The LM62440-Q1 features
selectable operating modes through the MODE/SYNC input pin. The LM62440-Q1 can operate in
one of three selectable modes:
- Auto mode: Pulse frequency modulation (PFM) operation is
enabled during light load and diode emulation prevents reverse current
through the inductor. See Section 9.4.3.2 for more details.
- FPWM mode: In FPWM mode, diode emulation is disabled,
allowing current to flow backwards through the inductor. This allows
operation at full frequency even without load current. See Section 9.4.3.3 for more details.
- SYNC mode: The LM62440-Q1 clock
locks to an external signal applied to the MODE/SYNC pin. As long as output
voltage can be regulated at full frequency and is not limited by minimum off
time or minimum on time, clock frequency is matched to the frequency of the
signal applied to the MODE/SYNC pin. While the LM62440-Q1 is in
SYNC mode, the device operates as though in FPWM mode: diode emulation is
disabled allowing the frequency applied to the MODE/SYNC pin to be matched
without a load.
In addition, the MODE/SYNC pin can be used to
activate or deactivate the spread spectrum feature of the LM6243540-Q1. The MODE/SYNC
pin can be configured in two ways: level dependent MODE/SYNC control (see Section 9.3.2.1) or pulse dependent MODE/SYNC pin control (see Section 9.3.2.2).