LMX2320TM National Semiconductor, LMX2320TM Datasheet - Page 13

• Manufacturer Part Number: LMX2320TM
• Description: IC FREQ SYNTH 2.0GHZ 20-TSSOP
• Manufacturer: National Semiconductor
• Series: PLLatinum™r
• Type: PLL Frequency Synthesizerr

Specifications of LMX2320TM

• Pll: Yes
• Input: CMOS, TTL
• Output: CMOS
• Number Of Circuits: 1
• Ratio - Input:output: 1:1
• Differential - Input:output: Yes/No
• Frequency - Max: 2GHz
• 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: 2.5GHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2320TM

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
but when LE is set HIGH, the charge pump output also becomes available at BISW. A typical circuit is shown below. The 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.
DS012339-52
13
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.
DS012339-24
DS012339-26
www.national.com
o
pin,