Fujitsu MB3842 Datasheet

Assp for power supply applications power management 2-ch switch ic

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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
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
is divided between the two channels, which operate independently of each other.
IN
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
• ENABLE
:EN threshold
:Power supply current at output off = 0 A
• 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
• Either channel may be operated alone.
PACKAGE
threshold
1.5 V)
IN
20-pin plastic SSOP
(FPT-20P-M03)
2.3V/2.1 V hysteresis 200 mV
EN 1.4V/1.6 V for MB3842, EN 1/2 V
EN
0.8V for MB3842, EN
DS04-27604-2E
2.5V)
IN
for MB3845
IN
V
for MB3845
IN

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Summary of Contents for Fujitsu MB3842

  • Page 1 FUJITSU SEMICONDUCTOR DS04-27604-2E 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.)
  • Page 2: Pin Assignment

    MB3842/MB3845 PIN ASSIGNMENT EN1, EN1 OUT1 VIN1 OUT1 SSOP-20P (FPT-20P-M03) VIN1 OUT1 VIN2 OUT2 VIN2 OUT2 OUT2 EN2, EN2 Enable Enable Slow Start Current Set Over Current The functions of pin 1 and pin 10 differ on the MB3842 and MB3845. EN for MB3842/EN for MB3845...
  • Page 3: Pin Description

    MB3842/MB3845 PIN DESCRIPTION Pin no. Symbol Descriptions Control signal input pin. Set “H” to turn switch on, “L” to turn toff. At 0.8 V or less, the chip is in STBY state (MB3842) and current consumption is less than 1 A. “L”...
  • Page 4 MB3842/MB3845 BLOCK DIAGRAM (for 1 channel) MB3842 OUT1 Over current Charge detection 1 pump1 COMP OSC1 COMP VIN1 BGR1 Temperature protection 1 MB3845 OUT1 Charge Over current pump1 detection 1 COMP OSC1 COMP VIN1 BGR1 Temperature protection 1...
  • Page 5: Absolute Maximum Ratings

    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.
  • Page 6 MB3842/MB3845 ELECTRICAL CHARACTERISTICS (per 1 ch) • MB3842/MB3845 = 5 V, Ta = +25 C) Value Parameter Symbol Condition Unit Min. Typ. Max. Switch resistance =0.6A — = 0 A — = 0.6 A — IN pin input current 0.8V for MB3842, —...
  • Page 7 MB3842/MB3845 DIAGRAM • Normal operation SW OFF SW ON SW ON Overcurrent does not occur • At V fall 2.3 V 2.1 V SW ON SW ON SW ON Overcurrent does not occur 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)
  • Page 8 MB3842/MB3845 (Continued) • At overcurrent detection SW ON • At over-temperature occurrence Over-temperature Over-temperature corrected occurs SW ON SW OFF Overcurrent does not occur 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.)
  • Page 9: Typical Characteristics

    MB3842/MB3845 TYPICAL CHARACTERISTICS • R vs. limit current characteristics These are the limiting value characteristics for CS pin-to-GND external resistance and output current (OC flag). 5.0 V 3.3 V 2.5 V 0.01 1000 10000 100000 • C vs. T (SS) characteristics There are the characteristics for SS pin-to-GND external capacitance and output ON time.
  • Page 10 MB3842/MB3845 (Continued) • SW resistance vs. temperature characteristics at 0.1 A at 0.6 A at 1 A Temperature Ta ( C) • Temperature-depended SW resistance vs. V (V) characteristics 40 C 25 C 100 C voltage (V) (Continued)
  • Page 11 MB3842/MB3845 (Continued) • Output power (I ) saturation characteristics Measurement circuit EN, EN “Open” 100 k These are the output saturation current characteristics in overcurrent state.(when not controlled by the OC pin warning flag) 1600 1400 not limited (CS GND) 1200 1000 set to 2.0k , 0.6A...
  • Page 12 MB3842/MB3845 (Continued) • OC pin flag pull-up resistance (pull-up power 5V) dependant overcurrent operation 1 V / 500 NS 50 k 1 V / 500 NS 1 V / 500 NS 10 k 1 V / 500 NS 100 k •...
  • Page 13: Functional Description

    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 (V 5 V, current limit at 600mA). Because the setting value is dependent on V voltage, the user should select the optimum resistance value for the value of V voltage .
  • Page 14: Typical Application

    MB3842/MB3845 TYPICAL APPLICATION Top View MB3842/MB3845 Control signal Pull-up resistance OUT1 Load OUT1 VIN1 VIN1 OUT1 VIN2 OUT2 VIN2 OUT2 Load OUT2 Pull-up resistance Control signal...
  • Page 15: Application Example

    MB3842/MB3845 APPLICATION EXAMPLE (1) Dual-Port Self-Powered Hub Application (NON-GANG Mode Connection) USB 5 V Controller Overcurrent MB3842/MB3845 ON/OFF EN1,EN1 OUT1 VIN1 OUT1 Port 1 Power Supply OUT1 VIN1 OUT2 VIN2 Port 2 OUT2 VIN2 OUT2 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 V and GND, or between OUT and GND as required.
  • Page 16 MB3842/MB3845 (2) Dual-Port Bus Powered Hub Application (GANG Mode Connection) Overcurrent MB3842/MB3845 ON/OFF EN1,EN1 USB Port1( 4) OUT1 OUT1 VIN1 400 mA MAX (100 mA 4) VIN1 OUT1 Upstream Port VIN2 OUT2 USB Port2( 4) VIN2 OUT2 OUT2 400 mA MAX (100 mA 4) EN2,EN2 USB Port 100mA MAX Par Port...
  • Page 17: Usage Precaution

    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.
  • Page 18: Package Dimension

    INDEX 4.40±0.10 6.40±0.20 5.40(.213) (.173±.004) (.252±.008) "A" +0.10 +0.05 Details of "A" part 0.65±0.12 0.22 0.15 –0.05 –0.02 (.0256±.0047) +.004 +.002 .009 .006 –.002 –.001 0.10±0.10(.004±.004) (STAND OFF) 10° 0.50±0.20 5.85(.230)REF (.020±.008) Dimensions in mm (inches). 1994 FUJITSU LIMITED F20012S-2C-4...
  • Page 19 (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.

This manual is also suitable for:

Mb3845

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