Datasheet

LMK01000
www.ti.com SNAS437G –FEBRUARY 2008–REVISED OCTOBER 2009
CLKoutX_DLY[3:0] -- Clock Output Delays
These bits control the delay stages for each clock output. In order for these delays to be active, the respective
CLKoutX_MUX (See Section 2.3.2) bit must be set to either "Delayed" or "Divided and Delayed" mode. By
adding the delay block to the output path a fixed delay of approximately 400 ps is incurred in addition to the
delay shown in the table below.
CLKoutX_DLY[3:0] Delay (ps)
0 0 (default)
1 150
2 300
3 450
4 600
5 750
6 900
7 1050
8 1200
9 1350
10 1500
11 1650
12 1800
13 1950
14 2100
15 2250
CLKoutX_EN bit -- Clock Output Enables
These bits control whether an individual clock output is enabled or not. If the EN_CLKout_Global bit is set to zero
or if GOE pin is held low, all CLKoutX_EN bit states will be ignored and all clock outputs will be disabled.
CLKoutX_EN bit Conditions CLKoutX State
0 EN_CLKout_Global bit = 1 Disabled (default)
GOE pin = High / No Connect 1
1 Enabled
REGISTER R9
R9 only needs to be programmed if Vboost is set to 1. Program all other bits in R9 as indicated in register map
(See Section 2.2)
Vboost - Voltage Boost Bit
Enabling this bit sets all clock outputs in voltage boost mode which increases the voltage at these outputs. This
can improve the noise floor performance of the output, but also increases current consumption, and can cause
the outputs to be too high to meet the LVPECL/LVDS specifications.
Vboost bit f
CLKoutX
< 1300 MHz 1300 MHz ≤ f
CLKoutX
< 1500 1500 MHz ≤ f
CLKoutX
≤ 1600 MHz
MHz
0 Recommended to hit voltage level Insufficient voltage level for LVDS/LVPECL specifications, but saves
specifications for LVPECL/LVDS current
1 Voltage May overdrive LVPECL/LVDS Voltage is sufficient for Insufficient voltage for
specifications, but noise floor is about 2-4 dB LVDS/LEVPECL specifications. LVDS/LVPECL specifications, but
better and current consumption is increased Current consumption is still higher than when Vboost=0.
increased, but noise floor is Increased current consumption.
about the same.
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