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MICROELECTRONICS
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
Features
Compliant to USB Specifications Two Independent Switches Input from 3V to 5.5V Min. Continuous Load Current 500mA per port Max. ON-Resistance 140mW Max. Short Circuit Current Limit 1.25A Individual Open-Drain Fault Flag Pins ON-State Supply Current 110A (typ.) OFF-State Supply Current 0.75A (typ.) Thermal Shutdown Undervoltage Lockout (UVLO) Typically 2.4V 1ms Turn-ON (soft-start) and Fast Turn-OFF Active-High or Active-Low Enable Versions
Description
GM2526 is a dual high-side integrated power switch with independent enable and flag functions, designed for selfpowered and bus-powered Universal Serial Bus (USB) applications. GM2526 requires few external components. Each of the two switch channels supply up to 500mA as required by USB downstream devices. Each switch's low on-resistance meets USB voltage drop requirements. Fault current is 750mA (typical). A flag output indicates fault conditions to the local USB controller. The soft-start feature prevents the transient voltage drop on the upstream port that can occur when the switch is enabled in bus-powered applications. Thermal shutdown protection prevents switch failure from high-current loads. Undervoltage lockout (UVLO) hold GM2526 off unless there is a correct input voltage. GM2526 has 3.3V and 5V logic-compatible Enable inputs. GM2526 is available in Active-High and Active-Low versions, and comes in 8-pin DIP and SOIC packages.
Application
USB Power Management USB Host- and Self-Powered Hubs USB Bus-Powered Hubs Hot Plug-In Power Supplies Battery-Charger Circuits
CONNECTION DIAGRAM
8 OUTA ENA/ ENA 1 FLGA 2 LOGIC, CHARGE PUMP 7 IN
ENB/ ENB 4
5 OUTB 6 GND
GM2526 H/ L
www.gammamicro.com
PRELIMINARY
GM2526 V0.1
1
FLGB 3
LOGIC, CHARGE PUMP
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
MARKING INFORMATION & PIN CONFIGURATIONS (TOP VIEW)
SOP-8
IN OUTA GND OUTB
8765
GM2526 AYWW
12 34
ENB/ ENB FLGB
ENA/ ENA FLGA
A= Assembly Location Y= Year WW= Weekly
ORDERING INFORMATION
Ordering Number
GM2526HS8T GM2526HS8R GM2526LS8T GM2526LS8R
Package
SOP - 8 SOP - 8 SOP - 8 SOP - 8
Shipping
100 Units / Tube 2,500 Units / Tape & Reel 100 Units / Tube 2,500 Units / Tape & Reel
* For detail Ordering Number identification, please see last page.
PIN DESCRIPTION
PIN NUMBER PIN SYMBOL EN(A/B) EN(A/B) FLG(A/B) FUNCTION Enable (Input): Logic-compatible enable input. High input > 2.1V typical Low input < 1.9V typical (H active high, L active low). Do not float. Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent, and thermal shutdown, UVLO, OVLO 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.
1/4
2/3
GM2526
6 7
GND IN OUT(A/B)
8/5
2
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
BLOCK DIAGRAM
GM2526
FLGA
OUTA ENA/ ENA Charge Pump DRIVER Current Limit Thermal Shutdown UVLO, OVLO
OSC.
1.2VReference
IN
Charge Pump
Current Limit Gate Control OUTB FLGB
ENB/ ENB
GND
FUNCTIONAL CHARACTERISTICS TEST CIRCUIT
5V 0.1F 10k GM2526 ENA/ ENA FLGA FLGB ENB/ ENB OUTA IN GND OUTB IOUT Ferrite Bead (1 output shown)
CL
RL
GM2526
3
ILOAD (For Current Limit Response)
MICROELECTRONICS
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage Fault Flag Voltage Output Voltage Fault Flag Current Output Current Control Input Storage Temperature Range
SYMBOL
VIN VFLG VOUT IFLG IOUT VEN TS
VALUE
6 6 6 50 Internally limited -0.3 to 12 -65 to +150
UNIT
V V V mA mA V C
Operation Rating
PARAMETER
Supply Voltage Ambient Operating Temperature
SYMBOL
VIN TA
VALUE
3 to 5.5 -40 to 85
UNIT
V C
GM2526
4
MICROELECTRONICS
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
ELECTRICAL CHARACTERISTICS VIN = 5V, TA = 25C (unless otherwise noted)
CHARACTERISTICS
Supply Current All switch on, OUT= open (Note 3) Low-to-high transition Enable Input Threshold High-to-low transition (Note 3) 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 VEN= 0V to 5.5V VIN= 5V , IOUT= 500mA, each switch VIN= 2.7V, IOUT= 500mA, each switch RL= 10W each output RL= 10W each output RL= 10W each output RL= 10W each output each output (output disabled) each output each output (enable into load)= 4.0V ramped load applied to enabled output, VOUT 4.0V TJ increasing TJ decreasing VIN =5V, IL =10mA VIN =3.3V, IL =10mA Error Flag Off Current UVLO Threshold VFLG =5V VIN = increasing VIN =decreasing Note 1: Exceeding the absolute maximum rating may damage the device. Note 2: The device is not guaranteed to function outside its operating rating. Note 3: Off is 0.8V and on is 2.4V for the GM2526-H. Off is 2.4V and on is The enable input has approximately 200mV of hysteresis. 0.8 -1.0 0.5 0.5 1.9 0.01 1 100 140 0.5 1 1 1 0.75 1.6 135 125 10 15 0.01 2.5 2.3 1.0 140 mW 180 20 20 10 1.25 2.2 C 25 W 40 1 V A ms ms s s A A A A A pF 110 2.1 160 2.4 V
TEST CONDITIONS
Switch off, OUT= open (Note 3)
MIN
-
TYP
0.75
MAX
5
UNIT
A
Overtemperature Shutdown Threshold
Error Flag Output Resistance
0.8V for the GM2526-L.
GM2526
5
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
FUNCTIONAL DESCRIPTION
The GM2526-H (active-high) and GM2526-L (active-low) are dual high-side switches. Fault conditions turn off (or inhibit turn-on) of one or more of the output transistors, depending upon the type of fault, activate the opendrain error flag transistors, and sinking current to ground.
Input and Output
IN (input) is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUTx (output) is the source of its respective MOSFET. In a typical application, current flows through the switch from IN to OUT toward the load. If VOUT is greater than VIN when a switch is enabled, current will flow from OUT to IN since the MOSFET is bidirectional when active. The output MOSFET and driver circuitry are also designed to allow the MOSFET source to be externally forced to a higher voltage than the drain (VOUT > VIN) when the output is off. In this situation, the GM2526 avoids undesirable current flow from OUT to IN. If VIN falls below 2.5V, and UVLO disables both switches.
Thermal Shutdown
Thermal shutdown shuts off the affected output MOSFETs and signals all fault flags if the die temperature exceeds 135C. Hysteresis of 10C pre-vents the switch from turning on until the die temperature drops to 125C. Note: over-temperature detection functions only when at least one switch is enabled.
Current Limit Induced Thermal Shutdown
GM2526 raises the output MOSFET on-resistance until series combination of the MOSFET on-resistance and load impedance limit current to 850mA (typ.). Normally the increased power dissipation will activate thermal shutdown, and disabling affected channels of GM2526. If you prefer to avoid this, you can respond to the fault and disable the current limited channel externally before GM2526 reaches shutdown temperature. The time between the flag indicates a current limit fault and thermal shutdown depends on ambient temperature, board layout, and load impedance. But, you will have typically a few hundred milliseconds. If you do not want GM2526 to go into thermal shutdown, the USB controller recognize a fault and disable the appropriate channel within this time. If the fault is not removed or the switch is not disabled within this time, then GM2526 will experience thermal oscillation of about 2Hz. This does not damage GM2526.
Undervoltage Lockout
UVLO prevents the output MOSFET from turning on until VIN exceeds approximately 2.5V. Until turn-on, the FLAG will be low. After the switch turns on, UVLO signals the fault flag and shuts off the output MOSFET if the voltage drops below approximately 2.3V. Undervoltage detect functions only when at least one switch is enabled.
Current Sensing and Limiting
The current-limit threshold is preset internally. The preset level prevents damage to the output MOSFET and external load, but allows a minimum current of 0.5A through each channel's output MOSFET. The current-limit circuit senses a portion of the output MOSFET switch current. The current sense resistor shown in the block diagram is virtual and has no voltage drop. The reaction to an overcurrent condition varies according to the circumstances: (a) If a switch is powered on or enabled into a heavy load or short-circuit, the switch immediately goes into a constant-current mode, and reducing the output voltage. The fault flag goes low until the load is reduced. (b) When a heavy load is applied, a large transient current may flow until the current limit circuitry responds. At which point the device limits current to less than the short-circuit current limit specification. (C) GM2526 currentlimit profile exhibits a small (~500mA) foldback effect. Once past the current-limit threshold, GM2526 operates in constant-current mode (see "short circuit current limit" in the Electrical Characteristics). Note, GM2526 will deliver load current up to the current-limit threshold, typically 1.6A.
GM2526
6
Fault Flag
FLG is an N-channel, open-drain MOSFET output. The faultflag is active (low) for one or more of the following conditions: undervoltage current limit, or thermal shutdown. The flag output MOSFET can sink a 10mA load to 100mV (typically) above ground. You can "wire NOR" multiple FLG pins to a common pull-up resistor.
MICROELECTRONICS
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
APPLICATION INFORMATION Supply Filtering
To control supply transients, place a 0.1F to 1F bypass capacitor from IN to GND right at GM2526. Without this bypass capacitor, an output short can cause ringing from supply lead inductance on the input and damage the internal control circuitry. Input or output transients must never exceed the absolute maximum supply voltage (VIN max = 6V).
3V to 5.5V
0.1F to 1F ENA FLGA FLGB ENB OUTA IN GND OUTB
GM2526
Figure1. Supply Bypassing
Enable Input
EN must been driven logic high or logic low for a clearly defined input. Floating the input will have unpredictable (but certainly undesirable) results. EN must never be allowed to go negative with respect to GND.
Soft Start
The GM2526 has high impedance when off, which gradually shifts to a low impedance as the chip turns on. This reduces the inrush current and voltage drop, which occured when charging a capacitive load, thus meeting the USB voltage drop requirements for bus-powered applications as shown in Figure 3. You can use the soft start circuit shown in Figure 4 to meet USB transient regulation specifications with large load capacitances (CBULK > 10uF). GM2526 provides inrush current limiting for these applications
Transient Overcurrent Filter
When GM2526 is turned on, large capacitance values at the output of GM2526 cause the inrush current to cross GM2526's short circuit current-limit threshold and assert the flag. The duration of this situation depends + on the value of the output capacitance. V
USB Controller OVERCURRENT
10k 10k
GM2526 ENA FLGA FLGB ENB OUTA IN GND OUTB
0.1F
While the capacitors are charging, GM2526 enters into Into constant-current mode. As the capacitance is charged, the current decreases below the short circuit current-limit threshold, and the flag is deasserted. In USB applications, output bulk capacitance must be used to support hot-plug events. When the GM2526 is enabled, the flag may go active for about 1ms due to inrush current exceeding the current-limit setpoint. During hot-plug events, inrush currents may also cause the flag to go active for about 30s. Since these situations are not relevant overcurrent faults, the USB controller must ignore the flag during these events. To prevent needless overcurrent reporting, you can use a 1ms RC filter as shown in Figure 2, or you can program a 1ms debounce routine, which may be programmed into the USB logic controller.
GM2526
7
Figure 2. Transient Filter
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
USB Controller GM2526 VBUS ENA FLGA USB HUB 4.7F GND FLGB ENB OUTA IN GND OUTB 0.1F Cable Bus Powered Hub
Downstream USB Device
CBULK
Capacitive Load
Cable
Figure 3. SOFT START (Single Channel)
USB Controller GM2526 VBUS ENA FLGA USB HUB 4.7F FLGB ENB OUTA IN GND OUTB CBULK GND
Cable
USB Function CBULK
USB Function
USB Peripheral
GM2526
Figure 4. INRUSH CURRENT- LIMIT APPLICATION
8
MICROELECTRONICS
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Power Management GM2526
DUAL USB POWER SWITCH Power Management
SOP-8(SO-8) PACKAGE OUTLINE DIMENSIONS
0.008 +0.0018 -0.0005
8
0.028
+0.022 -0.013 +0.56 -0.33
(0.20
+0.05 -0.01
) (0.71
)
Pad Layout
0.060 1.52
0.236 0.008
R
0.154
+0.003 -0.004
(5.99
+0.21 -0.20
)
0.275 7.0
0.155 4.0
PIN INDENT
(3.91 0.1)
0.024 0.6
0.050 1.270
Inches ( mm )
0.191
+0.004 -0.002 +0.10 -0.05
(4.85
)
0.063 0.005 (1.60 0.13)
0.057 (1.45)
Inches ( mm )
0.0025 0.0015 (0.175 0.075)
0.050 (1.270)
0.016
+0.004 -0.003 +0.10 -0.08
(0.41
)
ORDERING NUMBER
GM 2526 H S8 T
Gamma Micro. Shipping R: Tape & Reel T: Tube
Circuit Type Package S8: SOP-8
Active level H: Active level L: Active level
GM2526
9

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