LMX2335LM National Semiconductor, LMX2335LM Datasheet - Page 15

• Manufacturer Part Number: LMX2335LM
• Description: IC FREQ SYNTHESIZER DUAL 16-SOIC
• Manufacturer: National Semiconductor
• Series: PLLatinum™r
• Type: PLL Frequency Synthesizerr

Specifications of LMX2335LM

• Pll: Yes with Bypass
• Input: CMOS, TTL
• Output: CMOS
• Number Of Circuits: 1
• Ratio - Input:output: 3:1
• Differential - Input:output: No/No
• Frequency - Max: 1.1GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Frequency-max: 1.1GHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2335LM

Functional Description
X — don’t care condition
Note 11: When the F
Note 12: Lock detect output provided to indicate when the VCO frequency is in “lock”. When the loop is locked and a lock detect mode is selected, the pins output
is HIGH, with narrow pulses LOW. In the RF1/RF2 lock detect mode a locked condition is indicated when RF2 and RF1 are both locked.
Note 13: The Fastlock mode utilized the F
occurs whenever the RF loop’s Icpo magnitude bit #17 is selected HIGH (while the #19 and #20 mode bits are set for Fastlock).
Note 14: The RF2 counter reset mode resets RF2 PLL’s R and N counters and brings RF2 charge pump output to a TRI-STATE condition. The RF1 counter reset
mode resets RF1 PLL’s R and N counters and brings RF1 charge pump output to a TRI-STATE condition. The RF1 and RF2 counter reset mode resets all counters
and brings both charge pump output to a TRI-STATE condition. Upon removal of the Reset bits the N counter resumes counting in “close” alignment with the R
counter. (The maximum error is one prescaler cycle).
POWERDOWN OPERATION
Synchronous and asynchronous powerdown modes are
both available by microwire selection. Synchronously pow-
erdown occurs if the respective loop’s R18 bit (Do TRI-
STATE) is LOW when its N20 bit (Pwdn) becomes HI. Asyn-
chronous powerdown occurs if the loop’s R18 bit is HI when
its N20 bit becomes HI.
In the synchronous powerdown mode, the powerdown func-
tion is gated by the charge pump to prevent unwanted
frequency jumps. Once the powerdown program bit N20 is
loaded, the part will go into powerdown mode when the
charge pump reaches a TRI-STATE condition.
In the asynchronous powerdown mode, the device powers
down immediately after the LE pin latches in a HI condition
on the powerdown bit N20.
Activation of either the IF or RF PLL powerdown conditions
in either synchronous or asynchronous modes forces the
respective loop’s R & N dividers to their load state condition
and debiasing of it’s respective Fin input to a high imped-
RF1 R[19]
(RF1 LD)
X
X
X
X
0
0
1
1
0
0
1
1
o
LD output is disabled it is actively pulled to a low logic state.
RF2 R[19]
(RF2 LD)
0
1
0
1
0
0
1
1
0
1
0
1
o
LD output pin to switch a second loop filter damping resistor to ground during fastlock operation. Activation of Fastlock
(Continued)
TABLE 3. The F
RF1 R[20]
(RF1 F
0
0
0
0
0
1
0
1
1
1
1
1
O
)
o
LD Output Truth Table
15
RF2 R[20]
(RF2 F
ance state. The oscillator circuitry function does not become
disabled until both IF and RF powerdown bits are activated.
The MICROWIRE control register remains active and ca-
pable of loading and latching data during all of the power-
down modes.
The device returns to an actively powered up condition in
either synchronous ar asynchronous modes immediately
upon LE latching LOW data into bit N20.
0
0
0
0
1
0
1
0
1
1
1
1
R18
0
1
0
1
O
)
N20
0
0
1
1
Disabled (Note 11)
RF2 Lock Detect (Note 12)
RF1 Lock Detect (Note 12)
RF1/RF2 Lock Detect (Note 12)
RF2 Reference Divider Output
RF1 Reference Divider Output
RF2 Programmable Divider Output
RF1 Programmable Divider Output
Fastlock (Note 13)
RF2 Counter Reset (Note 14)
RF1 Counter Reset (Note 14)
RF1 and RF2 Counter Reset (Note 14)
Powerdown Mode Select Table
PLL Active
PLL Active (Charge Pump Output
TRI-STATE)
Synchronous Powerdown Initiated
Asynchronous Powerdown Initiated
Powerdown Status
Output State
F
o
LD
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