LMX2301TM National Semiconductor, LMX2301TM Datasheet - Page 9

• Manufacturer Part Number: LMX2301TM
• Description: IC FREQ SYNTHESIZER 20-TSSOP
• Manufacturer: National Semiconductor
• Series: PLLatinum™r
• Type: PLL Frequency Synthesizerr

Specifications of LMX2301TM

• Pll: Yes
• Input: Clock
• Output: CMOS
• Number Of Circuits: 1
• Ratio - Input:output: 2:1
• Differential - Input:output: Yes/No
• Frequency - Max: 160MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Frequency-max: 160MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2301TM

Analog Switch
The analog switch is useful for radio systems that utilize a frequency scanning mode and a narrow band mode The purpose of
the analog switch is to decrease the loop filter time constant allowing the VCO to adjust to its new frequency in a shorter
amount of time This is achieved by adding another filter stage in parallel The output of the charge pump is normally through the
D
second filter stage (LPF-2) is effective only when the switch is closed (in the scanning mode)
Typical Crystal Oscillator Circuit
A typical circuit which can be used to implement a crystal
oscillator is shown below
o
pin but when LE is set HIGH the charge pump output also becomes available at BISW A typical circuit is shown below The
TL W 12458 – 20
9
Typical Lock Detect Circuit
A lock detect circuit is needed in order to provide a steady
LOW signal when the PLL is in the locked state A typical
circuit is shown below
TL W 12458– 19
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TL W 12458– 21
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