CMX993 Datasheet, PDF (15/26 Pages) CML Microcircuits – Programmable 30dB Output Gain Range

Quadrature Modulator
CMX993/CMX993W
Gain Control Register b6-b3: Modulator Attenuation
b6 b5 b4 b3
F4 F3 F2 F1
1
1
0
0 30dB Attenuation
1
0
1
1 27.5dB Attenuation
1
0
1
0 25dB Attenuation
1
0
0
1 22.5dB Attenuation
1
0
0
0 20dB Attenuation
0
1
1
1 17.5dB Attenuation
0
1
1
0 15dB Attenuation
0
1
0
1 12.5dB Attenuation
0
1
0
0 10dB Attenuation
0
0
1
1 7.5dB Attenuation
0
0
1
0 5dB Attenuation
0
0
0
1 2.5dB Attenuation
0
0
0
0 0dB Attenuation (Max Gain)
Gain Control Register b7: Reserved for Modulator Attenuation, set to '0'.
6.4 Frequency Control Register: C-BUS address $08
8-bit write-only
Bit:
7
6
5
4
3
2
1
0
0
0
0
DIV
0
0
F2
F1
Frequency Control Register b7-5 and b3-2: Reserved for future use, set to '0'.
Frequency Control Register b4: Local Oscillator Divider Control
Writing ‘b4’ = 1 will enable "divide the local oscillator by 4" mode, writing ‘b4’ = 0 will enable the
"divide the local oscillator by 2" mode.
NOTE: Divide by 4 mode is not recommended for operation below 200MHz LO frequency (50MHz
RF output). For output frequencies below 50MHz the divide by 2 mode is recommended.
Frequency Control Register b1-b0
Controls the operating frequency band.
b1 b0
F2 F1
0 0 Operation below 500MHz
0 1 Operation above 500MHz
1 0 reserved
1 1 reserved
Note: Frequencies are the operating frequency, not the
local oscillator input frequency.
 2013 CML Microsystems Plc
15
D/993/10