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Part: A2526ELTR
Category:
Microprocessors
-> System Components
Description: Usb Power Control Switches
Company: Allegro Micro Systems, Inc.
Datasheet: Download A2526ELTR datasheet File size : 735 kB
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Datasheet text preview:
2526 AND 2536
A2526EL
GATE GATE CONTROL CONTROL
USB DUAL POWER CONTROL SWITCHES
The A2526EL and A2536EL 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 ENABLE inputs are active high; the A2536EL 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 an 8-lead SOIC package on tape and reel ("TR" suffix is added to part number) for use with automatic handling equipment.
Data Sheet 27447.2A
ENA FLGA FLGB ENB
1 2 3 4
8 7 6 5
OUTA IN GND OUTB
Dwg. PP-070-6
ABSOLUTE MAXIMUM RATINGS Supply Voltage, VIN ............ 6.0 V Output Voltage, VOUT ......... 6.0 V Output Current, IOUT ........ Internally Limited ENABLE Voltage Range, VEN ....... 0.3 V to 10 V Fault Flag Voltage, VFLG ..... 8.0 V Fault Flag Current, IFLG .... 50 mA Package Power Dissipation, PD ......... See Graph Operating Temperature Range, TA .. -40°C to +85°C Junction Temperature, TJ ....... +150°C* Storage Temperature Range, TS ... -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.
Features
s s s s s s s s s s s s s s s s s 2.7 V to 5.8 V Input Up to 500 mA Continuous Load Current per Port 140 m 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 A2526EL (active-high) Improved Replacement for MIC2526-1 A2536EL (active-low) Improved Replacement for MIC2526-2 USB Hosts and Self-Powered Hubs USB Bus-Powered Hubs Hot Plug-In Power Supplies Battery-Charger Circuits
Applications
2526 AND 2536 USB DUAL POWER CONTROL SWITCHES
FUNCTIONAL BLOCK DIAGRAM
FLGA
A2536 ONLY
OUTA
CHARGE PUMP
GATE CONTROL
ENA
CURRENT LIMIT
OSC
TSD
UVLO
1.2 V REF.
IN
A2536 ONLY ENB
CHARGE PUMP
GATE CONTROL
CURRENT LIMIT
OUTB FLGB GND
Dwg. FP-049-1
A2536EL
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
2.0
1.5
GATE GATE CONTROL CONTROL
ENA FLGA FLGB ENB
1 2 3 4
8 7 6 5
OUTA IN GND OUTB
1.0
0.5
RJA = 108°C/W
Dwg. PP-070-7
Always order by complete part number, e.g., A2526ELTR , where "TR" indicates tape and reel.
0 25
50
75 100 TEMPERATURE IN °C
125
150
Dwg. GP-009-3
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 2000, 2001 Allegro MicroSystems, Inc.
2526 AND 2536 USB DUAL POWER CONTROL SWITCHES
Electrical Characteristics at TA = 25°C, VIN = 5 V, each output tested separately (unless otherwise noted).
Limits Parameter Operating Voltage Range Switch Resistance Test Conditions VIN VIN = 5 V, IOUT = 500 mA VIN = 3.3 V, IOUT = 500 mA Output Leakage Current Maximum Load Current Short-Circuit Current Limit Current-Limit Threshold ENABLE Input Threshold Each output (output disabled), VIN = 5 V, VOUT = 0 Each output Each output (enabled into load), VOUT = 4 V Ramped load applied to enabled output, VOUT 4 V Low-to-high transition High-to-low transition ENABLE Input Hysteresis ENABLE Input Current ENABLE Input Cap. Output Turn-On Delay Output Turn-On Rise Time Output Turn-Off Delay Output Turn-Off Fall Time Error Flag Output Resistance Error Flag Off Current Supply Current RL = 10 , CL = 1 µF, 50% VENABLE to 10% VOUT RL = 10 , CL = 1 µF, 10% VOUT to 90% VOUT RL = 10 , CL = 1 µF, 50% VENABLE to 90% VOUT RL = 10 , CL = 1 µF, 90% VOUT to 10% VOUT VIN = 5 V, IL = 10 mA VIN = 3.3 V, IL = 10 mA V FLG = 5 V Both switches disabled (see note), OUT = open Both switches enabled (see note), OUT = open UVLO Threshold I n c r e a s i n g VI N Decreasing VIN Over-Temperature Shutdown Threshold Increasing TJ D e c r e a s i n g TJ VEN = 0 V to 5.5 V Min 2.7 -- -- -- 500 0.5 -- -- 0.8 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Typ -- 100 100 <1.0 -- 0.75 0.9 2.1 1.9 0.2 ±0 . 0 1 1.0 0.5 0.6 10 25 8.0 10 0.01 0.2 125 2.35 2.2 165 155 Max 5.8 140 140 10 -- 1.25 -- 2.4 -- -- ± 1.0 -- -- -- -- -- -- -- -- 5.0 160 -- -- -- -- Units V m m µA mA A A V V V µA pF ms ms µs µs µA µA µA V V °C °C
Note -- Disabled is 0.8 V and enabled is 2.4 V (active high) for the A2526EL. Disabled is 0.8VIN and enabled is 0.8 V (active low) for the A2536EL.
www.allegromicro.com
3
2526 AND 2536 USB DUAL POWER CONTROL SWITCHES
FUNCTIONAL DESCRIPTION
Power switch The power switch is an N-channel MOSFET with a maximum on-state resistance of 140 m (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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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2526 AND 2536 USB DUAL POWER CONTROL SWITCHES
NO-LOAD SWITCHING PERFORMANCE
VOUT 1 V/o
200 s/o
VOUT 1 V/o
50 s/o
VENABLE
VENABLE
VOUT 1 V/o
50 s/o
VENABLE
www.allegromicro.com
5
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