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Device Configuration
4.2.13.1
OUT0 VOD Settings
75-
Ω
OUT0has programmable peak to peak setting from 720 mV to 880 mV. In default mode, output
voltage setting is expected to be 800mV ±15 mV. To increase or decrease the output voltage swing, the
content of Reg 0x80[7:4] has to be read first and then increased or decreased respectively. Note: In raw
mode, the VOD setting would use register setting -3 (irrespective of the data rate).
RAW
FF
04
07
//Select Channel Registers
RAR
80
XX
F0
//Read Register 0x80[7:4]
RAW
80
XX
F0
//Adjust by 1, 2, or 3 to get the desired output voltage swing
4.2.13.2
OUT0 Power Down or Power Up
The LMH0318 OUT0 75
Ω
current mode output draws high current and can be powered down to save
power.
RAW
FF
04
07
//Select Channel Registers
RAW
80
03
03
//Power Down OUT0
RAW
FF
04
07
//Select Channel
RAW
80
02
03
//Power up OUT0
4.2.13.3
OUT1 VOD Settings
OUT1 VOD settings can have a range of 600 mv to 1300 mv:
RAW
FF
04
07
//Select Channel Registers
RAW
84
00
70
//Set drv_1_sel_vod to 0 (570 mVp-p)
RAW
84
20
70
//Set drv_1_sel_vod to 2 (730 mVp-p)
RAW
84
40
70
//Set drv_1_sel_vod to 4 (900 mVp-p)
RAW
84
60
70
//Set drv_1_sel_vod to 6 (1035 mVp-p)
4.2.13.4
OUT1 De-Emphasis Settings
There are 15 output de-emphasis settings for the LMH0318 OUT1, ranging from 0 dB to -11 dB. The de-
emphasis values come from register 0x85, bits 2:0 and 0x85 bit 3, which is the de-emphasis range bit.
RAW
FF
04
07
//Select Channel Registers
RAW
85
00
0F
//OUT1 DE Setting set to 0 dB
RAW
85
02
0F
//OUT1 DE Setting set to -2 dB
RAW
85
07
0F
//OUT1 DE Setting set to -11 dB
4.2.13.5
OUT1 Power Down
If needed the OUT1 output can be powered down:
RAW
FF
04
07
//Select Channel Registers
RAW
84
03
03
//Power Down out1
RAW
84
02
03
//Power Up OUT1 (normal operating State)
17
SNLU183 – September 2015
LMH0318 Programming Guide
Copyright © 2015, Texas Instruments Incorporated