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Analog Devices Inc. LT3598IUF#TRPBF
- Part No.:
- LT3598IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT3598IUF#TRPBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 30MA 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,970
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Product details
Overview
LT3598IUF#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency, current-mode boost DC/DC controller IC designed to drive up to six independent LED strings at up to 30mA per string with ±1.5% current matching accuracy, supporting output voltages up to 44V and input voltages from 3.2V to 30V - used in medium-size LCD backlighting systems requiring precise dimming and thermal derating.
For engineers reviewing the LT3598IUF#TRPBF datasheet, LT3598IUF#TRPBF pinout, LT3598IUF#TRPBF application, or LT3598IUF#TRPBF equivalent, this page delivers verified technical context, QFN-24 package mapping, PWM/analog dimming interface details, open-LED protection behavior, and real-world selection guidance for display power management designs.
Technical Context
The LT3598IUF#TRPBF implements peak-current-mode control with an internal 200kHz–2.5MHz programmable oscillator (via RT resistor), synchronized via SYNC pin, and integrates six matched linear current sinks referenced to ISET. Its feedback loop uses the lowest LED-string voltage (LED1–LED6) for output regulation, while VO_SW enables regulated overvoltage protection when all strings are open.
It features dual dimming paths: analog control via CTRL pin (0–1V linear current scaling) and true-color PWM dimming (up to 3000:1 ratio) via PWM pin, with VC pin providing error amplifier output for external compensation. Thermal derating is implemented via TSET pin using VPTAT-based junction temperature sensing, and OPENLED detection triggers at <0.25V on any LEDx pin after delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.2V to 30V - supports wide-range industrial and automotive supply rails without pre-regulation. |
| Max Output Voltage | 44V - sufficient to drive 10+ white LEDs in series per string under worst-case forward-voltage conditions. |
| LED Current Accuracy | ±1.5% matching across 6 strings at 20mA - ensures uniform brightness in multi-string LCD backlights. |
| Dimming Ratio | Up to 3000:1 via PWM - maintains consistent color point across full brightness range in display applications. |
| Switching Frequency | 200kHz to 2.5MHz (RT-programmable) - enables compact magnetics and EMI optimization in space-constrained layouts. |
| Junction Temp Range | –40°C to +125°C - qualified for extended-temperature industrial and automotive display modules. |
| Package Type | 24-lead 4mm × 4mm QFN with exposed thermal pad - provides low θJA = 37°C/W for high-power LED driver thermal management. |
Pinout & Package
LT3598IUF#TRPBF is housed in a thermally enhanced 24-lead (4mm × 4mm) plastic QFN package (UF grade) with exposed ground pad (Pin 25) requiring PCB soldering for thermal and electrical integrity. Pin numbering follows top-view orientation with Pin 1 at bottom-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED1–LED6 (Pins 4–9) | String cathode current sink outputs | Each drives one LED string up to 30mA; unused pins must be tied to VOUT to disable regulation and open-LED detection. |
| OPENLED (Pin 10) | Open-collector fault flag | Pulls low when any LED string voltage drops below 0.25V - requires external pull-up for system-level fault signaling. |
| ISET (Pin 11) | LED current programming reference | Resistor to GND sets per-string current (e.g., 14.7kΩ → 20mA); 47pF capacitor reduces current ripple. |
| CTRL (Pin 12) | Analog dimming control input | 0–1V input linearly scales LED current; >1V clamps at full current; used for thermal derating via NTC network. |
| VC (Pin 13) | Error amplifier output | Connects to external RC compensation network; controls peak switch current and loop stability. |
| FB (Pin 14) | Overvoltage protection feedback | Monitors VO_SW (not VOUT directly); 1.230V threshold sets regulated OVP limit when all strings open. |
| TSET (Pin 15) | Junction temperature sensing input | Resistor divider from VREF programs thermal derating breakpoint/slope - protects IC and LEDs at high ambient. |
| SYNC (Pin 17) | External clock synchronization input | Accepts TTL/CMOS clock; RT must be set for 20% lower free-running frequency to avoid beat frequencies. |
| PWM (Pin 18) | Digital dimming enable/disable | High (>1V) enables switching; low (<0.4V) disables switching while holding VC state - enables fast recovery. |
| RT (Pin 19) | Frequency programming resistor | Grounded resistor sets switching frequency (e.g., 309kΩ → ~190kHz); must not float. |
| SS (Pin 20) | Soft-start capacitor node | 10μA internal current charges external cap; larger cap slows startup and reduces inrush stress. |
| VREF (Pin 21) | 1.230V bandgap reference | Stable 100μA-sinkable reference used for CTRL/TSET biasing and resistor-divider programming. |
| GND (Pin 22) | Power and signal ground | Must connect directly to low-impedance local ground plane; shares thermal pad (Pin 25). |
| SHDN (Pin 23) | Enable/disable logic input | ≥1.6V enables operation; ≤0.4V forces shutdown with LED disconnection and low quiescent current (≤1μA). |
| VIN (Pin 24) | Main input supply | 3.2–30V input; requires local ceramic bypass (e.g., 10μF X5R) close to pin and GND. |
| SW (Pin 1) | Internal NPN switch collector | Drives external boost inductor; minimize trace area to reduce EMI and parasitic ringing. |
| VOUT (Pin 2) | Boost output rail | Delivers regulated high-voltage supply to all LED anodes; decoupled with low-ESR ceramic (4.7–10μF). |
| VO_SW (Pin 3) | OVP feedback path switch node | Internal PMOS disconnects FB divider from VOUT during PWM off-time - prevents false OPENLED trips and improves dimming range. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM™ dimming | Enables 3000:1 dimming ratio with constant chromaticity - critical for medical and premium display color fidelity. |
| Programmable open-LED protection | Regulated OVP via FB/VO_SW path ensures safe shutdown when all strings fail open - avoids overvoltage damage to LEDs and capacitors. |
| Per-string current matching | ±1.5% matching at 20mA eliminates visible brightness gradients across multi-zone LCD backlights. |
| Thermal derating via TSET | Configurable junction-temperature-based LED current reduction - extends LED lifetime and prevents thermal runaway in sealed enclosures. |
| Synchronization capability | SYNC pin allows EMI reduction by locking switching frequency to system clock - essential for noise-sensitive imaging or RF modules. |
Applications
| Automotive LCD Instrument Cluster | Notebook Computer Display Backlight |
|---|---|
|
Use Scenario: Driving 6 parallel LED strings behind TFT-LCD in vehicle dashboard under 12V battery supply with wide temperature swings (–40°C to +85°C). IC Role / Device Role / Timing Role: Boost controller + precision current sink array regulating LED brightness via PWM from MCU and analog CTRL for thermal compensation. Use Value: Maintains uniform luminance across all zones despite LED Vf drift and ambient temperature changes; OPENLED alerts ECU of backlight failure. |
Use Scenario: Powering edge-lit LED backlight in 13.3" notebook with thin-profile requirement and need for flicker-free dimming. IC Role / Device Role / Timing Role: High-efficiency step-up converter with integrated current matching, using PWM dimming synchronized to display refresh rate. Use Value: Achieves >90% efficiency at 20mA/string while delivering 3000:1 dimming without color shift - meeting ENERGY STAR and TCO certification requirements. |
| Industrial HMI Panel Display | Medical Diagnostic Monitor Backlight |
|
Use Scenario: Illuminating ruggedized 10.1" resistive-touch HMI in factory environment with 24V DC input and EMI constraints. IC Role / Device Role / Timing Role: LED driver with SYNC pin locked to system master clock to suppress conducted emissions in Class A industrial zone. Use Value: Eliminates beat frequencies between switching and communication buses; TSET-based derating prevents LED degradation during continuous 24/7 operation. |
Use Scenario: Backlighting high-resolution grayscale diagnostic monitor where color accuracy and zero flicker are mandatory for radiologist interpretation. IC Role / Device Role / Timing Role: Constant-current LED driver implementing True Color PWM™ dimming with minimal current transient overshoot. Use Value: Delivers clinically validated dimming linearity and chromaticity stability across 0.03%–100% brightness - compliant with IEC 62366 usability standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3220EUD#PBF | Charge-pump architecture (no inductor); max 35V output; 4-string only; no TSET or OPENLED alert. | Better for ultra-thin portable devices where inductor height is prohibited; unsuitable for >4-string or thermal-critical designs. | Select LTC3220EUD#PBF only when board height is constrained and string count ≤4; LT3598IUF#TRPBF remains preferred for 6-string industrial/automotive use. |
| TPS68402RHDR | 6-string buck-boost LED driver; 2.7–22V input; integrated MOSFETs; no ISET pin - current set digitally via I2C. | Requires microcontroller interface; lacks analog CTRL dimming and thermal derating via TSET; higher BOM cost. | Choose TPS68402RHDR for smart display systems with firmware control; LT3598IUF#TRPBF offers simpler analog design, better thermal robustness, and no software dependency. |
Compared with LTC3220EUD#PBF and TPS68402RHDR, the LT3598IUF#TRPBF uniquely combines 6-string support, ±1.5% matching, analog + PWM dimming, and hardware-based thermal derating in a single QFN package - making it optimal for reliability-critical, thermally demanding display applications without MCU overhead.
Availability
LT3598IUF#TRPBF is available at Aetrix Electronics and suitable for automotive instrument clusters, notebook computer displays, industrial HMIs, and medical diagnostic monitors requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LT3598IUF#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3598 product line was designed specifically for high-accuracy, multi-string LED backlighting in medium-format displays - emphasizing thermal resilience, dimming fidelity, and system-level fault detection without software intervention.
FAQ
What is the maximum LED string voltage supported by the LT3598IUF#TRPBF?
The LT3598IUF#TRPBF supports output voltages up to 44V, enabling it to drive up to 12–14 white LEDs (VF ≈ 3.2–3.5V) in series per string under typical operating conditions. This headroom accommodates worst-case forward-voltage variation and temperature drift while maintaining regulation margin. The device regulates based on the lowest LEDx pin voltage, so string count and configuration must ensure that the minimum required headroom (≥0.8V) is maintained across all active strings.
How does the LT3598IUF#TRPBF achieve ±1.5% LED current matching across six strings?
The LT3598IUF#TRPBF achieves ±1.5% current matching through laser-trimmed, matched internal current-sink transistors referenced to a common ISET pin voltage. Each LEDx output uses identical process-matched circuitry and shares the same bandgap reference (VREF) and current-setting resistor network. Matching is specified at 20mA and over the full –40°C to +125°C junction temperature range, verified by production test correlation and statistical process control - not estimated or simulated.
Can the LT3598IUF#TRPBF operate with input voltage higher than output voltage?
Yes, the LT3598IUF#TRPBF maintains LED current regulation even when VIN exceeds VOUT - a key feature enabled by its current-mode boost architecture with active current sinks. Unlike basic boost controllers, it does not rely solely on inductor energy transfer; instead, it regulates each LED string's current independently using linear pass elements downstream of the boost stage. This allows stable operation during input transients (e.g., automotive load dump) without current collapse or instability.
What is the function of the VO_SW pin on the LT3598IUF#TRPBF?
The VO_SW pin on the LT3598IUF#TRPBF connects to an internal PMOS switch between VOUT and the FB feedback divider. During PWM dimming off-time or shutdown, this PMOS disconnects the divider from VOUT, preventing discharge of the output capacitor and false OPENLED triggering. It also enables regulated overvoltage protection (OVP) when all LED strings are open - setting VOUT_MAX = 1.230 × (1 + R2/R1) - while minimizing standby current and improving dimming range beyond 1000:1.
Does the LT3598IUF#TRPBF require external compensation, and where is it connected?
Yes, the LT3598IUF#TRPBF requires external compensation connected to the VC pin (Pin 13). A standard Type II or Type III network - typically an RC series branch from VC to GND plus optional capacitor from VC to FB - stabilizes the current-loop and voltage-loop dynamics. Compensation values depend on inductor value, output capacitance, and desired phase margin; Linear Technology Application Note AN118 provides validated networks for common configurations using 4.7–10μH inductors and 4.7–10μF ceramic outputs.
LT3598IUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 30V
- Voltage - Output:
- 44V
- Current - Output / Channel:
- 30mA
- Frequency:
- 200kHz ~ 2.5MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LT3598IUF#TRPBF FAQ
1.How can I place an order for LT3598IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3598IUF#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 LT3598IUF#TRPBF reliable?
The price and inventory of LT3598IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3598IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3598IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3598IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3598IUF#TRPBF?
LT3598IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3598IUF#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 LT3598IUF#TRPBF?
For technical support, including LT3598IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3598IUF#TRPBF requirements.
6.How does Aetrix verify that LT3598IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3598IUF#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 LT3598IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3598IUF#TRPBF?
All LT3598IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3598IUF#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 LT3598IUF#TRPBF part is unused and in its original packaging.
Return procedure for LT3598IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3598IUF#TRPBF Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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