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Analog Devices Inc. LTC3218EDDB#TRMPBF
- Part No.:
- LTC3218EDDB#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LTC3218EDDB#TRMPBF.pdf
- Description:
- IC LED DRIVER RGLTR 150MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:559
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Product details
Overview
LTC3218EDDB#TRMPBF from Analog Devices (formerly Linear Technology) is a high-current, low-noise switched-capacitor LED driver IC designed for camera flash and torch applications in portable devices. It delivers up to 400mA pulsed LED current from a 2.9V–4.5V Li-ion input, features automatic 1x/2x mode switching, integrated 220mΩ high-side current sense, and operates in a compact 3mm × 2mm 10-lead DFN package with exposed thermal pad.
For engineers reviewing the LTC3218EDDB#TRMPBF datasheet, LTC3218EDDB#TRMPBF pinout, LTC3218EDDB#TRMPBF application, or LTC3218EDDB#TRMPBF equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with functional distinctions, and supply-chain-ready availability details - all grounded in the official Linear Technology LTC3218 datasheet (3218fb) and product documentation.
Technical Context
The LTC3218EDDB#TRMPBF uses a constant-frequency, low-noise charge pump architecture with internal soft-start and automatic mode switching between 1× (direct pass-through) and 2× (voltage-doubling) operation based on dropout detection at the ILED node. Its regulation loop senses voltage across an internal 220mΩ high-side resistor between CPO and ILED to control LED current with ±15% accuracy over temperature and input voltage.
It supports three distinct operating modes via ENF/ENT logic: shutdown (both low), torch (ENT high, ENF low), and flash (ENF high, ENT low or both high), each with dedicated current programming resistors (ISETT and ISETF) and built-in 2-second flash timeout for LED protection. The 1MHz oscillator enables use of small ceramic flying and output capacitors (2.2μF and 4.7μF typical).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.9V to 4.5V - Matches standard Li-ion/polymer battery discharge profile; no external LDO needed. |
| Max LED Current | 400mA pulsed (flash mode) - Sufficient for high-brightness camera flash in smartphones and DSCs. |
| Torch Current Accuracy | ±15% over temp - Achieved via internal 220mΩ sense resistor and stable 1.21V reference at ISET pins. |
| Oscillator Frequency | 1MHz typical - Enables use of tiny 2.2μF X5R/X7R ceramic flying capacitor; reduces EMI vs lower frequencies. |
| Thermal Shutdown Threshold | ~165°C junction - Protects device during sustained high-current operation; auto-recovery at ~150°C. |
| Shutdown Current | 1.1μA max - Minimizes battery drain in standby; critical for always-on mobile camera modules. |
| Flash Timeout Duration | 2 seconds - Hardware-enforced safety limit prevents LED overheating; resets only after full shutdown. |
Pinout & Package
Package: 10-lead (3mm × 2mm) plastic DFN with exposed thermal pad (Pin 11), RoHS-compliant, lead-free finish. Exposed pad must be soldered to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CP (Pin 1) | Flying capacitor terminal | Connects to one side of 2.2μF ceramic flying cap; carries high dv/dt switching waveform; requires short, wide trace. |
| CM (Pin 9) | Flying capacitor terminal | Connects to other side of flying cap; forms charge transfer path with CP; sensitive to layout-induced noise coupling. |
| CPO (Pin 2) | Charge pump output | Regulated high-side output node; supplies current to ILED; requires 4.7μF ceramic bypass to GND for ripple control. |
| ILED (Pin 3) | LED current output | High-side LED anode driver; current flows from CPO → ILED → LED → GND; voltage drop here triggers mode switching. |
| ENT (Pin 4) | Torch enable / shutdown control | Pull-down enabled (250kΩ); high = torch mode; low + ENF low = shutdown; floating defaults to shutdown. |
| ISETT (Pin 5) | Torch current programming | Resistor to GND sets continuous torch current (e.g., 10.2kΩ → 100mA); uses 850× VREF/ISET ratio. |
| ISETF (Pin 6) | Flash current programming | Resistor to GND sets pulsed flash current (e.g., 10.2kΩ → 290mA flash); uses 2450× or 3300× VREF/ISET ratio. |
| ENF (Pin 7) | Flash enable / safety timer input | Pull-down enabled (250kΩ); high = flash mode; held >2s forces low-power disable; requires clean digital drive. |
| GND (Pin 8) | Analog/digital ground | Main signal return; connects to low-impedance PCB ground plane; separate from power ground paths for noise isolation. |
| VIN (Pin 10) | Input power supply | 2.9V–4.5V battery input; requires ≥1.6μF ceramic bypass close to pin; sensitive to input ripple and ESR. |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor architecture | Eliminates magnetic EMI, board space, and cost of inductors; enables ultra-thin mobile designs with <1mm component height. |
| Automatic 1x/2x mode switching | Monitors (VCPO – VILED) dropout in real time; switches only when needed - preserves efficiency without manual control logic. |
| Integrated 220mΩ high-side sense resistor | Removes need for external sense resistor and associated layout errors; improves current accuracy and thermal stability. |
| Single-resistor current programming | Supports simplified design: tie ISETT and ISETF together and use one resistor for fixed-ratio torch/flash current scaling. |
| Output disconnect in shutdown | Internal ~90kΩ pull-down on CPO isolates LED from battery during shutdown - prevents leakage-driven dim glow. |
Applications
| Smartphone Camera Flash | Digital Still Camera (DSC) Torch |
|---|---|
Use Scenario: High-intensity, short-duration illumination for low-light photography in compact handheld devices. IC Role / Device Role / Timing Role: High-current LED driver with hardware-enforced 2s flash timeout and automatic mode switching to maintain brightness across battery voltage sag. Use Value: Delivers 400mA peak current without inductor, enabling slim bezel-free smartphone designs while protecting LEDs from thermal overstress. |
Use Scenario: Continuous, adjustable brightness lighting for macro or video assist in consumer-grade digital cameras. IC Role / Device Role / Timing Role: Precision torch-mode current regulator using ISETT resistor; maintains stable 50–150mA output despite VIN variation from 2.9V to 4.5V. Use Value: Eliminates need for external current-setting DAC or PWM dimming circuitry - reduces BOM count and firmware complexity. |
| Tablet Front-Facing Illumination | Portable Medical Imaging Light |
Use Scenario: Uniform, flicker-free front-panel lighting for facial recognition or video conferencing in tablets. IC Role / Device Role / Timing Role: Low-noise constant-frequency charge pump delivering regulated 100mA torch current with <10mV ripple on CPO. Use Value: Meets stringent EMI requirements for USB-C/DisplayPort coexistence; avoids interference with high-speed data lines. |
Use Scenario: Reliable, calibrated illumination source in handheld diagnostic tools requiring consistent light intensity. IC Role / Device Role / Timing Role: Safety-critical LED driver with thermal shutdown (~165°C) and short-circuit detection on CPO to prevent hazardous failure modes. Use Value: Complies with IEC 60601-1 creepage/clearance requirements via DFN package and no-inductor design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3214EDDB#TRMPBF | Higher 500mA flash current rating; same 3mm × 2mm DFN package; requires larger flying cap (≥3.3μF) for full output. | Better suited for dual-LED flash arrays or higher-lumen applications where 400mA is insufficient. | Select LTC3214EDDB#TRMPBF if >400mA peak current is required and board layout allows slightly higher input capacitance. |
| LTC3217EUD#TRPBF | Four independent LED outputs; 600mA total; 16-lead 3mm × 3mm QFN; supports multi-color or multi-zone lighting. | Designed for advanced camera systems with separate main/flash/AF assist LEDs - not single-output compatible. | Choose LTC3217EUD#TRPBF only when system-level architecture demands independent control of ≥2 LED strings. |
Compared with LTC3218EDDB#TRMPBF, LTC3214EDDB#TRMPBF offers higher flash current headroom in identical footprint, while LTC3217EUD#TRPBF trades single-output simplicity for multi-channel flexibility and larger package - neither is pin-compatible, but both address adjacent design requirements in the Linear LED driver family.
Availability
LTC3218EDDB#TRMPBF is available at Aetrix Electronics and suitable for smartphone camera modules, digital still camera torch circuits, and portable medical imaging devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3218EDDB#TRMPBF 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 LTC3218 series.
The LTC3218 belongs to Linear's high-efficiency LED driver product line, engineered specifically for space-constrained, battery-powered imaging applications demanding low EMI, precise current regulation, and robust thermal protection.
FAQ
What is the maximum continuous LED current supported by the LTC3218EDDB#TRMPBF?
The LTC3218EDDB#TRMPBF supports up to 150mA continuous LED current in torch mode, as specified in the Electrical Characteristics table under "High Output Current: 150mA (Continuous), 400mA (Pulsed)". This rating assumes proper thermal management via the exposed pad and ambient temperature ≤85°C. Exceeding 150mA continuously risks triggering thermal shutdown.
How does the LTC3218EDDB#TRMPBF implement automatic mode switching between 1x and 2x operation?
The LTC3218EDDB#TRMPBF monitors the voltage difference (VCPO – VILED) at its internal sense node. When this delta falls below 7mV (typical dropout threshold), the device initiates a 500μs delay to allow LED forward voltage stabilization, then transitions from 1x to 2x boost mode. The switch is fully autonomous and requires no external control signals or firmware intervention.
Can the LTC3218EDDB#TRMPBF drive multiple LEDs in series?
No - the LTC3218EDDB#TRMPBF is a single-output, high-side constant-current driver optimized for one LED anode connection at the ILED pin. Its maximum output compliance voltage is limited by the CPO rail (≤5.3V clamp), making it unsuitable for >2 white LEDs in series (requiring >6V). For multi-LED strings, consider LTC3209 or LTC3210-series alternatives.
What is the purpose of the exposed thermal pad (Pin 11) on the LTC3218EDDB#TRMPBF DFN package?
The exposed thermal pad (Pin 11) on the LTC3218EDDB#TRMPBF must be soldered directly to a low-impedance PCB ground plane. It serves dual roles: (1) primary thermal path to dissipate up to 1.2W of power during 400mA flash operation, and (2) low-inductance ground reference for internal switching nodes. Omitting pad connection causes immediate thermal shutdown under load.
Does the LTC3218EDDB#TRMPBF require external compensation components for stability?
No - the LTC3218EDDB#TRMPBF uses an internally compensated control loop. Stability relies entirely on correct external capacitor selection: 2.2μF X5R/X7R ceramic for CP/CM, 4.7μF for CPO, and ≥1.6μF for VIN. Using polarized (tantalum/aluminum) or low-capacitance ceramics (<3μF actual at bias/temp) will cause oscillation or poor transient response.
LTC3218EDDB#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.9V
- Voltage - Supply (Max):
- 4.5V
- Voltage - Output:
- 5.3V
- Current - Output / Channel:
- 150mA
- Frequency:
- 1MHz
- Dimming:
- -
- Applications:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x2)
LTC3218EDDB#TRMPBF FAQ
1.How can I place an order for LTC3218EDDB#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3218EDDB#TRMPBF 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 LTC3218EDDB#TRMPBF reliable?
The price and inventory of LTC3218EDDB#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3218EDDB#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3218EDDB#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3218EDDB#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3218EDDB#TRMPBF?
LTC3218EDDB#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3218EDDB#TRMPBF 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 LTC3218EDDB#TRMPBF?
For technical support, including LTC3218EDDB#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3218EDDB#TRMPBF requirements.
6.How does Aetrix verify that LTC3218EDDB#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3218EDDB#TRMPBF 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 LTC3218EDDB#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3218EDDB#TRMPBF?
All LTC3218EDDB#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3218EDDB#TRMPBF, 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 LTC3218EDDB#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3218EDDB#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3218EDDB#TRMPBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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