IMP2525 - Daily Silver Imp

IMP2525
POWER MANAGEMENT
USB High-Side Power Switch
– Single switch
– 0.14Ω "ON" resistance at 3V
– MIC2525 pin compatible
The IMP2525 high-side power switch IC is designed for self-powered
and bus-powered Universal Serial Bus (USB) power supply and power
management applications. The IMP2525 conforms to USB standards
with a low output switch ON-resistance (RON) and minimal voltage drop
across the switch. The fault current is limited to 750mA typically, and
a flag output conveys fault conditions to the local USB controller.
The IMP2525 provides a “Soft-Start” function that ramps up the ONcurrent to eliminate any excessive voltage drop on the input side that
could occur due to charging a capacitive load in bus-powered applications. Self-monitoring features include thermal shutdown to prevent
catastrophic switch failure from high-current loads and undervoltage
lockout (UVLO) that insures that the device remains off unless there is a
valid supply voltage present. The Enable input logic can be interfaced
with both 3.3V and 5V logic. Both active-HIGH and active-LOW enable
logic versions are available. The IMP2525 devices are available in 8-pin
DIP and 8-pin SO packages.
Key Features
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
Meets or exceeds USB Rev. 1.1 specification
Low MOSFET RON (0.14Ω at 3V)
2.7V to 5.5V input operation
Current limiting
Soft-start turn-on (1ms) prevents turn-on glitches
500mA continuous load current
MOSFET short-circuit current limit (1.25A max)
Low supply current
– 110µA ON state current, 1µA OFF state current
Active-LOW or Active-HIGH Enable input
3.3V or 5V logic compatibility
Fault Flag indicates three fault conditions:
– Undervoltage
– Current limit
– Thermal shutdown
Open-drain Fault Flag output
2.4V Undervoltage Lockout (UVLO)
Pin compatible with the Micrel MIC2525
IMP offers a complete family of USB power management products. For
dual-switch applications see the IMP2526 data sheet and for quad-switch
application, see the IMP2524. The single-switch IMP2525A features a
50% lower switch resistance, 0.07Ω.
◆ USB power management
◆ USB hosts and self-powered hubs
◆ Battery-charger circuits and power supplies
Block Diagrams
IN
EN
Applications
7
1
8
1.2V
Reference
Power
Switch
Gate
Control
UVLO
Thermal
Shutdown
Oscillator
NC/OUT
6
Current
Limit
OUT
2
Charge
Pump
3
FLG
GND
IMP2525
2525_01.eps
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1
IMP2525
Pin Configuration
SO/DIP
8
EN
1
FLG
2
GND
NC
8
IMP2525
OUT
7
IN
3
6
NC/OUT
4
5
NC
*
EN
FLG
1
2
Logic,
Charge
Pump
OUT
6
7
IN
3
*Connect pins 6 and 8 for MIC2525 compatibility
GND
2525_02.eps
2525_03.eps
Pin Descriptions
Pin Number
Name
1
EN
2
FLG
Fault flag output. This open-drain output goes into an active-LOW state in response to
undervoltage, current limit or thermal shutdown conditions.
Ground. Power supply return for the internal circuitry of the IC.
3
GND
4, 5
NC
6
NC/OUT
7
IN
8
OUT
Function
Enable input. This pin is the MOSFET switch driver logic input. Both active-HIGH
(-1 suffix) and active-LOW (-2 suffix) logic devices are available.
No connection. These pins have no internal connections to the device.
No connection. This pin has no internal connection to the device. Connect pins 6 and 8 to
maintain pin-compatibility with the MIC2525.
Positive power supply voltage input. This is the switching MOSFET drain connection
as well as the positive supply for the IC.
MOSFET source. The output pin supplies power to the load.
Ordering Information
2
Part Number
Enable Logic
Temperature Range
Pins-Package
IMP2525-1BM
Active HIGH
– 40°C to +85°C
8-SO
IMP2525-2BM
Active LOW
– 40°C to +85°C
8-SO
IMP2525-1BN
Active HIGH
– 40°C to +85°C
8-DIP
IMP2525-2BN
Active LOW
– 40°C to +85°C
8-DIP
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Daily Silver IMP
IMP2525
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V
Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +6.0V
Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA
Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +6.0V
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Enable Input . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to 12V
Storage Temperature . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 5 sec.) . . . . . . . 260°C
Package Thermal Resistance
SO (θJA ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120°C/W
DIP(θJA ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130°C/W
Note: All voltages are referenced to GND.
These are stress ratings only and functional operation is not
implied. Exposure to absolute maximum ratings for prolonged
time periods may affect device reliability.
Electrical Characteristics
Unless otherwise noted, VIN = 5V and TA = 25°C.
Parameter
Symbol Conditions
Supply Voltage Range
VIN
Operating Temperature Range
TA
Min
TA = – 40°C to +85°C
Typ
Max
Units
2.7
5.5
V
– 40
85
°C
Supply Current
Switch OFF
IIN OFF
Switch OFF, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2525-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2525-2
0.75
5
µA
Supply Current
Switch ON
IIN ON
Switch ON, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2525-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2525-2
110
160
µA
Enable Input Threshold
VENH
LOW to HIGH (“0” to “1”) Enable Voltage, Note 1, 2
2.1
2.4
V
VENL
HIGH to LOW (“1” to “0”) Enable Voltage, Note 1, 2
0.8
1.9
VEN = 0V to 5.5V
–1
±0.01
1
µA
Enable Input Current
IEN
Enable Input Capacitance
CEN
Switch ON Resistance
RON
1
pF
VIN = 5V, IOUT = 500mA
0.1
0.14
VIN = 3.3V, IOUT = 500mA
0.14
0.18
Ω
Output Turn-On Delay
TDON
RL = 10Ω
0.25
ms
Output Turn-On Rise Time
TRON
RL = 10Ω
1
ms
Output Turn-Off Delay
TDOFF
RL = 10Ω, Note 2
1
20
µs
Output Turn-Off Fall Time
TFOFF
RL = 10Ω, Note 2
1
20
µs
Output Leakage Current
IOFF
10
µA
Short-circuit Current Limit
ISC
0.75
1.25
A
0.50
Overtemperature Shutdown
TJ increasing
135
Threshold
TJ decreasing
125
Error Flag Output Resistance
RFLAG
°C
VIN = 5V, IL = 10mA
10
25
VIN = 3.3V, IL = 10mA
15
40
1
Error Flag Output Current
IFLAG
VFLAG = 5V
0.01
UVLO Threshold
VUVLO
VIN Increasing
2.5
VIN Decreasing
2.3
Ω
µA
V
Notes 1. Switch OFF is VEN ≤ 0.8V and Switch ON is VEN ≥ 2.4V for the IMP2525-1. Switch OFF is VEN ≥ 2.4V and Switch ON is VEN ≤ 0.8V
for the IMP2525-2. The Enable input has approximately 200mV of hysteresis.
2. Over operating temperature range, –40°C ≤ TA ≤ 85°C.
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IMP2525
Detailed Descriptions
The IMP2525 is a high-side N-channel MOSFET switch that interfaces with a USB controller by means of a Switch-Enable input
and a Fault-Flag output. The Enable input turns ON the power
MOSFET with either a logic “1” for the IMP2525-1 or logic “0” for
the IMP2525-2. Any one of three fault conditions will activate the
open-drain Fault-Flag Output to alert the controller that the
power MOSFET has been turned OFF.
Input and Output
The IN (input) pin is the power supply connection to the logic circuitry and the “High-Side” of the switch (the Drain of the power
MOSFET). The OUT (output) pin is the “Low-Side” of the switch
(the Source of the power MOSFET). In a typical circuit, current
flows through the switch from IN to OUT toward the load.
The switch is referred to as a “High-Side” switch since it drives
the positive (or high) side of the load. The output MOSFET source
can be forced to a higher voltage than the drain (VOUT > VIN) when
the output is OFF with little leakage current. If, however, VIN
drops below 2.3V, reverse current may flow out the IN pin regardless of the enable state.
When the power switch is ON, current can flow in either
direction.
Fault Flag - FLG Pin
The Fault Flag pin, FLG, connects to an N-channel, open-drain
MOSFET and goes LOW (“0”) for an occurrence of one or more of
three conditions: undervoltage, current limit, or thermal shutdown. The FLG output MOSFET is capable of sinking a 10mA
load to typically 100mV above ground. Table 1 gives the states of
the FLG and OUT pins when a fault condition is detected.
Thermal Shutdown
Thermal shutdown is active when the output switch is enabled
(turned ON). Thermal shutdown shuts off the output MOSFET
and sets the Fault Flag if the on-chip temperature sensor exceeds
135°C. The switch is held OFF until the die temperature drops to
125°C or below. This 10°C of hysteresis will result in ON-OFF
short-circuit cycling if the short-circuit condition is not removed
or the bus-controller does turn off the switch with the Enable
input. Over temperature detection is active only if the chip is
enabled.
Undervoltage Lockout
The Undervoltage lockout (UVLO) prevents the output
MOSFET from being put into the ON state until the positive supply voltage, VIN, exceeds 2.5V. When the output switch is in the
ON state and the positive supply voltage drops below 2.3V, the
UVLO circuitry will assert the Fault Flag, FLG, and shut OFF the
output MOSFET. The FLG output will only assert an active LOW
state when the MOSFET switch is in the ON state. Undervoltage
detection is active only if the chip is enabled.
Current Limiting
Current limiting is achieved by sensing the voltage drop from
Drain-to-Source of the power MOSFET. When the internal threshold is exceeded the power MOSFET is turned OFF.
Table 1. Fault Flag Conditions - Switch Enabled
Condition
4
Cause
FLG pin “0” Until
Thermal Shutdown
TJ > 135°C
TJ ≤ 125°C
Turns OFF
Undervoltage Lockout (UVLO)
VIN < 2.3V
VIN > 2.5V
Turns OFF
Current Limiting
IO > 0.5A (step load)
IO > 0.63A (ramped load)
Enable off or
Thermal Shutdown
Stays ON
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Switch State (FLG = “0”)
Daily Silver IMP
IMP2525
Application Information
Supply Filtering
Enable Input
IMP strongly recommends the use of a 0.1µF to 1µF bypass capacitor to control transients on the power supply pin. This capacitor,
connected from IN to GND, should be in close proximity to the
IMP2525 for maximum transient suppression. The lack of suitable
bypassing can result in ringing on the IN input when transients
occur. This ringing, due to supply lead inductance, could damage
IMP2525 control circuitry if the 8V maximum input rating is
exceeded.
As with any logic input, the enable pin, EN, must be driven to a
definitive logic state at all times. Floating the input can result in
spurious operation. Do not drive EN below GND.
4.0V to 5.5V
IMP2525
7
IN
3
GND
0.1µF to 1µF
Fault Flag Output
Soft Start
The IMP2525 provides a “Soft-Start” function that ramps up the
ON-current to eliminate any excessive voltage drop that could
occur due to charging a capacitive load in bus-powered applications. The "Soft-Start" results from a switch ON resistance, RON,
that is ramped down from a high impedance to 0.14Ω in milliseconds. This RON ramping reduces the inrush current and related
transients occur when charging capacitive loads; a requirement
for meeting the USB voltage drop standards for bus-powered
applications (see Figure 2). In circuits with large load capacitances,
CBULK, exceeding 10µF, the soft-start circuit shown in Figure 3 can
be used to limit the inrush start-up current to USB transient specifications. The current limiting feature of the IMP2525 provides
this high-load, soft-start operation.
2525_04.eps
Figure 1. Supply Bypassing
USB
Controller
IMP2525-xBM
1
VBUS
2
3
USB
Host
4.7µF
EN
OUT
FLG
IN
GND
OUT
4 NC
8
7
6
NC 5
Capacitive
Load
0.1µF
CBULK
GND
Cable
Bus Powered Hub
Cable
Downstream USB Device
2525_06.eps
Figure 2. Soft-Start Application
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IMP2525
Application Information
USB
Controller
IMP2525-2
1
VBUS
2 FLG
3
USB Hub
8
OUT
EN
7
IN
GND
USB
Function
6
OUT
NC 5
4 NC
4.7µF
CBULK
GND
Cable
USB Peripheral
2525_07.eps
Figure 3. Inrush Current-Limit Application
Transient Overcurrent Filter
V+
If a heavy capacitive load is suddenly connected to the output, the
switch current-limiting function may cause the fault-flag to go
low for 10µs to 200µs as the switch, in a constant current mode,
charges the capacitance. If this transient over-current fault reporting is not wanted, a simple 1ms RC low-pass filter in series with
the fault flag circuit will prevent this momentary flag (Figure 4).
10k
USB Controller
10k
IMP2525
2
OVERCURRENT
FLG
0.1µF
2525_05.eps
Figure 4. Transient Filter
VCC
5.0V
10k
Upstream
VBUS
100mA max
VBUS
IN
OUT
VIN
ON/OFF
OVERCURRENT
D+
LDO
3.3V
USB Controller
GND
GND
100k
1
2
EN
Ferrite
Beads
OUT
8
7
FLG
IN
IMP2525-2
6
OUT
D–
GND
1µF
D+
150µF
D–
+
USB
Port
GND
3
1µF
VBUS
GND
0.1µF
2525_08.eps
Data
Data
Figure 5. Single-Port Self-Powered Hub Application
6
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Daily Silver IMP
IMP2525
Package Dimensions
Plastic DIP (8-Pin)
Inches
D1
Millimeters
Max
Min
Max
Plastic DIP (8-Pin)*
Min
E
D
E1
A A2
L A1
0°–15°
e
C
b2
eA
eB
b
Plastic DIP (8-Pin)a.eps
SO (8-Pin)
0°– 8°
L
––––
5.33
–––––
0.38
–––––
0.195
2.92
4.95
0.014
0.022
0.36
0.56
b2
0.045
0.070
1.14
1.78
b3
0.030
0.045
0.80
1.14
D
0.355
0.400
9.02
10.16
D1
0.005
–––––
0.13
–––––
E
0.300
0.325
7.62
8.26
6.10
A
–––––
0.210
A1
0.015
A2
0.115
b
E1
0.240
0.280
e
0.100
–––––
2.54
7.11
eA
0.300
–––––
7.62
eB
–––––
0.430
eC
–––––
0.060
L
0.115
0.150
–––––
10.92
2.92
3.81
SO (8-Pin)**
E
H
C
D
A
e
B
A1
SO (8-Pin).eps
A
0.053
0.069
1.35
1.75
A1
0.004
0.010
0.10
0.25
B
0.013
0.020
0.33
0.51
C
0.007
0.010
0.19
0.25
e
0.050
1.27
E
0.150
0.157
3.80
4.00
H
0.228
0.244
5.80
6.20
L
0.016
0.050
0.40
1.27
D
0.189
0.197
4.80
5.00
* JEDEC Drawing MS-001BA
** JEDEC Drawing MS-012AA
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IMP2525
Daily Silver IMP Microelectronics Co.,Ltd
7 keda Road , Hi-Tech Park,
NingBo,Zhejiang, P.R.C.
Post Code : 315040
Tel:(086)-574-87906358
Fax:(086)-574-87908866
e-mail:[email protected]
Website:www.ds-imp.com.cn
The IMP logo is a registered trademark of Daily Silver IMP.
All other company and product names are trademarks of their respective owners.
2005 Daily Silver IMP
Revision : A
Issue Date: 08/08/05
Type: Product