Datasheet

MAX8819A/MAX8819B/MAX8819C
PMIC with Integrated Chargers and Smart
Power Selector in a 4mm x 4mm TQFN
______________________________________________________________________________________ 13
Typical Operating Characteristics (continued)
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
MAXIMUM LED CURRENT
vs. TEMPERATURE
TEMPERATURE (°C)
LED CURRENT (mA)
MAX8819A toc35
-40 -15 10 35 60 85
24.5
24.6
24.7
24.8
24.9
25.0
25.1
25.2
25.3
25.4
25.5
MINIMUM LED CURRENT
vs. TEMPERATURE
TEMPERATURE (°C)
LED CURRENT (mA)
MAX8819A toc36
-40 -15 10 35 60 85
0.730
0.735
0.740
0.745
0.750
Pin Description
PIN NAME FUNCTION
1 COMP4 External Compensation Capacitor for REG4
2 FB4 REG4 Feedback Input
3 OVP4 Overvoltage Protection Node for REG4
4 PG4 REG4 Power Ground
5 LX4 Inductor Switching Node for REG4
6 GND Analog Ground
7 EN4 REG4 Enable Input and Dimming Control Digital Input
8 RST1
Active-Low, Open-Drain Reset Output. RST1 pulls low to indicate that FB1 is below its regulation
threshold. RST1 goes high 200ms after FB1 reaches its regulation threshold. RST1 is high-impedance
when EN123 is low, and DC is unconnected.
9 BAT
Positive Battery Terminal Connection. Connect BAT to the positive terminal of a single-cell Li+/Li-Poly
battery. Bypass BAT to GND with a 4.7μF ceramic capacitor.
10 SYS
System Supply Output. Bypass SYS to GND with a 10μF ceramic capacitor. When a valid voltage is
present at DC and DLIM[1:2] ≠ 11, V
SYS
is limited to 4.35V (MAX8819A/MAX8819C) or 5.3V
(MAX8819B). When the system load (I
SYS
) exceeds the input current limit, V
SYS
drops 75mV
(V
BSREG
) below V
BAT
, allowing both the external power source and the battery to service SYS. SYS is
connected to BAT through an internal 70mΩ system load switch when a valid source is not present at
DC.
11 DC
DC Power Input. DC is capable of delivering 1A to SYS. DC supports both AC adapters and USB
inputs. As shown in Table 1, the DC current limit is controlled by DLIM1 and DLIM2.
12 CEN Battery Charger Enable Input
13 FB1
Feedback Input for REG1. Connect FB1 to the center of a resistor voltage-divider from the REG1
output capacitors to GND to set the output voltage from 1V to V
SYS
.