MAX797H Maxim, MAX797H Datasheet - Page 7

• Manufacturer Part Number: MAX797H
• Description: High-Voltage / Step-Down Controller with Synchronous Rectifier for CPU Power
• Manufacturer: Maxim

Similarly, at 150kHz, the minimum duty factor is
0.425µs / 6.67µs = 0.064. This means that duty factor is
not an issue except at the maximum input voltage and
minimum output voltage. For example, if V
the lowest V
Figure 1. Powering V+ and VL from a Regulated +5V supply
OUT
High-Voltage, Step-Down Controller with
that does not require less than the
_______________________________________________________________________________________
Synchronous Rectifier for CPU Power
REGULATED
SHDN
SS
REF
SYNC
GND
SUPPLY
SKIP
V+
MAX797H
+5V
IN
VL
FB
is 40V,
PGND
CSH
BST
CSL
DH
LX
DL
minimum duty factor is 40V x 0.064 = 2.56V. If V
V
the output voltage, but may extend the period and
switch at 75kHz instead of 150kHz. It may also alter-
nate between these two frequencies.
IN
is less than this value, the IC will properly regulate
+4V TO +40V
POWER INPUT
OUTPUT
+3.3V
OUT
7
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