My Inquiry
My Account
Analog Devices Inc. LT3599IUH#PBF
- Part No.:
- LT3599IUH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LT3599IUH#PBF.pdf
- Description:
- IC LED DRV RGLTR PWM 120MA 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:223
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3599IUH#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 voltage range of 3.1V to 30V. It enables True Color PWM dimming up to 3000:1 in automotive and notebook TFT LCD backlight applications.
For engineers reviewing the LT3599IUH#PBF datasheet, LT3599IUH#PBF pinout, LT3599IUH#PBF application, or LT3599IUH#PBF equivalent, key selection considerations include its 32-pin 5mm × 5mm QFN thermal package, programmable switching frequency (200kHz–2.1MHz), analog + PWM dimming capability, open/short LED fault detection, and regulated current operation even when VIN > VOUT.
Technical Context
The LT3599IUH#PBF implements constant-frequency peak-current-mode control with an internal 2A NPN power switch and integrated PMOS disconnect switch (VO_SW) for enhanced PWM dimming range. Its feedback loop uses the lowest LED-string cathode voltage (LED1–LED4) for dynamic output regulation during multi-string operation.
It features dual dimming paths: analog control via CTRL pin (0–1V, up to 20:1 ratio) and high-fidelity PWM dimming via dedicated PWM pin (0.033%–100% duty cycle, up to 3000:1). Fault management includes OPENLED and SHORTLED open-collector flags, programmable LED current derating via TSET, and overvoltage protection using FB with external resistor 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% across all strings at 100mA - ensures uniform brightness in multi-string displays |
| Input Voltage Range | 3.1V to 30V - supports wide-range industrial and automotive supplies without pre-regulation |
| Max Output Voltage | 44V - sufficient for driving 10+ white LEDs in series per string |
| Switching Frequency Range | 200kHz to 2.1MHz (resistor-programmable via RT) - enables EMI optimization and compact magnetics |
| Dimming Capability | True Color PWM up to 3000:1 + analog dimming up to 20:1 - preserves color fidelity while enabling ultra-low-brightness control |
| Thermal Rating | –40°C to +125°C junction - qualified for automotive cabin and industrial display environments |
Pinout & Package
LT3599IUH#PBF is housed in a thermally enhanced 32-pin (5mm × 5mm) plastic QFN package with exposed pad (Pin 33) soldered to PCB ground for optimal thermal dissipation (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply connection | Accepts 3.1V–30V; requires local ceramic bypass capacitor to GND |
| SW | Internal NPN switch collector | Drives external boost inductor; minimize trace area to reduce EMI |
| VOUT | Boost output node | Supplies power to all LED strings; max 44V rating |
| LED1–LED4 | LED string cathode outputs | Each sinks programmed current; OPENLED/SHORTLED detection enabled per string |
| CTRL | Analog dimming control input | 0–1V sets LED current proportionally; >1V has no effect |
| PWM | Digital dimming enable/disable input | High (>1V) enables switching; low (<0.4V) disables with VC state retention |
| ISET | LED current programming node | Resistor to GND sets nominal current (e.g., 13.3kΩ → 99mA) |
| TSET | Junction temperature derating threshold | Programs thermal foldback onset point for LED current reduction |
| FB | Overvoltage protection feedback | 1.223V reference; used with R1/R2 divider to clamp VOUT when all strings open |
| VO_SW | PMOS-controlled feedback node | Isolates FB divider during PWM off-time to extend dimming range and reduce leakage |
| OPENLED / SHORTLED | Fault flag outputs | Open-collector alerts - pulled low on detected open-circuit or high-side short |
| DISABLE4 | LED4 string disable control | Tie to VREF to disable LED4; allows 3-string operation with LED4 tied to LED3 |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM dimming | 3000:1 ratio with constant chromaticity - eliminates color shift in display backlights |
| ±1.5% LED current matching | Across all four strings and temperature - critical for uniform luminance in large-area LCDs |
| Regulated current with VIN > VOUT | Maintains stable LED current even during input voltage transients exceeding output voltage |
| Programmable thermal derating | TSET pin enables custom LED current vs. junction temperature curve to prevent LED degradation |
| Integrated fault protection | Dedicated OPENLED/SHORTLED flags plus automatic string disable on short - improves system reliability |
| Synchronization capability | SYNC pin accepts external clock; RT resistor set 20% below sync frequency for deterministic timing |
Applications
| Automotive Navigation Displays | Notebook LCD Backlight |
|---|---|
|
Use Scenario: TFT LCD backlight in vehicle infotainment systems operating across –40°C to +105°C ambient. IC Role / Device Role / Timing Role: Four-string LED driver with synchronized PWM dimming and thermal derating for LED lifetime extension. Use Value: ±1.5% current matching prevents visible banding; 3000:1 dimming enables night-driving readability without color shift. |
Use Scenario: Slim-profile notebook display requiring high-efficiency, low-EMI backlight with ultra-low brightness mode. IC Role / Device Role / Timing Role: Boost converter + precision current regulator with VO_SW isolation for extended PWM range. Use Value: 2.1MHz max switching enables tiny inductors; 5mm × 5mm QFN fits tight board space; <1µA shutdown current extends battery life. |
| Desktop Monitor Backlight | Industrial HMI Panels |
|
Use Scenario: High-brightness desktop monitor with flicker-free dimming and consistent white point across brightness levels. IC Role / Device Role / Timing Role: Constant-current LED driver with analog + PWM dimming paths and open/short diagnostics. Use Value: Dual dimming modes allow UI designers to select best method per use case; OPENLED flag enables graceful failure handling. |
Use Scenario: Ruggedized human-machine interface panel in factory automation with wide input voltage and thermal stress. IC Role / Device Role / Timing Role: Robust LED driver with UVLO hysteresis, 30V max input, and –40°C to +125°C operation. Use Value: Programmable SHDN/UVLO prevents brown-out resets; TSET-based derating protects LEDs during prolonged high-temp operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | 4-channel synchronous buck-boost LED driver; supports higher efficiency at lower VOUT but lacks integrated OPENLED/SHORTLED flags | Better suited for battery-powered portable devices where VIN may dip below VOUT; less ideal for fixed 12V/24V automotive systems | Select LTC3783EFE#PBF when bidirectional voltage conversion and >90% efficiency at light load are prioritized over fault diagnostics |
| TPS68400RHDR | Texas Instruments 4-channel boost LED driver; 1.5MHz fixed frequency, ±2% current matching, no TSET thermal derating or VO_SW isolation | Lower cost alternative with simpler layout; missing True Color PWM architecture and thermal foldback programming | Choose TPS68400RHDR for cost-sensitive consumer displays where 3000:1 dimming and precise thermal management are not required |
Compared with LT3599IUH#PBF, LTC3783EFE#PBF offers superior efficiency in buck-boost topology but sacrifices integrated fault reporting, while TPS68400RHDR provides basic 4-string driving at lower BOM cost but omits critical display-grade features like thermal derating and VO_SW-enhanced dimming range.
Availability
LT3599IUH#PBF is available at Aetrix Electronics and suitable for automotive navigation displays, notebook LCD backlights, and industrial HMI panels requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across temperature.
Supply support for LT3599IUH#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 full technical and manufacturing continuity for legacy Linear products including the LT3599 family.
The LT3599 product line was engineered specifically for high-reliability, multi-string LED backlighting in automotive and premium computing displays - emphasizing precision current matching, thermal robustness, and diagnostic integrity.
FAQ
What is the maximum LED string voltage supported by the LT3599IUH#PBF?
The LT3599IUH#PBF supports up to 44V output voltage, sufficient to drive 10–12 white LEDs in series per string depending on forward voltage. This rating is confirmed in Absolute Maximum Ratings and validated across temperature in Typical Performance Characteristics graphs showing stable regulation up to 44V under load.
Does the LT3599IUH#PBF support dimming when input voltage exceeds output voltage?
Yes, the LT3599IUH#PBF maintains accurate LED current regulation even when VIN > VOUT - a documented feature in the Description and Applications Information sections. This behavior is enabled by its current-mode control architecture and independent current-sense path, verified in Electrical Characteristics tables showing consistent LED current across input voltage sweeps.
How is LED current matching accuracy maintained across temperature for the LT3599IUH#PBF?
The LT3599IUH#PBF achieves ±1.5% LED current matching across –40°C to +125°C, as specified in Electrical Characteristics (Note "l" indicating full-temp-range guarantee). This is realized through matched internal current-sense circuitry and on-chip trimming, with graphical data (Figure TA01b) confirming <±0.5% deviation over 0°C–100°C.
Can the LT3599IUH#PBF drive fewer than four LED strings?
Yes, the LT3599IUH#PBF supports 1–4 string configurations. LED4 can be disabled via the DISABLE4 pin (tie to VREF), and unused LED pins may be paralleled (e.g., LED1+LED2, LED3+LED4) as described in the Operation section. All fault detection and regulation remain active for connected strings.
What package type and thermal characteristics apply to the LT3599IUH#PBF?
The LT3599IUH#PBF uses a 32-pin 5mm × 5mm plastic QFN package with exposed thermal pad (Pin 33 = GND). Its thermal resistance is θJA = 34°C/W and θJC = 10°C/W, with maximum junction temperature rated at 125°C - confirmed in Order Information and Absolute Maximum Ratings tables.
LT3599IUH#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN 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:
- 32-QFN (5x5)
LT3599IUH#PBF FAQ
1.How can I place an order for LT3599IUH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3599IUH#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 LT3599IUH#PBF reliable?
The price and inventory of LT3599IUH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3599IUH#PBF is usually 5 days.
3.What payment methods are accepted for LT3599IUH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3599IUH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3599IUH#PBF?
LT3599IUH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3599IUH#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 LT3599IUH#PBF?
For technical support, including LT3599IUH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3599IUH#PBF requirements.
6.How does Aetrix verify that LT3599IUH#PBF is sourced from the original manufacturer or authorized distributors?
All LT3599IUH#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 LT3599IUH#PBF meets industry standards.
7.What is the process for return or replacement of LT3599IUH#PBF?
All LT3599IUH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3599IUH#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 LT3599IUH#PBF part is unused and in its original packaging.
Return procedure for LT3599IUH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3599IUH#PBF Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
