My Inquiry
My Account
Analog Devices Inc. LT3517IFE#PBF
- Part No.:
- LT3517IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3517IFE#PBF.pdf
- Description:
- IC LED DRV RGLTR PWM 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:737
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3517IFE#PBF from Analog Devices is a constant-frequency current-mode DC/DC LED driver IC with an internal 1.5A/45V power switch, supporting boost, buck, and buck-boost topologies. It delivers precise constant-current regulation via 100mV high-side current sensing, enables 5000:1 true-color PWM dimming, and operates from 3V to 30V input across –40°C to 125°C. It is used in automotive lighting systems requiring robust transient protection up to 40V and open-LED fault detection.
For engineers reviewing the LT3517IFE#PBF datasheet, LT3517IFE#PBF pinout, LT3517IFE#PBF application, or LT3517IFE#PBF equivalent, key selection considerations include its 16-pin TSSOP package, adjustable switching frequency (250kHz–2.5MHz), dual-loop (voltage + current) regulation architecture, and integrated PMOS gate driver for LED disconnect control.
Technical Context
The LT3517IFE#PBF implements a dual-loop control system where the current loop dominates during LED current regulation and the voltage loop activates for overvoltage protection (FB threshold = 1.01V). Its internal 1.5A/45V N-channel MOSFET switch supports peak currents up to 2.3A and features 300mV typical VCE(SAT) at 1A.
Switching frequency is set via an external RT resistor (250kHz–2.5MHz range) or synchronized to an external clock on SYNC, with built-in 20% frequency offset requirement for stable locking. The CTRL pin provides analog dimming (10:1 ratio) by scaling the 100mV current sense threshold down to 9mV, while PWM input enables ultra-high-ratio digital dimming with stored VC node state for fast recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 30V continuous; withstands 40V transients - enables direct integration into 24V automotive rails with load-dump immunity. |
| Switch Current Limit | 1.5A typical, 2.3A max - supports driving multi-string LED arrays up to ~1A average output with margin for surge. |
| Current Sense Threshold | 100mV ±3% - minimizes power loss in sense resistor and improves accuracy vs. higher-voltage alternatives. |
| Dimming Ratio | 5000:1 PWM + 10:1 analog CTRL - achieves flicker-free, high-fidelity color mixing in display backlighting. |
| Operating Temperature | –40°C to +125°C junction - qualified for under-hood automotive and industrial ambient environments. |
| Shutdown Current | <1µA - preserves battery life in always-on vehicle modules during sleep mode. |
| Package | 16-lead plastic TSSOP - surface-mount compatible with standard reflow profiles and accessible for manual prototyping. |
Pinout & Package
The LT3517IFE#PBF is housed in a 16-lead plastic TSSOP package with exposed thermal pad connected internally to GND. Pin 1 is located at the bottom-left corner when viewing the top marking side with the notch or dot oriented left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply rail | Accepts 3V–30V; requires local 2.2µF ceramic bypass capacitor to suppress high di/dt noise. |
| SHDN | Enable/disable control | Logic-high ≥1.2V enables operation; ≤0.45V disables with <1µA quiescent draw. |
| PWM | Digital dimming input | Active-low signal; disables main switch and forces TG high to disconnect LED string. |
| CTRL | Analog current setpoint | Scales current sense threshold from 9mV to 100mV linearly; tie to VREF for full-scale operation. |
| ISP / ISN | High-side current sense inputs | Differential pair measuring voltage across external sense resistor; rail-to-rail input range supports wide LED Vf variation. |
| TG | PMOS gate driver output | Inverted PWM signal drives external PMOS between VISP and (VISP – 7V); internal 7V clamp prevents gate overvoltage. |
| TGEN | Top-gate enable input | ≥1.5V enables TG output; internal 40kΩ pull-down ensures safe default-off state. |
| FB | Voltage feedback input | Regulates to 1.01V threshold; triggers switch disable if LED string overvoltage occurs. |
| VC | Error amplifier output | gm = 550µS; connects to RC compensation network for loop stability in constant-current or constant-voltage modes. |
| RT | Frequency programming | Resistor-to-GND sets oscillator frequency; must not be left floating or capacitively loaded. |
| SYNC | External clock input | Accepts TTL/CMOS clock; requires RT resistor tuned to 20% lower free-running frequency for reliable synchronization. |
| SW | Power switch drain | Connects to inductor/diode node; trace must be minimized to reduce EMI and switching losses. |
| VREF | 2.0V precision reference | Stable 2.0V ±2% output sourcing up to 100µA; used for biasing CTRL, RT, and external circuitry. |
| GND | Signal and power ground | All ground connections converge here; exposed pad must be soldered to PCB ground plane for thermal and EMI performance. |
| SS | Soft-start timing | Capacitor-to-GND controls ramp rate of VC; 0.1µF yields smooth startup with minimal inrush. |
Key Features
| Feature | Design Value |
|---|---|
| Triple topology support | Configurable as boost, buck, or buck-boost - eliminates need for separate drivers across diverse LED voltage requirements (e.g., 3V–48V strings). |
| Open LED protection | Automatic shutdown when ISP–ISN differential falls below 10mV - prevents overvoltage damage to LEDs and downstream circuitry. |
| Integrated PMOS gate driver | TG output with 7V clamp and 200ns turn-on/off delays - enables fast, low-loss LED string disconnect during PWM off-time to preserve output capacitor charge. |
| Adjustable frequency with sync | 250kHz–2.5MHz via RT resistor or external clock - allows optimization for efficiency (low fSW) or compactness (high fSW) without changing layout. |
| Low shutdown current | <1µA - meets automotive ISO 16750-2 quiescent current requirements for always-connected modules. |
| Thermal protection | Internal overtemperature shutdown at TJ > 160°C - safeguards device during sustained overload or poor heatsinking conditions. |
Applications
| Automotive Headlamp Control | Industrial Display Backlighting |
|---|---|
Use Scenario: Adaptive front-lighting system (AFS) in passenger vehicles using white LED arrays with dynamic beam shaping. IC Role / Device Role / Timing Role: Constant-current LED driver regulating 700mA through 6-series white LEDs while synchronizing switching to avoid EMI interference with radar receivers. Use Value: 40V transient tolerance withstands ISO 7637-2 pulse 5a load dump; 5000:1 PWM dimming enables smooth transition between low-beam and high-beam without color shift. | Use Scenario: High-brightness LCD backlight for factory HMIs operating in wide temperature ranges. IC Role / Device Role / Timing Role: Buck-mode LED driver powering 4 parallel strings of 10-series blue LEDs from 24V rail with analog dimming for brightness calibration. Use Value: 100mV current sense reduces heat in sense resistor; –40°C to 125°C rating ensures reliability in uncontrolled industrial enclosures. |
| Aerospace Cabin Lighting | Barcode Scanner Illumination |
Use Scenario: Dimmable LED lighting in commercial aircraft cabins with strict EMC and safety requirements. IC Role / Device Role / Timing Role: Buck-boost LED driver maintaining constant 350mA output across 18–32V avionics bus variations while providing fail-safe open-LED detection. Use Value: Dual-loop regulation prevents overvoltage during LED failure; TSSOP package supports conformal coating for humidity resistance. | Use Scenario: Pulsed illumination source in handheld barcode scanners requiring microsecond-level LED turn-on precision. IC Role / Device Role / Timing Role: Boost-mode driver delivering 100mA to red LED array with 100ns PWM edge fidelity enabled by stored VC state recovery. Use Value: Fast transient response (<2µs recovery) ensures consistent barcode capture under varying ambient light; 16-pin TSSOP simplifies automated assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3474EFE#PBF | Single-topology (boost-only); 1.3A switch; fixed 1.3MHz fSW; no SYNC or TG pin | Lacks buck/buck-boost flexibility and PMOS disconnect - suitable only for fixed-voltage LED strings above input rail | Select when cost-sensitive designs require simpler boost-only operation without topology reconfiguration. |
| LM3409QMHX/NOPB | Adjustable fSW (200kHz–2MHz); 1.25A switch; no integrated VREF or CTRL pin; requires external op-amp for analog dimming | No true-color PWM dimming; higher BOM count due to external compensation and reference components | Choose for high-volume automotive applications where TI's Q-grade qualification and AEC-Q100 compliance are mandatory. |
Compared with LT3517IFE#PBF, LT3409QMHX/NOPB offers AEC-Q100 qualification but requires external circuitry for analog dimming and lacks triple-topology flexibility, while LT3474EFE#PBF simplifies design for boost-only use cases but omits critical features like open-LED protection and synchronous dimming control.
Availability
LT3517IFE#PBF is available at Aetrix Electronics and suitable for automotive lighting, industrial HMI backlighting, and aerospace cabin illumination requiring stable component supply, long-term lifecycle management, and traceable sourcing.
Supply support for LT3517IFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3517IFE#PBF belongs to Linear's high-reliability LED driver product line, engineered specifically for demanding lighting applications requiring wide input range, robust fault protection, and precision current regulation across extreme temperatures.
FAQ
What is the maximum allowable input voltage for continuous operation of the LT3517IFE#PBF?
The LT3517IFE#PBF supports continuous operation up to 30V on the VIN pin. It can withstand nonrepetitive 40V transients for up to one second, making it suitable for 24V automotive systems subject to load-dump events per ISO 7637-2. Exceeding 30V continuously risks exceeding thermal limits and degrading long-term reliability.
How does the LT3517IFE#PBF achieve 5000:1 PWM dimming ratio?
The LT3517IFE#PBF achieves 5000:1 PWM dimming by combining precise timing control with stored-state recovery: the PWM input disables switching while preserving the VC node voltage on the external compensation capacitor, enabling sub-2µs recovery when the signal returns high. At 2MHz switching frequency, this allows minimum on/off times of 2µs within a 10ms maximum period - yielding exactly 5000:1 ratio as confirmed in the datasheet's Equation (1).
Can the LT3517IFE#PBF operate in buck configuration with an input voltage lower than the LED forward voltage?
No - the LT3517IFE#PBF cannot regulate in buck mode when VIN is less than the total LED forward voltage. In buck topology, VIN must exceed Vf(LED) + Vdrop(switch+diode). For sub-input LED strings, the device must be configured in boost or buck-boost mode. The datasheet Figure 4 explicitly shows buck-boost level-shifting for such cases.
What is the function of the TG and TGEN pins on the LT3517IFE#PBF?
The TG pin is the top-gate driver output that delivers an inverted PWM signal to drive an external PMOS transistor between VISP and (VISP – 7V), enabling LED string disconnect during dimming. The TGEN pin enables or disables this function: ≥1.5V activates TG, while grounding TGEN disables it. An internal 40kΩ pull-down ensures safe default-off behavior if TGEN is left unconnected.
Does the LT3517IFE#PBF require external compensation components, and where are they connected?
Yes - the LT3517IFE#PBF requires external compensation on the VC pin to stabilize the current/voltage control loop. A typical configuration uses a 10nF capacitor from VC to GND; a series resistor may be added to increase slew rate during fast transients. Compensation values depend on selected inductor, output capacitor, and operating mode - design guidelines are provided in the "Loop Compensation" section of the datasheet.
LT3517IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 30V
- Voltage - Output:
- -
- Current - Output / Channel:
- 1.5A (Switch)
- Frequency:
- 250kHz ~ 2.5MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3517IFE#PBF FAQ
1.How can I place an order for LT3517IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3517IFE#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 LT3517IFE#PBF reliable?
The price and inventory of LT3517IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3517IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3517IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3517IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3517IFE#PBF?
LT3517IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3517IFE#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 LT3517IFE#PBF?
For technical support, including LT3517IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3517IFE#PBF requirements.
6.How does Aetrix verify that LT3517IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3517IFE#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 LT3517IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3517IFE#PBF?
All LT3517IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3517IFE#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 LT3517IFE#PBF part is unused and in its original packaging.
Return procedure for LT3517IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3517IFE#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…
