MM516
User's Manual
43
Revision 1.4 7-8-2011
Hardware Description Manual
5.8.2 Status after Reset
The chip status after a reset is as follows:
Warm Reset: Data rate and RAM data remain available
Cold Reset: Data rate and RAM data not available
5.9 Power Supply
5.9.1 Switch-mode Regulator
The on-chip switch-mode 1.8V regulator, may be used to power a 1.8V rail which can drive the chip I/O supplies,
and the input to the low-voltage regulators. An external filter circuit of a low-resistance 22μH series inductor with an
effective series resistance in the range 0.4-0.8Ω, followed by a low ESR 4.7μF shunt capacitor is required between
the LX terminal and the 1.8V supply rail, which should also be connected to the pin VDD_SMP_CORE. A decoupling
capacitor of at least 2.2μF is required between BAT_P and BAT_N. It is essential that the series resistance of tracks
between the BAT_P and BAT_N terminals, the filter and decoupling components, and the external voltage source
are minimised to maintain high-efficiency power conversion, and low supply ripple.
The regulator may be enabled by the VREGENABLE_H pin, by the device firmware, or by the internal battery charger.
The regulator is switched into a low-power pulse skipping mode when the device is sent into deep-sleep mode, or
in reset.
When this regulator is not used the terminals BAT_P and LX must be grounded or left unconnected.
5.9.2 Low-voltage Linear Regulator
The on-chip low-voltage regulator is used to power all the chip 1.5V supplies except for VDD_AUDIO. The
output of this regulator is connected internally to VDD_ANA, and must be connected externally to the other 1.5V
supply pads. A smoothing circuit using a low ESR capacitor (2.2μF) and a resistor (2.2Ω) to ground should be
connected to the output of the regulator. Alternatively use a 2.2μF capacitor with an ESR of at least 2Ω.
This regulator may be enabled by the VREGENABLE_L pin, by the device firmware, or by the internal battery charger.
The regulator is switched into a low power mode when the device is in deep-sleep mode, or in reset.
When this regulator is not used the terminal VREGIN_L must be left unconnected, or tied to VDD_ANA.
5.9.3 Low-voltage Audio Linear Regulator
The on-chip low-voltage audio regulator is used to power VDD_AUDIO. The output of this regulator is
connected internally to VDD_AUDIO. A smoothing circuit using a series connected 2.2μF low ESR capacitor and a
2.2Ω resistor to ground should be connected to the output of the regulator. Alternatively a 2.2μF capacitor with at
least 2Ω ESR may be used.
This regulator may be enabled by the VREGENABLE_L pin or by the device firmware. The regulator is switched into
a low power mode when no audio cells are enabled, or when the chip is in reset.
