MAX8893A Datasheet, PDF (29/50 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
Low-Dropout Linear Regulators
The MAX8893A/MAX8893B/MAX8893C contain five low-
dropout, low-quiescent-current, high-accuracy, linear
regulators (LDOs). The LDO output voltages are set
through the I²C serial interface. The LDOs include
an internal reference, error amplifier, p-channel pass
transistor, and internal programmable voltage-divider.
Each error amplifier compares the reference voltage to
a feedback voltage and amplifies the difference. If the
feedback voltage is lower than the reference voltage,
the pass-transistor gate is pulled lower, allowing more
current to pass to the output and increasing the output
voltage. If the feedback voltage is too high, the pass-
transistor gate is pulled up, allowing less current to pass
to the output.
Default Regulator Output Voltages
The default regulator output voltages are set as shown
in Table 1. All regulator output voltages (BUCK, LDO1,
LDO2, LDO3, LDO4, and LDO5) are programmable
through the I²C serial interface.
Enable Inputs (ENBUCK, ENLDO_,
ENLS, ENUSB)
The MAX8893A/MAX8893B/MAX8893C have individ-
ual enable inputs for each regulator, load switch, and
USB switch. The individual enable inputs (ENBUCK,
ENLDO1, ENLDO2, ENLDO3, ENLDO45, ENLS) are
logically ORed with the corresponding I²C serial inter-
face control bit. ENUSB input is logically NANDed with
the EUSB bit. See Tables 2, 3, and 4 for enable logic
truth tables. The enable inputs (ENBUCK, ENLDO_, and
ENLS) are internally pulled to AGND by an 800kI (typ)
pulldown resistor. ENUSB is internally pulled up to BATT
by an 800kω (typ) pullup resistor.
Any valid enable input signal turns on the MAX8893A/
MAX8893B/MAX8893C. After the IC is up, the I²C inter-
face is active and the IC can be reprogrammed through
the I²C interface. To turn off the IC, both I²C bus and
enable inputs must be low.
All I²C register values return to the default value when no
enable input signals are present.
Table 1. Default Regulator Output Voltages
PART
MAX8893A
BUCK (V)
1.0
LDO1 (V)
2.8
LDO2 (V)
2.6
MAX8893B
1.0
2.6
2.6
MAX8893C
1.0
1.8
2.6
LDO3 (V)
3.3
3.3
3.3
LDO4 (V)
3.0
3.3
3.3
LDO5 (V)
1.0
2.8
3.0
Table 2. Truth Table for BUCK, LDO1 to LDO3, and Load Switch
ENABLE INPUT (ENBUCK, ENLDO1,
ENLDO2, ENLDO3, OR ENLS)
CORRESPONDING I²C ON/OFF
CONTROL BIT
CORRESPONDING REGULATOR OR
SWITCH
0
0
Off
0
1
On
1
0
On
1
1
On
Table 3. Truth Table for LDO4 and LDO5
ENABLE INPUT
(ENLDO45)
0
0
0
0
1
1
ELDO4 BIT
0
0
1
1
0
1
ELDO5 BIT
0
1
0
1
0
1
LDO4
Off
Off
On
On
On
On
LDO5
Off
On
Off
On
On
On
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