lp5522tmx National Semiconductor Corporation, lp5522tmx Datasheet - Page 11

• Manufacturer Part Number: lp5522tmx
• Description: Programmable Led Driver
• Manufacturer: National Semiconductor Corporation

LED OFF time counter can saturate also if Training end command is not given or no new ON time has been started. In this case
saturated OFF time is recorded and chip goes to Standby.
Recommended External Components
INPUT CAPACITOR, C
Although not required for normal operation, a capacitor can
be added to V
layer ceramic capacitor (MLCC) is recommended. MLCCs
with a X7R or X5R temperature characteristic are preferred.
CURRENT SET RESISTOR, R
If other than 5 mA current is required, R
used to adjust the current. For 20 mA current 24 kΩ resistor
List of Recommended External Components
Symbol
C
R
LED
IN
ISET
IN
to reduce line noise. A surface-mount multi-
Symbol Explanation
VDD Bypass Capacitor
Current Set Resistor for 20 mA LED Current
IN
ISET
ISET
resistor can be
11
Value
100
24
User defined
is required. Accuracy of the resistor directly effects to the ac-
curacy of the LED current. 1% or better is recommended.
LED
Forward voltage of LED must be less than minimum input
voltage minus minimum headroom voltage (V
ple with 2.7V input voltage and 20 mA LED current the max-
imum LED forward voltage is 2.7V - 100 mV = 2.6V.
Unit
nF
kΩ
Type
Ceramic, X7R or X5R
1%
20217217
HR
). For exam-
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