Datasheet LTC6908-1, LTC6908-2 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | Resistor Set SOT-23 Oscillator with Spread Spectrum Modulation |
| Páginas / Página | 16 / 1 — FEATURES. DESCRIPTION. LTC6908-1: Complementary Outputs (0°/180°). … |
| Revisión | B |
| Formato / tamaño de archivo | PDF / 582 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTION. LTC6908-1: Complementary Outputs (0°/180°). LTC6908-2: Quadrature Outputs (0°/90°)
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Versión de texto del documento
LTC6908-1/LTC6908-2 Resistor Set SOT-23 Oscillator with Spread Spectrum Modulation
FEATURES DESCRIPTION
n
LTC6908-1: Complementary Outputs (0°/180°)
The LTC®6908 is an easy-to-use precision oscillator that n
LTC6908-2: Quadrature Outputs (0°/90°)
provides 2-outputs, shifted by either 180° or 90°. The n
50kHz to 10MHz Frequency Range
oscillator frequency is programmed by a single external n
One External Resistor Sets the Frequency
resistor (RSET) and spread spectrum frequency modula- n
Optional Spread Spectrum Frequency Modulation
tion (SSFM) can be activated for improved electromag-
for Improved EMC Performance
netic compatibility (EMC) performance. n
±10% Frequency Spreading
The LTC6908 operates with a single 2.7V to 5.5V supply n 400µA Supply Current Typical (V+ = 5V, 50kHz) and provides rail-to-rail, 50% duty cycle square wave out- n Frequency Error ≤1.5% Max (TA = 25°C, V+ = 3V) puts. A single resistor from 10k to 2M is used to select an n ±40ppm/°C Temperature Stability oscillator frequency from 50kHz to 10MHz (5V supply). n Fast Start-Up Time: 260µs Typical (1MHz) The oscillator can be easily programmed using the simple n Outputs Muted Until Stable formula outlined below: n Operates from a Single 2.7V to 5.5V Supply n Available in Low Profile (1mm) ThinSOT and DFN fOUT =10MHz • 10k/RSET (2mm × 3mm) Packages The LTC6908’s SSFM capability modulates the output frequency by a pseudorandom noise (PRN) signal to decrease the peak electromagnetic radiation level and
APPLICATIONS
improve EMC performance. The amount of frequency n Switching Power Supply Clock Reference spreading is fixed at ±10% of the center frequency. When n Portable and Battery-Powered Equipment SSFM is enabled, the rate of modulation is selected by n Precision Programmable Oscillator the user. The three possible modulation rates are fOUT/16, n Charge Pump Driver fOUT/32 and fOUT/64. All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION 150kHz to 30MHz Output Frequency Spectrum 2.25MHz, 2.5V/8A Step-Down Regulator (9kHz Res BW)
0 VIN SSFM DISABLED 2.8V TO 5.5V CIN –10 100μF SV PV C IN TRACK IN 0.2μH BYP VOUT –20 V+ OUT1 RT SW 2.5V 8A –30 2.2M LTC3418 41.2k OUTPUT (dBc) 0.1μF LTC6908-1 PGOOD C –40 GND OUT2 OUT RUN/SS PGND 100μF 0 44.2k ×2 1000pF ITH SGND SSFM ENABLED –10 SET MOD 4.99k SYNC/MODE VFB 690812 TA01a –20 820pF 4.32k fOUT = 10MHz • 10k/RSET –30 OUTPUT (dBc) 2k –40 150kHz 30MHz FREQUENCY (FUNDAMENTAL AND HARMONICS SHOWN) 690812 TA01b Rev B Document Feedback For more information www.analog.com 1 Document Outline Features Applications Description Absolute Maximum Ratings Electrical Characteristics Pin Functions Operation Applications Information Typical Applications Package Description Typical Application
FEATURES DESCRIPTION
n
LTC6908-1: Complementary Outputs (0°/180°)
The LTC®6908 is an easy-to-use precision oscillator that n
LTC6908-2: Quadrature Outputs (0°/90°)
provides 2-outputs, shifted by either 180° or 90°. The n
50kHz to 10MHz Frequency Range
oscillator frequency is programmed by a single external n
One External Resistor Sets the Frequency
resistor (RSET) and spread spectrum frequency modula- n
Optional Spread Spectrum Frequency Modulation
tion (SSFM) can be activated for improved electromag-
for Improved EMC Performance
netic compatibility (EMC) performance. n
±10% Frequency Spreading
The LTC6908 operates with a single 2.7V to 5.5V supply n 400µA Supply Current Typical (V+ = 5V, 50kHz) and provides rail-to-rail, 50% duty cycle square wave out- n Frequency Error ≤1.5% Max (TA = 25°C, V+ = 3V) puts. A single resistor from 10k to 2M is used to select an n ±40ppm/°C Temperature Stability oscillator frequency from 50kHz to 10MHz (5V supply). n Fast Start-Up Time: 260µs Typical (1MHz) The oscillator can be easily programmed using the simple n Outputs Muted Until Stable formula outlined below: n Operates from a Single 2.7V to 5.5V Supply n Available in Low Profile (1mm) ThinSOT and DFN fOUT =10MHz • 10k/RSET (2mm × 3mm) Packages The LTC6908’s SSFM capability modulates the output frequency by a pseudorandom noise (PRN) signal to decrease the peak electromagnetic radiation level and
APPLICATIONS
improve EMC performance. The amount of frequency n Switching Power Supply Clock Reference spreading is fixed at ±10% of the center frequency. When n Portable and Battery-Powered Equipment SSFM is enabled, the rate of modulation is selected by n Precision Programmable Oscillator the user. The three possible modulation rates are fOUT/16, n Charge Pump Driver fOUT/32 and fOUT/64. All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION 150kHz to 30MHz Output Frequency Spectrum 2.25MHz, 2.5V/8A Step-Down Regulator (9kHz Res BW)
0 VIN SSFM DISABLED 2.8V TO 5.5V CIN –10 100μF SV PV C IN TRACK IN 0.2μH BYP VOUT –20 V+ OUT1 RT SW 2.5V 8A –30 2.2M LTC3418 41.2k OUTPUT (dBc) 0.1μF LTC6908-1 PGOOD C –40 GND OUT2 OUT RUN/SS PGND 100μF 0 44.2k ×2 1000pF ITH SGND SSFM ENABLED –10 SET MOD 4.99k SYNC/MODE VFB 690812 TA01a –20 820pF 4.32k fOUT = 10MHz • 10k/RSET –30 OUTPUT (dBc) 2k –40 150kHz 30MHz FREQUENCY (FUNDAMENTAL AND HARMONICS SHOWN) 690812 TA01b Rev B Document Feedback For more information www.analog.com 1 Document Outline Features Applications Description Absolute Maximum Ratings Electrical Characteristics Pin Functions Operation Applications Information Typical Applications Package Description Typical Application