MAX8893A Datasheet, PDF (48/50 Pages) Maxim Integrated Products – μPMICs for Multimedia Application Processors in a 3.0mm x 2.5mm WLP

FPMIC for Multimedia Application Processor
in 2.5mm x 3.0mm WLP
Inductor Selection
The recommended inductor for the step-down converter
is from 1.0FH and 4.7FH. Low inductance values are
physically smaller, but require faster switching, resulting
in some efficiency loss. The inductor’s DC current rating
needs to be only 100mA greater than the application’s
maximum load current because the step-down converter
features zero current overshoot during startup and load
transients.
For output voltages above 2.0V, when light load efficien-
cy is important, the minimum recommended inductor is
2.2FH. For optimum voltage-positioning load transients,
choose an inductor with DC series resistance in the
50mω to 150mω range. To achieve higher efficiency at
heavy loads (above 200mA) or minimum load regulation
(but some transient overshoot), the inductor resistance
should be kept below 100mω. For light -oad applications
up to 200mA, much higher resistance is acceptable with
very little impact on performance. See Table 17 for some
suggested inductors.
Capacitors for LDOs
For LDOs, the required output capacitance is depen-
dent on the load currents. With rated maximum load
currents, 2.2FF (typ) capacitors are recommended for
LDO1, LDO2, LDO3, and LDO5 and a 1.0FF capacitor is
recommended for LDO4. For loads less than 150mA, it
is sufficient to use 1.0FF capacitors for stable operation
over the full temperature range for LDO1, LDO2, LDO3,
and LDO5. Reduce output noise and improve load tran-
sient response, stability, and power-supply rejection by
using larger output capacitors.
USB High-Speed Switch
USB Switching
The USB high-speed switch is fully compliant with the
USB 2.0 specification. The low on-resistance and low
on-capacitance of these switches make it ideal for high-
performance switching applications. It is ideal for routing
USB data lines (see Figure 14) and for applications that
require switching between multiple USB hosts (see Figure
15). The USB switch also features overvoltage fault pro-
tection to guard systems against shorts to the USB VBUS
voltage that is required for all USB applications.
ASIC I
D+
HI-SPEED
USB
TRANSCEIVER ^D-
ASIC II
D+
HI-SPEED
USB
TRANSCEIVER ^D-
MAX8893A
MAX8893B
V_BUS
MAX8893C
NC1
COM1
NO1
D+
NC2
COM2
NO2
D-
GND
USB
CONNECTOR
Figure 14. USB Data Routing/Typical Application Circuit
MAX8893A
MAX8893B
MAX8893C
NC1
D+ COM1
NO1
HI-SPEED
USB
TRANSCEIVER
NC2
D- COM2
NO2
D+
USB
D-
HOST I
D+
USB
D-
HOST II
Figure 15. Switching Between Multiple USB Hosts
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