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DS04-27604-2E

FUJITSU SEMICONDUCTOR

DATA SHEET

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. 100m

) 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 (V

IN

 

>

 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.
V

IN

 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. 100m

)

• Low input voltage operation (2.5 V to 5.5 V)
• Switch current (max. 0.6 A)
• UVLO

:V

IN  

threshold 

2.3V/2.1 V hysteresis 200 mV

• ENABLE

:EN threshold 

EN 1.4V/1.6 V for MB3842, EN 1/2 V

IN

 for MB3845

:Power supply current at output off = 0

µ

A     EN 

0.8V for MB3842, EN 

=

 V

IN

 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 (V

IN 

 

 1.5 V)

• Either channel may be operated alone.

PACKAGE

 20-pin plastic SSOP

(FPT-20P-M03)

Summary of Contents for MB3842

Page 1: ...s 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 VIN ...

Page 2: ...OUT1 OUT2 OUT2 OUT2 OC2 GND 1 2 3 4 5 6 7 8 9 10 EN1 EN1 SS1 CS1 VIN1 VIN1 VIN2 VIN2 CS2 SS2 EN2 EN2 SSOP 20P FPT 20P M03 EN Enable CS Current Set OC Over Current EN Enable SS Slow Start The functions of pin 1 and pin 10 differ on the MB3842 and MB3845 EN for MB3842 EN for MB3845 ...

Page 3: ... 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 3 8 CS Current limit setting pin The limit current level is set by connecting this pin to external resistance 4 5 6 7 VIN Switch output pin An UVLO VIN power monitor function is provided so that when VIN reaches 2 3V typ or higher the OC pin vo...

Page 4: ... EN1 VIN1 OSC1 BGR1 COMP FF1 Q S R OC1 OUT1 CS1 COMP MB3842 SS1 EN1 VIN1 OSC1 BGR1 COMP FF1 Q S R OC1 OUT1 CS1 COMP MB3845 Temperature protection 1 Charge pump1 Over current detection 1 Charge pump1 Over current detection 1 Temperature protection 1 ...

Page 5: ...es 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 Parameter Symbol Condition Rating Unit Max Min Input voltage VIN 0 3 7 0 V ENABLE voltage VEN...

Page 6: ...2 kΩ 0 06 0 1 0 14 A OC sink current IOCS VOC 0 4 V at OC active 2 0 5 0 mA IOCL VOC 5 0 V at OC non active 1 0 µA Temperature protection Tj TLIM 125 C OUT pin rise time tON SS pin Open OUT pin 100 kΩ pull down 100 200 µs OUT pin fall time tOFF SS pin Open OUT pin 100 kΩ pull down 50 120 µs Parameter Symbol Condition Value Unit Min Typ Max ENABLE pin input current IENH VEN 5 V ISW 0 A 5 10 µA IENL...

Page 7: ...N SW ON 5 V Hi Low 5 V 5 V Normal operation SW ON SW ON SW ON 2 3 V 2 1 V 5 V Hi Low 5 V 5 V 0 V VIN EN EN VOUT IOUT OC Overcurrent does not occur At VIN fall 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 ...

Page 8: ...er temperature corrected Over temperature occurs SW OFF VIN EN EN VOUT IOUT OC 5 V Hi Low 5 V 5 V 0 V Overcurrent does not occur Latch set Latch released At over temperature occurrence 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 ...

Page 9: ... vs limit current characteristics VIN 5 0 V VIN 3 3 V VIN 2 5 V 100 10 1 0 1 10 100 1000 10000 100000 CSS pF t ON ms CSS vs TON SS characteristics ThesearethelimitingvaluecharacteristicsforCSpin to GND external resistance and output current OC flag There are the characteristics for SS pin to GND external capacitance and output ON time ...

Page 10: ...0 0 20 40 60 80 100 120 at 0 1 A at 0 6 A at 1 A 40 C 25 C 100 C 150 140 130 120 110 100 90 80 70 60 50 2 3 4 5 6 7 SW resistance vs temperature characteristics Temperature depended SW resistance vs VIN V characteristics SW resistance mΩ Temperature Ta C SW resistance mΩ VIN voltage V ...

Page 11: ...A VSW V Measurement circuit These are the output saturation current characteristics in overcurrent state when not controlled by the OC pin warning flag RLIM not limited CS GND RLIM set to 2 0kΩ 0 6A Temperature protection range RLIM set to 6 2kΩ 0 1A Overcurrent flag set when set for 0 1A Overcurrent flag set when set for 0 6A Unlimited Output power ISW saturation characteristics Open ...

Page 12: ...cs Power dissipation P D W 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 1 V 500 NS 50 kΩ Temperature Ta C 1 V 500 NS 1 kΩ GND 1 V 500 NS 10 kΩ 1 V 500 NS 100 kΩ OC pin flag pull up resistance pull up power 5V dependant overcurrent operation ...

Page 13: ...ems 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...

Page 14: ...PPLICATION CSS RLIM RLIM CSS EN1 EN1 SS1 CS1 VIN1 VIN1 VIN2 VIN2 CS2 SS2 EN2 EN2 GND OC1 OUT1 OUT1 OUT1 OUT2 OUT2 OUT2 OC2 GND MB3842 MB3845 Top View Control signal Control signal Pull up resistance Load Load Pull up resistance ...

Page 15: ...t ON OFF Power Supply USB Port 1 USB Port 2 MB3842 MB3845 EN1 EN1 SS1 CS1 VIN1 VIN1 VIN2 VIN2 CS2 SS2 EN2 EN2 GND OC1 OUT1 OUT1 OUT1 OUT2 OUT2 OUT2 OC2 GND 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 ...

Page 16: ...stream Port MB3842 MB3845 USB Port1 4 USB Port2 4 400 mA MAX 100 mA 4 400 mA MAX 100 mA 4 EN1 EN1 SS1 CS1 VIN1 VIN1 VIN2 VIN2 CS2 SS2 EN2 EN2 GND OC1 OUT1 OUT1 OUT1 OUT2 OUT2 OUT2 OC2 GND USB Port 100mA MAX Par Port Smoothing capacitors should be placed between VIN and GND or between OUT and GND as required ...

Page 17: ...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 neg...

Page 18: ...s of A part 5 85 230 REF 6 50 0 10 256 004 0 65 0 12 5 40 213 4 40 0 10 6 40 0 20 NOM 252 008 173 004 0256 0047 006 001 002 0 02 0 05 0 15 009 002 004 0 05 0 10 0 22 049 004 008 0 10 0 20 1 25 0 10 004 A INDEX Mounting height Dimensions in mm inches 20 pin plastic SSOP FPT 20P M03 These dimensions do not include resin protrusion ...

Page 19: ...lic 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 w...

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