Datasheet

MAX1564
Triple 1.2A USB Switch in 4mm x 4mm
Thin QFN
_______________________________________________________________________________________ 7
Detailed Description
Undervoltage Lockout (UVLO) and Input
Voltage Requirements
The MAX1564 includes undervoltage-lockout (UVLO)
circuitry to prevent erroneous switch operation when
the input voltage is low during startup and brownout
conditions. The IC is disabled when the input voltage is
less than 2.5V (typ). FLT_ asserts low during a UVLO
condition.
Current-Limit Fault Protection
The MAX1564 uses two methods to protect the circuit
from overcurrent conditions. During an overcurrent
event, the IC senses the switch output voltage and
selects either continuous current limiting or short-circuit
Pin Description
PIN NAME FUNCTION
1 INA
Input Power Supply for OUTA. Provides power to OUTA. INA, INB, INC, and V
CC
must be connected
together externally. Bypass with a 0.1µF capacitor to GND. Additional capacitors can be used as
required.
2V
CC
Input Power Supply for the MAX1564. Provides power to the IC. INA, INB, INC, and V
CC
must be
connected together externally.
3 INB
Input Power Supply for OUTB. Provides power to OUTB. INA, INB, INC, and V
CC
must be connected
together externally.
4INC
Input Power Supply for OUTC. Provides power to OUTC. INA, INB, INC, and V
CC
must be connected
together externally.
5 SEL
Polarity Control Input. Selects the polarity of ONA, ONB, and ONC. Connect to V
CC
for active-high
ON_ inputs. Connect to GND for active-low ON_ inputs.
6 SETI
Current-Limit Program Input. Connect a resistor from SETI to GND in the 26kΩ to 60kΩ range. I
LIM
=
1.37A x 26.1kΩ / R
SETI
.
7 FLTB
Fault-Indicator Output for Switch B. FLTB is an open-drain output that goes low when INB is below the
UVLO threshold, or when switch B is in current limit for greater than 20ms, or when switch B is in
thermal shutdown.
8 FLTC
Fault Indicator Output for Switch C. FLTC is an open-drain output that goes low when INC is below the
UVLO threshold, or when switch C is in current limit for greater than 20ms, or when switch C is in
thermal shutdown.
9 OUTC Power Output for Switch C. OUTC is high impedance during shutdown.
10 OUTB Power Output for Switch B. OUTB is high impedance during shutdown.
11 GND Ground. Connect ground to the exposed pad directly under the IC.
12 OUTA Power Output for Switch A. OUTA is high impedance during shutdown.
13 FLTA
Fault Indicator Output for Switch A. FLTA is an open-drain output that goes low when INA is below the
UVLO threshold, or when switch A is in current limit for greater than 20ms, or when switch A is in
thermal shutdown.
14 ONC
Control Input for Switch C. ONC is active high when SEL is connected to V
CC
and active low when
SEL is connected to GND.
15 ONB
Control Input for Switch B. ONB is active high when SEL is connected to V
CC
and active low when
SEL is connected to GND.
16 ONA
Control Input for Switch A. ONA is active high when SEL is connected to V
CC
and active low when
SEL is connected to GND.
— EP Exposed Pad. Connect exposed pad to a large ground plane to improve thermal power dissipation.