CAT4237TD-GT3 ON Semiconductor, CAT4237TD-GT3 Datasheet - Page 11

• Manufacturer Part Number: CAT4237TD-GT3
• Description: IC LED DRVR WHT BCKLGHT TSOT23-5
• Manufacturer: ON Semiconductor
• Type: Backlight, White LEDr

Specifications of CAT4237TD-GT3

• Constant Current: Yes
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 800kHz ~ 1.3MHz
• Voltage - Supply: 2.8 V ~ 5.5 V
• Voltage - Output: 30V
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-5, TSOT-5, TSOP-5
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 40mA
• Internal Switch(s): Yes
• Efficiency: 87%
• Number Of Digits: 8
• Low Level Output Current: 1 mA
• High Level Output Current: 40 mA
• Operating Supply Voltage: 2.8 V to 5.5 V
• Maximum Supply Current: 1.5 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: CAT4237TD-GT3TR

Board Layout
The traces that carry the high−frequency switching current
have to be carefully layout on the board in order to minimize
EMI, ripple and noise in general. The thicker lines on
Figure 28 show the switching current path. All these traces
have to be short and wide enough to minimize the parasitic
inductance and resistance. The loop shown on Figure 28
corresponds to the current path when the CAT4237 internal
switch is closed. On Figure 29 is shown the current loop,
The CAT4237 is a high−frequency switching regulator.
Figure 28. Closed−switch Current Loop
Closed
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when the CAT4237 switch is open. Both loop areas should
be as small as possible.
V
separately to the top LED anode. A ground plane under the
CAT4237 allows for direct connection of the capacitors to
ground. The resistor R
GND pin of the CAT4237 and not shared with the switching
current loops and any other components.
IN
Capacitor C
pin and GND. The capacitor C
Figure 29. Open−switch Current Loop
1
has to be placed as close as possible to the
1
must be connected directly to the
Open
2
has to be connected