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Analog Devices Inc. LT3599IFE#PBF
- Part No.:
- LT3599IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3599IFE#PBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,472
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Product details
Overview
LT3599IFE#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency 2A step-up DC/DC converter IC designed to drive four independent LED strings at up to 120mA per string with ±1.5% current matching, supporting output voltages up to 44V and input voltages from 3.1V to 30V. It enables True Color PWM dimming up to 3000:1 and analog dimming up to 20:1 in automotive and notebook TFT LCD backlight applications.
For engineers reviewing the LT3599IFE#PBF datasheet, LT3599IFE#PBF pinout, LT3599IFE#PBF application, or LT3599IFE#PBF equivalent, key selection considerations include its 28-pin TSSOP package, programmable switching frequency (200kHz–2.1MHz), integrated OPENLED/SHORTLED fault detection, thermal derating via TSET pin, and ability to regulate LED current even when VIN > VOUT.
Technical Context
The LT3599IFE#PBF implements constant-frequency peak-current-mode control with an internal 2A NPN power switch and dedicated current-sense circuitry for each of four LED strings. Its feedback loop uses the lowest LEDx pin voltage (among LED1–LED4) to regulate VOUT dynamically during normal operation.
It integrates dual dimming paths: analog control via CTRL pin (0–1V, linear ILED scaling) and high-fidelity PWM dimming via dedicated PWM pin with VC pin state retention during off-cycles. Fault protection includes open-LED detection (threshold <0.4V on LEDx), short-LED detection (threshold >0.8V between VOUT and LEDx), and programmable maximum output voltage regulation via FB/VO_SW divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED String Count | 4 independent strings, each programmable 30–120mA via ISET resistor |
| Current Matching Accuracy | ±1.5% over temperature (–40°C to 125°C), critical for uniform backlight luminance |
| Input Voltage Range | 3.1V to 30V - supports wide-range automotive and industrial supplies |
| Max Output Voltage | 44V - sufficient for 10+ white LEDs in series per string |
| Switching Frequency | 200kHz to 2.1MHz (resistor-programmable via RT pin); synchronizable to external clock |
| Dimming Capability | True Color PWM up to 3000:1; analog dimming up to 20:1 via CTRL pin |
| Thermal Protection | Junction temperature derating via TSET pin (595mV threshold); shutdown at 125°C max |
Pinout & Package
LT3599IFE#PBF is housed in a thermally enhanced 28-lead plastic TSSOP package (5mm × 6.2mm), with exposed pad (Pin 29) connected to GND for improved thermal dissipation. Pin count and layout match LT3599EFE#PBF and LT3599HFE#PBF variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply connection | Accepts 3.1V–30V; requires local ceramic bypass capacitor to GND |
| VOUT | Boost converter output | Drives all four LED strings; max 44V; connects to cathodes via current sources |
| LED1–LED4 | LED string cathode outputs | Each sinks programmed current; OPENLED/SHORTLED detection active per pin |
| DISABLE4 | LED4 enable/disable control | Connect to VREF to disable LED4; allows 3-string operation without hardware change |
| PWM | Digital dimming input | 0.4V low disables switching; ≥1V enables; preserves VC state during off-cycle |
| CTRL | Analog dimming input | 0–1V sets LED current proportionally; >1V has no effect; ties to VREF if unused |
| ISET | LED current programming | Resistor to GND sets nominal current (e.g., 13.3kΩ → 99mA/string) |
| RT | Frequency programming | Resistor to GND sets switching frequency; 324kΩ → 176kHz, 20kΩ → 2.3MHz |
| SHDN/UVLO | Shutdown & UVLO input | 1.36V threshold; 4µA hysteresis current enables programmable undervoltage lockout |
| FB | Overvoltage protection feedback | 1.223V reference; used with R1/R2 divider on VO_SW to clamp VOUT when all strings open |
| VC | Error amplifier output | Connects to external compensation network; controls peak switch current limit |
| GND | Analog ground reference | Tie directly to local ground plane; RT/ISET/TSET resistors referenced here |
| OPENLED | Open-string fault flag | Open-collector output pulled low if any LEDx voltage <0.4V |
| SHORTLED | Short-circuit fault flag | Open-collector output pulled low if VOUT–LEDx >0.8V (high-side short) |
| TSET | Thermal derating threshold | 595mV internal VPTAT comparator; reduces LED current above programmed junction temp |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM dimming | 3000:1 ratio with constant LED color - achieved by preserving VC state and disabling internal loads during PWM off-time |
| Programmable LED current derating | Configurable thermal foldback via TSET pin - protects LEDs by reducing current above user-defined junction temperature |
| Integrated fault detection | Per-string OPENLED and SHORTLED flags with latched reporting - eliminates need for external sense circuitry |
| VIN > VOUT regulation capability | Maintains precise LED current even when input exceeds output voltage - enables flexible system-level power architecture |
| Synchronizable switching frequency | RT resistor set 20% below SYNC clock frequency - avoids EMI interference in noise-sensitive systems |
| Disconnectable LED strings | DISABLE4 pin allows dynamic 4→3 string reconfiguration - simplifies design reuse across display variants |
Applications
| Automotive Navigation Displays | Notebook LCD Backlight |
|---|---|
Use Scenario: TFT LCD backlight in vehicle infotainment head units requiring AEC-Q200-compliant operation and wide temperature tolerance. IC Role / Device Role / Timing Role: Primary LED driver delivering regulated current to four parallel LED strings while monitoring open/short faults in real time. Use Value: ±1.5% current matching ensures uniform brightness across display; thermal derating prevents LED degradation at under-hood temperatures. |
Use Scenario: Slim-profile notebook displays needing high-efficiency, low-noise backlight control with deep dimming. IC Role / Device Role / Timing Role: Boost converter + multi-string current regulator enabling True Color PWM dimming up to 3000:1 without color shift. Use Value: 90% efficiency at 12W output minimizes thermal load; programmable frequency avoids audible noise in 200kHz–2.1MHz range. |
| Desktop Monitor Backlight | Industrial HMI Panels |
Use Scenario: High-brightness desktop monitors requiring stable luminance across varying input voltage (e.g., 12V adapter ±10%). IC Role / Device Role / Timing Role: Four-channel LED driver with input line regulation and output voltage clamping via FB/VO_SW path. Use Value: Regulates LED current even when VIN > VOUT - accommodates brown-out conditions without brightness collapse. |
Use Scenario: Ruggedized human-machine interface panels deployed in factory environments with wide ambient temperature swings. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with OPENLED/SHORTLED alert pins interfaced to microcontroller GPIOs for predictive maintenance. Use Value: –40°C to 125°C operating range and latchable fault flags support reliable long-term operation in uncontrolled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3599EFE#PBF | Same pinout and electrical specs; rated for 0°C to 125°C junction (vs. –40°C to 125°C for LT3599IFE#PBF) | Not suitable for cold-start automotive or extended industrial environments | Select LT3599IFE#PBF when guaranteed operation down to –40°C is required |
| LT3599IUH#PBF | Identical functionality but in 32-pin 5mm × 5mm QFN package with exposed pad; same –40°C to 125°C rating | Better thermal performance (θJA = 34°C/W vs. 28°C/W) and higher power density | Choose LT3599IUH#PBF for space-constrained designs needing lower junction rise |
Compared with LT3599EFE#PBF, LT3599IFE#PBF guarantees full –40°C operation; compared with LT3599IUH#PBF, it offers TSSOP compatibility for legacy layouts and easier hand-soldering, albeit with slightly higher thermal resistance.
Availability
LT3599IFE#PBF is available at Aetrix Electronics and suitable for automotive navigation displays, notebook LCD backlights, and industrial HMI panels requiring stable component supply, long lifecycle support, and AEC-Q200-aligned reliability.
Supply support for LT3599IFE#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 acquired Linear Technology in 2017 and maintains its precision analog and power management product lines with rigorous qualification standards.
The LT3599 family was designed specifically for high-accuracy, multi-string LED backlighting in automotive and portable displays, emphasizing current matching, fault resilience, and wide-input operation.
FAQ
What is the operating temperature range of the LT3599IFE#PBF?
The LT3599IFE#PBF is specified for a junction temperature range of –40°C to 125°C, with maximum junction temperature limited to 125°C. This rating is fully guaranteed across the entire range, making it suitable for automotive cabin and industrial environments where cold-start and sustained high-temperature operation are required. The LT3599IFE#PBF achieves this via process and test validation, unlike the LT3599EFE#PBF which is only characterized down to 0°C.
How does the LT3599IFE#PBF achieve ±1.5% LED current matching?
The LT3599IFE#PBF achieves ±1.5% LED current matching through matched internal current-sense transistors and precision bandgap references, validated over –40°C to 125°C. Each LED string uses its own dedicated current source with shared reference and biasing, minimizing process and temperature-induced mismatches. This specification is measured at 100mA per string and applies across the full operating temperature range, ensuring consistent luminance in multi-string backlight systems.
Can the LT3599IFE#PBF drive fewer than four LED strings?
Yes - the LT3599IFE#PBF supports dynamic reconfiguration: LED4 can be disabled using the DISABLE4 pin (tie to VREF), and its pin may be connected to LED3 to operate three strings. For two-string operation, LED1/LED2 and LED3/LED4 can be paralleled. The device automatically adjusts regulation using the lowest active LEDx voltage, maintaining accuracy without firmware changes. All fault detection remains active on enabled strings.
What is the purpose of the VO_SW pin on the LT3599IFE#PBF?
The VO_SW pin on the LT3599IFE#PBF is the drain of an internal PMOS switch that disconnects the FB voltage divider from VOUT during PWM off-time and shutdown. This prevents discharge of the output capacitor through the divider, enabling deeper PWM dimming (up to 3000:1) and reducing quiescent current. When active, VO_SW follows VOUT; when inactive, it floats - requiring external R1/R2 to connect between VO_SW and GND for overvoltage protection.
Does the LT3599IFE#PBF require external compensation components?
Yes - the LT3599IFE#PBF requires external compensation on the VC pin to stabilize the current-mode control loop. A standard Type II network (series RC from VC to GND, with parallel capacitor from VC to FB) is recommended. Component values depend on selected inductor, output capacitance, and switching frequency; typical designs use 1nF–10nF capacitors and 10kΩ–100kΩ resistors. The SS pin also requires an external capacitor (e.g., 10nF–100nF) to control soft-start ramp rate.
LT3599IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 4
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 30V
- Voltage - Output:
- 44V
- Current - Output / Channel:
- 120mA
- Frequency:
- 200kHz ~ 2.1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3599IFE#PBF FAQ
1.How can I place an order for LT3599IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3599IFE#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 LT3599IFE#PBF reliable?
The price and inventory of LT3599IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3599IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3599IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3599IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3599IFE#PBF?
LT3599IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3599IFE#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 LT3599IFE#PBF?
For technical support, including LT3599IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3599IFE#PBF requirements.
6.How does Aetrix verify that LT3599IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3599IFE#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 LT3599IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3599IFE#PBF?
All LT3599IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3599IFE#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 LT3599IFE#PBF part is unused and in its original packaging.
Return procedure for LT3599IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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