LMX25311778EVAL National Semiconductor, LMX25311778EVAL Datasheet - Page 26

• Manufacturer Part Number: LMX25311778EVAL
• Manufacturer: National Semiconductor

Specifications of LMX25311778EVAL

• Lead Free Status / Rohs Status: Not Compliant

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2.5 REGISTER R4
2.5.1 TOC[13:0] -- Time Out Counter for FastLock
When the value of this word is 3 or less, then FastLock is disabled, and this pin can only be used for general purpose I/O. When
this value is 4 or greater, the time out counter is engaged for the amount of phase detector cycles shown in the table below.
When this count is active, the FLout Pin is grounded, the FastLock current is engaged, and the resistors R3 and R4 are also
potentially changed. The table below summarizes the bits that control various values in and out of FastLock differences.
2.5.2 ICPFL[3:0] -- Charge Pump Current for Fastlock
When FastLock is enabled, this is the charge pump current that is used for faster lock time.
FastLock State
Steady State
Fastlock
ICPFL
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
TOC Value
16383
0
1
2
3
4
.
High Impedance
Grounded
FLout
Fastlock Charge Pump State
FLout Pin State
High Impedance
Charge Pump Current
High
Low
Low
Low
Low
10X
11X
12X
13X
14X
15X
16X
1X
2X
3X
4X
5X
6X
7X
8X
9X
26
.
ICPFL
ICP
16383 × 2 Phase Detector
Typical Fastlock Charge Pump Current
4 × 2 Phase Detector
Timeout Count
Always Enabled
R3_ADJ_FL
R3_ADJ
R3
0
0
0
.
at 3 Volts (µA)
1080
1170
1260
1350
1440
180
270
360
450
540
630
720
810
900
990
90
R4_ADJ_FL
R4_ADJ
R4