DA6116.010
5 October, 2017
GENERAL DESCRIPTION
Main features
The MAS6116 is designed for high-end audio systems that require high output voltages. In many audio
preamplifiers it's an advantage to get a lot of voltage swing out from the unit, close to +/-15V signal levels. In most
competing devices an op-amp is needed after the volume controller to get these levels since the IC can not work
with those high input signal levels. For such a system not only the signal is amplified but the noise as well. With
the MAS6116 high signal levels can be used everywhere inside the pre-amplifier and MAS6116 can then operate
with input signals up to +/- 18V and used as an attenuator. Very little noise usually comes out from the pre-amplifier
and the beauty is that the noise depends on the volume level. When listening at a lower volume levels the noise is
always inaudible. To improve the system performance even further the MAS6116 can be used in a balanced
configuration with one MAS6116 per channel.
The levels of the left and right analog channels are set by the serial interface. Both channels can be programmed
independently. The channel gains can be programmed from -111.5 dB to +15.5 dB with 0.5 dB resolution. The
code for -112 dB (00HEX) activates mute for maximum attenuation. MAS6116 operates from a single +5V supply
and accepts analog input signal levels up to ±18V.
MAS6116 has a zero cross detect function that changes the channel gain only when a zero crossing has been
detected in the input signal. This eliminates clicking sounds from the output signal when the gain is changed. The
zero cross detection circuit is also equipped with a timeout function to make sure the gain value is updated even
when there is no input signal.
Channel gains can also be changed instantly without using the zero cross detect function. This can be done with
dedicated instant gain change commands specified in Register Description on page 8. Using this feature to change
channel gains in large increments is not recommended because it may cause large transients in the output signal.
See chapter Changing the gain of the channels and chapter Write operation status register for further details.
The XMUTE pin in MAS6116 always uses the zero cross detection and timeout functions when entering to or
returning from the MUTE state. This prevents fast transients from occurring in the output signal.
Serial interface
Control information is written into or read back from the internal register via the serial control port. The serial control
port consists of a bi-directional pin for data (DATA), chip select pin (XCS) and control clock (CCLK) and supports
the serial communication protocol. All control instructions require two bytes of data; address byte and control/data
byte. The bits in the address and control/data byte are always written and read MSB bit first.
To shift the data in CCLK must be pulsed 16 times when XCS is low. The data is shifted into the serial input register
on the rising edges of CCLK pulses. The first 8 bits contain address information. The second byte contains the
control word. XCS must return to high after the second byte. That is, after the 16th CCLK XCS must be returned
to high. See chapter Serial interface timing diagram on page 14. See also figure 1 example of serial interface
signals during Normal write to both channels (command CBh=%1100 1011, don’t care bits 1) with written byte
AAh=%1010 1010.
3 (20)
MAS [ MICRO ANALOG SYSTEMS ]
