The LM706x0
is in active mode when VEN is above the precision enable threshold and the
internal bias rail is above the UV threshold level. In active mode, the device operates in
one of two modes depending on the load current, input voltage, output voltage, and PFM /
SYNCIN pin configuration:
- Forced pulse width modulation (FPWM)
mode. This mode of operation is configured by tying the PFM / SYNCIN pin to GND or driving
with an external clock source. The device operates in continuous conduction mode (CCM)
with fixed switching frequency regardless of the load current.
- Pulse frequency modulation (PFM) mode.
This mode of operation is configured by tying the PFM / SYNCIN pin to VDDA. The device
operates in discontinuous conduction mode (DCM) if the load current is less than half of
the peak-to-peak inductor current, otherwise the device operates in continuous conduction
mode (CCM). The transition between CCM and DCM is automatic.