A1PROS IMP2525-1BM

POWER
MANAGEMENT
USB Power Switch
IMP252 4/27
Quad USB High-Side Power Switch with Fault Detection
IMP2525
USB High-Side Power Switch
IMP2525A
Low-Resistance, USB High-Side Power Switch
IMP2526
Dual USB High-Side Power Switch
408-432-9100/www.impweb.com
U S B Po w e r S w i t c h P r o d u c t G u i d e
Product Selection Guide
Part Number
Type
Package
Switch "ON"
Resistance
Enable
Logic
Undervoltage
Lockout
Current
Limit
Thermal
Shutdown
Fault Flag
IMP2524-1BWM
Quad
16-pin, SO
0.14Ω
HIGH
IMP2524-2BWM
Quad
16-pin, SO
0.14Ω
LOW
IMP2524-1BN
Quad
16-pin, DIP
0.14Ω
HIGH
IMP2524-2BN
Quad
16-pin, DIP
0.14Ω
LOW
IMP2525A-1BM
Single
8-pin, SO
0.070Ω
HIGH
IMP2525A-2BM
Single
8-pin, SO
0.070Ω
LOW
IMP2525A-1BN
Single
8-pin, DIP
0.070Ω
HIGH
IMP2525A-2BN
Single
8-pin, DIP
0.070Ω
LOW
IMP2525-1BM
Single
8-pin, SO
0.14Ω
HIGH
IMP2525-2BM
Single
8-pin, SO
0.14Ω
LOW
IMP2525-1BN
Single
8-pin, DIP
0.14Ω
HIGH
IMP2525-2BN
Single
8-pin, DIP
0.14Ω
LOW
IMP2526-1BM
Dual
8-pin, SO
0.14Ω
HIGH
IMP2526-2BM
Dual
8-pin, SO
0.14Ω
LOW
IMP2526-1BN
Dual
8-pin, DIP
0.14Ω
HIGH
IMP2526-2BN
Dual
8-pin, DIP
0.14Ω
LOW
IMP2527-1BWM
Quad
16-pin, SO
0.30Ω
HIGH
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•
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•
IMP2527-2BWM
Quad
16-pin, SO
0.30Ω
LOW
IMP2527-1BN
Quad
16-pin, DIP
0.30Ω
HIGH
IMP2527-2BN
Quad
16-pin, DIP
0.30Ω
LOW
USBSEL01
All devices are pin-compatible with the MIC2525/2526 devices. Compared to the Micrel MIC2525, the enhanced IMP2525A has a 50% lower "ON"
resistance.
Product Cross Reference Guide
Micrel Part Number
MIC2524-1BWM
MIC2524-2BWM
MIC2524-1BN
MIC2524-2BN
MIC2525A-1BM
MIC2525A-2BM
MIC2525A-1BN
MIC2525A-2BN
MIC2525-1BM
MIC2525-2BM
MIC2525-1BN
MIC2525-2BN
MIC2526-1BM
MIC2526-2BM
MIC2526-1BN
MIC2526-2BN
MIC2527-1BWM
MIC2527-2BWM
MIC2527-1BN
MIC2527-2BN
IMP Part Number
IMP2524-1BWM
IMP2524-2BWM
IMP2524-1BN
IMP2524-2BN
IMP2525A-1BM
IMP2525A-2BM
IMP2525A-1BN
IMP2525A-2BN
IMP2525-1BM
IMP2525-2BM
IMP2525-1BN
IMP2525-2BN
IMP2526-1BM
IMP2526-2BM
IMP2526-1BN
IMP2526-2BN
IMP2527-1BWM
IMP2527-2BWM
IMP2527-1BN
IMP2527-2BN
Type
Package
Switch "ON" Resistance
Quad
Quad
Quad
Quad
Single
Single
Single
Single
Single
Single
Single
Single
Dual
Dual
Dual
Dual
Quad
Quad
Quad
Quad
16-pin, SO
16-pin, SO
16-pin, DIP
16-pin, DIP
8-pin, SO
8-pin, SO
8-pin, DIP
8-pin, DIP
8-pin, SO
8-pin, SO
8-pin, DIP
8-pin, DIP
8-pin, SO
8-pin, SO
8-pin, DIP
8-pin, DIP
16-pin, SO
16-pin, SO
16-pin, DIP
16-pin, DIP
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.070Ω vs. 0.14Ω for Micrel 2525
0.070Ω vs. 0.14Ω for Micrel 2525
0.070Ω vs. 0.14Ω for Micrel 2525
0.070Ω vs. 0.14Ω for Micrel 2525
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.14Ω
0.30Ω
0.30Ω
0.30Ω
0.30Ω
USBXref02
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP252 4/2 7
POWER MANAGEMENT
ADVANCE PRODUCT INFORMATION
Quad USB High-Side Power
Switch with Fault Detection
Key Features
The IMP2524 and IMP2527 are complete power management solutions
for bus-powered and self-powered USB hubs. Each device contains four
independent power switches and fault detection logic. The IMP2524
channel resistance is a low 140mΩ maximum and the IMP2527 channel
resistance is 300Ω maximum. Both device operate with voltage inputs
from 2.7V to 5.5V
The IMP2524/2527 conform to the new USB 1.1 standard. Fault current
is limited to 750mA typically, and a flag output for each switch conveys
fault information to the local USB controller. The IMP252x “Soft-Start”
function ramps the ON-current to eliminate any excessive voltage drop
on the input side that could occur when capacitive loads are charged.
◆
◆
◆
◆
◆
◆
◆
◆
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
sufficient supply voltage present.
◆
The switch Enable input logic can interface with both 3.3V and 5V logic.
Both active-HIGH (-1 devices) and active-LOW (-2 devices) enable logic
versions are available. Supply current is a low 0.75µA when disabled and
just 110µA when enabled
◆
◆
◆
◆
The quad IMP2524/7 devices are available in 16-pin DIP and 16-pin
SO packages and are pin compatible replacements for the Micrel
MIC2524-1/-2 and MIC2527-1/2 devices. IMP offers a complete family
of USB power management products. For single-switch applications see
the IMP2525 and IMP2525A data sheets. The single-switch IMP2525A
features a 0.07Ω switch resistance. For dual-switch applications, refer to
the IMP2526 data sheet.
Typical Application
Applications
◆ USB host and self-powered hubs
◆ USB video monitors
◆ USB printers
Ferrite Bead
IMP2527
5.1V ± 3%
5V ± 1%
or
IMP2524
5V ± 3%
4.7mF
USB Rev. 1.1 and 2.0 Compliant
Four independent switches
2.7V to 5.5V input operation
Low MOSFET ON resistance
– IMP2524: 0.1Ω, 0.14Ω maximum
– IMP2527: 0.2Ω, 0.3Ω maximum
500mA continuos load current per switch
Low supply current
– 110µA ON-state current, 0.75µA OFF-state
current
1.25A maximum current limit, 750mA typical
Thermal shutdown 2.4V undervoltage lockout
(UVLO)
Open-drain flag output
– Undervoltage
– Current limit
– Thermal shutdown
Output can be force higher than input
Active HIGH(-1) and active LOW(-2) enable
16-pin SO and DIP packages, Die available
Pin compatible with the Micrel MIC2524 and
MIC2527
10k
+
IN OUT
LDO
GND
V+
ON/OFF
OVERCURRENT
USB Controller
VBUS
27k
2
1
3
4
5
Data
D+
D–
6
GND
1mF
7
8
IMP2524
IMP2527
ENA
INA/B
FLGA INC/D
ENB
OUTA
FLGB OUTB
ENC OUTC
FLGC OUTD
END
GND
FLGD
GND
33mF*
+
16
D+
0.01mF
GND
15
14
13
12
11
D–
0.1mF
33mF*
Downstream
USB
Port 1
500mA max.
VBUS
+
D+
0.01mF
10
D–
GND
Downstream
USB
Port 2
500mA max.
9
VBUS
33mF*
+
Bold/Blue lines indicate 0.1" wide, 1-oz. copper high-current traces.
D+
0.01mF
D–
GND
Downstream
USB
Port 3
500mA max.
*33mF, 16V tantalum or 100mF, 10V electrolytic per port
VBUS
33mF*
+
D+
0.01mF
D–
GND
Downstream
USB
Port 4
500mA max.
2524/27_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2524/27
Pin Configuration
SO/DIP
FLGA
FLGA
1
16 FLGB
ENA
ENA
2
15 ENB
FLGB
OUTA
3
GND
4
13 INA/B
INC/D
5
12 GND
OUTC
6
11 OUTD
ENC
7
10 END
FLGC
FLGC
8
9
FLGD
IMP2524/27
14 OUTB
ENB
2
16
15
ENC
FLGD
END
7
1
FLGA
2
ENA
3
4
OUTA
GND
5
INC/D
6
OUTC
7
ENC
8
FLGC
9
FLGD
10
END
11
12
OUTD
GND
13
INA/B
14
OUTB
15
ENB
16
FLGB
13
Logic,
Charge
Pump
14
6
Logic,
Charge
Pump
8
9
10
Pin Descriptions
Name
Logic,
Charge
Pump
IMP2524/27
2524/27_02.eps
Pin Number
3
1
5
Logic,
Charge
Pump
11
4
12
GND
GND
OUTA
INA/B
OUTB
OUTC
INC/D
OUTD
2524/27_03.eps
Function
Fault Flag A output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions.
Enable A Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH
(-1 suffix) and active-LOW (-2 suffix) logic devices are available.
Channel-A switch output (MOSFET Source). The output pin drives the load into ON and OFF states.
Ground. Power supply return for the internal circuitry of the IC. Connect both pins 4 and 6 together.
Channel C and D positive power supply input voltage. This is the switching MOSFET drain connection.
It is the channel C and channel D supply voltage input for the logic and the charge-pump circuit.
Channel-C switch output (MOSFET Source). The output pin drives the load into ON and OFF states.
Enable C Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH
(-1 suffix) and active-LOW (-2 suffix) logic devices are available.
Fault Flag C output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions.
Fault Flag D output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions.
Enable D Input. This pin is the Channel B MOSFET switch driver control logic input. Both active-HIGH
(-1 suffix) and active-LOW (-2 suffix) logic devices are available.
Channel-D switch output (MOSFET Source). The output pin drives the load into ON and OFF states.
Ground. Power supply return for the internal circuitry of the IC. Connect both pins 4 and 6 together.
Channel A and B positive power supply input voltage. This is the switching MOSFET drain connection.
It is the channel A and channel B supply voltage input for the logic and the charge-pump circuit.
Channel-B switch output (MOSFET Source). The output pin drives the load into ON and OFF states.
Enable B Input. This pin is the Channel-B MOSFET switch driver control logic input. Both active-HIGH
(-1 suffix) and active-LOW (-2 suffix) logic devices are available.
Fault Flag B output. This open-drain output goes into an active-LOW state in response to undervoltage, current limit or thermal shutdown conditions.
2524/27t01
Ordering Information
Pin Number
Enable Logic
Typical “ON” Resistance
IMP2524-1BWM
IMP2524-2BWM
IMP2524-1BN
IMP2524-2BN
IMP2527-1BWM
IMP2527-2BWM
IMP2527-1BN
IMP2527-2BN
Active HIGH
Active LOW
Active HIGH
Active LOW
Active HIGH
Active LOW
Active HIGH
Active LOW
100mΩ
100mΩ
100mΩ
100mΩ
200mΩ
200mΩ
200mΩ
200mΩ
Temperature Range
–40°
–40°
–40°
–40°
–40°
–40°
–40°
–40°
C to +85°
C to +85°
C to +85°
C to +85°
C to +85°
C to +85°
C to +85°
C to +85°
C
C
C
C
C
C
C
C
Pins-Package
16-SO
16-SO
16-DIP
16-DIP
16-SO
16-SO
16-DIP
16-DIP
2524/27t02
2
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2524/27
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +8.0V
Fault Flag Voltage . . . . . . . . . . . . . . . . . . . . . . +8.0V
Fault Flag Current . . . . . . . . . . . . . . . . . . . . . . 50mA
Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +8.0V
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 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160°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 IMP2524/27-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2524/27-2
0.75
10
µA
Supply Current
Switch ON
IIN ON
Switch ON, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2524/27-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2524/27-2
110
320
µA
Enable Input Threshold
VENH
LOW to HIGH (“0” to “1”) Enable Voltage, Note 1
2.1
2.4
V
VENL
HIGH to LOW (“1” to “0”) Enable Voltage, Note 1
µA
Enable Input Current
IEN
Enable Input Capacitance
CEN
Switch ON Resistance
RON
Continuous Load Current
IL
0.8
1.9
VEN = 2.4V
0.01
1
VEN = 0.8V
0.01
1
1
pF
IMP2524: IOUT = 500mA each switch
0.10
0.14
IMP2527: IOUT = 500mA each switch
0.20
0.30
Each output
0.5
Ω
A
Output Turn-On Delay
TDON
RL = 10Ω each output
0.25
ms
Output Turn-On Rise Time
TRON
RL = 10Ω each output
1
ms
Output Turn-Off Delay
TDOFF
RL = 10Ω each output
1
20
µs
Output Turn-Off Fall Time
TFOFF
RL = 10Ω each output
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
VIN = 5V, IL = 10mA
10
VIN = 3.3V, IL = 10mA
15
Error Flag Output Current
IFLAG
VFLAG = 5V
0.01
UVLO Threshold
VUVLO
VIN Increasing
2.5
VIN Decreasing
2.3
°C
Ω
1
µA
V
Notes 1. Switch OFF is VEN ≤ 0.8V and Switch ON is VEN ≥ 2.4V for the IMP2524/27-1. Switch OFF is VEN ≥ 2.4V and Switch ON is
VEN ≤ 0.8V for the IMP2524/27-2. The Enable input has approximately 200mV of hysteresis.
© 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2524/27
Package Dimensions
Plastic DIP (16-Pin)
Inches
Min
D1
Min
Max
Plastic DIP (16-Pin)*
N
E1 E
D
A2 A
A1 L
e
0°–15°
B1
C
eA
eB
B
Plastic DIP (16-Pin).eps
SO (16-Pin)
E
H
0°– 8°
A
C
e
L
B
A1
A
A1
A2
B
B1
C
D
D1
E
E1
e
eA
eB
L
———
0.015
0.125
0.016
0.045
0.008
0.745
0.005
0.300
0.240
0.100
0.300
———
0.115
0.200
———
0.175
0.022
0.065
0.012
0.765
0.080
0.325
0.310
———
———
0.400
0.150
———
0.38
3.18
0.41
1.14
0.20
18.92
0.13
7.62
6.10
2.54
7.62
———
2.92
5.08
———
4.45
0.56
1.65
0.30
19.43
2.03
8.26
7.87
———
———
10.16
3.81
SO (16-Pin)**
D
4
Millimeters
Max
16-Pin (SO).eps
A
0.926
0.1043
A1
0.0040
0.0118
B
0.013
0.020
C
0.0091
0.0125
D
0.3977
0.4133
E
0.2914
0.2662
e
0.050 BSC
H
0.394
0.419
L
0.016
0.050
* JEDEC Drawing MO-058AB
** JEDEC Drawing MS-013AA
408-432-9100/www.impweb.com
2.35
2.65
0.10
0.30
0.33
0.51
0.23
0.32
10.10
10.50
7.40
7.60
1.27 BSC
10.00
10.65
0.40
1.27
2524/26_t03.at3
© 2000 IMP, Inc.
6
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.
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.
EN
◆ Meets or exceeds USB Rev. 1.1 and 2.0
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
Applications
◆ USB power management
◆ USB hosts and self-powered hubs
◆ Battery-charger circuits and power supplies
Block Diagrams
IN
Key Features
7
1
8
1.2V
Reference
UVLO
Power
Switch
Gate
Control
Thermal
Shutdown
Oscillator
NC/OUT
6
Current
Limit
OUT
2
Charge
Pump
3
FLG
GND
IMP2525
2525_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
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.
3
GND
Ground. Power supply return for the internal circuitry of the IC.
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
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
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
Supply Voltage Range
Symbol Conditions
VIN
Min
TA = – 40°C to +85°C
Typ
2.7
Max
Units
5.5
V
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
Operating Temperature Range
TA
Enable Input Current
IEN
Enable Input Capacitance
CEN
Switch ON Resistance
RON
– 40
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.
© 2000 IMP, Inc.
USB High-Side Power Switches
3
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
4
Condition
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
408-432-9100/www.impweb.com
Switch State (FLG = “0”)
© 2000 IMP, Inc.
6
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
© 2000 IMP, Inc.
USB High-Side Power Switches
5
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
VBUS
D+
150µF
D–
+
USB
Port
GND
3
1µF
GND
0.1µF
2525_08.eps
Data
Data
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
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
A
–––––
0.210
––––
5.33
A1
0.015
A2
0.115
–––––
0.38
–––––
0.195
2.92
4.95
b
b2
0.014
0.022
0.36
0.56
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
E1
0.240
0.280
e
0.100
–––––
eA
0.300
–––––
eB
–––––
0.430
eC
–––––
0.060
L
0.115
0.150
A
0.053
0.069
7.11
2.54
7.62
–––––
10.92
2.92
3.81
SO (8-Pin)**
E
H
C
D
A
e
B
A1
SO (8-Pin).eps
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
© 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2525A
POWER MANAGEMENT
Low-Resistance
USB High-Side Power Switch
- Single switch
- 0.07Ω "ON" resistance at 3V
- 50% lower resistance than MIC2525
- MIC2525 pin compatible
The IMP2525A high-side power switch IC is designed for self-powered
and bus-powered Universal Serial Bus (USB) power supply and power
management applications. The IMP2525A conforms to USB standards
with a low output switch ON-resistance (RON) and minimal voltage drop
across the switch. Switch resistance is 50% lower than the MIC2525. The
fault current is limited to 1.5A typically, and a flag output conveys fault
conditions to the local USB controller. The IMP2525A provides a
“Soft-Start” function that ramps up the ON-current 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 IMP2525A devices are available in 8-pin DIP and 8-pin SO packages.
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 IMP2525 matches the
performance of the Micrel MIC2525.
Block Diagrams
IN
EN
Key Features
◆ Meets or exceeds USB Rev. 1.1 and 2.0
specification
◆ Low MOSFET RON (0.07Ω at 3V)
◆ Pin compatible with the Micrel MIC2525
– 50% lower than MIC2525
◆ 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 (2.5A 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
◆ Open-drain Fault Flag indicates three fault
conditions:
– Undervoltage
– Current limit
– Thermal shutdown
◆ 2.4V Undervoltage Lockout (UVLO)
Applications
◆ USB power management
◆ USB hosts and self-powered hubs
◆ Battery-charger circuits and power supplies
7
1
8
1.2V
Reference
Current
Limit
50% Lower
Resistance
Than MIC2525
UVLO
OUT
6
Power
Switch
Gate
Control
2
Thermal
Shutdown
Oscillator
OUT
Charge
Pump
3
FLG
GND
IMP2525A
2525A_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP2525A
Pin Configuration
SO/DIP
8
EN
1
FLG
2
IMP2525A
8
OUT
7
IN
GND
3
6
OUT
NC
4
5
NC
EN
FLG
1
2
Logic,
Charge
Pump
OUT
6
7
IN
3
2525A_02.eps
GND
2525A_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.
3
GND
Ground. Power supply return for the internal circuitry of the IC.
4, 5
NC
6
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.
MOSFET source. The output pin supplies power to the load.
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
IMP2525A-1BM
Active HIGH
– 40°C to +85°C
8-SO
IMP2525A-2BM
Active LOW
– 40°C to +85°C
8-SO
IMP2525A-1BN
Active HIGH
– 40°C to +85°C
8-DIP
IMP2525A-2BN
Active LOW
– 40°C to +85°C
8-DIP
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2525A
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
Supply Voltage Range
Symbol Conditions
VIN
Min
TA = – 40°C to +85°C
Typ
2.7
Max
Units
5.5
V
85
°C
Supply Current
Switch OFF
IIN OFF
Switch OFF, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2525A-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2525A-2
0.75
5
µA
Supply Current
Switch ON
IIN ON
Switch ON, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2525A-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2525A-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
Operating Temperature Range
TA
Enable Input Current
IEN
Enable Input Capacitance
CEN
Switch ON Resistance
RON
– 40
1
pF
VIN = 5V, IOUT = 500mA
0.05
0.07
VIN = 3.3V, IOUT = 500mA
0.07
0.09
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
1.5
2.5
A
1.0
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 IMP2525A-1. Switch OFF is VEN ≥ 2.4V and Switch ON is
VEN ≤ 0.8V for the IMP2525A-2. The Enable input has approximately 200mV of hysteresis.
2. Over operating temperature range, –40°C ≤ TA ≤ 85°C.
© 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2525A
Detailed Descriptions
The IMP2525A 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
4
Condition
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 > 1.0A (step load)
IO > 1.25A (ramped load)
Enable off or
Thermal Shutdown
Stays ON
408-432-9100/www.impweb.com
Switch State (FLG = “0”)
© 2000 IMP, Inc.
6
IMP2525A
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 IMP2525A 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 IMP2525A 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
IMP2525A
7
IN
3
GND
0.1µF to 1µF
Fault Flag Output
Soft Start
The IMP2525A 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 0.07Ω 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 IMP2525A provides
this high-load, soft-start operation.
2525A_04.eps
Figure 1. Supply Bypassing
USB
Controller
IMP2525A-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
2525A_06.eps
Figure 2. Soft-Start Application
© 2000 IMP, Inc.
USB High-Side Power Switches
5
IMP2525A
Application Information
USB
Controller
IMP2525A-2
1
VBUS
EN
2 FLG
3
USB Hub
GND
4 NC
8
OUT
7
IN
USB
Function
6
OUT
NC 5
4.7µF
CBULK
GND
Cable
USB Peripheral
2525A_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
IMP2525A
2
OVERCURRENT
FLG
0.1µF
2525A_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
100k
1
2
EN
Ferrite
Beads
OUT
8
7
FLG
IN
IMP2525A-2
6
OUT
D–
GND
GND
GND
1µF
VBUS
D+
150µF
D–
+
USB
Port
GND
3
1µF
GND
0.1µF
2525A_08.eps
Data
Data
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2525A
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
A
–––––
0.210
––––
5.33
A1
0.015
A2
0.115
–––––
0.38
–––––
0.195
2.92
4.95
b
b2
0.014
0.022
0.36
0.56
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
E1
0.240
0.280
e
0.100
–––––
eA
0.300
–––––
eB
–––––
0.430
eC
–––––
0.060
L
0.115
0.150
A
0.053
0.069
7.11
2.54
7.62
–––––
10.92
2.92
3.81
SO (8-Pin)**
E
H
C
D
A
e
B
A1
SO (8-Pin).eps
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
© 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2526
POWER MANAGEMENT
Dual USB High-Side Power
Switch
Key Features
– Dual switch
– 0.14Ω /0.1Ω “ON” resistance at 3/5V
– MIC2526 pin compatible
The IMP2526 dual high-side power switch IC is designed for selfpowered and bus-powered Universal Serial Bus (USB) power supply
and general purpose power management applications. ON resistance is
a low 100mΩ at 5V input and 140mΩ at 3V input.
The IMP2526 conforms to the new USB Revision 1.1 standard. Fault
current is limited to 750mA typically, and a flag output for each switch
conveys fault information to the local USB controller. The IMP2526 “SoftStart” function ramps the ON-current to eliminate any excessive voltage
drop on the input side that could occur when capacitive loads are
charged.
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 sufficient supply voltage present.
The switch Enable input logic can interface with both 3.3V and 5V logic.
Both active-HIGH (-1 devices) and active-LOW (-2 devices) enable logic
versions are available. Supply current is a low 0.75µA when disabled and
just 110µA when enabled.
The IMP2526 devices are available in 8-pin DIP and 8-pin SO packages
and are pin compatible replacements for the Micrel MIC2526-1/-2. IMP
Block Diagrams
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
USB Rev. 1.1 and 2.0 compliant
2.7V to 5.5V input operation
Low MOSFET ON resistance (0.1Ω at 5V)
Low supply current
– 110µA ON state current, 1µA OFF state current
500mA continuous load current per switch
1.25A maximum current limit, 750mA typical
Thermal shutdown 2.4V undervoltage lockout
(UVLO)
Open-drain flag output
– Undervoltage
– Current limit
– Thermal shutdown
Active HIGH(-1) and active LOW(-2) enable
Pin compatible with the Micrel MIC2526
offers a complete family of USB power management
products. For single-switch applications see the IMP2525
and IMP2525A data sheets. The single-switch IMP2525A
features a 50% lower switch resistance, 0.07Ω. For quadswitch applications, refer to the IMP2524 data sheet.
Applications
◆
◆
◆
◆
USB host and self-powered hubs
Bus-powered hubs
Hot plug-in power supplies
Battery chargers
2
IMP2526
ENA
8
1
Charge
Pump
Oscillator
Gate
Control
Thermal
Shutdown
Gate
Control
Charge
Pump
ENB
7
5
3
© 2000 IMP, Inc.
IN
Current
Limit
4
6
OUTA
Current
Limit
1.2V
Reference
UVLO
FLGA
OUTB
FLGB
2526_01.eps
GND
408-432-9100/www.impweb.com
1
IMP2526
Pin Configuration
SO/DIP
IMP2526
ENA
ENA
1
FLGA
2
FLGB
3
ENB
IMP2526
4
8
OUTA
7
IN
6
GND
5
FLGA
FLGB
OUTB
ENB
2526_02.eps
8
1
2
Logic,
Charge
Pump
7
3
4
Logic,
Charge
Pump
5
OUTA
IN
OUTB
6
GND
2526_03.eps
Pin Descriptions
Pin Number
Name
Function
1, 4
ENA, ENB
2, 3
FLGA, FLGB
6
GND
7
IN
8, 5
OUTA, OUTB
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.
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.
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
IMP2526-1BM
Active HIGH
– 40°C to +85°C
8-SO
IMP2526-2BM
Active LOW
– 40°C to +85°C
8-SO
IMP2526-1BN
Active HIGH
– 40°C to +85°C
8-DIP
IMP2526-2BN
Active LOW
– 40°C to +85°C
8-DIP
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2526
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
Supply Voltage Range
Symbol Conditions
VIN
Min
TA = – 40°C to +85°C
Typ
2.7
Max
Units
5.5
V
85
°C
Supply Current
Switch OFF
IIN OFF
Switch OFF, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2526-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2526-2
0.75
5
µA
Supply Current
Switch ON
IIN ON
Switch ON, No load
VENOFF ≤ 0.8V, VENON ≥ 2.4V IMP2526-1
VENON ≤ 0.8V, VENOFF ≥ 2.4V IMP2526-2
110
160
µA
Enable Input Threshold
VENH
LOW to HIGH (“0” to “1”) Enable Voltage, Note 1
2.1
2.4
V
VENL
HIGH to LOW (“1” to “0”) Enable Voltage, Note 1
0.8
1.9
VEN = 0V to 5.5V
–1
±0.01
1
µA
Operating Temperature Range
TA
Enable Input Current
IEN
Enable Input Capacitance
CEN
Switch ON Resistance
RON
– 40
1
pF
VIN = 5V, IOUT = 500mA
0.10
0.14
VIN = 3.3V, IOUT = 500mA
0.14
0.18
Ω
Output Turn-On Delay
TDON
RL = 10Ω each output
0.25
ms
Output Turn-On Rise Time
TRON
RL = 10Ω each output
1
ms
Output Turn-Off Delay
TDOFF
RL = 10Ω each output
1
20
µs
Output Turn-Off Fall Time
TFOFF
RL = 10Ω each output
1
20
µs
Output Leakage Current
IOFF
10
µA
Short-circuit Current Limit
ISC
Overtemperature Shutdown
Threshold
0.50
0.75
1.25
135
TJ decreasing
125
VIN = 5V, IL = 10mA
10
25
15
40
0.01
1
Error Flag Output Resistance
RFLAG
Error Flag Output Current
IFLAG
VFLAG = 5V
UVLO Threshold
VUVLO
VIN Increasing
2.5
VIN Decreasing
2.3
VIN = 3.3V, IL = 10mA
A
°C
TJ increasing
Ω
µA
V
Notes 1. Switch OFF is VEN ≤ 0.8V and Switch ON is VEN ≥ 2.4V for the IMP2526-1. Switch OFF is VEN ≥ 2.4V and Switch ON is VEN ≤ 0.8V
for the IMP2526-2. The Enable input has approximately 200mV of hysteresis.
© 2000 IMP, Inc.
USB High-Side Power Switches
3
IMP2526
Detailed Descriptions
The IMP2526 dual high-side N-channel MOSFET switch interfaces with a USB controller by means of a Switch-Enable input
and a Fault-Flag output. The Enable input, with either a logic “1”
for the IMP2526-1 or logic “0” for the IMP2526-2, turns the power
MOSFET ON. 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 OUTA/B (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.
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
Fault Flag - FLG Pin
The Fault Flag pin, FLGA/B, connects to an N-channel, opendrain 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. Both flags may be
wire-NORed to a common pull-up resistor.
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 gives the states of the FLG and OUT pins when a fault
condition is detected.
Table 1. Fault Flag Conditions - Switch Enabled
Condition
Cause
FLG pin “0” Until
Switch State (FLG = “0”)
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*
* The switch and Fault Flag behavior during current-limiting is more complex than shown by this table. The detailed discussion on each of these
fault conditions gives additional information.
4
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2526
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
IMP2526 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
IMP2526 control circuitry if the 8V maximum input rating is
exceeded.
As with any logic input, the enable pins, ENA/ENB, must be
driven to a definitive logic state at all times. Floating the input
can result in spurious operation. Do not drive ENA/ENB
below GND.
2.7V to 5.5V
IMP2526
7
IN
6
GND
0.1µF to 1µF
Fault Flag Output
Soft Start
The IMP2526 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 IMP2526 provides
this high-load, soft-start operation.
2526_04.eps
Figure 1. Supply Bypassing
USB
Controller
IMP2526-xBM
1
VBUS
2
3
USB
Host
4.7µF
ENA
OUTA
FLGA
IN
FLGB
GND
4 ENB
8
7
6
OUTB 5
0.1µF
Capacitive
Load
CBULK
GND
Cable
Bus Powered Hub
Cable
Downstream USB Device
2526_06.eps
Figure 2. Soft-Start Application
© 2000 IMP, Inc.
USB High-Side Power Switches
5
IMP2526
Application Information
USB
Controller
IMP2526-2
1
VBUS
ENA
2 FLGA
3 FLGB
USB Hub
4
ENB
OUTA
IN
GND
OUTB
8
USB
Function
7
CBULK
6
5
USB
Function
4.7µF
CBULK
GND
Cable
USB Peripheral
2526_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
2
OVERCURRENT
IMP2526
FLG
0.1µF
2526_05.eps
Figure 4. Transient Filter
Upstream
VBUS
100mA max
10k
100k
10k
100k
VCC
5.0V
Ferrite
Beads
3.3V
USB Controller
VBUS
IN
OUT
D+
VIN
ON/OFF
OVERCURRENT
D–
LDO
OVERCURRENT
GND
GND
ON/OFF
1µF
8
ENA OUTA
IMP2526-2
7
2
FLGA
IN
3
FLGB GND 6
4
5
ENB OUTB
VBUS
1
+
47µF
0.1µF
D+
USB
Port 1
D–
GND
1µF
VBUS
Data
D+
47µF
+
USB
Port 2
D–
GND
Data
(Two Pair)
2526_08.eps
Figure 5. Single-Port Self-Powered Hub Application
6
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP2526
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
A
–––––
0.210
––––
5.33
A1
0.015
–––––
0.38
–––––
A2
0.115
0.195
2.92
4.95
b
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
E1
0.240
0.280
6.10
e
0.100
–––––
eA
0.300
–––––
eB
–––––
0.430
eC
–––––
0.060
L
0.115
0.150
7.11
2.54
7.62
–––––
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
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
e
0.050
1.75
0.25
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
© 2000 IMP, Inc.
USB High-Side Power Switches
7
Notes
Project
8
408-432-9100/www.impweb.com
© 2000 IMP, Inc.
6
IMP, Inc.
Corporate Headquarters
2830 N. First Street
San Jose, CA 95134-2071
Tel: 408-432-9100
Fax: 408-434-0335
e-mail: [email protected]
http://www.impweb.com
The IMP logo is a registered trademark of IMP, Inc.
All other company and product names are trademarks of their respective owners.
2000 © IMP, Inc.
Printed in USA
Publication #: 5001
Revision:
C
Issue Date:
07/13/00
Type:
Preliminary