LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 29

• Manufacturer Part Number: LED5000PHR
• Description: Current & Power Monitors & Regulators 3A monolithic Conv 850kHz Synch
• Manufacturer: STMicroelectronics

Specifications of LED5000PHR

• Rohs: yes
• Product: Current Regulators
• Supply Voltage - Max: 48 V
• Supply Voltage - Min: 5.5 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: HPSO-8
• Accuracy: +/- 3 %
• Input Voltage Range: 5.5 V to 48 V
• Output Current: 23 uA
• Sensing Method: High or Low Side
• Supply Current: 1.7 mA

LED5000
5.12
For the calculation we can estimate R
during the operation.
T
I
The overall internal losses are:
Equation 41
Equation 42
The junction temperature of device will be:
Equation 43
Where T
ambient. The junction-to-ambient (Rth
HSO8 package and mounted on the evaluation is about 40 °C/W.
Assuming the ambient temperature around 40 °C, the estimated junction temperature is:
Short-circuit protection
In overcurrent protection mode, when the peak current reaches the current limit threshold,
the device disables the power element and it is able to reduce the conduction time down to
the minimum value (approximately 100 nsec typical) to keep the inductor current limited.
This is the pulse-by-pulse current limitation to implement constant current protection feature.
In overcurrent condition, the duty cycle is strongly reduced and, in most applications, this is
enough to limit the switch current to the current threshold.
The inductor current ripple during ON and OFF phases can be written as:
●
Equation 44
●
Q
SW_EQ
has a typical value of 2.4 mA at V
ON phase
OFF phase
P
TOT
A
is approximately 12 ns.
is the ambient temperature and Rth
=
P
TOT
0.3
=
1.5
R
I
DSON_HS
2
L TON
0.7
=
T
+
Doc ID 023951 Rev 1
J
V
------------------------------------------------------------------------------------------------- - T
42
=
T
IN
I
J
OUT
60
–
=
1.5
V
IN
+
T
OUT
DSON_HS
J-A
= 48 V.
1.2W
2
A
+
) thermal resistance of the device assembled in
12
–
Rth
D
DCR
+
J A
V
J-A
10
40
–
= 300 m as a consequence of Tj increase
IN
L
–
L
9
is the thermal resistance junction-to-
+
-------
W
I
P
R
OUT
C
850
Application notes - buck conversion
TOT
DSON HS
110 C
f
10
SW
3
+
42
T
I
SW
ON
+
2.4
V
IN
10
I
–
Q
3
1.2W
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