Allegro A2536EM, A2536EL, A2526EM, A2526EL Datasheet
CONTACT FACTORY
Data Sheet
27447.2*
2526
AND
2536
USB DUAL POWER CONTROL SWITCHES
A2526EM
1
2
3
45
6
7
8
EN
A
FLG
A
FLG
B
EN
B
OUT
A
IN
GND
OUT
B
Dwg. PP-070-2
GATE
CONTROL
GATE
CONTROL
The A2526EL/M and A2536EL/M are integrated high-side dual
power switches, optimized for self-powered and bus-powered Universal Serial Bus (USB) applications. Few external components are
necessary to satisfy USB requirements. The A2526EL/EM ENABLE
inputs are active high; the A2536EL/EM are active low.
All devices are ideally suited for USB applications. Each switch
channel supplies up to 500 mA as required by USB peripheral devices.
In addition, the switch’s low on-resistance permits achieving the USB
voltage-drop requirements. Fault current is limited to typically
750 mA, satisfying the UL 25 VA safety requirements, and a flag
output is available to indicate a fault condition to the local USB
controller. Momentary voltage drops that may occur on the upstream
port when the switch is enabled in bus-powered applications is eliminated by a “soft start” feature.
Additional features include thermal shutdown to prevent catastrophic
switch failure from high-current loads, undervoltage lockout to ensure
that the device remains OFF unless there is a valid input voltage
present, and 3.3 V and 5 V logic-compatible enable inputs.
These switches are provided in 8-pin mini-DIP (suffix ‘M’) and
8-lead SOIC (suffix ‘L’) packages.
Features
■ 2.7 V to 5.8 V Input
■ Up to 500 mA Continuous Load Current per Port
■ 140 mΩ Maximum ON-Resistance
■ 1.25 A Maximum Short-Circuit Current Limit
■ Individual Open-Drain Fault Flag Outputs
■ 125 µA Typical ON-State Supply Current
■ <1 µA Typical OFF-State Supply Current
■ Outputs Can be Forced Higher Than Input (off-state)
■ Thermal Shutdown
■ 2.2 V Typical Undervoltage Lockout
■ 0.6 ms Turn On (soft-start) and Fast Turn Off
■ A2526 (active-high) Improved Replacement for MIC2526-1
■ A2536 (active-low) Improved Replacement for MIC2526-2
Applications
■ USB Hosts and Self-Powered Hubs
■ USB Bus-Powered Hubs
■ Hot Plug-In Power Supplies
■ Battery-Charger Circuits
Note that the A2526EM (DIP) and the
A2526EL (SOIC) are electrically identical and
share a common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
IN
..................... 6.0 V
Output Voltage, V
OUT
.................. 6.0 V
Output Current,
I
OUT
................. Internally Limited
ENABLE Voltage Range,
V
EN
......................... –0.3 V to 10 V
Fault Flag Voltage, V
FLG
.............. 8.0 V
Fault Flag Current, I
FLG
............. 50 mA
Package Power Dissipation,
P
D
................................. See Graph
Operating Temperature Range,
T
A
.......................... -40°C to +85°C
Junction Temperature, T
J
....... +150°C*
Storage Temperature Range,
T
S
........................... -65°C to 150°C
* Fault conditions that produce excessive
junction temperature will activate device
thermal shutdown circuitry. These conditions
can be tolerated but should be avoided.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2526
AND
2536
USB
DUAL POWER CONTROL
SWITCHES
2
FUNCTIONAL BLOCK DIAGRAM
Copyright © 2000, Allegro MicroSystems, Inc.
GATE
CONTROL
GATE
CONTROL
1
2
3
45
6
7
8
EN
A
FLG
A
FLG
B
EN
B
OUT
A
IN
GND
OUT
B
Dwg. PP-070-3
A2536EM
Note that the A2536EM (DIP) and the
A2536EL (SOIC) are electrically identical and
share a common terminal number assignment.
50 75 100 125 150
2.5
0.5
0
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
AMBIENT TEMPERATURE IN °C
2.0
1.5
1.0
25
Dwg. GP-009-2
SUFFIX 'L', R
θJA
= 108°C/W
SUFFIX 'M', R
θJA
= 60°C/W
Dwg. FP-049-1
OUT
B
FLG
B
EN
B
GATE
CONTROL
A2536 ONLY
GND
OUT
A
IN
FLG
A
EN
A
GATE
CONTROL
UVLO
TSD
CHARGE
PUMP
OSC
1.2 V
REF.
CHARGE
PUMP
A2536 ONLY
CURRENT
LIMIT
CURRENT
LIMIT
2526
AND
2536
USB
DUAL POWER CONTROL
SWITCHES
www.allegromicro.com
3
Electrical Characteristics at T
A
= 25°C, VIN = 5 V, each output tested separately (unless otherwise noted).
Limits
Parameter Test Conditions Min Typ Max Units
Operating Voltage Range V
IN
2.7 – 5.8 V
Switch Resistance VIN = 5 V, I
OUT
= 500 mA – 100 140 mΩ
VIN = 3.3 V, IOUT = 500 mA – 100 140 mΩ
Output Leakage Current Each output (output disabled), VIN = 5 V, V
OUT
= 0 – <1.0 10 µA
Maximum Load Current Each output 500 – – mA
Short-Circuit Current Limit Each output (enabled into load), V
OUT
= 4 V 0.5 0.75 1.25 A
Current-Limit Threshold Ramped load applied to enabled output, V
OUT
≤ 4 V – 0.9 – A
ENABLE Input Threshold Low-to-high transition – 2.1 2.4 V
High-to-low transition 0.8 1.9 – V
ENABLE Input Hysteresis – 0.2 – V
ENABLE Input Current VEN = 0 V to 5.5 V – ±0.01 ±1.0 µA
ENABLE Input Cap. – 1.0 – pF
Output Turn-On Delay RL = 10 Ω, CL = 1 µF, 50% V
ENABLE
to 10% V
OUT
–0.5– ms
Output Turn-On Rise Time RL = 10 Ω, CL = 1 µF, 10% V
OUT
to 90% V
OUT
–0.6– ms
Output Turn-Off Delay RL = 10 Ω, CL = 1 µF, 50% V
ENABLE
to 90% V
OUT
–10– µs
Output Turn-Off Fall Time RL = 10 Ω, CL = 1 µF, 90% V
OUT
to 10% V
OUT
–25– µs
Error Flag Output VIN = 5 V, IL = 10 mA – 8.0 – Ω
Resistance
VIN = 3.3 V, IL = 10 mA – 10 – Ω
Error Flag Off Current V
FLG
= 5 V – 0.01 – µA
Supply Current Both switches disabled (see note), OUT = open – 0.2 5.0 µA
Both switches enabled (see note), OUT = open – 125 160 µA
UVLO Threshold Increasing V
IN
–2.35– V
Decreasing V
IN
–2.2– V
Over-Temperature Increasing T
J
– 165 – °C
Shutdown Threshold
Decreasing T
J
– 155 – °C
Note — Disabled is ≤ 0.8 V and enabled is ≥ 2.4 V (active high) for the A2526EL/EM. Disabled is ≥ 0.8VIN and enabled is ≤ 0.8 V
(active low) for the A2536EL/EM.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2526
AND
2536
USB
DUAL POWER CONTROL
SWITCHES
4
FUNCTIONAL DESCRIPTION
Power switch
The power switch is an N-channel MOSFET with a maximum
on-state resistance of 140 mΩ (VIN = 5 V). Configured as a
high-side switch, the power switch prevents current flow in
either direction if disabled. The drain body diode is disconnected from the source when the switch is OFF allowing the
output voltage to exceed the input voltage without causing
current conduction. The power switch supplies a minimum of
500 mA per switch.
Charge pump
An internal charge pump supplies power to the driver circuit
and provides the necessary voltage to pull the gate of the
MOSFET above the source. The charge pump operates from
input voltages as low as 2.7 V. The charge pump is limited to
2.5 µA to establish a controlled turn on time of typically 1 ms.
Driver
The driver controls the gate voltage of the power switch. To
limit large current surges and reduce the associated electromagnetic interference (EMI) produced, the driver incorporates
circuitry that controls the rise times and fall times of the output
voltage. The rise time is typically 1 ms.
ENABLE (EN or EN)
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 µA maximum when a logic high is present
on EN (A2526) or a logic low is present (A2536). The proper
logic level restores bias to the drive and control circuits and
turns the power ON. The enable input is a compatible with both
TTL and CMOS logic levels.
Fault Flag (FLG)
This open drain output is asserted (active low) when an
overcurrent or over temperature condition is encountered. The
output will remain asserted until the overcurrent or over
temperature condition is removed.
Current sense
A sense FET monitors the current supplied to the load. The
sense FET measures current more efficiently than conventional
resistance methods. 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
drives the power FET into its saturation region, which switches
the output into a constant-current mode and holds the current
constant while varying the voltage on the load.
Thermal sense
An internal thermal-sense circuit shuts off the power switch
when the junction temperature rises to approximately 165°C.
Hysteresis is built into the thermal sense circuit. After the
device has cooled approximately 10°C, the switch turns back
ON. The switch continues to cycle off and on until the fault is
removed.
Undervoltage lockout
A voltage-sense circuit monitors the input voltage. When the
input voltage is approximately 2 V, a control signal turns OFF
the power switch.
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