LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 27

• 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
5.11
The input and output loops are minimized to avoid radiation and high frequency resonance
problems. The feedback pin to the sensing resistor path must be designed as short as
possible to avoid pick-up noise. Another important issue is the ground plane of the board.
Since the package has an exposed pad, it is very important to connect it to an extended
ground plane in order to reduce the thermal resistance junction-to-ambient and increase the
noise immunity during the switching operation.
In addition, to increase the design noise immunity, different signal and power grounds
should be designed in the layout (see
serves the small signal components, the device analog ground pin, the exposed pad and a
small filtering capacitor connected to the VCC pin. The power ground serves the device
ground pin and the input filter. The different grounds are connected underneath the output
capacitor. Neglecting the current ripple contribution, the current flowing through this
component is constant during the switching activity and so this is the cleanest ground point
of the buck application circuit.
Figure 17. Layout example
Thermal considerations
The dissipated power of the device is tied to three different sources:
●
Equation 37
Where D is the duty cycle of the application. Note that the duty cycle is theoretically given by
the ratio between V
Conduction losses due to the R
OUT
(n
LED
P
ON
Doc ID 023951 Rev 1
V
=
LED
R
RDSON_HS
+ 200 mV) and V
DSON
Chapter 5.13: Application circuit
, which are equal to:
I
OUT
2
Application notes - buck conversion
IN
, but in practice it is substantially
D
). The signal ground
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