LTC6908 - Dual Output Oscillator with Spread Spectrum Modulation
Features
- LTC6908-1: Complementary Outputs (0°/180°)
- LTC6908-2: Quadrature Outputs (0°/90°)
- 50kHz to 10MHz Frequency Range
- One External Resistor Sets the Frequency
- Optional Spread Spectrum Frequency Modulation for Improved EMC Performance
- ±10% Frequency Spreading
- 400µA Supply Current Typical (V+ = 5V, 50kHz)
- Frequency Error ≤1.5% Max (TA = 25°C, V+ = 3V)
- ±40ppm/°C Temperature Stability
- Fast Start-Up Time: 260µs Typical (1MHz)
- Outputs Muted Until Stable
- Operates from a Single 2.7V to 5.5V Supply
- Available in Low Profile (1mm) ThinSOT and DFN (2mm × 3mm) Packages
AEC-Q100 data available for specific packages
Typical Application
Description
The LTC6908 is an easy-to-use precision oscillator that provides 2-outputs, shifted by either 180° or 90°. The oscillator frequency is programmed by a single external resistor (RSET) and spread spectrum frequency modulation (SSFM) can be activated for improved electromagnetic compatibility (EMC) performance. The LTC6908 operates with a single 2.7V to 5.5V supply and provides rail-to-rail, 50% duty cycle square wave outputs. A single resistor from 10k to 2M is used to select an oscillator frequency from 50kHz to 10MHz (5V supply). The oscillator can be easily programmed using the simple formula outlined below:fOUT =10MHz • 10k/RSET
The LTC6908’s SSFM capability modulates the output frequency by a pseudorandom noise (PRN) signal to decrease the peak electromagnetic radiation level and improve EMC performance. The amount of frequency spreading is fi xed at ±10% of the center frequency. When SSFM is enabled, the rate of modulation is selected by the user. The three possible modulation rates are fOUT/16, fOUT/32 and fOUT/64.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC6908CDCB-1#PBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CDCB-1#TRMPBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CDCB-1#TRPBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CDCB-2#PBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CDCB-2#TRMPBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CDCB-2#TRPBF | 2x3 DFN-6 | DCB | C | 05-08-1715 | Yes |
| LTC6908CS6-1#PBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908CS6-1#TRMPBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908CS6-1#TRPBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908CS6-2#PBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908CS6-2#TRMPBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908CS6-2#TRPBF | SOT-23 | S6 | C | 05-08-1636 | Yes |
| LTC6908HS6-1#PBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908HS6-1#TRMPBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908HS6-1#TRPBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908HS6-2#PBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908HS6-2#TRMPBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908HS6-2#TRPBF | SOT-23 | S6 | H | 05-08-1636 | Yes |
| LTC6908IDCB-1#PBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IDCB-1#TRMPBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IDCB-1#TRPBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IDCB-2#PBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IDCB-2#TRMPBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IDCB-2#TRPBF | 2x3 DFN-6 | DCB | I | 05-08-1715 | Yes |
| LTC6908IS6-1#PBF | SOT-23 | S6 | I | 05-08-1636 | Yes |
| LTC6908IS6-1#TRMPBF | SOT-23 | S6 | I | 05-08-1636 | Yes |
| LTC6908IS6-1#TRPBF | SOT-23 | S6 | I | 05-08-1636 | Yes |
| LTC6908IS6-2#PBF | SOT-23 | S6 | I | 05-08-1636 | Yes |
| LTC6908IS6-2#TRMPBF | SOT-23 | S6 | I | 05-08-1636 | Yes |
| LTC6908IS6-2#TRPBF | SOT-23 | S6 | I | 05-08-1636 | 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
sales office or authorized distributor.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 |
|---|---|---|---|
| DC2073A-J | LTC6908-1 Silicon Oscillator Demo Board | $50.00 | |
| DC2073B-B | LTC1799 Silicon Oscillator Demo Board | $50.00 | |
| DC814A2-K | LTC6908-2 DEMO BOARD | BUFFER BOARD W/ ASSOCIATED DIP8 CLOCK BOARD | $50.00 | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC6908HS6-1#PBF | SOT-23 | H | $3.46 | Yes | ||
| LTC6908HS6-1#TRMPBF | SOT-23 | H | $3.46 | $2.46 | Yes | |
| LTC6908HS6-1#TRPBF | SOT-23 | H | $3.46 | $2.44 | Yes | |
| LTC6908HS6-2#PBF | SOT-23 | H | $3.46 | Yes | ||
| LTC6908HS6-2#TRMPBF | SOT-23 | H | $3.46 | $2.46 | Yes | |
| LTC6908HS6-2#TRPBF | SOT-23 | H | $3.46 | $2.44 | Yes | |
| LTC6908IS6-1#PBF | SOT-23 | I | $2.90 | Yes | ||
| LTC6908IS6-1#TRMPBF | SOT-23 | I | $2.90 | $2.06 | Yes | |
| LTC6908IS6-1#TRPBF | SOT-23 | I | $2.90 | $2.04 | Yes | |
| LTC6908IS6-2#PBF | SOT-23 | I | $2.90 | Yes | ||
| LTC6908IS6-2#TRMPBF | SOT-23 | I | $2.90 | $2.06 | Yes | |
| LTC6908IS6-2#TRPBF | SOT-23 | I | $2.90 | $2.04 | Yes | |
| Buy Now • Request Samples | ||||||
Applications
- Switching Power Supply Clock Reference
- Portable and Battery-Powered Equipment
- Precision Programmable Oscillator
- Charge Pump Driver
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC6908-1
LTC6908-2
OscCalc, an Excel based selection and synthesis tool, allows you to choose and configure the Silicon Oscillator best suited for your application.
- Download and open OscCalc
- Enable Macros
- Enter your desired switching frequency. Suitable silicon oscillators will be highlighted in green. Clicking on a part will show you the external component values and settings required to achieve your desired switching frequency.
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.