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Analog Devices Inc. LT3598IFE#TRPBF
- Part No.:
- LT3598IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3598IFE#TRPBF.pdf
- Description:
- IC LED DRV RGLTR PWM 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:708
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Product details
Overview
LT3598IFE#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency boost DC/DC LED driver IC designed to power up to six independent LED strings at up to 30mA per string with ±1.5% current matching accuracy, supporting notebook and automotive LCD backlighting with output voltage up to 44V and input range 3.2V–30V.
For engineers reviewing the LT3598IFE#TRPBF datasheet, LT3598IFE#TRPBF pinout, LT3598IFE#TRPBF application, or LT3598IFE#TRPBF equivalent, this page delivers verified technical context, real-world dimming performance (3000:1 True Color PWM™), thermal derating capability, overvoltage protection architecture, and validated alternative part comparisons - all grounded in the official LT3598 datasheet Rev. FB.
Technical Context
The LT3598IFE#TRPBF implements constant-frequency peak-current-mode control with an internal NPN power switch and six matched linear current sinks. Its feedback loop uses the lowest LED-string cathode voltage (LED1–LED6) for output regulation, enabling stable operation even when VIN exceeds VOUT.
It integrates programmable open-LED detection (0.25V threshold), temperature-based LED current derating via TSET/CTRL pins, regulated overvoltage protection using VO_SW/FB with internal PMOS isolation, and synchronization capability via SYNC pin with 20% frequency offset requirement relative to external clock.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.2V to 30V - supports wide-range industrial and automotive supplies without pre-regulation. |
| Output Voltage Max | 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 - ensures uniform brightness in multi-string display backlights. |
| Switching Frequency | 200kHz to 2.5MHz (RT-programmable) - enables compact magnetics and EMI optimization. |
| PWM Dimming Ratio | Up to 3000:1 - maintains consistent LED color across full brightness range via True Color PWM™. |
| Junction Temp Range | –40°C to 125°C - qualified for automotive cabin and industrial ambient environments. |
| Package Type | 24-lead TSSOP (FE package) - thermally enhanced with exposed pad tied to GND for PCB heat sinking. |
Pinout & Package
LT3598IFE#TRPBF is housed in a 24-lead plastic TSSOP (FE package) with exposed pad (Pin 25) soldered to PCB ground for thermal management (θJA = 38°C/W). Pin functions are electrically identical to the QFN variant but mapped to TSSOP layout.
| 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 remove from regulation loop. |
| OPENLED (Pin 7) | Open-LED fault flag | Open-collector output asserting low when any LED string opens; requires pull-up resistor. |
| ISET (Pin 8) | LED current programming | Resistor to GND sets per-string current (e.g., 14.7kΩ → 20mA); 47pF capacitor reduces ripple. |
| CTRL (Pin 9) | Analog dimming / thermal derating control | 0–1V input linearly scales LED current; used with NTC network for temperature-dependent derating. |
| VC (Pin 10) | Error amplifier output | Connects to external compensation network; controls peak switch current during regulation. |
| FB (Pin 11) | Overvoltage protection feedback | Monitors VO_SW via resistor divider; triggers OVP at 1.230V reference when all strings open. |
| TSET (Pin 12) | Junction temperature sensing | Resistor divider from VREF programs thermal shutdown breakpoint and slope for LED current reduction. |
| SYNC (Pin 14) | Frequency synchronization input | Accepts external clock; RT must be set for 20% lower free-running frequency to avoid jitter. |
| PWM (Pin 15) | Digital dimming enable | High (>1V) enables switching; low (<0.4V) disables switching while preserving VC state for fast recovery. |
| RT (Pin 16) | Frequency setting | Resistor to GND selects switching frequency (309kΩ → 190kHz; 14.7kΩ → 2.5MHz). |
| SS (Pin 17) | Soft-start timing | 10μA current charges external capacitor; controls ramp rate of VC to limit inrush current. |
| VREF (Pin 18) | 1.230V bandgap reference | Stable internal reference; supplies ≤100μA; used to bias CTRL/TSET resistor networks. |
| GND (Pin 19) | Power ground | Primary return path; connect directly to local ground plane; ties to exposed pad (Pin 25). |
| SHDN (Pin 20) | Enable/disable control | ≥1.6V enables device; ≤0.4V disables all switching and reduces quiescent current to <1μA. |
| VIN (Pin 21) | Main input supply | 3.2–30V input; requires local ceramic bypass capacitor (e.g., 4.7μF X5R/X7R). |
| SW (Pin 22) | Internal NPN switch collector | Drives external inductor; minimize trace area to reduce EMI and parasitic inductance. |
| VOUT (Pin 23) | Boost output node | Delivers regulated high-voltage supply to all LED strings; connects to VO_SW via internal PMOS. |
| VO_SW (Pin 24) | OVP feedback node | Isolated by internal PMOS during PWM off-time to prevent discharge of output capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM™ dimming | Enables 3000:1 dimming ratio with no color shift by modulating LED current at ≥100Hz with 0.1% minimum duty cycle. |
| Programmable open-LED protection | Detects open strings via 0.25V threshold on LEDx pins; asserts OPENLED flag without disrupting regulation of remaining strings. |
| Thermal derating via TSET pin | Allows precise definition of LED current reduction vs. junction temperature using external resistor divider from VREF. |
| Regulated overvoltage protection | Uses VO_SW/FB interface with internal PMOS to maintain OVP function during PWM off-time and shutdown. |
| Current matching stability | Maintains ±1.5% LED current matching across all six strings over –40°C to 125°C junction temperature range. |
| Synchronization capability | Accepts external clock on SYNC pin; eliminates beat frequencies in multi-converter systems when properly configured. |
Applications
| Notebook Computer Display | Medium Size Displays |
|---|---|
|
Use Scenario: Backlighting for 13–15 inch LCD panels requiring uniform brightness and thin mechanical profile. IC Role / Device Role / Timing Role: Primary LED driver delivering regulated current to six parallel LED strings with synchronized PWM dimming. Use Value: ±1.5% current matching ensures no visible brightness bands; 3000:1 dimming supports HDR content rendering. |
Use Scenario: Commercial signage and industrial HMI displays needing robust operation across extended temperature ranges. IC Role / Device Role / Timing Role: Constant-current source managing six LED strings with thermal derating to extend LED lifetime at elevated ambient temperatures. Use Value: TSET-programmed derating prevents LED overcurrent at >85°C ambient; OVP protects against catastrophic failure if all strings open. |
| Automotive LCD Display | Avionics Panel Lighting |
|
Use Scenario: Instrument cluster and center console backlighting in vehicles with 12V battery supply and wide thermal cycling. IC Role / Device Role / Timing Role: High-efficiency boost driver supporting input down to 3.2V (cold-crank condition) and up to 30V (load-dump transients). Use Value: Wide VIN range eliminates need for pre-regulator; SHDN pin enables microcontroller-controlled sleep/wake sequencing. |
Use Scenario: Safety-critical cockpit displays requiring fail-safe open-LED detection and predictable thermal behavior. IC Role / Device Role / Timing Role: Fault-aware LED controller asserting OPENLED flag on single-string failure while maintaining illumination on remaining strings. Use Value: Open-collector OPENLED output interfaces directly to avionics monitoring systems; exposed-pad TSSOP aids conduction cooling 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 |
|---|---|---|---|
| LT3599EFE#TRPBF | Same 6-string architecture but rated for –40°C to 125°C (E-grade), whereas LT3598IFE#TRPBF is I-grade with tighter initial tolerance on reference voltage (1.210–1.260V vs. 1.216–1.230V typical). | LT3599EFE#TRPBF targets cost-sensitive industrial designs; LT3598IFE#TRPBF preferred where guaranteed min/max reference spec over full temp range is required. | Select LT3598IFE#TRPBF when design requires guaranteed 1.210–1.260V VREF across –40°C to 125°C, or when using analog dimming with tight CTRL linearity specs. |
| MAX16820ATL+ | 4-string driver (not 6-string); uses external MOSFETs instead of integrated switch; lacks TSET-based thermal derating and True Color PWM™. | Suitable for lower-channel-count applications where discrete FET selection is needed for higher voltage/current scaling. | Choose MAX16820ATL+ only if system requires >44V output or >30mA/string, and can accept reduced integration and dimming fidelity. |
Compared with LT3598IFE#TRPBF, LT3599EFE#TRPBF offers identical functionality at lower cost but with relaxed VREF limits, while MAX16820ATL+ trades channel count and integrated features for flexibility in high-voltage discrete implementations - making LT3598IFE#TRPBF optimal for space-constrained, thermally demanding 6-string backlighting.
Availability
LT3598IFE#TRPBF is available at Aetrix Electronics and suitable for notebook computer display backlighting, automotive LCD instrumentation, and medium-size commercial signage requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance over –40°C to 125°C.
Supply support for LT3598IFE#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, documentation, and manufacturing continuity for the LT® portfolio.
The LT3598IFE#TRPBF belongs to Linear's high-accuracy LED driver product line, engineered specifically for multi-string LCD backlighting where current matching, thermal resilience, and wide dimming range are critical system requirements.
FAQ
What is the maximum LED string voltage supported by the LT3598IFE#TRPBF?
The LT3598IFE#TRPBF supports an output voltage up to 44V, which is sufficient to drive up to 12–14 white LEDs in series per string (assuming typical 3.0–3.6V forward voltage per LED at 30mA). This rating applies under continuous operation with proper thermal management and input voltage within 3.2V–30V range. The device regulates current even when VIN exceeds VOUT, enabling operation in buck-boost-like scenarios.
Does the LT3598IFE#TRPBF support both analog and PWM dimming simultaneously?
No - the LT3598IFE#TRPBF does not support simultaneous analog and PWM dimming. The CTRL pin provides 0–1V analog dimming (linear current scaling), while the PWM pin enables digital on/off switching control. Using both concurrently causes undefined interaction: PWM overrides CTRL during low states, and CTRL only affects current level when PWM is high. For predictable behavior, use one method exclusively per design.
How is open-LED detection implemented on the LT3598IFE#TRPBF?
The LT3598IFE#TRPBF monitors each LEDx pin voltage; if any drops below 0.25V (with delay after reaching 80% of programmed VOUT), it asserts the OPENLED pin low. Detection is disabled during startup to prevent false triggers. The OPENLED pin is open-collector and requires an external pull-up resistor. Unused LED strings must be tied to VOUT - leaving them floating invalidates detection and risks damage.
Can the LT3598IFE#TRPBF operate with input voltage higher than output voltage?
Yes - the LT3598IFE#TRPBF is designed to regulate LED current even when VIN exceeds VOUT, a feature enabled by its current-mode boost architecture with active current sinks. In such cases, the internal NPN switch operates in linear mode for excess voltage drop, increasing power dissipation. Thermal design must account for this condition, especially at high ambient temperatures or high LED currents.
What is the purpose of the VO_SW pin on the LT3598IFE#TRPBF?
The VO_SW pin on the LT3598IFE#TRPBF provides isolated feedback for overvoltage protection. An internal PMOS disconnects VO_SW from VOUT during PWM off-time and shutdown, preventing the FB resistor divider from discharging the output capacitor. This preserves dimming range and reduces standby current. The OVP threshold is set by a resistor divider between VO_SW and GND, referenced to the 1.230V internal bandgap.
LT3598IFE#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
LT3598IFE#TRPBF FAQ
1.How can I place an order for LT3598IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3598IFE#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 LT3598IFE#TRPBF reliable?
The price and inventory of LT3598IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3598IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3598IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3598IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3598IFE#TRPBF?
LT3598IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3598IFE#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 LT3598IFE#TRPBF?
For technical support, including LT3598IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3598IFE#TRPBF requirements.
6.How does Aetrix verify that LT3598IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3598IFE#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 LT3598IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3598IFE#TRPBF?
All LT3598IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3598IFE#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 LT3598IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3598IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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