MAX8893A Datasheet, PDF (31/50 Pages) Maxim Integrated Products – μPMICs for Multimedia Application Processors in a 3.0mm x 2.5mm WLP

µPMICs for Multimedia Application Processors
in a 3.0mm x 2.5mm WLP
Analog Signal Levels
The on-resistance of the USB switch is very low and
stable as the analog input signals are swept from ground
to VIN (see the Typical Operating Characteristics). These
switches are bidirectional, allowing NO_, NC_, and
COM_ to be configured as either inputs or outputs. The
charge-pump-assisted n-channel architecture allows the
switch to pass analog signals that exceed VIN up to the
overvoltage fault protection threshold. This allows USB
signals that exceed VIN to pass, allowing compliance
with USB requirements for voltage levels.
Overvoltage Fault Protection
The USB switch features overvoltage fault protection
on COM_. Fault protection protects the switch and USB
transceiver from damaging voltage levels. When volt-
ages on COM_ exceed the fault protection threshold
(VFP), COM_, NC_, and NO_ are high impedance.
Enable Input (ENUSB)
The USB switch features a shutdown mode that reduces
the quiescent current supply and places COM_ in high
impedance. Drive ENUSB high to place the USB switch
in shutdown mode. Drive ENUSB low to allow the USB
switch to enter normal operation.
Load Switch
The MAX8893A/MAX8893B/MAX8893C include an ultra-
low RON p-channel MOSFET load switch. The switch
has its own enable input, ENLS. When it is enabled, its
output soft-starts with I²C programmed rising time to
avoid inrush current. See Table 8. The switch input is
from the step-down converter output and can operate
over the 0.8V to 2.4V range. With LS_ADEN bit set to 1,
when the switch is disabled, an internal 100ω resistor is
connected between the load switch output and ground
for quick discharging.
I²C Serial Interface
An I²C-compatible, 2-wire serial interface controls all the
regulator output voltages, load switch timing, individual
enable/disable control, and other parameters. The serial
bus consists of a bidirectional serial-data line (SDA) and
a serial-clock input (SCL). The MAX8893A/MAX8893B/
MAX8893C are slave-only devices, relying upon a
master to generate a clock signal. The master initiates
data transfer to and from the MAX8893A/MAX8893B/
MAX8893C and generates SCL to synchronize the data
transfer (Figure 8).
I²C is an open-drain bus. Both SDA and SCL are bidi-
rectional lines, connected to a positive supply voltage
through a pullup resistor. They both have Schmitt trig-
gers and filter circuits to suppress noise spikes on the
bus to assure proper device operation.
SDA
t_LOW
t_SU,DAT
SCL
t_HD,STA
START CONDITION
t_HIGH
t_R
t_F
t_HD,DAT
Figure 8. 2-Wire Serial Interface Timing Detail
t_SU,STA
t_HD,STA
REPEATED START CONDITION
t_BUF
t_SU,STO
STOP
START
CONDITION CONDITION
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