CMX993 Datasheet, PDF (14/26 Pages) CML Microcircuits – Programmable 30dB Output Gain Range

Quadrature Modulator
CMX993/CMX993W
6.2 General Control Register: C-BUS address $02
This register controls general features such as powersave.
All bits of this register are cleared to 0 by a General Reset command.
8-bit write-only
Bit:
7
6
I/Q Pwr
0
5
4
3
2
1
0
V_REF
Filter
Input Wideband
0
Filter Amp
Amps Pwr Amps Pwr
Filter
Gain
Amps Pwr
Reduction
CMX993
only
CMX993W
only
CMX993W
only
General Control Register b7-b1: Select high input gain
These bits control power up/power down of the various blocks of the IC. In all cases,
‘1’ = power up, ‘0’ = power down.
b7
Enable I/Q modulator and local oscillator sections
b6
reserved, set to ‘0’
b5
Enable internal bias circuits and bandgap reference (V_REF and BV_REF).
b4
CMX993 – Enable filter amplifiers
CMX993W – reserved, set to ‘0’
b3
Enable input amplifiers
b2
CMX993 – reserved, set to ‘0’
CMX993W – Enable wide bandwidth filter amplifiers
b1
reserved, set to ‘0’
General Control Register b0: Filter Amplifier Gain Reduction
b0 = 1
b0 = 0
b0
CMX993W – Wide bandwidth filter amplifier gain reduction by adding
1k between output and negative input.
CMX993W – Normal Operation
CMX993 – reserved, set to ‘0’
6.3 Gain Control Register: C-BUS address $05
This register controls the gain of the I/Q modulator.
Bit:
7
6
5
4
3
2
0
F4
F3
F2
F1
0
Gain Control Register b2-b0: Reserved for future use, set to '0'.
8-bit write-only
1
0
0
0
 2013 CML Microsystems Plc
14
D/993/10