Datasheet
MAX8819A/MAX8819B/MAX8819C
PMIC with Integrated Chargers and Smart
Power Selector in a 4mm x 4mm TQFN
26 ______________________________________________________________________________________
4) EN4 to turn on the display’s backlight.
5) CEN is asserted by the μP to start a charge cycle.
6) The external supply is removed from DC and V
SYS
falls. The regulators remain enabled because EN123
and EN4 are asserted, but the battery charging cur-
rent drops to zero even though CEN is still asserted.
CHG goes high-impedance.
7) System is turned off by deasserting EN123, EN4,
and CEN. OUT1, OUT2, and OUT3 power down in
the opposite order of power-up. RST1 goes low to
reset the μP.
Step-Up Converter (REG4)
The step-up converter (REG4) operates by regulating
the voltage at FB4 to 0.5V. REG4 operates from the
system voltage (V
SYS
); this voltage can vary from 2.6V to
4.35V (MAX8819A/MAX8819C) or 5.3V (MAX8819B). The
1MHz switching frequency allows for tiny external com-
ponents. The step-up converter control scheme opti-
mizes the efficiency while achieving low EMI and low
input ripple.
If the step-up converter (REG4) is not needed, disable
REG4 by grounding EN4, LX4, PG4, and OVP4. COMP4
can be unconnected.
REG4 WLED Driver Configuration
Figure 1 shows that REG4 is configured as a white light
emitting diodes (WLED) driver, typically used to drive
up to six devices with an output voltage up to 24V. The
full-scale current is set by resistor R1, according to the
following relationship:
I
V
R
where V V no ally
IV mA
FS
FB
FB
FS
==
<=
4
4
1
05
0 5 16 30 9
, . min
./ .Ω
EN4
I
LED
SHUTDOWN
FULL
31/32
30/32
29/32
28/32
27/32
5/32
4/32
3/32
2/32
1/32
FULL
31/32
1 3332313029285432
t
LO
t
HI
t
SHDN
2ms (typ)
> 500ns
0
t
SOFT-START
6/32
t
HI_INIT
> 100μs
SHUTDOWN
STEP
500ns TO 500μs
Figure 8. Dimming Control Timing Diagram
MANUFACTURER SERIES
INDUCTANCE
(µH)
ESR (mΩ)
CURRENT
RATING (mA)
DIMENSIONS (mm)
DE2812C 10 290 580 3.0 x 2.8 x 1.2 = (10.8mm)
3
TOKO
DB3018C 10 240 630 3.2 x 3.2 x 1.8 = (18.4mm)
3
FDK MIP3226 10 160 900 3.2 x 2.6 x 1 = (8.32mm)
3
Table 4. REG4 Recommended Inductors
MANUFACTURER PART NUMBER
CONTINUOUS
CURRENT
(mA)
FORWARD VOLTAGE
(mV)
BREAKDOWN
VOLTAGE
(V)
PACKAGE
CMDSH05-4 500 470 40 SOD-323
Central Semiconductor
CMHSH5-4 500 510 40 SOD-123
NXP PMEG3005EB 500 500 30 SOD-523
ON Semiconductor MBR0530L 500 430 30 SOD-123
Table 5. REG4 Recommended Diodes