PAM8904Q
Document number: DS38977 Rev. 2 - 2
November 2016
© Diodes Incorporated
Application Information
Charge Pump Mode Setting
The Charge Pump Mode (CPM) pins CPM
1
and CPM
2
are used to set the charge pump into mode 1x V
DD
, 2x V
DD
, 3x V
DD
or they can be used to
put the PAM8904Q in to a forced low current shutdown mode.
Care must be taken when using the 3x mode with a V
DD
supply of 4V or more as this will force the V
OUT
to exceed its maximum specification. The
table shows the safe operating range of the PAM8904Q.
Timing Chart and Device Operation
When one or both of the CPM pins are pulled high, the device enters normal operation mode, refer to the above table for the mode selection.
Once the PAM8904Q senses a valid signal on the D
IN
pin, the charge pump will start and provide the desired voltage on the V
OUT
pin and the
output drive VO
1
and VO
2
start to function after time t
ON
which is typically between 270µs and 350µs depending on the mode chosen. Once the
input signal on D
IN
is removed, the PAM8904Q senses this and waits typically 42ms to ensure the signal has been removed. If there is no further
valid signal within the time period t
OFF
, the PAM8904Q enters into a low current standby mode.
