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Analog Devices Inc. LT3466EDD#PBF
- Part No.:
- LT3466EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3466EDD#PBF.pdf
- Description:
- IC LED DRV RGLTR PWM 400MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:541
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Product details
Overview
LT3466EDD#PBF from Analog Devices (formerly Linear Technology) is a dual, independent step-up DC/DC converter IC designed to drive up to 20 white LEDs (10 per channel) with constant current, featuring integrated Schottky diodes, 200 mV feedback reference, and 2 MHz programmable switching frequency. It operates from 2.7 V to 24 V input, delivers up to 39.5 V clamped output per channel, and supports asymmetric LED string configurations in handheld display backlighting.
For engineers reviewing the LT3466EDD#PBF datasheet, LT3466EDD#PBF pinout, LT3466EDD#PBF application, or LT3466EDD#PBF equivalent, key selection criteria include dual-channel independent dimming control via CTRL1/CTRL2, open-LED protection threshold at 39.5 V, internal soft-start for inrush suppression, and DFN-10 package thermal performance with exposed pad grounding.
Technical Context
The LT3466EDD#PBF implements two fully independent current-mode PWM converters sharing only the bandgap reference, oscillator bias, and RT timing interface. Each channel features dedicated SWx, VOUTx, FBx, and CTRLx pins, enabling separate regulation of LED strings with differing forward voltages or counts.
Its constant-frequency architecture uses an external RT resistor (200 kHz–2 MHz range) and internal slope compensation; peak switch current limit is 400 mA per channel with 360 mV saturation voltage, and feedback error amplifiers regulate FB1/FB2 to 200 mV ±8 mV over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 24 V - supports single Li-ion (3.0–4.2 V), dual alkaline (1.8–3.0 V with auxiliary supply), or industrial 12–24 V rails. |
| Output Voltage Limit | 39.5 V max per channel - provides open-LED protection without external clamp circuitry. |
| Feedback Reference | 200 mV ±8 mV - enables precise LED current setting with low-loss RFB resistors (e.g., 10 Ω for 20 mA). |
| Switch Current Limit | 400 mA per channel - ensures safe operation with 47 µH inductors driving 8–10 white LEDs at 15–20 mA. |
| Switching Frequency | Programmable 200 kHz to 2 MHz via RT pin - balances inductor size (15–68 µH) vs. efficiency (81% @ 8/8 LEDs, 3.6 V in). |
| Quiescent Current | 25 µA in shutdown (CTRL1 = CTRL2 = 0 V) - minimizes battery drain in portable standby modes. |
| Operating Temperature | –40°C to +85°C - qualified for consumer handhelds and automotive cabin displays. |
Pinout & Package
LT3466EDD#PBF is housed in a thermally enhanced 10-pin (3 mm × 3 mm × 0.75 mm) plastic DFN package with exposed pad (Pin 11) that must be soldered to PCB ground for thermal and electrical integrity. θJA = 43°C/W, θJC = 2.96°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (FB1) | Converter 1 feedback input | Connects to cathode of lowest LED in string 1; regulates ILED1 ≈ 200 mV / RFB1. |
| 2 (CTRL1) | Converter 1 dimming/shutdown control | 0–1.6 V analog dimming input; <50 mV disables channel; >1.6 V enables full current. |
| 3 (RT) | Oscillator timing resistor connection | Pull to GND with 20.5 kΩ–267 kΩ sets fSW = 2 MHz–200 kHz; nominal RT pin voltage = 0.54 V. |
| 4 (CTRL2) | Converter 2 dimming/shutdown control | Independent analog dimming input identical in function to CTRL1. |
| 5 (FB2) | Converter 2 feedback input | Regulates ILED2 ≈ 200 mV / RFB2; supports asymmetric string lengths vs. FB1. |
| 6 (VOUT1) | Converter 1 regulated output | Connected to cathode of internal Schottky diode; requires ≥1 µF ceramic output capacitor to GND. |
| 7 (SW1) | Converter 1 power switch node | Drives external inductor L1; voltage swings from VIN to ~VOUT1 + VF(SCHOTTKY). |
| 8 (VIN) | Main input supply | Accepts 2.7–24 V; requires local 1 µF X5R/X7R ceramic bypass capacitor. |
| 9 (SW2) | Converter 2 power switch node | Independent switch node for second inductor L2; no shared power path with SW1. |
| 10 (VOUT2) | Converter 2 regulated output | Second independent high-voltage output; clamped at 39.5 V during open-circuit fault. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent LED drivers | Enables main/sub-display backlighting with separate brightness control-no cross-talk or shared regulation error. |
| Integrated Schottky diodes | Eliminates 2 external diodes per channel, reducing BOM count, board area, and forward drop losses (~0.85 V @ 300 mA). |
| Internal soft-start | 600 µs controlled ramp per channel limits inrush current during power-up, preventing input rail sag or capacitor stress. |
| Asymmetric string support | Each channel regulates independently-e.g., 6 LEDs on CH1, 8 LEDs on CH2-without requiring matched forward voltages. |
| Open-LED protection | Auto-clamps VOUTx at 39.5 V when string opens; allows remaining channel to operate normally-critical for dual-display reliability. |
Applications
| Main/Sub Display Backlighting | Digital Camera LCD Backlight |
|---|---|
|
Use Scenario: Dual-panel smartphones or PDAs requiring independent brightness control for primary and secondary screens. IC Role / Device Role / Timing Role: LT3466EDD#PBF acts as dual constant-current LED driver, regulating each string separately using FB1/FB2 and CTRL1/CTRL2. Use Value: Enables simultaneous but differentiated backlighting-e.g., brighter main screen, dimmed sub-display for status-without extra ICs or layout complexity. |
Use Scenario: Compact digital cameras with high-resolution rear LCDs needing uniform illumination across variable ambient light conditions. IC Role / Device Role / Timing Role: LT3466EDD#PBF drives 8–10 white LEDs in series per channel at 15–20 mA, using internal 200 mV reference for stable current. Use Value: Delivers >81% efficiency at 3.6 V input, minimizing heat in sealed camera enclosures while supporting PWM or analog dimming via CTRL pins. |
| Handheld Computer UI Lighting | Automotive Infotainment Display |
|
Use Scenario: Ruggedized handheld computers used in field service, requiring reliable backlighting across wide temperature (-40°C to +85°C) and input voltage (2.7–24 V) ranges. IC Role / Device Role / Timing Role: LT3466EDD#PBF serves as dual-output boost controller with open-circuit protection, ensuring one failed LED string doesn't disable the entire UI. Use Value: Maintains partial functionality during LED failure-e.g., keypad backlight remains active even if main display string opens-improving system robustness. |
Use Scenario: Automotive center-stack displays powered from 12 V battery rail, driving multiple white LED strings for high-brightness daytime visibility. IC Role / Device Role / Timing Role: LT3466EDD#PBF operates up to 24 V input and clamps outputs at 39.5 V, safely accommodating load-dump transients and cold-crank low-voltage events. Use Value: Eliminates need for external overvoltage protection components while sustaining >39 V output capability required for 10-LED strings at 3.8 V VF. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3220EUD#PBF | Charge-pump topology (no inductors); fixed 2×/3× gain; max 36 V output; no RT-programmable frequency. | Better EMI profile and smaller solution size where inductor avoidance is critical; lower max LED count (12 total). | Select LTC3220EUD#PBF for space-constrained, low-EMI designs with ≤6 LEDs per string and no need for >36 V output. |
| TPS68400RHDR | Single-chip dual boost with I²C interface; 1.2 V to 5.5 V input; integrated MOSFETs; no internal diodes. | Enables digital brightness control and fault reporting via I²C; requires external Schottky diodes and higher external component count. | Select TPS68400RHDR when system-level digital control, telemetry, or tighter input voltage range (<5.5 V) is prioritized over analog simplicity. |
Compared with LTC3220EUD#PBF and TPS68400RHDR, the LT3466EDD#PBF offers superior output voltage headroom (39.5 V), analog dimming simplicity, and integrated diodes-making it optimal for cost-sensitive, high-VF LED strings in battery-powered dual-display systems.
Availability
LT3466EDD#PBF is available at Aetrix Electronics and suitable for main/sub-display backlighting, digital camera LCDs, and handheld computer UI lighting requiring stable component supply, long-term manufacturability, and guaranteed parametric performance across –40°C to +85°C.
Supply support for LT3466EDD#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 product support, datasheets, and application engineering for legacy Linear parts including the LT3466 family.
The LT3466 product line was engineered specifically for dual-string white LED backlighting in portable electronics, emphasizing independent regulation, integrated power components, and robust fault protection for consumer-grade reliability.
FAQ
What is the maximum number of white LEDs the LT3466EDD#PBF can drive?
The LT3466EDD#PBF can drive up to 20 white LEDs-10 in series per channel-provided the total forward voltage per string does not exceed 39.5 V (the open-circuit clamp voltage). At 3.6 V input and 20 mA per LED, typical configurations include 8/8 or 10/10 strings using 47 µH or 68 µH inductors with RT = 63.4 kΩ or 147 kΩ respectively. The LT3466EDD#PBF's dual independent architecture ensures both strings operate reliably even with mismatched counts.
Does the LT3466EDD#PBF require external Schottky diodes?
No, the LT3466EDD#PBF integrates two Schottky diodes-one per boost channel-eliminating the need for external diodes. Each internal diode has a typical forward voltage drop of 0.85 V at 300 mA and reverse leakage <5 µA at 20 V. This integration reduces bill-of-materials count, PCB area, and conduction losses compared to discrete-diode solutions, and is explicitly confirmed in the device's "Dual Full Function White LED Step-Up Converter with Built-In Schottky Diodes" title and functional block diagram.
How is dimming implemented on the LT3466EDD#PBF?
Dimming on the LT3466EDD#PBF is implemented independently per channel using analog voltage inputs on CTRL1 and CTRL2. Applying 0–1.6 V linearly scales LED current from 0 to full scale (e.g., 20 mA); voltages above 1.6 V have no additional effect. Alternatively, a filtered PWM signal (e.g., 10 kHz with RC corner <1 kHz) can be applied to these pins. The LT3466EDD#PBF's internal circuitry directly converts CTRL pin voltage into a proportional reference for the feedback amplifier, enabling smooth, flicker-free brightness control without external DACs or microcontroller GPIO overhead.
What happens if one LED string opens while the other remains connected?
If one LED string opens (e.g., open-circuit fault), the corresponding channel (VOUT1 or VOUT2) clamps at 39.5 V and enters low-duty-cycle regulation to maintain that voltage-while the other channel continues normal operation unaffected. This behavior is guaranteed by the LT3466EDD#PBF's internal open-LED protection circuitry and is validated in Figure 4a/b of the datasheet. The un-faulted channel sustains its programmed LED current, preserving partial system functionality-a critical advantage in dual-display applications where redundancy matters.
Can the LT3466EDD#PBF operate from a 2-cell alkaline battery?
Yes-the LT3466EDD#PBF supports input voltages as low as 2.7 V, making it compatible with two AA/AAA alkaline cells (1.8 V fresh, up to 3.0 V under load). For optimal efficiency, the IC can be powered from a clean 3.3 V logic rail while the inductors connect directly to the battery-enabling LED operation down to ~1.8 V input. This configuration is demonstrated in Figure 9 of the datasheet and leverages the LT3466EDD#PBF's wide input range and low quiescent current (25 µA in shutdown) to maximize battery life in portable devices.
LT3466EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 24V
- Voltage - Output:
- 39.5V
- Current - Output / Channel:
- 400mA
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3466EDD#PBF FAQ
1.How can I place an order for LT3466EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3466EDD#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 LT3466EDD#PBF reliable?
The price and inventory of LT3466EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3466EDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3466EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3466EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3466EDD#PBF?
LT3466EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3466EDD#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 LT3466EDD#PBF?
For technical support, including LT3466EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3466EDD#PBF requirements.
6.How does Aetrix verify that LT3466EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3466EDD#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 LT3466EDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3466EDD#PBF?
All LT3466EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3466EDD#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 LT3466EDD#PBF part is unused and in its original packaging.
Return procedure for LT3466EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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