Datasheet

MAX16936
36V, 220kHz to 2.2MHz Step-Down Converter
with 28µA Quiescent Current
10Maxim Integrated
can be approximated as:
OUT OUT ON_H
SUP
V (I R )
V
0.98
+×
=
Note: The equation above does not take into account
the efficiency and switching frequency, but is a good
first-order approximation. Use the R
ON_H
number from
the max column in the Electrical Characteristics table.
Linear Regulator Output (BIAS)
The device includes a 5V linear regulator (BIAS) that
provides power to the internal circuit blocks. Connect
a 1FF ceramic capacitor from BIAS to AGND. When the
output voltage is set between 3V and 5.5V, the internal
linear regulator only provides power until the output is in
regulation. The internal linear regulator turns off once the
output is in regulation and allows OUT to provide power
to the device. The internal regulator turns back on once
the external load on the output of the device is higher
than 100mA. In addition, the linear regulator turns on any-
time the output voltage is outside the 3V to 5.5V range.
Power-Good Output (PGOOD)
The device features an open-drain power-good output,
PGOOD. PGOOD asserts when V
OUT
rises above 95%
of its regulation voltage. PGOOD deasserts when V
OUT
drops below 92% of its regulation voltage. Connect
PGOOD to BIAS with a 10kI resistor.
Synchronization Input (FSYNC)
FSYNC is a logic-level input useful for operating mode
selection and frequency control. Connecting FSYNC to
BIAS or to an external clock enables fixed-frequency
Figure 1. Internal Block Diagram
FBSW
OUT COMP PGOOD EN
FB
SOFT
START
SLOPE
COMP
FBOK
EAMP
HSD
LSD
AON
LOGIC
CS
REF
HVLDO
SWITCH
OVER
PWM
SUP BIAS
BST
SUPSW
LX
PGND
SYNCOUT
BIAS
FSYNC FOSC AGND
OSC
MAX16936