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A2525EM
Datasheet
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Allegro A2535EM, A2535EL, A2525EM, A2525EL Datasheet

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Data Sheet
27447.1*
2525
AND
2535
USB POWER CONTROL SWITCHES
A2525EM
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
■ 100 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
■ A2525 (active-high) Improved Replacement for MIC2525-1
■ A2535 (active-low) Improved Replacement for MIC2525-2
Applications
■ USB Hosts and Self-Powered Hubs
■ USB Bus-Powered Hubs
■ Hot Plug-In Power Supplies
■ Battery-Charger Circuits
Note that the A2525EM (DIP) and the A2525EL (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.
1
2
3
45
6
7
8
EN
FLG
GND
NC
OUT
IN
NC
NC
Dwg. PP-070A
GATE
CONTROL
NC NC
NC
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2525
AND
2535
USB POWER CONTROL SWITCHES
2
FUNCTIONAL BLOCK DIAGRAM
Copyright © 2000, Allegro MicroSystems, Inc.
A2535EM
Note that the A2535EM (DIP) and the A2535EL (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
1
2
3
45
6
7
8
EN
FLG
GND
NC
OUT
IN
NC
NC
Dwg. PP-070-1A
GATE
CONTROL
NC NC
NC
CURRENT
LIMIT
GND
OUT
1.2 V REF.
Dwg. FP-049
IN
FLG
EN
GATE
CONTROL
UVLO
TSD
CHARGE
PUMP
OSC
A2535 ONLY
2525
AND
2535
USB
POWER CONTROL
SWITCHES
www.allegromicro.com
3
Electrical Characteristics at T
A
= 25°C, VIN = 5 V.
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 Output disabled, VIN = 5 V, V
OUT
= 0 – <1.0 10 µA
Maximum Load Current 500 – – mA
Short-Circuit Current Limit 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 Switch disabled (see note), OUT = open – 0.2 5.0 µA
Switch enabled (see note), OUT = open – 100 160 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 A2525EL/EM. Disabled is ≥ 0.8VIN and enabled is ≤ 0.8 V
(active low) for the A2535EL/EM.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2525
AND
2535
USB 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 (A2525) or a logic low is present (A2535). 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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