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Analog Devices Inc. LTC3218EDDB#TRPBF
- Part No.:
- LTC3218EDDB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LTC3218EDDB#TRPBF.pdf
- Description:
- IC LED DRIVER RGLTR 150MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,006
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Product details
Overview
LTC3218EDDB#TRPBF 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 a 2-second flash timeout for LED protection - deployed in smartphones and digital still cameras.
For engineers reviewing the LTC3218EDDB#TRPBF datasheet, LTC3218EDDB#TRPBF pinout, LTC3218EDDB#TRPBF application, or LTC3218EDDB#TRPBF equivalent, key selection criteria include programmable torch/flash current via dual external resistors (ISETT/ISETF), dropout-based mode transition timing, thermal shutdown at ~165°C, and compatibility with 3mm × 2mm DFN layout constraints.
Technical Context
The LTC3218EDDB#TRPBF uses a constant-frequency, multi-mode charge pump architecture with internal soft-start and automatic mode switching triggered by Δ(VCPO – VILED) detection at 7mV. Its control loop regulates LED current by modulating switch strength based on voltage sensed across the integrated 220mΩ high-side resistor between CPO and ILED pins.
Operation spans three distinct modes: shutdown (ENT = ENF = LOW), torch (ENT = HIGH, ENF = LOW), and flash (ENT = LOW/ENF = HIGH or both HIGH), each with dedicated current ratios (850×, 2450×, or 3300× ISET). The 1MHz oscillator enables compact 2.2μF flying capacitors and ensures low EMI in space-constrained mobile PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.9V to 4.5V - matches nominal Li-ion/polymer battery range; supports full operation without external LDO. |
| Max Output Current | 400mA pulsed (flash mode) - sufficient for high-intensity camera flash; continuous rating is 150mA. |
| Current Sense Resistor | 220mΩ internal high-side - eliminates external sense resistor, reduces BOM count and board area. |
| Flash Timeout | 2 seconds - hardware-enforced safety limit prevents LED thermal damage during sustained flash activation. |
| Oscillator Frequency | 1MHz typical - enables use of small ceramic flying capacitors (2.2μF) and minimizes output ripple. |
| Operating Temp Range | –40°C to +85°C - qualified for consumer handheld device ambient conditions including cold-weather operation. |
| Shutdown Current | 1.1μA typical - preserves battery life during extended standby in always-on imaging subsystems. |
Pinout & Package
Package: 10-lead (3mm × 2mm) plastic DFN with exposed pad (Pin 11), RoHS-compliant, moisture-sensitive level 1. Thermal performance requires soldering the exposed pad directly to a low-impedance ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CP / CM (Pins 1, 9) | Flying capacitor terminals | Connect 2.2μF X5R/X7R ceramic capacitor; high dv/dt nodes requiring tight layout and Faraday shielding. |
| CPO (Pin 2) | Charge pump output | Supplies boosted voltage to ILED; clamped at 5.3V; requires 4.7μF bypass to GND for ripple suppression. |
| ILED (Pin 3) | LED anode current output | Delivers regulated current to LED cathode (GND); voltage drop across internal 220mΩ resistor enables sensing. |
| ENT (Pin 4) | Torch enable / shutdown control | Pull-up enabled; sets torch mode when HIGH; forces shutdown when LOW (with ENF). |
| ISETT (Pin 5) | Torch current programming | Resistor to GND sets 1029/RSETT mA torch current; ratio fixed at 850× ISET. |
| ISETF (Pin 6) | Flash current programming | Resistor to GND sets 2965/RSETF mA (ENT=LOW/ENF=HIGH) or 3993/RSETF mA (both HIGH) flash current. |
| ENF (Pin 7) | Flash enable / timeout trigger | Activates flash mode; internal 2s timer disables output if held HIGH beyond timeout - no external circuit needed. |
| GND (Pin 8) | Power and signal ground | Low-impedance return path; must connect to solid ground plane; exposed pad (Pin 11) is also GND. |
| VIN (Pin 10) | Input power supply | 2.9V–4.5V battery input; requires ≥1.6μF ceramic bypass capacitor close to pin for stability. |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor architecture | Eliminates magnetic EMI, simplifies layout, and avoids inductor saturation issues in thin mobile form factors. |
| Automatic 1x/2x mode switching | Transitions only upon detected dropout (ΔV = 7mV), minimizing unnecessary efficiency loss in 2x mode. |
| Dual independent current programming | Separate ISETT and ISETF pins allow optimized torch brightness and flash intensity without shared resistor trade-offs. |
| Integrated thermal shutdown | Deactivates output at ~165°C junction temperature and auto-recovers at ~150°C - protects IC and LED under overload. |
| Output disconnect in shutdown | Internal ~90kΩ pull-down isolates ILED from CPO during shutdown, preventing unintended LED leakage or bias. |
Applications
| Smartphone Camera Flash | Digital Still Camera Torch Mode |
|---|---|
|
Use Scenario: High-intensity, short-duration illumination for low-light photography in compact handheld devices. IC Role / Device Role / Timing Role: LED driver IC providing precisely timed 400mA pulsed current with hardware-enforced 2s cutoff. Use Value: Prevents LED overheating and color shift while enabling consistent flash luminance across battery voltage range (2.9V–4.5V). |
Use Scenario: Steady, medium-brightness illumination for video recording or UI backlighting in portable cameras. IC Role / Device Role / Timing Role: Constant-current source delivering 50–150mA regulated torch output via ISETT resistor. Use Value: Maintains uniform LED brightness over full battery discharge without software intervention or DAC overhead. |
| Mobile Barcode Scanner Illumination | Portable Medical Imaging Device Light Source |
|
Use Scenario: Brief, repeatable LED bursts synchronized with image capture in handheld scanners. IC Role / Device Role / Timing Role: Fast-turn-on (160μs) flash controller triggered by ENT/ENF logic transitions. Use Value: Enables sub-millisecond flash timing alignment with CMOS sensor exposure windows for accurate decode. |
Use Scenario: Reliable, low-noise illumination for dermatological or endoscopic imaging where spectral stability matters. IC Role / Device Role / Timing Role: Low-EMI charge pump driver eliminating inductor-induced interference near sensitive analog sensors. Use Value: Ensures clean optical output without switching noise coupling into adjacent signal chains or ADC references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3214EDDB#TRPBF | Higher 500mA flash current; same 3mm × 2mm DFN package; adds 1.5x boost mode. | Supports brighter flash in larger-sensor modules; requires revised RSET values due to different current ratios. | Choose when >400mA peak current is required and additional boost flexibility justifies minor BOM change. |
| LTC3217EUD#TRPBF | Four independent LED outputs; 16-lead 3mm × 3mm QFN; 600mA total flash capability. | Designed for multi-LED arrays (e.g., front/rear dual-flash); not pin-compatible; needs new layout. | Choose for systems requiring spatially distributed lighting or independent brightness control per LED channel. |
Compared with LTC3218EDDB#TRPBF, LTC3214EDDB#TRPBF offers higher flash headroom and expanded mode options in identical footprint, while LTC3217EUD#TRPBF trades single-output simplicity for multi-channel flexibility at the cost of larger package and layout redesign.
Availability
LTC3218EDDB#TRPBF 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 across production lifecycles.
Supply support for LTC3218EDDB#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 its high-performance analog IC portfolio, emphasizing precision power management, signal conditioning, and interface solutions for demanding applications.
The LTC3218EDDB#TRPBF belongs to Linear's LED driver product line, engineered specifically for low-noise, high-current flash/torch functions in battery-powered imaging systems where size, efficiency, and reliability are critical.
FAQ
What is the maximum continuous LED current supported by the LTC3218EDDB#TRPBF?
The LTC3218EDDB#TRPBF supports up to 150mA continuous LED current in torch mode. This rating is thermally limited and verified across the full –40°C to +85°C operating temperature range. Exceeding this value continuously risks triggering thermal shutdown at ~165°C junction temperature, though pulsed flash operation up to 400mA is permitted for durations ≤10 seconds with appropriate duty cycling.
How does the LTC3218EDDB#TRPBF implement automatic mode switching between 1x and 2x charge pump operation?
The LTC3218EDDB#TRPBF monitors the voltage difference Δ(VCPO – VILED) and initiates 1x-to-2x mode transition when it drops to 7mV - indicating impending dropout. After a 500μs warm-up delay to allow LED forward voltage stabilization, the IC switches modes. No external components or configuration are required; the behavior is fully internal and deterministic per the datasheet's electrical characteristics table.
Can the LTC3218EDDB#TRPBF drive multiple LEDs in series?
No, the LTC3218EDDB#TRPBF is designed exclusively for single-LED anode-driving configurations. Its ILED pin delivers current to one LED anode with cathode tied to GND. Driving multiple LEDs in series would exceed the maximum CPO clamp voltage of 5.3V and violate the specified minimum LED forward voltage (2.2V at 50mA). For multi-LED strings, consider alternatives like LTC3209 or LTC3210-series devices.
What is the purpose of the exposed pad (Pin 11) on the LTC3218EDDB#TRPBF DFN package?
The exposed pad (Pin 11) on the LTC3218EDDB#TRPBF is electrically and thermally connected to GND. It must be soldered to a large copper ground plane using multiple thermal vias to ensure effective heat dissipation and low-impedance grounding. Omitting this connection degrades thermal resistance (θJA = 76°C/W nominal) and may cause premature thermal shutdown under 400mA flash loads.
How do I calculate the required ISETF resistor value for a 350mA flash current using the LTC3218EDDB#TRPBF?
For 350mA flash current with ENT = LOW and ENF = HIGH, use the formula RSETF = 2965 / ILED (from Table 1). Substituting gives RSETF = 2965 / 0.35 ≈ 8.47kΩ. A standard 1% value of 8.45kΩ yields 350.9mA, well within tolerance. Ensure the resistor is placed close to Pin 6 and uses low-TC material for stable current over temperature.
LTC3218EDDB#TRPBF 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#TRPBF FAQ
1.How can I place an order for LTC3218EDDB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3218EDDB#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 LTC3218EDDB#TRPBF reliable?
The price and inventory of LTC3218EDDB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3218EDDB#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3218EDDB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3218EDDB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3218EDDB#TRPBF?
LTC3218EDDB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3218EDDB#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 LTC3218EDDB#TRPBF?
For technical support, including LTC3218EDDB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3218EDDB#TRPBF requirements.
6.How does Aetrix verify that LTC3218EDDB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3218EDDB#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 LTC3218EDDB#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3218EDDB#TRPBF?
All LTC3218EDDB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3218EDDB#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 LTC3218EDDB#TRPBF part is unused and in its original packaging.
Return procedure for LTC3218EDDB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3218EDDB#TRPBF Tags
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BCR402RE6327HTSA1
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