This is the block which compensates the output voltage regulation by VF characteristic fluctuation of the secondary side
output diode according to the load current.
The current which flows into the built-in N-Channel MOSFET is monitored, and the current according to the compensation
quantity and the time constant which are determined by the external resistor and the capacitor of the COMP terminal is
drawn from the REF terminal. The output voltage rises and is rectified when feedback current which flows into the external
resistor of the REF terminal decreases and the REF terminal voltage falls.
8. TSD
This is the temperature protection block.
If the chip’s junction temperature, Tj, inside the IC is above 175°C (Typ), it will be detected and this block will be in the
protection state and the SW terminal becomes Hi-Z.
If Tj falls to below 150°C (Typ), it will return automatically through soft start.
9. OCP
This is the over-current protection block.
If the peak current during the ON-Time of the built-in N-Channel MOSFET reaches 2.75A (Typ), it will be detected and the
N-Channel MOSFET is turned OFF.
If output voltage goes to 50% or less of the setting voltage, the peak detection current of OCP will be controlled by 1.6A
(Typ).The min off time is 1.5μs (Typ) when the OCP is operated under the condition where the output voltage is 50% of
the set voltage.
Absolute Maximum Ratings
(Ta = 25 °C)
Parameter
VIN Input Power Voltage
SW Terminal Voltage
SDX/EN Terminal Voltage
FB Terminal Voltage
REF Terminal Voltage
COMP Terminal Voltage
Power Dissipation
Storage Temperature Range
Maximum Junction Temperature
(Note 1)
Symbol
V
IN
V
SW
V
SDX/EN
V
FB
V
REF
V
COMP
Pd
Tstg
Tjmax
Rating
BD7F200HFN-LB
45
60
V
IN
V
IN
-0.3V to lower value of V
IN
+0.3V or 45V
7
7
1.75
(Note 2)
BD7F200EFJ-LB
Unit
V
V
V
V
V
V
3.75
-55 to +150
150
(Note 3)
W
°C
°C
(Note 1)
Not to exceed Power Dissipation (Pd).
(Note 2)
Reduced by 14.0mW/°C for temperatures above 25°C (when mounted on a one-layer glass-epoxy board with 70mm × 70mm × 1.6mm dimension,
65% copper foil density)
(Note 3)
Reduced by 30.0mW/°C for temperatures above 25°C (when mounted on four-layer glass-epoxy board with 70mm × 70mm × 1.6mm dimension.)
Caution:
Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated
over the absolute maximum ratings.
Recommended Operating Conditions
Parameter
VIN Input Power Voltage
SW Terminal Voltage
Junction Temperature
(Note4)
Symbol
V
IN
V
SW
Tj
Limit
Min
8
-
-40
Typ
24
-
-
Max
40
50
+125
Unit
V
V
°C
(Note 4)
Life time is derated at junction temperature greater than 125°C.
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