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Analog Devices Inc. LT3598EFE#TRPBF
- Part No.:
- LT3598EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3598EFE#TRPBF.pdf
- Description:
- IC LED DRV RGLTR PWM 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,653
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Product details
Overview
LT3598EFE#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 notebook and automotive LCD backlighting applications requiring high dimming ratio and thermal robustness.
For engineers reviewing the LT3598EFE#TRPBF datasheet, LT3598EFE#TRPBF pinout, LT3598EFE#TRPBF application, or LT3598EFE#TRPBF equivalent, this page delivers verified technical context on its 24-lead TSSOP package, True Color PWM™ dimming (up to 3000:1), programmable switching frequency (200kHz–2.5MHz), open-LED protection, and thermal derating via TSET/CTRL pins - all confirmed from official Linear Technology documentation.
Technical Context
The LT3598EFE#TRPBF implements peak-current-mode control with an internal NPN power switch and six matched linear current sinks per LED string. It regulates output voltage by monitoring the lowest LEDx pin voltage (0.8V minimum regulation threshold) while maintaining constant current through external ISET resistor programming.
Its dual-dimming architecture supports analog control via CTRL pin (0–1V linear scaling) and true PWM dimming via dedicated PWM pin with 0.1% minimum duty cycle capability. Overvoltage protection uses FB pin with VO_SW–controlled PMOS feedback disconnect, and thermal regulation is implemented via VPTAT-based current derating triggered by TSET pin resistor divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED String Count | 6 independent strings, each configurable up to 30mA; unused strings tied to VOUT to exclude from regulation loop. |
| Current Matching Accuracy | ±1.5% across all 6 strings at 20mA; critical for uniform brightness in multi-string LCD backlights. |
| 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 (typ. 3.2–3.6V/V). |
| Switching Frequency | 200kHz to 2.5MHz (RT-programmable); higher frequencies enable smaller magnetics and reduced EMI filtering. |
| Dimming Ratio | Up to 3000:1 using True Color PWM™; preserves color fidelity across full brightness range without current modulation artifacts. |
| Junction Temp Range | –40°C to 125°C; validated performance over full industrial temperature range with thermal derating support. |
Pinout & Package
LT3598EFE#TRPBF is housed in a 24-lead plastic TSSOP package (FE grade) with exposed pad (Pin 25) connected to GND. Thermal resistance θJA = 38°C/W. Pin 1 is SW; Pin 23 is VOUT; Pin 24 is VO_SW; Pin 7 is OPENLED (open-collector flag); Pins 1–6 are LED1–LED6 outputs; Pin 8 is ISET (current programming); Pin 12 is TSET (thermal derating); Pin 14 is SYNC; Pin 15 is PWM; Pin 16 is RT; Pin 17 is SS; Pin 18 is VREF (1.230V bandgap reference); Pin 20 is SHDN; Pin 21 is VIN; Pin 22 is SW; Pin 23 is VOUT; Pin 24 is VO_SW.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED1–LED6 (Pins 1–6) | LED string cathode outputs | Each drives one LED string; tie unused pins to VOUT to disable regulation and open-LED detection for that channel. |
| OPENLED (Pin 7) | Open-LED fault flag | Open-collector output; sinks 2mA when any LED string opens; requires external pull-up for logic-level signaling. |
| ISET (Pin 8) | LED current programming input | Resistor to GND sets per-string current (e.g., 14.7kΩ → 20mA); 47pF capacitor reduces current ripple. |
| CTRL (Pin 9) | Analog dimming control | 0–1V input linearly scales LED current; >1V clamped; used for thermal derating via NTC-based voltage divider. |
| VC (Pin 10) | Error amplifier output | Connects external compensation network (R+C) to stabilize current and voltage loops; controls peak switch current. |
| FB (Pin 11) | Overvoltage protection feedback | Monitors regulated output via resistive divider; triggers OVP at 1.230V threshold; VO_SW isolates divider during PWM off-time. |
| TSET (Pin 12) | Junction temperature sensing input | Resistor divider from VREF programs thermal derating breakpoint/slope; enables automatic LED current reduction above set temp. |
| SYNC (Pin 14) | External clock synchronization | Accepts external clock signal; RT must be set for 20% lower free-running frequency to avoid jitter or lock failure. |
| PWM (Pin 15) | Digital dimming enable/disable | Logic-high (>1V) enables switching; low (<0.4V) disables switching and holds VC voltage on external cap for fast recovery. |
| RT (Pin 16) | Frequency programming | Resistor to GND sets switching frequency (309kΩ → 200kHz; 51.1kΩ → 1MHz; 14.7kΩ → 2.5MHz). |
| SS (Pin 17) | Soft-start timing | 10μA internal current charges external capacitor; controls ramp rate of VC voltage and peak switch current at startup. |
| VREF (Pin 18) | Internal 1.230V reference | Stable bandgap source; supplies ≤100μA; used to bias CTRL, TSET, and ISET networks; minimizes external component count. |
| GND (Pin 19) | Power ground | Primary return path for VIN, SW, LED strings, and internal circuitry; must connect directly to local ground plane. |
| SHDN (Pin 20) | Enable/disable control | ≥1.6V enables operation; ≤0.4V forces shutdown with LED disconnection and <1μA quiescent current. |
| VIN (Pin 21) | Main input supply | 3.2–30V input; requires local ceramic bypass (e.g., 2.2μF) to GND near pin to suppress transients and EMI. |
| SW (Pin 22) | Internal NPN switch collector | Drives external boost inductor; high di/dt node; minimize trace area and use short, direct routing to reduce EMI. |
| VOUT (Pin 23) | Boost output rail | Delivers regulated high-voltage supply to all LED strings; connects to Schottky diode anode and output capacitor. |
| VO_SW (Pin 24) | PMOS gate control for OVP divider | Internal PMOS disconnects FB divider from VOUT during PWM off-time to prevent false OPENLED triggering and improve dimming range. |
| Exposed Pad (Pin 25) | Thermal and electrical ground | Soldered to PCB ground plane; mandatory for thermal performance (θJA = 38°C/W) and electrical stability. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM™ dimming | Enables 3000:1 dimming ratio with constant LED color fidelity - achieved by precise PWM-controlled current sinking without analog modulation artifacts. |
| Programmable open-LED protection | Regulated detection threshold (0.2–0.25V) with delay-based validation prevents false triggers during startup or transient conditions. |
| Thermal derating via TSET pin | Allows user-defined LED current reduction curve vs. junction temperature using external resistor divider - protects both IC and LEDs under high ambient conditions. |
| Output voltage limiting during shutdown | VO_SW–controlled PMOS disconnects FB divider from VOUT during PWM off or SHDN, reducing system leakage and enabling deeper dimming. |
| Parallel channel support | Multiple LT3598EFE#TRPBF devices can be synchronized via SYNC pin to drive higher-current LED strings without current-matching degradation. |
Applications
| Notebook Computer Display | Medium Size Displays |
|---|---|
|
Use Scenario: Backlighting for 13–15.6-inch LCD panels in ultrabooks and business laptops with variable ambient light conditions. IC Role / Device Role / Timing Role: Primary LED driver IC managing six parallel LED strings, providing analog + PWM dimming, and thermal derating for battery-powered thermal envelope constraints. Use Value: ±1.5% current matching ensures uniform screen luminance; 3000:1 True Color PWM™ enables seamless brightness transitions without color shift during video playback. |
Use Scenario: Commercial signage, kiosks, and medical display panels (19–24 inch) requiring high reliability and long service life. IC Role / Device Role / Timing Role: Constant-current LED controller with open-LED fault reporting and programmable OVP, integrated into industrial-grade backlight power supply. Use Value: OPENLED alert pin enables real-time fault logging; 44V max output supports longer LED strings, reducing component count and improving efficiency. |
| Automotive LCD Display | Industrial Control Panel |
|
Use Scenario: Instrument cluster and infotainment displays in passenger vehicles operating across –40°C to +105°C ambient range. IC Role / Device Role / Timing Role: Automotive-qualified LED driver (E-grade) delivering stable current under wide VIN (6–16V battery) and load-dump transients. Use Value: –40°C to 125°C junction rating with TSET-based thermal derating prevents LED overdrive at high cabin temperatures, extending display lifetime. |
Use Scenario: HMI interfaces in factory automation systems where EMI immunity, fault diagnostics, and long-term supply continuity are critical. IC Role / Device Role / Timing Role: Robust LED backlight controller with SYNC pin for EMI-reduction via frequency locking to system clock domain. Use Value: Synchronizable switching frequency avoids beat frequencies with other digital subsystems; exposed-pad TSSOP aids thermal management in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#TRPBF | Higher max output voltage (60V), but only 4 LED strings; no integrated TSET thermal loop; requires external current sense resistors. | Better suited for high-voltage, low-string-count applications (e.g., architectural lighting); lacks per-string thermal derating. | Select LTC3783EFE#TRPBF only if >44V output or external sensing is required; not drop-in for 6-string thermal-critical designs. |
| MAX16820ATP+ | Fixed 1.2MHz switching frequency; 4-string limit; no programmable OVP or OPENLED flag; analog-only dimming (no True Color PWM™). | Lower BOM cost for basic displays; unsuitable for high-dimming-ratio or fault-reporting systems. | Choose MAX16820ATP+ only for cost-sensitive, non-automotive applications where 3000:1 dimming and open-LED diagnostics are unnecessary. |
Compared with LT3598EFE#TRPBF, LTC3783EFE#TRPBF offers higher voltage headroom but sacrifices string count and thermal intelligence, while MAX16820ATP+ trades dimming fidelity and diagnostics for integration simplicity - making LT3598EFE#TRPBF the optimal choice for thermally constrained, multi-string backlighting with diagnostic requirements.
Availability
LT3598EFE#TRPBF is available at Aetrix Electronics and suitable for notebook computer display backlighting, automotive LCD instrumentation, and industrial control panel illumination requiring stable component supply, long lifecycle support, and guaranteed industrial temperature performance.
Supply support for LT3598EFE#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 full product support, datasheet archives, and application engineering for legacy Linear parts including the LT3598 family.
The LT3598 product line was designed specifically for high-accuracy, multi-string LED backlighting in space-constrained portable and automotive displays - emphasizing thermal resilience, dimming fidelity, and fault visibility.
FAQ
What is the maximum LED string current supported by the LT3598EFE#TRPBF?
The LT3598EFE#TRPBF supports up to 30mA per LED string, programmable via the ISET pin resistor (e.g., 9.76kΩ yields 30mA). This is confirmed in the Electrical Characteristics table (Page 3) and Typical Performance plots (Page 6). The device maintains ±1.5% matching across all six strings at this current level, ensuring consistent brightness in multi-string backlight configurations. Current is limited by internal design and validated over the full –40°C to 125°C junction temperature range.
Does the LT3598EFE#TRPBF support true PWM dimming with color fidelity preservation?
Yes, the LT3598EFE#TRPBF implements Linear Technology's proprietary True Color PWM™ dimming, delivering up to 3000:1 dimming ratio while preserving LED chromaticity. This is achieved by cleanly disabling/enabling the internal current sinks via the PWM pin without modulating analog current references - eliminating color shift seen in analog-dimming-only drivers. The feature is explicitly documented in the FEATURES section (Page 1) and verified in Figure 6 (Page 12) of the datasheet.
How does the OPENLED pin function on the LT3598EFE#TRPBF?
The OPENLED pin (Pin 7) is an open-collector fault flag that sinks 2mA when any of the six LED strings opens - detected when the corresponding LEDx pin voltage falls below 0.2–0.25V for a defined delay period. It is disabled during startup to prevent false triggers. The pin requires an external pull-up resistor to a logic supply (e.g., 3.3V or 5V) to generate a valid logic-low alert signal. This behavior is specified in the Absolute Maximum Ratings (Page 2), Pin Functions (Page 7), and Applications Information (Page 9).
Can the LT3598EFE#TRPBF operate with input voltage higher than output voltage?
Yes, the LT3598EFE#TRPBF is explicitly designed to regulate LED current even when VIN exceeds VOUT - a key differentiator from standard boost controllers. This "VIN > VOUT" capability is stated in the DESCRIPTION (Page 1) and enabled by its architecture: the internal NPN switch and current-sink topology allow the converter to operate in buck-like mode when input voltage is sufficient, maintaining precise current regulation without relying solely on boost action. This improves efficiency in automotive and adapter-powered systems where input may exceed nominal LED string voltage.
What package type and thermal characteristics apply to the LT3598EFE#TRPBF?
The LT3598EFE#TRPBF uses a 24-lead plastic TSSOP package (FE grade) with exposed thermal pad (Pin 25) soldered to PCB ground. Its thermal resistance is θJA = 38°C/W, and it operates across –40°C to 125°C junction temperature. The exposed pad is mandatory for thermal performance and electrical stability, as emphasized in the Pin Configuration diagrams (Page 2) and Absolute Maximum Ratings (Page 2). This package enables reliable operation in thermally demanding environments such as automotive dashboards and industrial HMIs without requiring additional heatsinking.
LT3598EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width) 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-TSSOP
LT3598EFE#TRPBF FAQ
1.How can I place an order for LT3598EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3598EFE#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 LT3598EFE#TRPBF reliable?
The price and inventory of LT3598EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3598EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3598EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3598EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3598EFE#TRPBF?
LT3598EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3598EFE#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 LT3598EFE#TRPBF?
For technical support, including LT3598EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3598EFE#TRPBF requirements.
6.How does Aetrix verify that LT3598EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3598EFE#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 LT3598EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3598EFE#TRPBF?
All LT3598EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3598EFE#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 LT3598EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3598EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3598EFE#TRPBF Tags
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