MAX8821 MAXIM [Maxim Integrated Products], MAX8821 Datasheet - Page 9

• Manufacturer Part Number: MAX8821
• Description: White LED Charge Pump with Mono Class D Audio Amp and Dual LDO
• Manufacturer: MAXIM [Maxim Integrated Products]

I
V
LED6
I
NEG
LED
V
V
I
I
IN
IN
IN
IN
(V
IN1
LED STARTUP WAVEFORMS
= V
WAVEFORMS (V
1.5x MODE OPERATING
IN2
White LED Charge Pump with Mono Class D
(V
= V
ALL LEDs ON, I
400ns/div
1ms/div
IN
IN3
= 4V)
30
25
20
15
10
5
0
= V
IN
_______________________________________________________________________________________
-40
= 3V)
DD
LED
-20
= 25.6mA
MAX8821 toc12
= 3.6V, V
MAX8821 toc09
LED CURRENT vs. AMBIENT
0
TEMPERATURE (°C)
TEMPERATURE
CURRENT DERATING ENABLED
AC-COUPLED
50mV/div
AC-COUPLED
100mV/div
50mA/div
0A
20mA/div
0V
2V/div
200mA/div
0A
20mA/div
0A
0A
20
AGND
40
= V
I
I
LED6
LED6
60
V
V
I
I
PGND1
IN
IN
IN
IN
LED LINE TRANSIENT WITH MODE CHANGE
Typical Operating Characteristics (continued)
80
LED SHUTDOWN WAVEFORMS
(V
= V
100
IN
PGND2
= 3.8V TO 3.4V TO 3.8V)
ALL LEDs AT 25.6mA SETTING
(V
1ms/div
1ms/div
IN
= 0V, circuit of Figure 2, T
Audio Amp and Dual LDO
= 4V)
V
I
NEG
LED
V
I
IN
IN
MAX8821 toc10
MAX8821 toc13
WAVEFORMS (V
3.8V
3.4V
200mA/div
0A
20mA/div
AC-COUPLED
50mV/div
20mA/div
1x MODE OPERATING
0A
50mA/div
0A
0A
ALL LEDs ON, I
400ns/div
A
= +25°C, unless otherwise noted.)
I
I
I
LED6
LED6
LED5
V
I
IN
IN
LED LINE TRANSIENT WITH MODE CHANGE
IN
= 4V)
LED
= 25.6mA
(V
MAX8821 toc08
IN
= 4.2V TO 3.8V TO 4.2V)
LED RAMP-UP
ALL LEDs AT 25.6mA SETTING
AC-COUPLED
100mV/div
200mA/div
0A
20mA/div
0A
2V/div
0V
400ms/div
1ms/div
MAX8821 toc11
MAX8821 toc14
4.2V
3.8V
20mA/div
10mA/div
200mA/div
0A
0A
0A
10mA/div
0A
9