B2526-1M Bay Linear, Inc., B2526-1M Datasheet - Page 3

• Manufacturer Part Number: B2526-1M
• Description: 3.3V dual USB high side power switch
• Manufacturer: Bay Linear, Inc.

DETAILED DESCRIPITION
Power Switch
The power switch is an N-Channel MOSFET with a maximum on-state resistance of 140m (V
minimum of 500mA per switch.
Enable
The Logic enable disables the power switch and the bias for the charge pump, driver and other circuitry to reduce the supply current to
less than 5 A when a logic high is present on the EN pin for B2526-2 or a logic low is present on EN for B2526-1. The enable input
is compatible with both TTL and CMOS logic levels.
Driver
The driver controls the gate voltage of the power switch. To Limit large current surges the driver incorporates circuitry that controls
the rise and fall times of the output voltage.
Charge Pump
An internal charge pump supplies power to the driver circuit and provides the necessary voltages to pull the gate of the MOSFET
above the source.
Fault Flag FLG (A)/(B)
FLG is a N-Channel, open drain MOSFET output. The fault flag is active (low) for one or more of the following conditions: under-
voltage (while 2V
typically 100mV above ground. Multiple FLG pins may be “wired NORed” to a common pull-up resistor.
Thermal Shutdown
An internal thermal sense circuit shuts off the power switch when the junction temperature rises to approximately 150 C. Hysteresis is
built into the thermal sense circuit.
Current Sense
A sense FET monitors the current supplied to the load. When an overload or short circuit is encountered, the current sense circuitry
sends a control signal to the driver. The driver in turn reduces the gate voltage and sends the power FET into its saturation region,
which switches the output into a constant current mode. The 2526 current-limit profile exhibits a small foldback effect of
approximately 500mA. Once this current-limit threshold is exceeded the device enters constant current mode. The constant current is
specified as the short circuit current limit in the “Electrical Characteristics" table. It is important to note that the 2526 will deliver load
current up to the current-limit Threshold which is typically 1.6A (2.2Amax)."
Under-Voltage Lockout (UVLO)
UVLO prevents the output MOSFET form turning on until V
the switch turns on, if the voltage drops below approximately 2.3V, UVLO shuts off the output MOSFET and signals fault flag.
Under-voltage detection functions only when at least one switch is enabled.
PIN DESCRIPTION
Bay Linear, Inc
Pin No.
1 & 4
2 & 3
8 & 5
6
7
Pin Name
EN (A)/(B)
FLAG (A)/(B)
GND
V
V
IN
OUT
2418Armstrong St., Livermore CA USA 94550
V
IN
(A)/(B)
2.7V), current limit or thermal shutdown. The flag output MOSFET is capable of sinking a 10mA load to
Pin Function
Enable (Input): Logic-compatible enables input. High input > 2.1V typical.
Low input < 1.9V typical (B2526-1 active high, B2526 -2 active low).
Fault Flag (Output): Active-low, open-drain output. Indicates over current,
UVLO and thermal shutdown.
Ground: Supply return.
Supply Input: Output MOSFET drain. Also supplies IC’s internal circuitry. Connect to positive
supply.
Switch Output: Output MOSFET source. Typically connect to switched side of load.
IN
Tel: [phone], Fax: [phone]
exceeds 2.5V. In the under-voltage state, the FLG will be low. After
IN
= 5V). the power switch supplies a
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B2526