Datasheet

to 2.4V, the internal voltage reference. Pull V
SS_SHDN
below 0.25V to disable the controller.
Undervoltage lockout shuts down the controller when
V
CC
is less than 6.6V. The regulators for V+ and the ref-
erence remain on during shutdown.
Current-Sense Comparator
The current-sense (CS) comparator and its associated
logic limit the peak current through the MOSFET.
Current is sensed at CS as a voltage across a sense
resistor between the source of the MOSFET and GND.
To reduce switching noise, connect CS to the external
MOSFET source through a 100Ω resistor or an RC low-
_______________________________________________________________________________________ 9
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
NDRV
V
OUT
C
OUT
C
DD
C
CC
V
DD
R
SENSE
R
1
R
2
100Ω
M1
V
IN
N
T
N
P
N
S
C
IN
V
CC
CS
GND
FB
V+
MAX5019
MAX5020
C
SS
SS_SHDN
Figure 3. Nonisolated Flyback Converter
NDRV
V
OUT
C
OUT
C
DD
C
CC
V
DD
R
SENSE
100Ω
M1
V
IN
N
T
N
P
N
S
C
IN
FB
V
CC
CS
GND
V+
MAX5019
MAX5020
R
1
R
2
C
SS
SS_SHDN
Figure 4. Isolated Flyback Converter