Datasheet

MAX16955

36V, 1MHz Step-Down Controller

with Low Operating Current

Maxim Integrated

Pin Description (continued)

PIN NAME FUNCTION

9 OUT

Output Sense and Negative Current-Sense Input. When using the internal preset 5V feedback divider

(FB = BIAS), the controller uses OUT to sense the output voltage. Connect OUT to the negative

terminal of the current-sense element.

10 PGOOD

Open-Drain Power-Good Output. A logic-high voltage on PGOOD indicates that the output voltage is in

regulation. PGOOD is pulled low when the output voltage is out of regulation. Connect a 10k pullup

resistor from PGOOD to the digital interface voltage.

11 PGND

Power Ground. Connect the input and output filter capacitors’ negative terminals to PGND. Connect

PGND externally to SGND at a single point, typically at the output capacitor return terminal.

12 DL

Low-Side Gate-Driver Output. DL swings from V

BIAS

to PGND. If a resistor is needed between DL and the

gate of the MOSFET, proper resistance value could be provided based on application circuit review result.

13 BIAS

Internal 5V Linear Regulator Output. BIAS provides power for bias and gate drive. Connect a 1μF to

10μF ceramic capacitor from BIAS to PGND. Connect BIAS and SUP to a 5V rail, if available.

14 LX

External Inductor Connection. Connect LX to the switched side of the inductor. LX serves as the lower

supply rail for the DH high-side gate driver.

15 DH

High-Side Gate-Driver Output. DH swings from LX to BST. If a resistor is needed between DH and the gate

of the MOSFET, proper resistance value could be provided based on application circuit review result.

16 BST

Boost Flying Capacitor Connection. Connect a ceramic capacitor between BST and LX. See the Boost-

Flying Capacitor Selection section for details.

— EP

Exposed Pad. Internally connected to ground. Connect EP to a large contiguous copper plane at SGND

potential to improve thermal dissipation. Do not use as the main ground connection.