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LTC6903/LTC6904 1kHz - 68MHz Serial Port Programmable Oscillator
FEATURES
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DESCRIPTIO
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1kHz to 68MHz Square Wave Output 0.5% (Typ) Initial Frequency Accuracy Frequency Error <1.1% Over All Settings 10ppm/°C Typical Frequency Drift Over Temperature 0.1% Resolution 1.7mA Typical Supply Current (f < 1MHz, VS = 2.7V) 2.7V to 5.5V Single Supply Operation Jitter <0.4% Typical 1kHz to 8MHz Easy to Use SPI (LTC6903) or I2C (LTC6904) Serial Interface Output Enable Pin –40°C to 125°C Operation MS8 Package
The LTC®6903/LTC6904 are low power self contained digital frequency sources providing a precision frequency from 1kHz to 68MHz, set through a serial port. The LTC6903/LTC6904 require no external components other than a power supply bypass capacitor, and they operate over a single wide supply range of 2.7V to 5.5V. The LTC6903/LTC6904 feature a proprietary feedback loop that linearizes the relationship between digital control setting and frequency, resulting in a very simple frequency setting equation: 2078(Hz) f = 2OCT • ;1kHz < f < 68MHz DAC 2 – 1024 Where OCT is a 4-bit digital code and DAC is a 10-bit digital code. The LTC6903 is controlled by a convenient SPI compatible serial interface. The LTC6904 uses an industry standard I2C compatible interface.
, LTC and LT are registered trademarks of Linear Technology Corporation. U.S. Patent Numbers 6342817 and 6614313.
U APPLICATIO S
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Precision Digitally Controlled Oscillator Power Management Direct Digital Frequency Synthesis (DDS) Replacement Replacement for DAC and VCO Switched Capacitor Filter Clock
TYPICAL APPLICATIO
A Microcontroller Controlling Its Clock
40 5V MICROCONTROLLER OSC1/CLKIN OSC2/CLKOUT MCLR/VP–P RC5/SDO RC3/SCK/SCL RC2/CCP1 GND SDI LTC6903 SCK SEN CLK 1µF CLK 0.01µF PIC16F73 POWER-UP CLOCK FREQUENCY IS 1039Hz 0 –1.0 10 V+ OE 10Ω
VS = 3V TA = 25°C f = 1039Hz 443 30 UNITS TESTED
10k
UNITS
20
5V 0.1µF
VDD VSS VSS
6903 TA01
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LTC6903 Frequency Error Distribution
0 0.5 –0.5 FREQUENCY ERROR (%) 1.0
6903 TA01b
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LTC6903/LTC6904
ABSOLUTE
(Note 1)
AXI U RATI GS
U W U PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
TOP VIEW GND SDI SCK SEN/ADR* 1 2 3 4 8 7 6 5 V+ OE CLK CLK
Total Supply Voltage (V+ to GND) .............................. 6V Maximum Voltage on any Pin ........................... (GND – 0.3V) ≤ VPIN ≤ (V+ + 0.3V) Output Short Circuit Duration (Note 2) ............ Indefinite Operating Temperature Range (Note 3) LTC6903CMS8/LTC6904CMS8 ........... –40°C to 85°C LTC6903IMS8/LTC6904IMS8 ............. –40°C to 85°C LTC6903HMS8/LTC6904HMS8 ......... –40°C to 125°C Specified Temperature Range (Note 4) LTC6903CMS8/LTC6904CMS8 ........... –40°C to 85°C LTC6903IMS8/LTC6904IMS8 ............. –40°C to 85°C LTC6903HMS8/LTC6904HMS8 ......... –40°C to 125°C Storage Temperature Range .................. –65°C to 150°C Lead Temperature (Soldering, 10sec)................... 300°C
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V + = 2.7V to 5.5V, GND = 0V, unless otherwise noted.
SYMBOL ∆fi ∆f PARAMETER Initial Frequency Accuracy Total Frequency Accuracy (Note 7) CONDITIONS f = 1.039kHz, V + = 3V, CLOAD = 5pF Single Output Active: Over All Settings, V + = 2.7V, CLOAD = 5pF Over All Settings, V + = 5.5V, CLOAD = 5pF LTC6903CMS8, LTC6904CMS8: Over All Settings, V + = 2.7V, CLOAD = 5pF Over All Settings, V + = 5.5V, CLOAD = 5pF LTC6903HMS8, LTC6903IMS8, LTC6904HMS8, LTC6904IMS8: Over All Settings, V + = 2.7V, CLOAD = 5pF Over All Settings, V + = 5.5V, CLOAD = 5pF MIN TYP MAX ±0.75 0.5 0.5
q q
ELECTRICAL CHARACTERISTICS
fMAX fMIN ∆f/∆T ∆f/∆V
Maximum Operating Frequency Minimum Operating Frequency Frequency Drift Over Temperature Frequency Drift Over Supply Long Term Frequency Stability Timing Jitter (See Graph) Duty Cycle 1.039kHz to 8.5MHz 1.039kHz to 68MHz 1.039kHz to 1MHz 1.039kHz to 68MHz CLK, CLK Pins, V + = 2.7V V + = 5.5V, 4mA Load V + = 2.7V, 4mA Load V + = 5.5V, 1mA Load V + = 2.7V, 1mA Load
q q q q q q q q q
ROUT VOH
Output Resistance High Level Output Voltage
VOL
Low Level Output Voltage
2
U
W W
W
MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 200°C/W
LTC6903CMS8 LTC6903IMS8 LTC6903HMS8 LTC6904CMS8 LTC6904IMS8 LTC6904HMS8 MS8 PART MARKING*
* SEN (LTC6903) ADR (LTC6904)
LTABN LTAES
*The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges.
UNITS % % % % %
1.1 1.6 1.65 2
0.5 0.5
q q
0.5 0.5 68 1.039 10 0.05 300 0.4 1 49 50 50 45 4.8 2 5.2 2.3 5.3 2.3 5.45 2.55 0.15 0.25 0.05 0.05
1.9 2.2
% % MHz kHz ppm/°C %/V ppm/√kHr % %
51
% % Ω V V V V
V + = 5.5V, 4mA Load V + = 2.7V, 4mA Load V + = 5.5V, 1mA Load V + = 2.7V, 1mA Load
0.3 0.45 0.15 0.2
V V V V
69034fa
LTC6903/LTC6904
The q denotes the specific.