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Analog Devices Inc. LT3591EDDB#TRPBF
- Part No.:
- LT3591EDDB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3591EDDB#TRPBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 500MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,445
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Product details
Overview
LT3591EDDB#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency, current-mode step-up DC/DC converter IC designed specifically as a white LED driver with integrated Schottky diode and high-side current sensing. It drives up to ten 3.3V white LEDs in series from a 2.5V–12V input (e.g., single Li-Ion cell), delivers ±5% reference accuracy, features 42V open-LED protection, and operates at 1MHz switching frequency in an 8-lead 3mm × 2mm DFN package.
For engineers reviewing the LT3591EDDB#TRPBF datasheet, LT3591EDDB#TRPBF pinout, LT3591EDDB#TRPBF application, or LT3591EDDB#TRPBF equivalent, key selection considerations include its one-wire LED string interface enabled by high-side current sense, 80:1 True Color PWM dimming range, internal Schottky diode, 200mV current-sense voltage, and compatibility with low-ESR ceramic output capacitors as small as 2.2µF.
Technical Context
The LT3591EDDB#TRPBF employs constant-frequency current-mode control with a 1.25V bandgap reference and ramp-compensated PWM comparator (A2) to regulate peak inductor current. Its error amplifier (A1) compares the 200mV (typ) VCAP–VLED sense voltage against the reference to set output current, while the CTRL pin modulates the sense threshold from 0V to 1.5V for analog dimming or shutdown.
Operation relies on internal 500mA (min) switch current limit, 92–94% maximum duty cycle, and overvoltage protection clamping VCAP at 42V (typ) during open-LED fault conditions. The integrated Schottky diode eliminates external rectification, and the exposed thermal pad (Pin 9) must be soldered to PCB ground for thermal performance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.5V to 12V - supports single Li-Ion (3.0–4.2V), dual alkaline (2.0–3.2V), or 3.3V logic supply inputs |
| Switching Frequency | 1MHz (typ) - enables use of compact 22µH inductors and low-ESR ceramic capacitors |
| LED Current Sense Voltage | 200mV (typ) - sets ILED = 200mV / RSENSE; enables precise current programming with 1% resistors |
| Open-LED Protection | 42V clamp (typ) - limits CAP pin voltage during LED string disconnection or failure |
| Dimming Range | 80:1 True Color PWM - preserves LED chromaticity across full brightness range without color shift |
| Package | 8-lead DFN (3mm × 2mm × 0.75mm) - low-profile surface-mount package with exposed thermal pad (Pin 9) |
| Efficiency | Up to 85% at 10 LEDs, 3.6V input - measured with 22µH inductor and 2.2µF output capacitor |
Pinout & Package
LT3591EDDB#TRPBF is housed in an 8-lead plastic DFN package (3mm × 2mm, 0.75mm height) with exposed thermal pad (Pin 9) requiring connection to PCB ground for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Input power supply | Accepts 2.5V–12V input; requires local 1µF ceramic bypass capacitor |
| GND (Pin 2) | Ground reference | Primary ground return; connects to PCB ground plane |
| SW (Pin 4) | Power switch node | Connects to inductor; high dV/dt node requiring minimal trace area to reduce EMI |
| CAP (Pin 5) | Output capacitor node | Drives cathode of internal Schottky; connects to 2.2µF output capacitor and sense resistor |
| LED (Pin 7) | LED string anode/sense point | Connects to anode of first LED and sense resistor; completes high-side current sense path |
| CTRL (Pin 8) | Dimming & shutdown control | 0–1.5V analog dimming; <50mV disables driver; must not float |
| Exposed Pad (Pin 9) | Thermal & electrical ground | Must be soldered to PCB ground for thermal dissipation and optimal performance |
Key Features
| Feature | Design Value |
|---|---|
| High-side current sense | Enables "one-wire" LED string connection - LED cathodes can be grounded anywhere, simplifying layout and reducing interconnect count |
| Integrated Schottky diode | Eliminates external diode, saves board space, and reduces BOM count in portable designs |
| Single-pin dimming/shutdown | CTRL pin provides both functions: analog dimming (0–1.5V) and hard shutdown (<50mV), reducing control signal routing |
| True Color PWM dimming | 80:1 range with no forward-current-induced color shift - critical for camera flash and display backlight uniformity |
| 42V open-LED protection | Clamps CAP voltage during LED string open-circuit faults, preventing overvoltage damage and enabling safe fault detection |
Applications
| Cellular Phone Backlight | Digital Camera Flash |
|---|---|
Use Scenario: Driving 6–10 white LEDs for main display backlight in slim smartphones powered by single Li-Ion cells. IC Role / Device Role / Timing Role: Constant-current boost converter with high-side sensing and integrated Schottky, regulating LED current independent of battery voltage sag. Use Value: Enables uniform brightness across full LED string without ballast resistors; 1MHz operation allows ultra-compact 22µH inductor and 2.2µF ceramic capacitor. | Use Scenario: Providing high-current pulsed drive (up to 100mA per LED) for multi-LED flash arrays in compact digital cameras. IC Role / Device Role / Timing Role: High-efficiency, fast-response LED driver supporting direct PWM dimming at ≥80Hz to avoid visible flicker and preserve color fidelity. Use Value: 80:1 True Color PWM ensures consistent white point across intensity levels; 42V open-LED protection safeguards circuit during flash LED failure. |
| GPS Receiver Display | MP3 Player UI Lighting |
Use Scenario: Powering small 2–4 LED strings for monochrome or segmented LCD backlight in automotive-grade GPS units operating from 2.5V–12V supplies. IC Role / Device Role / Timing Role: Wide-input boost driver with stable current regulation across temperature (–40°C to 85°C) and input voltage variation. Use Value: ±5% reference accuracy and 200mV sense voltage ensure tight LED current matching; DFN package fits constrained front-panel layouts. | Use Scenario: Driving 3–5 white LEDs for OLED or segment LCD status lighting in battery-powered MP3 players with 3.3V logic rails. IC Role / Device Role / Timing Role: Low-quiescent-current (4–5mA typ) LED driver using logic-supply VIN to extend battery life while maintaining brightness control. Use Value: CTRL pin dimming enables seamless integration with microcontroller DAC or filtered PWM outputs; internal Schottky reduces component count and footprint. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3491EDD#TRPBF | 2.3MHz switching frequency; drives up to 6 LEDs; lower max VOUT (27V); SC70/DFN packages | Better suited for space-constrained, lower-LED-count applications (e.g., earbud indicators); less headroom for 10-LED strings | Select when higher frequency (reduced inductor size) and fewer LEDs are required; verify 27V VOUT margin for target string voltage |
| LT3465AEDD#TRPBF | 1.2MHz/2.7MHz dual-frequency option; drives up to 6 LEDs; integrated Schottky; 34V max VOUT | Targeted at mid-power LED applications with tighter input ranges (2.7V–16V); lacks 42V open-LED clamp | Choose for cost-sensitive designs needing dual-frequency flexibility and 6-LED support; confirm open-circuit protection requirements |
Compared with LT3591EDDB#TRPBF, LT3491EDD#TRPBF offers higher switching frequency but reduced LED count and output voltage headroom, while LT3465AEDD#TRPBF provides dual-frequency operation and broader input range but supports only six LEDs and lacks the 42V open-LED clamp critical for robust 10-LED systems.
Availability
LT3591EDDB#TRPBF is available at Aetrix Electronics and suitable for cellular phone backlighting, digital camera flash modules, GPS receiver displays, and MP3 player UI lighting requiring stable component supply, long-lifecycle support, and guaranteed parametric performance over –40°C to 85°C.
Supply support for LT3591EDDB#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 acquired Linear Technology in 2017 and maintains its precision analog and power management product lines with full datasheet, design tool, and technical support continuity.
The LT3591EDDB#TRPBF belongs to Linear's high-efficiency LED driver family, engineered for portable consumer electronics where compact size, high conversion efficiency, and accurate current regulation are essential for battery-powered white LED applications.
FAQ
What is the recommended inductor value for LT3591EDDB#TRPBF in a 10-LED application?
A 22µH shielded power inductor with 490–600mA saturation current and low DCR (e.g., Taiyo Yuden NR4018T220M or TDK VLCF4018T-220MR49-2) is recommended for LT3591EDDB#TRPBF driving ten white LEDs. This value balances size, efficiency (>85% at 3.6V input), and stability across temperature while supporting the 1MHz switching frequency and 500mA minimum switch current limit.
How does the high-side current sense in LT3591EDDB#TRPBF simplify PCB layout?
The high-side current sense in LT3591EDDB#TRPBF eliminates the need for a grounded sense resistor, allowing the entire LED string cathode to connect directly to system ground anywhere on the board. This removes the requirement for a dedicated ground-return trace from the LED string, reduces routing complexity, avoids ground-loop issues, and enables flexible mechanical placement of LEDs relative to the LT3591EDDB#TRPBF IC.
Can LT3591EDDB#TRPBF operate from two AA batteries?
Yes, LT3591EDDB#TRPBF can operate from two AA batteries (2.0V–3.2V) using the low-input-voltage configuration: connect the batteries to the inductor (SW pin), and power the IC's VIN pin from a separate 3.3V logic rail. This architecture maintains regulation down to 2.5V VIN while enabling LED operation below the IC's minimum input threshold, extending runtime in alkaline-powered devices.
What is the function of the exposed thermal pad (Pin 9) on LT3591EDDB#TRPBF?
The exposed thermal pad (Pin 9) on LT3591EDDB#TRPBF serves as the primary thermal conduction path and must be soldered to a PCB ground plane. It lowers thermal resistance (θJA = 76°C/W) to dissipate heat from the internal 500mA switch and Schottky diode, ensuring reliable operation at full load across –40°C to 85°C. Leaving it unconnected degrades thermal performance and may cause premature thermal shutdown.
Does LT3591EDDB#TRPBF support true PWM dimming without color shift?
Yes, LT3591EDDB#TRPBF supports True Color PWM dimming with an 80:1 range. By rapidly switching the LED current fully on/off at frequencies ≥80Hz (e.g., via external NMOS controlled by the same PWM signal applied to CTRL), it maintains constant forward current magnitude during "on" periods - preserving LED chromaticity and eliminating perceptible color shift across all brightness levels.
LT3591EDDB#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 12V
- Voltage - Output:
- -
- Current - Output / Channel:
- 500mA (Switch)
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x2)
LT3591EDDB#TRPBF FAQ
1.How can I place an order for LT3591EDDB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3591EDDB#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 LT3591EDDB#TRPBF reliable?
The price and inventory of LT3591EDDB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3591EDDB#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3591EDDB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3591EDDB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3591EDDB#TRPBF?
LT3591EDDB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3591EDDB#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 LT3591EDDB#TRPBF?
For technical support, including LT3591EDDB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3591EDDB#TRPBF requirements.
6.How does Aetrix verify that LT3591EDDB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3591EDDB#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 LT3591EDDB#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3591EDDB#TRPBF?
All LT3591EDDB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3591EDDB#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 LT3591EDDB#TRPBF part is unused and in its original packaging.
Return procedure for LT3591EDDB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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