LMX2371TM National Semiconductor, LMX2371TM Datasheet - Page 17

• Manufacturer Part Number: LMX2371TM
• Description: IC FREQ SYNTH DUAL 20-TSSOP
• Manufacturer: National Semiconductor
• Series: PLLatinum™r
• Type: PLL Frequency Synthesizerr

Specifications of LMX2371TM

• Pll: Yes with Bypass
• Input: CMOS, TTL
• Output: CMOS
• Number Of Circuits: 1
• Ratio - Input:output: 3:1
• Differential - Input:output: Yes/No
• Frequency - Max: 2GHz, 1.2GHz
• 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: 2GHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2371TM

2.0 Programming Description
2.3.7 Power Down Mode Table
2.4 PROGRAMMABLE MODES
Several modes of operation can be programmed with bits R15–R19 including the phase detector polarity, charge pump magni-
tude, charge pump TRI-STATE and the output of the Fo/LD pin. The programmable modes are shown in Table 1. Truth table for
the programmable modes and Fo/LD output are shown in Table 2 and Table 3.
2.4.1 Programmable Modes Table
2.4.2 Mode Select Truth Table
Note 7: Both synchronous and asynchronous power down modes are available with the LMX237x family to be able to adapt to different types of applications. The
MICROWIRE control register remains active and capable of loading and latching in data during all of the powerdown modes.
Note 8: ICP
Note 9: See Section 2.4.3
2.4.3 Phase Detector Polarity (Aux_PD_POL, Main_PD_POL)
Depending upon VCO characteristics, the Aux_PD_POL
(Aux_R15) and Main_PD_POL (Main_R15) bits should be
set accordingly:
When VCO characteristics are positive like (1), R15 should
be set HIGH;
When VCO characteristics are negative like (2), R15 should
be set LOW.
FoLD 1
FoLD 3
R19
Powered Down
Powered Down
o
(charge pump current magnitude) is dependent on Vp. The ICP
Main PLL
f
OUT
Active
Active
VCO CHARACTERISTICS
/Lock Detect
0
1
FoLD 0
FoLD 2
R18
CP
Normal Operation
Powered Down
Powered Down
Auxiliary PLL
o
TRI-STATE
_TRI (Note 7)
Active
Active
DS101026-5
Main_CP
Aux_CP
TRI-STATE
Charge
Pump
(Continued)
R17
o
o
_TRI
_TRI
Counters
Main
OFF
OFF
CP
o
ON
ON
LOW current state = 1/4 x ICP
17
o
1X Current
4X Current
_4X (Note 8)
Main_CP
Aux_CP
Magnitude
Charge
Pump
R16
o
o
_4X
_4X
Counters
Auxiliary
OFF
OFF
ON
ON
o
Main_PD_POL
Aux_PD_POL
HIGH current.
PD_POL (Note 9)
Detector
Polarity
Phase
R15
HIGH
LOW
OSC
OFF
in
ON
ON
ON
Address[1:0]
Buffer
0 0
1 0
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