimized DC/DC conversion in space-constrained portable and industrial applications.
FAQ
What is the primary function of the LTC3809EDD#TRPBF in a power supply design?
The LTC3809EDD#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 2.75V–9.8V input, delivers 0.6V–VIN output, and enables high efficiency across load ranges via selectable Burst Mode®, pulse-skipping, or forced continuous operation. Its role is to provide precise, flexible, and low-noise voltage regulation in battery-powered and noise-sensitive systems.
Does the LTC3809EDD#TRPBF require an external current sense resistor?
No, the LTC3809EDD#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's drain-to-source terminals (between VIN and SW pins) to determine peak inductor current. This eliminates sense resistor losses, improves efficiency, reduces thermal stress, and saves PCB area - a defining feature confirmed in the datasheet's title, features list, and functional description.
How is the switching frequency set on the LTC3809EDD#TRPBF?
The switching frequency of the LTC3809EDD#TRPBF is set either by the PLLLPF pin (when unsynchronized) or via external synchronization on the SYNC/MODE pin. With PLLLPF floating, frequency defaults to 550kHz; tying PLLLPF to GND selects 300kHz, and to VIN selects 750kHz. When SYNC/MODE receives an external clock (250–750kHz), the internal oscillator phase-locks to it, disabling Burst Mode® but enabling precise EMI control - all confirmed in the Electrical Characteristics table and Applications Information section.
What package type is used for the LTC3809EDD#TRPBF, and why is the exposed pad critical?
The LTC3809EDD#TRPBF uses a 10-lead (3mm × 3mm) plastic DFN package with an exposed thermal pad (Pin 11). This pad is electrically and thermally connected to GND and must be soldered to the PCB ground plane. It is critical because it provides the primary thermal path for heat dissipation - the datasheet specifies θJA = 43°C/W for this package, and omitting the solder connection would cause excessive junction temperature, reliability degradation, and potential thermal shutdown during sustained load conditions.
Can the LTC3809EDD#TRPBF operate with input voltage below 3V?
Yes, the LTC3809EDD#TRPBF supports input voltages as low as 2.75V, making it suitable for single-cell Li-ion (2.8–4.2V) and alkaline battery applications. Its undervoltage lockout (UVLO) has a rising threshold of 2.25V, ensuring reliable startup and operation down to near-dead battery levels. The 100% duty cycle capability further enables regulation when VIN drops close to VOUT - all verified in Absolute Maximum Ratings, Electrical Characteristics, and Dropout Operation sections of the datasheet.
LTC3809EDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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-DFN (3x3)
LTC3809EDD#TRPBF FAQ
1.How can I place an order for LTC3809EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3809EDD#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 LTC3809EDD#TRPBF reliable?
The price and inventory of LTC3809EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3809EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3809EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3809EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3809EDD#TRPBF?
LTC3809EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3809EDD#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 LTC3809EDD#TRPBF?
For technical support, including LTC3809EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3809EDD#TRPBF requirements.
6.How does Aetrix verify that LTC3809EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3809EDD#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 LTC3809EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3809EDD#TRPBF?
All LTC3809EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3809EDD#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 LTC3809EDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3809EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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