FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27604-2E
ASSP For Power Supply Applications
Power Management 2-ch Switch IC
MB3842/MB3845
■ DESCRIPTION
The MB3842/3845 is a power management switch with built-in 2-channel low-on resistance (typ. 100mΩ) switch.
Output control is by means of a control signal, and the MB3842 is designed for high-active operation (output on
when EN is Hi), while the MB3845 is designed for low-active operation (output on when EN is low.)
To provide adaptability to a variety of operations, the MB3842/3845 features low input voltage (VIN > 2.5V)
operation and stable low-on resistance independent of input voltage. The switching current limit can be set from
100mA to 600mA by using external resistance, and when overcurrent conditions are detected the OC output goes
low to provide an external notification signal.
VIN is divided between the two channels, which operate independently of each other.
In addition, an off-state reverse current prevention function is provided to ensure accurate on/off switching action.
■ FEATURES
• Low on resistance switch (typ. 100mΩ)
• Low input voltage operation (2.5 V to 5.5 V)
• Switch current (max. 0.6 A)
• UVLO
• ENABLE
:VIN threshold
:EN threshold
2.3V/2.1 V hysteresis 200 mV
EN 1.4V/1.6 V for MB3842, EN 1/2 VIN for MB3845
:Power supply current at output off = 0µA EN < 0.8V for MB3842, EN = VIN for MB3845
• External setting for soft start time and switch current limit.
• Over-temperature detection (switch latched off), over-current detection (not latched)
• OC pin flag set following overcurrent detection, over-temperature detection, or UVLO detection.
• Reverse current prevention at OFF (VIN ≥ 1.5 V)
• Either channel may be operated alone.
■ PACKAGE
20-pin plastic SSOP
(FPT-20P-M03)
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MB3842/MB3845
■ PIN DESCRIPTION
Pin no.
Symbol
Descriptions
Control signal input pin.
EN
(MB3842)
Set “H” to turn switch on, “L” to turn toff. At 0.8 V or less, the chip is in STBY state
and current consumption is less than 1µA.
“L” level is 1.4V (typ), “H” level is 1.6V (typ), with 200mV (typ) hysteresis.
Control signal input pin.
Set “L” to turn switch on, “H” to turn off.
1/10
EN
(MB3845)
At “H” level = VIN, the chip is in STBY state and current consumption is less than
1µA.
Normally used as CMOS inverter input, so that recommended use is “L” level at
GND +0.5V or less, and “H” level is VIN -0.5V or greater.
Slow start setting pin. Used to adjust the switch on/off timing.
Add external capacitance to delay operation. Leave open when not in use.
In open mode voltages up to 12 V are present. Care should be taken in mounting
to prevent leakage current generation because high impedance is required.
2/9
3/8
SS
CS
Current limit setting pin.
The limit current level is set by connecting this pin to external resistance.
Switch output pin.
An UVLO (VIN power monitor function) is provided so that when VIN reaches 2.3V
(typ.) or higher the OC pin voltage goes to “H” level. Also if the VIN voltage drops to
2.1 V (typ.) or lower the OC output goes to “L” state.
200mV (typ) hysteresis is provided.
4/5/6/7
11/20
VIN
GND
Ground pin.
External notification pin.
When the switch is in on mode this pin normally outputs a “H” level signal, but
changes to “L” level when an overcurrent, overtemperature, or UVLO condition is
detected.
12/19
OC
This is an open drain connection, and should be pulled up to high potential using
resistance.
13/14/15
16/17/18
OUT
Switching output pin.(N-ch MOSFET source)
3
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MB3842/MB3845
■ BLOCK DIAGRAM (for 1 channel)
MB3842
OUT1
CS1
Over current
detection 1
Charge
pump1
+
COMP
−
SS1
EN1
Q
S
R
FF1
+
COMP
−
OSC1
OC1
VIN1
BGR1
Temperature
protection 1
MB3845
OUT1
CS1
Charge
pump1
Over current
detection 1
+
COMP
−
SS1
Q
S
R
FF1
EN1
+
COMP
−
OSC1
OC1
VIN1
BGR1
Temperature
protection 1
4
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MB3842/MB3845
■ ABSOLUTE MAXIMUM RATINGS
Rating
Unit
Parameter
Input voltage
Symbol
Condition
Max.
–0.3
–0.3
—
Min.
VIN
VEN
ISW
—
—
—
7.0
V
V
ENABLE voltage
Switch current
7.0
1.8
A
Power dissipation
Storage temperature
PD
Ta = +85°C
—
216
+125
mW
°C
TSTG
—
–55
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current,
temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.
■ RECOMMENDED OPERATING CONDITIONS
Value
Parameter
Symbol
Condition
Unit
Min.
2.5
0
Typ.
5.0
—
Max.
5.5
5.5
0.6
10
Input voltage
VIN
VEN
ISW
—
V
V
ENABLE voltage
Switch current
VEN ≤ VIN
VIN = 2.5 V to 5.5 V
—
—
—
A
SS pin capacitance
OC sink current
CSS*
IOCS
—
—
nF
mA
kΩ
kΩ
VIN = 5.0 V, VOC = 0.4 V
VIN = 5.0 V (ISW = 0.6 A)
VIN = 5.0 V (ISW = 0.1 A)
2.0
1.4
3.6
5.0
2.0
6.2
—
2.6
9.1
Current limit
resistance
RLIM*
TOP
Operating
temperature
—
–20
—
+85
°C
* : For CSS, RLIM settings, see “TYPICAL CHARACTERISTICS” and “FUNCTIONAL DESCRIPTION”.
WARNING: The recommended operating conditions are required in order to ensure the normal operation of the
semiconductor device. All of the device's electrical characteristics are warranted when the device is
operated within these ranges.
Always use semiconductor devices within their recommended operating condition ranges. Operation
outside these ranges may adversely affect reliability and could result in device failure.
No warranty is made with respect to uses, operating conditions, or combinations not represented on
the data sheet. Users considering application outside the listed conditions are advised to contact their
FUJITSU representatives beforehand.
5
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MB3842/MB3845
■ ELECTRICAL CHARACTERISTICS (per 1 ch)
• MB3842/MB3845
(VIN = 5 V, Ta = +25°C)
Value
Parameter
Symbol
Condition
Unit
Min.
—
Typ.
100
350
1.0
Max.
150
550
1.5
Switch resistance
RON
IIN1
ISW =0.6A
ISW = 0 A
ISW = 0.6 A
mΩ
µA
—
IIN2
—
mA
IN pin input current
EN < 0.8V for MB3842,
EN = VIN for MB3845
IIN3
—
—
1.0
µA
VIUH
VIUL
VIUHY
ISWH
ISWL
IOCS
IOCL
VIN at OC = L → H
VIN at OC = H → L
VIUHY = VIUH – VIUL
RLIM = 2.0 kΩ
2.1
1.9
2.3
2.1
200
0.6
0.1
5.0
—
2.5
2.3
300
0.78
0.14
—
V
V
UVLO threshold
UVLO hysteresis width
Switch current limit
100
0.42
0.06
2.0
mV
A
RLIM = 6.2 kΩ
A
VOC = 0.4 V at OC active
VOC = 5.0 V at OC non-active
—
mA
µA
°C
OC sink current
—
1.0
—
Temperature protection (Tj)
OUT pin rise time
TLIM
+125
—
SS pin: Open
OUT pin: 100 kΩ pull down
tON
—
—
100
50
200
120
µs
µs
SS pin: Open
OUT pin: 100 kΩ pull down
OUT pin fall time
tOFF
• MB3842
(VIN = 5 V, Ta = +25°C)
Value
Parameter
Symbol
Condition
Unit
Min.
—
Typ.
5
Max.
10
IENH
IENL
VEN = 5 V, ISW = 0 A
µA
µA
V
ENABLE pin input current
VEN = 0 V, ISW = 0 A
—
0.0
—
VTHEN
VTLEN
VENHY
—
—
1.45
1.25
100
1.60
1.40
200
1.75
1.55
300
ENABLE pin threshold
voltage
V
ENABLE hysteresis width
VENHY = VTHEN – VTLEN
mV
• MB3845
(VIN = 5 V, Ta = +25°C)
Value
Parameter
Symbol
Condition
Unit
Min.
—
Typ.
0.0
0.0
—
Max.
—
IENH
IENL
VEN = 5 V, ISW = 0 A
µA
µA
V
ENABLE pin input current
ENABLE pin input voltage
VEN = 0 V, ISW = 0 A
—
—
VILEN
VIHEN
—
—
0
0.8
5.0
3.0
—
V
6
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MB3842/MB3845
■ DIAGRAM
• Normal operation
5 V
VIN
Hi
EN
EN
Low
SW OFF
SW ON
SW ON
5 V
VOUT
Overcurrent does not occur
IOUT
OC
5 V
5 V
• At VIN fall
2.3 V
VIN
2.1 V
Hi
EN
EN
Low
SW ON
SW ON
SW ON
5 V
VOUT
Overcurrent does not occur
IOUT
OC
5 V
= 0 V
Note: The OC pin should be pulled up using a separate power supply and resistance.
(This illustration shows pull-up with a separate 5V source.)
(Continued)
7
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MB3842/MB3845
(Continued)
• At overcurrent detection
5 V
VIN
Hi
EN
EN
Low
SW ON
OFF
ON
OFF
5 V
VOUT
IOUT
OC
5 V
= 0 V
5 V
• At over-temperature occurrence
Over-temperature
VIN
Over-temperature corrected
occurs
Hi
EN
EN
Low
5 V
SW ON
SW OFF
VOUT
Overcurrent does not
occur
IOUT
OC
5 V
= 0 V
Latch released
Latch set
Note: The OC pin should be pulled up using a separate power supply and resistance.
(This illustration shows pull-up with a separate 5V source.)
8
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MB3842/MB3845
■ TYPICAL CHARACTERISTICS
• RLIM vs. limit current characteristics
ThesearethelimitingvaluecharacteristicsforCSpin-to-GND
external resistance and output current (OC flag).
10
1
VIN = 5.0 V
VIN = 3.3 V
VIN = 2.5 V
0.1
0.01
100
1000
10000
100000
RLIM (Ω)
• CSS vs. TON (SS) characteristics
There are the characteristics for SS pin-to-GND external
capacitance and output ON time.
100
10
VIN = 5.0 V
VIN = 3.3 V
VIN = 2.5 V
1
0.1
10
100
1000
10000
100000
CSS (pF)
(Continued)
9
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MB3842/MB3845
(Continued)
• SW resistance vs. temperature characteristics
150
140
130
120
110
100
90
at 0.1 A
at 0.6 A
at 1 A
80
70
60
50
−60
−40
−20
0
20
40
60
80
100
120
Temperature Ta (°C)
• Temperature-dependedSWresistancevs. VIN (V)characteristics
150
140
130
120
110
100
90
−40 °C
25 °C
100 °C
80
70
60
50
2
3
4
5
6
7
VIN voltage (V)
(Continued)
10
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MB3842/MB3845
(Continued)
• Output power (ISW) saturation characteristics
5 V
Measurement circuit
VIN
EN, EN OC
SS
VIL/VIH
ISW
“Open”
A
OUT
GND
CS
2 Ω
100 kΩ
RLIM
VSW
5 V
These are the output saturation current characteristics in
overcurrent state.(when not controlled by the OC pin warning flag)
1600
1400
1200
1000
800
600
400
200
0
RLIM not limited (CS GND)
RLIM set to 2.0kΩ, 0.6A
Unlimited
6.2 k (0.1 A)
2 k (0.6 A)
Overcurrent flag set
(when set for 0.6A)
Temperature protection
range
RLIM set to 6.2kΩ, 0.1A
Overcurrent flag set
(when set for 0.1A)
0
1
2
3
4
5
6
VSW (V)
(Continued)
11
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MB3842/MB3845
(Continued)
• OC pin flag pull-up resistance (pull-up power 5V) dependant overcurrent operation
1 V / 500 NS
50 kΩ
1 V / 500 NS
1 kΩ
GND
1 V / 500 NS
10 kΩ
1 V / 500 NS
100 kΩ
• Power derating characteristics
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
−20
0
20
40
60
80
100
Temperature Ta (°C)
12
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MB3842/MB3845
■ FUNCTIONAL DESCRIPTION
Current Limit Setting
By placing resistance between the CS and GND pins, the current limit can be set between 100mA and 600mA
within ±30% accuracy (VIN = 5 V, current limit at 600mA). Because the setting value is dependent on VIN voltage,
the user should select the optimum resistance value for the value of VIN voltage . When the switching current
exceeds the set value, the OC pin goes to “L” level as an external notification signal, but there is no latching
function. To hold operation on “off” state, the input signal to the EN and EN pins should be used.
When a direct connection to GND is used, there is no current limitation.
When the connection is open, the switch is in a state of continuously held current limits.
Thermal Shutdown
The MB3842/MB3845 has a thermal shutdown function which turns the switch off and sets the latch to protect
the device when junction temperature exceeds 125°C.
At the same time the OC output signal goes to “L” level to notify external systems.
The latch function can be reset by sending a low signal to the EN input of the MB3842, or a high signal to the
EN input of the MB3845.
Slow Start
The on/off switching time can be delayed by applying capacitance between the SS and GND pins. Controlling
the on time can soften surge current to the load side capacitance when power is turned on.
For details, see “Css vs. tON (SS) characteristics” on p. 9.
UVLO
A VIN voltage monitoring function is provided, so that when VIN voltage exceeds 2.3 V (typ) the OC pin voltage
goes to “H” level. When VIN voltage falls below 2.1V (typ), the OC output goes to “L” state.
Error Flag OC Pin
The OC pin produces a “L” signal in case of a UVLO, overcurrent, or over-temperature condition. In case of
overcurrent, the output has a pulse waveform. See P12.
(note) Output current limit setting resistance values are shown on P9, and in the following table. (CS pin-to-GND)
Standard Values
VIN/ISW
VIN 5.0V
VIN 3.3V
VIN 2.5V
0.1 A
0.2 A
0.3 A
0.4 A
0.5 A
0.6 A
0.7 A
0.8 A
0.9 A
1.0 A
6.2 kΩ 4.3 kΩ 3.3 kΩ 2.7 kΩ 2.2 kΩ 2.0 kΩ 1.8 kΩ 1.6 kΩ 1.4 kΩ 1.3 kΩ
9.1 kΩ 5.6 kΩ 4.3 kΩ 3.3 kΩ 2.7 kΩ 2.4 kΩ 2.0 kΩ 1.8 kΩ 1.6 kΩ 1.5 kΩ
13 kΩ
7.5 kΩ 5.1 kΩ 3.9 kΩ 3.0 kΩ 2.7 kΩ 2.2 kΩ 2.0 kΩ 1.8 kΩ 1.6 kΩ
13
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MB3842/MB3845
■ TYPICAL APPLICATION
Top View
MB3842/MB3845
EN1
EN1
GND
OC1
Control signal
Pull-up resistance
CSS
SS1
RLIM
OUT1
OUT1
OUT1
CS1
VIN1
VIN1
Load
VIN2
VIN2
OUT2
OUT2
OUT2
OC2
Load
RLIM
CS2
SS2
Pull-up resistance
CSS
EN2
EN2
GND
Control signal
14
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MB3842/MB3845
■ APPLICATION EXAMPLE
(1) Dual-Port Self-Powered Hub Application (NON-GANG Mode Connection)
USB 5 V Controller
Overcurrent
MB3842/MB3845
ON/OFF
GND
EN1,EN1
SS1
OC1
OUT1
CS1
VIN1
VIN1
OUT1
OUT1
USB
Port 1
Power Supply
5 V
OUT2
OUT2
OUT2
OC2
VIN2
USB
Port 2
VIN2
CS2
SS2
GND
EN2,EN2
*The MB3842 can also be adapted for use with 3.3V controllers.
USB Port 500mA MAX Par Port
Smoothing capacitors should be placed between VIN and GND, or between OUT and GND as required.
15
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MB3842/MB3845
(2) Dual-Port Bus Powered Hub Application (GANG Mode Connection)
USB
Overcurrent
MB3842/MB3845
ON/OFF
GND
EN1,EN1
OC1
SS1
USB Port1(×4)
OUT1
OUT1
OUT1
OUT2
OUT2
OUT2
OC2
CS1
VIN1
VIN1
VIN2
VIN2
CS2
400 mA MAX
(100 mA ×4)
5 V
Upstream Port
USB Port2(×4)
400 mA MAX
(100 mA ×4)
SS2
EN2,EN2
GND
USB Port 100mA MAX Par Port
Smoothing capacitors should be placed between VIN and GND, or between OUT and GND as required.
16
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MB3842/MB3845
■ USAGE PRECAUTION
1. Never use settings exceeding maximum rated conditions.
Exceeding maximum rated conditions may cause permanent damage to the LSI.
Also, it is recommended that recommended operating conditions be observed in normal use.
Exceeding recommended operating conditions may adversely affect LSI reliability.
2. Use this device within recommended operating conditions.
Recommended operating conditions are values within which normal LSI operation is warranted.
Standard electrical characteristics are warranted within the range of recommended operating conditions and
within the listed conditions for each parameter.
3. Printed circuit board ground lines should be set up with consideration for common
impedance.
4. Take appropriate static electricity measures.
• Containers for semiconductor materials should have anti-static protection or be made of conductive material.
• After mounting, printed circuit boards should be stored and shipped in conductive bags or containers.
• Work platforms, tools, and instruments should be properly grounded.
• Working personnel should be grounded with resistance of 250 kΩ to 1 MΩ between body and ground.
5. Do not apply negative voltages.
The use of negative voltages below –0.3 V may create parasitic transistors on LSI lines, which can cause
abnormal operation.
6. Reverse Current Prevention Function
Current cannot flow back to the VIN pin with the switch off, even when the OUT pin voltage is higher than the
VIN pin (OUT ≥ VIN), however when VIN pin voltage is lower than 1.5 V circuit functions are lost, so that in this
case there is danger of reverse current flow. For applications in which reverse flow is not acceptable, set
VIN ≥ 1.5 V.
■ ORDERING INFORMATION
Part number
MB3842PFV
MB3845PFV
MB3845PFV-ER
Package
Remarks
20-pin Plastic SSOP
(FPT-20P-M03)
17
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MB3842/MB3845
■ PACKAGE DIMENSION
*: These dimensions do not include resin protrusion.
20-pin plastic SSOP
(FPT-20P-M03)
1.25 +–00..1200
*
6.50±0.10(.256±.004)
(Mounting height)
.049 +–..000048
0.10(.004)
INDEX
*
4.40±0.10 6.40±0.20
(.173±.004) (.252±.008)
5.40(.213)
NOM
"A"
0.22 +–00..0150
.009 +–..000024
0.15 +–00..0025
.006 +–..000012
Details of "A" part
0.10±0.10(.004±.004)
0.65±0.12
(.0256±.0047)
(STAND OFF)
0
10°
0.50±0.20
(.020±.008)
5.85(.230)REF
Dimensions in mm (inches).
C
1994 FUJITSU LIMITED F20012S-2C-4
18
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MB3842/MB3845
FUJITSU LIMITED
All Rights Reserved.
The contents of this document are subject to change without notice.
Customers are advised to consult with FUJITSU sales
representatives before ordering.
The information and circuit diagrams in this document are
presented as examples of semiconductor device applications, and
are not intended to be incorporated in devices for actual use. Also,
FUJITSU is unable to assume responsibility for infringement of
any patent rights or other rights of third parties arising from the use
of this information or circuit diagrams.
The products described in this document are designed, developed
and manufactured as contemplated for general use, including
without limitation, ordinary industrial use, general office use,
personal use, and household use, but are not designed, developed
and manufactured as contemplated (1) for use accompanying fatal
risks or dangers that, unless extremely high safety is secured, could
have a serious effect to the public, and could lead directly to death,
personal injury, severe physical damage or other loss (i.e., nuclear
reaction control in nuclear facility, aircraft flight control, air traffic
control, mass transport control, medical life support system, missile
launch control in weapon system), or (2) for use requiring
extremely high reliability (i.e., submersible repeater and artificial
satellite).
Please note that Fujitsu will not be liable against you and/or any
third party for any claims or damages arising in connection with
above-mentioned uses of the products.
Any semiconductor devices have an inherent chance of failure. You
must protect against injury, damage or loss from such failures by
incorporating safety design measures into your facility and
equipment such as redundancy, fire protection, and prevention of
over-current levels and other abnormal operating conditions.
If any products described in this document represent goods or
technologies subject to certain restrictions on export under the
Foreign Exchange and Foreign Trade Law of Japan, the prior
authorization by Japanese government will be required for export
of those products from Japan.
F0001
FUJITSU LIMITED Printed in Japan
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