LTC3577_15 Datasheet, PDF (15/54 Pages) Linear Technology – Highly Integrated 6-Channel Portable PMIC

LTC3577/LTC3577-1
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified
LED Driver Efficiency 6 LEDs
90
85
80
75
70
65
60
3V
3.6V
55
4.2V
4.8V
5.5V
50
0 2 4 6 8 10 12 14 16 18 20
I_LED (mA)
3577 G40
LED Driver Efficiency 4 LEDs
90
85
80
75
70
65
60
3V
3.6V
55
4.2V
4.8V
5.5V
50
0 2 4 6 8 10 12 14 16 18 20
I_LED (mA)
3577 G41
DAC Code vs LED Current
70
60dB = 20mA
60
0dB = 20μA
R_{LED_FS} = 20k
50
40
30
20
10
LED Boost Start-Up Transient
I_LED
10mA/DIV
V_BOOST
20V/DIV
I_L
200mA/DIV
0
0 10 20 30 40 50 60 70
DAC CODE
3577 G43
2ms/DIV
3577 G44
LED PWM
vs Constant Current Efficiency
90
80
70
60
MAX PWM
CONSTANT
50
CURRENT
40
30
20
10
0
1.E-06
1.E-05 1.E-04 1.E-03 1.E-02 1.E-01
LED CURRENT (A)
3577 G46
Battery Discharge
vs Temperature
200
175
V_BUS = 5V
150
125
V_BUS = 0V
100
75
50 _{VBAT = 4.1V}
V_NTC < V_{TOO_HOT}
25 _{5x MODE}
I_VOUT = 0mA
0
50 60 70 80
90 100 110 120
TEMPERATURE (°C)
3577 G47
LED Boost Current Limit
vs Temperature
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
–40 –20 0 20 40 60 80
TEMPERATURE (°C)
100 120
3577 G42
LED Boost Maximum Duty Cycle
vs Temperature
96.6
96.5
96.4
96.3
96.2
96.1
96.0
95.9
95.8
95.7
–50
3V
3.6V
4.2V
5.5V
–25 0 25 50 75
TEMPERATURE (°C)
100 125
3577 G45
Too Hot BAT Discharge
200
180
V_NTC < V_{TOO_HOT}
V_BUS = 0V
160
140
120
100
80
60
40
20
0
3.8
3.9
4.0
4.1
V_BAT (V)
4.2
3577 G48
3577fa
15