Datasheet

MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
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Pin Description (continued)
PIN
MAX8543
MAX8544
NAME FUNCTION
13 16 LX Inductor Connection
14 17 DH
High-Side MOSFET Gate-Driver Output. Connect DH to the gate of the high-side
external MOSFETs. DH is pulled low in shutdown.
15 18 BST
Boost Capacitor Connection. Connect a 0.1µF or larger ceramic capacitor from BST to
LX. BST provides power for the high-side MOSFET gate drive.
16 19 FSYNC
Frequency Set and Synchronization. Connect a resistor from FSYNC to GND to set the
switching frequency or drive with a clock signal to synchronize between 160kHz and
1.2MHz. See the Switching Frequency and Synchronization section.
— 1 ILIM2
Analog Programmable Current-Limit Input for Low-Side MOSFET (V
LX
- V
PGND
).
Connect a resistor from ILIM2 to ground to set the overcurrent threshold. See the
Setting the Current Limits section.
— 10 MODE
Current-Limit Operating-Mode Selection. Connect MODE to VL for latch-off current limit
or connect to GND for automatic-recovery current limit with the MAX8544. The MAX8543
always uses automatic-recovery current limit.
—11POK
Power-OK. POK is an open-drain output that is high impedance when the output is
above 91% of its nominal regulation voltage. POK is pulled low when the output is out
of regulation and when the part is in shutdown. To use POK as a logic-level signal,
connect a pullup resistor from POK to the logic supply.
— 20 SYNCO
Synchronization Output. Provides a clock output that is 180° out of phase with the rising
edge of DH for out-of-phase synchronization of another MAX8544.