MAX1946ETA+T Maxim Integrated Products, MAX1946ETA+T Datasheet - Page 9

• Manufacturer Part Number: MAX1946ETA+T
• Description: IC SW USB SNGL W/FB 8-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX1946ETA+T

• Applications: USB, Peripherals
• Current - Supply: 40µA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 1. Functional Diagram
An internal micropower charge pump generates a high-
side supply that drives the gate of an internal 75mΩ
NMOS switch.
SEL sets the active polarity of the logic input of the
MAX1946. Connect ON to the same voltage as SEL to
enable OUT. Connect ON to the opposite voltage as
SEL to disable OUT (see Table 1). The output enters a
high-impedance state when disabled.
The MAX1946 includes a UVLO circuit to prevent erro-
neous switch operation when the input voltage goes
low during startup and brownout conditions. Input volt-
ages less than 2.5V inhibit operation of the device.
FAULT asserts low during a UVLO condition.
The MAX1946 senses the switch output voltage and
selects continuous current limiting for V
than 1V or short-circuit current limiting for V
than 1V. When V
operates in a continuous current-limit mode that limits
output current to 1.1A. When V
device operates in short-circuit current-limit mode,
sourcing 1.2A pulses to the load. When either fault con-
dition persists for 20ms, the output turns off and the
Output Fault Protection and Autoreset
On/Off Control and Undervoltage
OUT
_______________________________________________________________________________________
Single USB Switch with Autoreset and
is greater than 1V, the device
SEL
ON
IN
OUT
Lockout (UVLO)
is less than 1V, the
MAX1946
OUT
OUT
greater
Fault Blanking in Tiny TDFN
less
SHUTDOWN
CHARGE
THERMAL
PUMP
UVLO
20ms TIMERS
FAULT LOGIC
GND
fault flag asserts. The output automatically restarts
20ms after the short or overload is removed.
The MAX1946 detects short-circuit removal by sourcing
25mA from the output and monitoring the output volt-
age. When the voltage at the output exceeds 0.5V for
20ms, the fault flag resets, the output turns back on,
and the 25mA current source turns off.
When the MAX1946 die temperature exceeds +160°C
the switch turns off and FAULT goes low. Thermal shut-
down does not utilize the 20ms fault-blanking timeout
period. When the junction temperature cools by 15°C
the switch turns on again and FAULT returns high.The
switch cycles on and off if the overload condition per-
sists, resulting in a pulsed output that reduces the aver-
age system load.
Table 1. On/Off Control
25kHz
OSC
GND
SEL
V
BIAS
IN
25mA
ILIM
REF
GND
GND
ON
V
V
IN
IN
FAULT
IN
OUT
Thermal Shutdown
OUT BEHAVIOR
OFF
OFF
ON
ON
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