LT3922 - 36V, 2A Synchronous Step-Up LED Driver
Features
- ±2% LED Current Regulation
- ±2% Output Voltage Regulation
- 5000:1 PWM Dimming at 100Hz
- 128:1 Internal PWM Dimming
- Spread-Spectrum Frequency Modulation
- Silent Switcher® Architecture for Low EMI
- Operates in Boost, Buck Mode and Buck-Boost Mode
- 2.8V to 36V Input Voltage Range
- Up to 34V LED String Voltage
- 2A, 40V Internal Switches
- 200kHz to 2MHz with SYNC Function
- Analog or Duty Cycle LED Current Control
- Open/Short LED Protection and Fault Indication
- Thermally Enhanced 28-Pin (4mm × 5mm) QFN
Typical Application
Description
The LT®3922 is a monolithic, synchronous, step-up DC/ DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. The LT3922 will maintain ±2% current regulation through an external sense resistor over a wide range of output voltages.
The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922 also includes a driver for an external high side PMOS for PWM dimming and an internal PWM signal generator for analog control of PWM dimming when an external signal is not available.
Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LT3922EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3922EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3922HUFD#PBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT3922HUFD#TRPBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT3922IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT3922IUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3922EUFD#PBF | 4x5 QFN-28 | E | $5.64 | $3.95 | Yes | |
| LT3922EUFD#TRPBF | 4x5 QFN-28 | E | $5.70 | $4.01 | Yes | |
| LT3922HUFD#PBF | 4x5 QFN-28 | H | $6.57 | $4.60 | Yes | |
| LT3922HUFD#TRPBF | 4x5 QFN-28 | H | $6.63 | $4.66 | Yes | |
| LT3922IUFD#PBF | 4x5 QFN-28 | I | $6.22 | $4.35 | Yes | |
| LT3922IUFD#TRPBF | 4x5 QFN-28 | I | $6.28 | $4.41 | Yes | |
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC2247A | LT3922 Demo Board | Sync Boost LED Driver, 4V ≤ VIN ≤ 28V, VLED = 34V @ Up to 330mA, 2MHz fSWITCH | $100.00 | |
| Buy Now | |||
Applications
- Automotive and Industrial Lighting
- Machine Vision
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Design Tools
LTspice
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Models for the following parts are available in LTspice:
LT3922
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
