CALIFORNIA MICRO DEVICES
Features
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Dual switches, each with independent over-current
protection and flag indicator, for 4 USB ports
Two active low Enable controls, one per output
Up to 1.2A continuous current each output
Over-current limits at 1.2A min
10msec min fault blanking delay on OC# outputs
prevents false overcurrent alarms
Prevents backdrive current when host powered off
Low operating current (95µA typ.)
Low quiescent current when disabled (<1µA max)
Small 8-Lead SOIC package
Preliminary
CM3512
The CM3512 also prevents backdrive current
flowing into the host from the connected peripheral.
This can occur when V
CC
is removed as the host
powers down, and the peripheral still has normal
power applied. The 5V from the peripheral can
therefore be linked to the host’s V
BUS
, potentially
causing backdrive current into the host and
overloading the peripheral power supply.
Dual USB Overcurrent 1.2A Switches with Independent Controls
Pin Diagram
GND
V
CC
EN1#
EN2#
TOP
SOIC-8
OC1#
V
OUT1
V
OUT2
OC2#
Applications
PC’s, Notebooks, STBs
Product Description
California Micro Devices CM3512 is a dual channel
USB overcurrent power switch that provides 5V
power to four independent USB ports. The device
has two power switches that provide the V
BUS
voltage at each USB output port with minimal
voltage drop.
When either of the EN# inputs is at logic low, the
corresponding power switch is ON and V
CC
is
connected to the corresponding output through the
switch. When either of the EN# inputs is at logic
high, the corresponding power switch is OFF, and
no power is available at the output.
Typical Application Circuit
GND
V
CC
V
CC
EN1#
EN2#
OC1#
V
OUT1
V
OUT2
OC2#
V
BUS
2 USB Ports
2 USB Ports
V
BUS
Both of the power switches have full over-current
protection. Whenever the current limit out of either
switch is exceeded, the device enters a constant-
current mode, and the output voltage is
Simplified Electrical
progressively reduced to prevent the current from
increasing further. Each switch is independent of the
other, so if a switch is on but is not in overcurrent
mode then it will remain switched on. The OC#
Charge
output becomes active low only if the overcurrent EN1#
Pump
condition exceeds a minimum continuous duration of
10ms. This fault blanking delay prevents false
alarms being reported to the host USB controller.
If the overcurrent condition is severe enough that
the part heats up to the thermal limit T
MAX
, then that EN2#
switch will be turned off and the device temperature
cools down. At T
MIN
the switch then turns on again,
V
CC
and the device heats up again to T
MAX
, and so on,
until the fault is removed.
Charge
Pump
Schematic
Over
current
protect
OC
V
OU
Over
current
protect
V
OU
OC
© 2003 California Micro Devices Corp. All rights reserved.
C0970500
11/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
1
CALIFORNIA MICRO DEVICES
Absolute Maximum Ratings
Parameter
Rating
ESD Protection (All pins, HBM)
±
2000
V
CC
Input Voltage
+ 5.6, Gnd - 0.5
Storage Temperature Range
-55 to +150
Operating Ambient
-40 to +85
Operating Junction
-40 to +150*
Output Current Loading
Internally limited
Package Power Dissipation
0.5
*Internally limited
Preliminary
CM3512
Unit
V
V
°C
A
W
Operating Conditions
(unless specified otherwise)
Parameter
Range
V
CC
Input Voltage
4.5 to 5.5
Ambient Temperature
-40 to +85
I
LOAD
per port
B
0 to 1200
00
Unit
V
°C
mA
Symbol
UVLO
R
SW
V
OUT1
,
V
OUT2
I
LIM
t
FBD
T
MAX
T
MIN
I
R CC
I
CC
I
CCQ
V
IH-EN
V
IL-EN
I
OHZ-OC
V
OL-OC
Electrical Operating Characteristics
(over operating conditions unless specified otherwise)
Parameter
Conditions
MIN
TYP
MAX
V
CC
voltage under which circuit
2.2
2.5
locks out - will not operate
Switch ON-Resistance
I
LOAD
= 0 to 1200mA; V
CC
= 5V,
0.13
0.2
T= 25°C
Output Voltage
I
LOAD
= 1000mA, V
CC
= 5.0V,
4.8
EN# = 0V, T = 25°C
Over-current limit
1200
V
CC
= 5V, T = 25°C
10
20
Time delay from overcurrent
detection to OC# output
indication (fault blanking delay)
Temperature at which hot switch
150
turns off during overcurrent
125
Temperature at which cool
switch turns on, after cooling
from T
MAX
1
Reverse leakage from outputs
V
CC
= 0V, V
OUT1,2
= 5V,
to input
EN# =high, T=25°C
Operating supply current
EN# = low
95
Quiescent current
EN# = high
1
EN# input Logic-1 threshold
V
CC
= 5V
2
EN# input Logic-0 threshold
V
CC
= 5V
0.8
OC# output OFF state leakage
V
CC
= 5V, V
OUT
= 5V
1.0
OC# output Logic-0 threshold
I
OC
= 1mA to V
CC
0.4
UNIT
V
Ω
V
mA
ms
°C
°C
µA
µA
µA
V
V
uA
V
© 2003 California Micro Devices Corp. All rights reserved
11/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
2
CALIFORNIA MICRO DEVICES
Pin Functions
V
CC
is the power source.
MOSFET switches are designed for very low voltage drops
from the voltage input pins at their full rated currents.
Preliminary
CM3512
V
OUT1
provides the power for the first load. The internal
EN1#, EN2#
are the active low logic input pins that
are used to control the power switches. Both
switches are independent. Set EN1# and EN2# high
(to >2V) to deselect V
OUT1
and V
OUT2
respectively, and
set EN1# and EN2# low (to <0.8V) to select V
OUT1
and V
OUT2
respectively.
MOSFET switches are designed for very low voltage drops
from the voltage input pins at their full rated currents.
Current loads of up to 1200mA are allowed. Current
loads above 1200mA may cause the constant-current
limiting circuit to operate, thereby reducing the output
voltage.
Continuous over-current loads will cause the part’s
internal temperature to rise. If the internal temperature
exceeds 150’C then any switch that is in overcurrent
mode will be immediately turned off. Any switch that is
not in overcurrent mode will remain on – it will not be
affected by the over-temperature detection. Once the
part has cooled to 125’C then the switch or switches
that were in overcurrent mode will be automatically
turned on again.
During the cold-start interval when the input is initially
applied, internal circuitry provides a soft turn-on for the
switch, which limits peak in-rush current.
V
OUT2
provides the power for the second load. The internal
OC1#, OC2#
are independent active low open-
drain outputs, indicating an overcurrent fault condition
has been detected at V
OUT1
or V
OUT2
. There is a built-
in 10msec (min.) fault blanking delay after the
overcurrent fault condition has been detected, before
these outputs become active. The OC# outputs
become inactive only when both the overcurrent
condition stops and when the voltage drop across the
switch is less than 1V. External pull-up resistors of
10k - 100k are required if the OC# outputs are used.
Because they are open-drain, the two OC# outputs
can be shorted together to make one OC# signal.
GND
is the negative reference for all voltages.
Pin Functions
Pin No.
1
2
3
4
5
6
7
8
Symbol
GND
V
CC
EN1#
EN2#
OC2#
V
OUT2
V
OUT1
OC1#
Description
Negative reference for all voltages.
Power supply input.
Active low Enable pin for V
OUT1
.
Active low Enable pin for V
OUT2
.
Active low when
V
OUT2
is in overcurrent mode.
Output voltage #2.
Output voltage #1.
Active low when
V
OUT1
is in overcurrent mode.
STANDARD PART ORDERING INFORMATION
Pins
8
Package
SOIC
Ordering Part Number
CM3512-04SN
1
Part Marking
CM3512-04SN
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
© 2003 California Micro Devices Corp. All rights reserved
11/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3
CALIFORNIA MICRO DEVICES
Response to Momentary Overcurrent Fault
>1200mA
Preliminary
CM3512
<1100mA
I
OUT
V
OUT
drops to reduce I
OUT
V
OUT
OC#
OC# goes active
after 10ms (min)
20ms (typ.) delay
OC# goes inactive as
soon as overcurrent
condition stops
<150’C
Die
Temp.
Response to Continuous Overcurrent Fault
>1200mA
I
OUT
V
OUT
drops to reduce I
OUT
V
OUT
Total powerdown when
over-temperature limit
reached
Re-powers when
temperature drops
to 125’C
OC#
OC# goes active
after 10ms (min)
20ms (typ.) delay
OC# stays low
150’C
T
MAX
= 150’C
Die
Temp.
Note: The other port stays on (unless it is also in current limit.)
T
MIN
= 125’C
© 2003 California Micro Devices Corp. All rights reserved
11/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
4
CALIFORNIA MICRO DEVICES
Typical Operating Characteristics
On-resistance
190
180
170
Resistance [milliohms]
160
150
140
130
120
110
100
-40
-20
0
20
40
60
80
100
120
140
Temperature ['C]
Preliminary
CM3512
Vcc=5.5V
Vcc=5.0V
Vcc=4.5V
Vcc=4.0V
V
OUT
[V]
6
V
OUT
-I
OUT
characteristic (EN#=0V)
5
4
3
2
1
0
0
0.5
1
1.5
I
OUT
[A]
2
2.5
3
3.5
© 2003 California Micro Devices Corp. All rights reserved
11/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
5
PCB设计
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