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Analog Devices Inc. LT3599HFE#PBF
- Part No.:
- LT3599HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3599HFE#PBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:140
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Product details
Overview
LT3599HFE#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency 2A boost 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 - used in automotive and industrial TFT LCD backlighting systems.
For engineers reviewing the LT3599HFE#PBF datasheet, LT3599HFE#PBF pinout, LT3599HFE#PBF application, or LT3599HFE#PBF equivalent, this page delivers verified specifications including programmable switching frequency (200kHz–2.1MHz), True Color PWM dimming up to 3000:1, open/short LED fault detection, thermal derating via TSET, and operation up to 150°C junction temperature.
Technical Context
The LT3599HFE#PBF implements constant-frequency peak-current-mode control with an internal 2A NPN power switch and integrated PMOS disconnect switch (VO_SW) for PWM-controlled output disconnection. It uses dual feedback loops: one regulating VOUT via FB pin (1.223V reference) during normal operation, and another enabling overvoltage protection when all LED strings are open.
LED current is set by ISET resistor (11k–44.2kΩ) and optionally scaled via CTRL pin voltage (0–1V), while dimming is supported via analog control (20:1 range) or high-fidelity PWM (3000:1 range). Fault management includes OPENLED and SHORTLED open-collector flags, DISABLE4 for selective string shutdown, and programmable current derating based on junction temperature via TSET.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Output Voltage | 44V - supports 10+ white LEDs per string in series for large-panel LCD backlights. |
| LED Current per String | Up to 120mA - programmable via ISET resistor; 99mA typical at RISET = 13.3kΩ. |
| Current Matching | ±1.5% - ensures uniform brightness across four LED strings without external calibration. |
| Switching Frequency | 200kHz to 2.1MHz - adjustable via RT resistor; synchronizable to external clock. |
| Junction Temp Range | –40°C to +150°C - H-grade qualification enables under-hood automotive use. |
| PWM Dimming Ratio | Up to 3000:1 - maintains consistent LED color across full dimming range. |
| Input Voltage Range | 3.1V to 30V - accommodates 12V/24V automotive rails and wide-input industrial supplies. |
Pinout & Package
LT3599HFE#PBF is housed in a thermally enhanced 28-lead plastic TSSOP package (5mm × 4.4mm) with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance (θJA = 28°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Internal NPN switch collector | Connects to boost inductor; requires minimal trace area to reduce EMI. |
| VOUT | Boost output node | Supplies power to all four LED strings; rated for 45V absolute max. |
| LED1–LED4 | LED string cathode outputs | Each drives one LED string; supports open/short detection and individual disable via DISABLE4. |
| ISET | LED current programming input | Resistor-to-ground sets per-string current (30–120mA); tolerance directly impacts matching. |
| PWM | Digital dimming control | High (>1V) enables switching; low (<0.4V) disables switching and holds VC state for fast recovery. |
| CTRL | Analog dimming input | 0–1V linearly scales LED current; beyond 1V, no further effect - preserves color fidelity. |
| FB | Overvoltage protection feedback | 1.223V reference; used only when all LED strings are open to clamp VOUT. |
| SHDN/UVLO | Enable + programmable UVLO | 1.36V threshold with 4µA hysteresis current; allows resistor-divider-based input rail monitoring. |
| TSET | Thermal derating threshold | Programs junction temperature breakpoint; above it, LED current decreases to protect LEDs. |
| OPENLED / SHORTLED | Fault flag outputs | Open-collector alerts: OPENLED asserts if any string opens; SHORTLED if any LED pin shorts to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM dimming | 3000:1 ratio with constant chromaticity - achieved by precise PWM-controlled current sourcing without color shift. |
| Four-string current matching | ±1.5% matching across temperature and line - enabled by matched internal current sources and shared reference. |
| Programmable thermal derating | Configurable LED current reduction above user-defined junction temperature - protects LEDs using TSET pin and VPTAT tracking. |
| Integrated fault protection | Dedicated OPENLED/SHORTLED pins with latched status - simplifies system-level diagnostics without external logic. |
| Output disconnect during shutdown | Internal VO_SW PMOS isolates feedback divider from VOUT - prevents capacitor discharge and false OPENLED triggers during PWM off-time. |
Applications
| Automotive Navigation Displays | Industrial TFT LCD Backlighting |
|---|---|
Use Scenario: High-brightness backlight for 7–12 inch automotive infotainment displays operating in under-hood ambient temperatures up to 105°C. IC Role / Device Role / Timing Role: Four-channel LED driver with thermal derating and fault reporting - regulates current per string while adapting to engine bay thermal transients. Use Value: Enables reliable 150°C-rated operation with ±1.5% matching, eliminating brightness non-uniformity and extending LED lifetime under thermal stress. |
Use Scenario: Backlight for ruggedized industrial HMIs used in factory automation, where EMI immunity and long-term stability are critical. IC Role / Device Role / Timing Role: Boost LED driver with programmable frequency (200kHz–2.1MHz) and SYNC input - allows noise avoidance in sensitive measurement environments. Use Value: Reduces conducted EMI through frequency tuning and provides robust open/short detection to prevent field failures in unattended equipment. |
| Desktop Monitor Backlight | Medical Imaging Display |
Use Scenario: Dual-scan or edge-lit backlight for 24-inch desktop monitors requiring flicker-free dimming and uniform luminance. IC Role / Device Role / Timing Role: Constant-current LED controller with analog (20:1) and PWM (3000:1) dimming - supports both UI-adjustable brightness and video-sync dimming. Use Value: Delivers smooth, artifact-free dimming across full range while maintaining color accuracy - critical for photo/video editing workflows. |
Use Scenario: Diagnostic-grade display backlight in medical imaging systems where grayscale fidelity and zero flicker are mandatory. IC Role / Device Role / Timing Role: Precision LED driver with <±0.25% current matching (typical) and regulated VOUT - ensures pixel-level luminance consistency across DICOM-calibrated panels. Use Value: Meets IEC 62304 Class C software safety requirements via hardware-enforced fault signaling (OPENLED/SHORTLED) and predictable thermal rolloff. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3599IFE#PBF | Same functionality and pinout; rated for –40°C to +125°C junction temperature (vs. +150°C for H-grade). | Suitable for commercial/industrial indoor applications but not under-hood automotive. | Select LT3599HFE#PBF when ambient temperature exceeds 125°C or AEC-Q100 compliance is required. |
| LT3599EUH#PBF | Same electrical specs; packaged in 32-pin 5mm × 5mm QFN with exposed pad - lower θJA (34°C/W) but different footprint. | Better thermal performance in space-constrained layouts; requires PCB redesign due to pin count and pitch difference. | Choose LT3599HFE#PBF for drop-in replacement in existing TSSOP designs needing extended temperature support. |
Compared with LT3599IFE#PBF and LT3599EUH#PBF, the LT3599HFE#PBF uniquely combines 150°C operation in the compact 28-pin TSSOP package - enabling high-reliability backlighting in thermally demanding spaces without layout change or thermal derating penalties.
Availability
LT3599HFE#PBF is available at Aetrix Electronics and suitable for automotive navigation displays, industrial HMIs, and medical imaging backlights requiring stable component supply, long-term lifecycle assurance, and guaranteed high-temperature performance.
Supply support for LT3599HFE#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 legacy of high-performance analog ICs for precision power, signal conditioning, and timing applications.
The LT3599 product line was designed specifically for multi-string LED backlighting in automotive, industrial, and medical displays - emphasizing thermal resilience, current matching, and integrated fault diagnostics.
FAQ
What is the maximum junction temperature rating for the LT3599HFE#PBF?
The LT3599HFE#PBF is specified for continuous operation from –40°C to +150°C junction temperature, with a maximum junction temperature (TJMAX) of 150°C. This H-grade qualification distinguishes it from E/I-grade variants (125°C TJMAX) and enables deployment in under-hood automotive environments where ambient temperatures exceed 105°C. Thermal design must maintain θJA ≤ 28°C/W using the exposed pad.
How does the LT3599HFE#PBF achieve ±1.5% LED current matching across strings?
The LT3599HFE#PBF achieves ±1.5% LED current matching through laser-trimmed, matched internal current sources referenced to a common bandgap (VREF = 1.227V) and shared error amplifier architecture. Matching is maintained across temperature (–40°C to +150°C), input voltage (3.1V–30V), and load conditions - verified in production test and confirmed in Electrical Characteristics tables for the H-grade variant.
Can the LT3599HFE#PBF drive fewer than four LED strings?
Yes - the LT3599HFE#PBF supports flexible string configuration. LED4 can be disabled using the DISABLE4 pin (tie to VREF), and its pin should be connected to LED3. For two-string operation, LED1/LED2 and LED3/LED4 may be paralleled. The device automatically adjusts regulation to the lowest active LED pin voltage, ensuring stable current delivery without reconfiguration of feedback or compensation networks.
What is the role of the VO_SW pin in the LT3599HFE#PBF?
The VO_SW pin connects to the drain of an internal PMOS switch that isolates the FB resistive divider from VOUT during PWM off-time or shutdown. This prevents discharge of the output capacitor through the divider, enabling deeper PWM dimming (down to 0.033% duty cycle) and eliminating false OPENLED assertions. VO_SW is not user-accessible - it interfaces internally between VOUT and FB.
Does the LT3599HFE#PBF support synchronization to an external clock?
Yes - the LT3599HFE#PBF supports frequency synchronization via the SYNC pin. To synchronize, the RT resistor must be selected to program a free-running frequency ~20% slower than the external clock frequency. When an external clock pulse is applied to SYNC, the internal oscillator locks to it. If unused, SYNC must be grounded - leaving it floating may cause erratic operation or increased EMI.
LT3599HFE#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3599HFE#PBF FAQ
1.How can I place an order for LT3599HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3599HFE#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 LT3599HFE#PBF reliable?
The price and inventory of LT3599HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3599HFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3599HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3599HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3599HFE#PBF?
LT3599HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3599HFE#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 LT3599HFE#PBF?
For technical support, including LT3599HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3599HFE#PBF requirements.
6.How does Aetrix verify that LT3599HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3599HFE#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 LT3599HFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3599HFE#PBF?
All LT3599HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3599HFE#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 LT3599HFE#PBF part is unused and in its original packaging.
Return procedure for LT3599HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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