Bay Linear
Inspire the Linear Power
Dual USB High Side Power Switch
B2526
Description
The Bay Linear B2526 is a dual high-side power switch
recommended for self-powered and bus-powdered universal
serial for bus (USB) application conforming to USB
requirements. USB voltage drop requirements, fault current
limited to 750mA, flag output to indicate fault connections to
the local USB controller are features that meet USB
requirements.
Additional features such as thermal shutdown to prevent
catastrophic switch failure from excessively high current
loads, under voltage lockout (UVLO) to ensure that the device
remains off unless there is a valid input voltage present, and
3.3V or 5V logic compatible enable inputs. Two versions of
the enable pin, Active High or Active Low are available in 8-
pin Dip and 8-pin SOIC packages.
Features
•
•
•
•
•
•
•
•
•
3.0V to 5.5V Input
110µA Typical on-State Supply Current
µ
1µA Typical off-State Supply Current
µ
500mA Minimum Continuous Load Current
1.25A Maximum Current Limit
2.4V Typical Under Voltage Lockout (UVLO)
Open-Drain Fault Flag Pin
Thermal Shutdown
Available with Active-High or Active-Low Enable
Applications
•
•
•
•
•
USB Host and self-Powered Hubs
USB Power Management
Battery-Charger Circuits
Hot Plug-In Power Supplies
Bus-Powered Hubs
Package Information
Ordering Information
Package
SO-8
8 DIP
Active High
B2526-1M
B2526-1P
Enable
Active Low
B2526-2M
B2526-2P
8
Out (A)
SO-8
EN (A)
FLAG (A)
FLAG (B)
EN (B)
1
2
3
4
8
V
OUT
(A)
V
IN
GND
V
OUT
(B)
EN (A)
FLG (A)
1
2
Logic
Charge
Pump
7
IN
Logic
Charge
Pump
5
Out (B)
BAY
7
B2526
6
5
FLB (B)
EN (B)
3
4
Top View
6
GND
Bay Linear, Inc
2418Armstrong St., Livermore CA USA 94550
Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B2526
ABSOLUTE MAXIMUM RATINGS
Supply Voltage…………………………………...6V
Fault Flag Voltage………………………………..6V
Fault Flag Current……………………………..50mA
Output Voltage……………………………………6V
Output Current……………………Internally Limited
Enable Input……………………………-0.3V to 12V
Storage Temperature………………-65°C to +150°C
Lead Temperature (Soldering 5 sec.)………….260°C
OPERATING RATING
Supply Voltage ..................................................+3V to +5.5V
Ambient Operating Temperature.................... -40°C to +85°C
Thermal Resistance
SOIC .................................................................. 120°C/W
DIP..................................................................... 130°C/W
ELECTRICAL CHARACTERISTICS
at V
IN
= 5V, Ta=25°C, unless otherwise specified. (Note 1)
Units
Parameters
Supply Current
Enable Input Threshold
Enable Input Current
Enable Input Capacitance
Switch Resistance
Output Turn-On Delay
Output Turn-On Rise Time
Output Turn-Off Delay
Output Turn-Off Fall Time
Output Leakage Current
Continuous Load Current
Short Circuit Current Limit
Current Limit Threshold
Over temperature Shutdown
Threshold
Error Flag Output Resistance
Error Flag Off Current
UVLO Threshold
Conditions
(Note1) Switch Off, OUT = Open
(Note1) Switch On, OUT = Open
Low to High Transition
High to Low Transition, (Note1)
V
EN
= 0V to 5.5V
V
IN
= 5V
I
OUT
= 500mA, Each Switch
V
IN
= 3.3V I
OUT
= 500mA, Each Switch
R
L
= 10Ω
R
L
= 10Ω
R
L
= 10Ω
R
L
= 10Ω
Each output (output disabled)
Each output
Each output (enable into load), V
OUT
= 4.0V
Ramped Load applied to enable output, V
OUT
≤
4.0V
T
J
Increasing
T
J
Decreasing
V
IN
= 5.0V, I
L
= 10mA
V
IN
= 3.3V, I
L
= 10mA
V
FLAG
= 5V
V
IN
= Increasing
V
IN
= Decreasing
Typ
Min
0.75
110
2.1
1.9
± 0.01
1
100
140
0.5
1
1
1
0.5
0.5
Max
5
160
µA
V
µA
pF
mΩ
ms
ms
µs
µs
µA
A
A
A
°C
Ω
1
µA
V
2.4
1
140
180
0.8
-1
20
20
10
0.75
1.6
135
125
10
15
0.01
2.5
2.3
1.25
2.2
General Note: Devices are ESD protected, however, handling precautions recommended.
Note 1: Off is
≤
0.8V and is
≥
2.4V for the B2526-1. Off is
≥
2.4V and on is
≤
0.8V for the B2526-2. The Enable input has approximately 200mV of hysteresis.
TEST CIRCUIT
(Only 1 Output Shown)
5V
10K
0.1µF
µ
B2526
EN (A)
FLG (A)
FLG (B)
EN (B)
Out (A)
IN
GND
Out (B)
Ferrite
Bead
I
OUT
R
L
C
L
+
(for Current
Limit
Response)
I
LOAD
Functional Characteristics Test Circuit
Bay Linear, Inc
2418Armstrong St., Livermore CA USA 94550
Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B2526
PIN DESCRIPTION
Pin No.
1&4
2&3
6
7
8&5
Pin Name
EN (A)/(B)
FLAG (A)/(B)
GND
V
IN
V
OUT
(A)/(B)
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.
DETAILED DESCRIPITION
Power Switch
The power switch is an N-Channel MOSFET with a maximum on-state resistance of 140mΩ (V
IN
= 5V). the power switch supplies a
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 5µA 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
<
V
IN
<
2.7V), current limit or thermal shutdown. The flag output MOSFET is capable of sinking a 10mA load to
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
IN
exceeds 2.5V. In the under-voltage state, the FLG will be low. After
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.
Bay Linear, Inc
2418Armstrong St., Livermore CA USA 94550
Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B2526
Bay Linear, Inc
2418Armstrong St., Livermore CA USA 94550
Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B2526
B4300
B2526
Two-Port Self Powered Hub (Using B2526 & B4300)
Bay Linear, Inc
2418Armstrong St., Livermore CA USA 94550
Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
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