LNK3202/3204-6
BYPASS
(BP/M)
DRAIN
(D)
REGULATOR
5.0 V
FAULT
PRESENT
IFBSD
IFB
BYPASS PIN
CAPACITOR
DETECT
5.2 V
AUTO-RESTART
COUNTER
BYPASS PIN
UNDERVOLTAGE
+
-
OVL
CURRENT LIMIT
CLOCK
RESET
COMPARATOR
5.0 V
4.5 V
+
-
V
ILIMIT
JITTER
CLOCK
THERMAL
SHUTDOWN
DCMAX
OSCILLATOR
S
Q
Q
FEEDBACK
(FB)
R
2.0 V -VT
LEADING
EDGE
BLANKING
OVP
DETECT
SOURCE
(S)
PI-7879-100416
Figure 3. Functional Block Diagram.
Pin Functional Description
SOURCE (S) Pin:
This pin is the power MOSFET source connection. It is also the
ground reference for the BYPASS and FEEDBACK pins.
DRAIN (D) Pin:
Power MOSFET drain connection. Provides internal operating current
for both start-up and steady-state operation.
BYPASS (BP/M) Pin:
This pin has multiple functions:
• It is the connection point for an external bypass capacitor for the
internally generated 5.0 V supply.
P Package (DIP-8C)
G Package (SMD-8C)
D Package (SO-8C)
• It is a mode selector for the current limit value, depending on the
value of the capacitance added. Use of a 0.1 μF capacitor results
in the standard current limit value. Use of a 1 μF capacitor results
in the current limit being reduced, allowing design with lowest cost
surface mount buck chokes.
• It provides a shutdown function. When the current into the BYPASS
pin exceeds IBPSD for a time equal to 2 to 3 cycles of the internal
oscilator (fOSC), the device enters auto-restart. This can be used to
provide an output overvoltage protection function with external
circuitry.
8
7
6
5
1
2
BP/M
S
S
1
2
8
7
BP/M
FB
S
S
S
S
FB
6
5
S
S
4
D
4
D
FEEDBACK (FB) Pin:
During normal operation, switching of the power MOSFET is con-
trolled by the FEEDBACK pin. MOSFET switching is terminated when
a current greater than IFB (49 μA) is delivered into this pin. Line
overvoltage protection is detected when a current greater than IFBSD
(670 μA) is delivered into this pin for 2 consecutive switching cycles.
PI-7842-022416
Figure 4. Pin Configuration.
2
Rev. F 01/17
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