Fujitsu MB3845, MB3842 User Manual

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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 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 addition, an off-state reverse current prevention function is provided to ensure accurate on/off switching action.

is low.)

> 2.5V)

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 :V

• ENABLE :EN threshold EN 1.4V/1.6 V for MB3842, EN 1/2 V

• 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 2.3V/2.1 V hysteresis 200 mV

:Power supply current at output off = 0µA EN < 0.8V for MB3842, EN = V

≥ 1.5 V)

20-pin plastic SSOP

(FPT-20P-M03)

for MB3845

MB3842/MB3845

PIN ASSIGNMENT

■

EN1, EN1

SS1

CS1

VIN1

SSOP-20P

(FPT-20P-M03)

GND

OC1

OUT1

VIN1

VIN2

CS2

SS2

EN2, EN2

EN Enable

EN Enable SS Slow Start

OUT1

OUT2

OC2

GND

CS Current Set OC Over Current

The functions of pin 1 and pin 10 differ on the MB3842 and MB3845. EN for MB3842/EN

for MB3845

PIN DESCRIPTION

■

Pin no. Symbol Descriptions

Control signal input pin.

(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.

MB3842/MB3845

1/10

Control signal input pin. Set “L” to turn switch on, “H” to turn off.

(MB3845)

At “H” level = V 1µA. Normally used as CMOS inverter input, so that recommended use is “L” level at GND +0.5V or less, and “H” level is V

Slow start setting pin. Used to adjust the switch on/off timing.

2/9 SS

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.

3/8 CS

Current limit setting pin. The limit current level is set by connecting this pin to external resistance.

Switch output pin. An UVLO (V

4/5/6/7 VIN

(typ.) or higher the OC pin v oltage goes to “H” lev el. Also if the V

2.1 V (typ.) or lower the OC output goes to “L” state. 200mV (typ) hysteresis is provided.

11/20 GND Ground pin.

External notification pin. When the switch is in on mode this pin normally outputs a “H” level signal, but

12/19 OC

changes to “L” level when an overcurrent, overtemperature, or UVLO condition is detected. This is an open drain connection, and should be pulled up to high potential using resistance.

, the chip is in STBY state and current consumption is less than

-0.5V or greater.

power monitor function) is provided so that when VIN reaches 2.3V

voltage drops to

13/14/15 16/17/18

OUT Switching output pin.(N-ch MOSFET source)

MB3842/MB3845

BLOCK DIAGRAM (for 1 channel)

■

MB3842

OUT1

SS1

EN1

VIN1

Temperature

protection 1

MB3845

Charge

pump1

OSC1

BGR1

FF1

Over current

detection 1

COMP

−

CS1

COMP

−

OC1

OUT1

CS1

OC1

SS1

EN1

VIN1

Charge

pump1

OSC1

BGR1

Temperature

protection 1

FF1

Over current

detection 1

COMP

−

COMP

−

ABSOLUTE MAXIMUM RATINGS

■

MB3842/MB3845

Parameter Symbol Condition

Unit

Max. Min.

Rating

Input voltage V ENABLE voltage V Switch current I Power dissipation P Storage temperature T

STG

Ta = +85°C — 216 mW

— –0.3 7.0 V — –0.3 7.0 V ——1.8A

— –55 +125 °C

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. Typ. Max.

Input voltage V ENABLE voltage V Switch current I SS pin capacitance C OC sink current I

OCS

VEN ≤ VIN 0—5.5V VIN = 2.5 V to 5.5 V — — 0.6 A

* — — — 10 nF

VIN = 5.0 V, VOC = 0.4 V 2.0 5.0 — mA

—2.55.05.5V

= 5.0 V (ISW = 0.6 A) 1.4 2.0 2.6 kΩ

Current limit resistance

Operating temperature

* :For CSS, R

LIM

settings, see “TYPICAL CHARACTERISTICS” and “FUNCTIONAL DESCRIPTION”.

LIM

= 5.0 V (ISW = 0.1 A) 3.6 6.2 9.1 kΩ

— –20 — +85 °C

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 de vices within their recommended operating condition r anges. Oper ation 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.

MB3842/MB3845

ELECTRICAL CHARACTERISTICS (per 1 ch)

■

• MB3842/MB3845 (VIN = 5 V, Ta = +25°C)

Parameter Symbol Condition

Min. Typ. Max.

Value

Unit

Switch resistance R

IN pin input current

I I

ISW =0.6A — 100 150 mΩ

ISW = 0 A — 350 550 µA

IN1

ISW = 0.6 A — 1.0 1.5 mA

IN2

EN < 0.8V for MB3842,

IN3

= VIN for MB3845

VIN at OC = L → H 2.1 2.3 2.5 V

IUH

——1.0µA

UVLO threshold

UVLO hysteresis width V

SWH

IUHY

VIN at OC = H → L 1.9 2.1 2.3 V

IUL

= V

IUHY

= 2.0 kΩ 0.42 0.6 0.78 A

LIM

IUH

– V

IUL

100 200 300 mV

Switch current limit

I I

SWL

OCS

= 6.2 kΩ 0.06 0.1 0.14 A

LIM

VOC = 0.4 V at OC active 2.0 5.0 — mA

OC sink current

VOC = 5.0 V at OC non-active — — 1.0 µA

LIM

SS pin: Open

OUT pin: 100 kΩ pull down SS pin: Open

OUT pin: 100 kΩ pull down

— +125 — — °C

— 100 200 µs

—50120µs

Temperature protection (T

OUT pin rise time t

OUT pin fall time t

OCL

OFF

• MB3842 (V

Parameter Symbol Condition

Min. Typ. Max.

= 5 V, Ta = +25°C)

Value

Unit

ENH

VEN = 5 V, ISW = 0 A — 5 10 µA

ENABLE pin input current

ENABLE pin threshold voltage

ENABLE hysteresis width V

V V

ENL

THEN

TLEN

ENHY

VEN = 0 V, ISW = 0 A — 0.0 — µA

— 1.45 1.60 1.75 V — 1.25 1.40 1.55 V

ENHY

= V

THEN

– V

TLEN

• MB3845 (V

Parameter Symbol Condition

ENABLE

pin input current

pin input voltage

V V

I I

ENH

ENL

IHEN

VEN = 5 V, ISW = 0 A — 0.0 — µA VEN = 0 V, ISW = 0 A — 0.0 — µA

ILEN

—0—0.8V —3.0—5.0V

100 200 300 mV

= 5 V, Ta = +25°C)

Value

Unit

Min. Typ. Max.

DIAGRAM

■

MB3842/MB3845

• Normal operation

VIN

SW OFF

OUT

IOUT

Overcurrent does not occur

•At VIN fall

VIN

5 V

Low

SW ON SW ON

5 V

2.3 V

2.1 V

SW ONSW ONSW ON

OUT

Overcurrent does not occur

OUT

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.)

Low

5 V

= 0 V

(Continued)

MB3842/MB3845

(Continued)

• At overcurrent detection

VIN

5 V

OUT

IOUT

SW ON

OFF ON OFF

• At over-temperature occurrence

VIN

Over-temperature occurs

Low

5 V

= 0 V

5 V

Over-temperature corrected

OUT

Overcurrent does not occur

SW ON

Latch set

SW OFF

Latch released

Low

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.)

TYPICAL CHARACTERISTICS

■

LIM

•R

vs. limit current characteristics

MB3842/MB3845

These are the limiting value characteristics for CS pin-to-GND external resistance and output current (OC flag).

ISW(A)

0.1

0.01 100 1000 10000 100000

•CSS vs. TON (SS) characteristics

100

LIM (Ω)

VIN = 5.0 V V

IN = 3.3 V

IN = 2.5 V

There are the characteristics for SS pin-to-GND external capacitance and output ON time.

tON(ms)

0.1 10 100 1000 10000 100000

SS (pF)

VIN = 5.0 V V

IN = 3.3 V IN = 2.5 V

(Continued)

MB3842/MB3845

(Continued)

• SW resistance vs. temperature characteristics

150

140

130

120

110

100

SW resistance (mΩ)

−60 −40 −20 0 20 40 60 80 100 120

Temperature Ta (°C)

• T emperature-depended SW resistance vs. V

150 140 130

(V) characteristics

at 0.1 A at 0.6 A at 1 A

120 110 100

−40 °C 25 °C

100 °C

SW resistance (mΩ)

80 70 60 50

234567

VIN voltage (V)

(Continued)

• Output power (ISW) saturation characteristics

MB3842/MB3845

Measurement circuit

1600

1400

IL/VIH

“Open”

RLIM

5 V

VIN

EN, EN OC

SS CS

OUT

GND

VSW

2 Ω

100 kΩ

5 V

These are the output saturation current characteristics in overcurrent state.(when not controlled by the OC pin warning flag)

not limited (CS GND)

LIM

1200

1000

800

ISW (mA)

600

400

200

0234561

set to 2.0kΩ, 0.6A

LIM

Temperature protection

range

set to 6.2kΩ, 0.1A

LIM

VSW (V)

Overcurrent flag set

(when set for 0.6A)

Overcurrent flag set

(when set for 0.1A)

Unlimited

6.2 k (0.1 A) 2 k (0.6 A)

(Continued)

MB3842/MB3845

(Continued)

• OC pin flag pull-up resistance (pull-up po wer 5V) dependant overcurrent operation

1 V / 500 NS 1 kΩ

GND

1 V / 500 NS 10 kΩ

• Power derating characteristics

1 V / 500 NS 50 kΩ

1 V / 500 NS 100 kΩ

0.9

0.8

0.7

(W)

0.6

0.5

0.4

Power dissipation P

0.3

0.2

0.1

−20 0 20 40 60 80 100

Temperature Ta (°C)

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 the user should select the optimum resistance value for the value of V 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 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. t

= 5 V, current limit at 600mA). Because the setting value is dependent on VIN voltage,

voltage . When the switching current

pins should be used.

(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 V

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/I

5.0V 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

3.3V 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

2.5V 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

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

MB3842/MB3845

TYPICAL APPLICATION

■

Control signal

MB3842/MB3845

EN1 EN1

CSS

SS1

RLIM

CS1

VIN1

VIN2

GND

OC1

OUT1

OUT2

Top View

Pull-up resistance

Load

Control signal

RLIM

CSS

VIN2

CS2

SS2

EN2 EN2

OUT2

OC2

GND

Load

Pull-up resistance

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

GND

Power Supply

SS1

CS1

VIN1

5 V

VIN2

CS2

SS2

EN2,EN2

OC1

OUT1

OUT2

OC2

GND

*The MB3842 can also be adapted for use with 3.3V controllers.

USB Port 1

USB Port 2

USB Port 500mA MAX Par Port Smoothing capacitors should be placed between V

and GND, or between OUT and GND as required.

MB3842/MB3845

(2) Dual-Port Bus Powered Hub Application (GANG Mode Connection)

USB

Overcurrent

5 V

Upstream Port

ON/OFF

MB3842/MB3845

EN1,EN1

SS1

CS1

VIN1

VIN2

CS2

SS2

EN2,EN2

GND

OC1

USB Port1(×4)

OUT1

400 mA MAX (100 mA ×4)

OUT1

OUT2

USB Port2(×4)

OUT2

400 mA MAX (100 mA ×4)

OC2

GND

USB Port 100mA MAX Par Port Smoothing capacitors should be placed between V

and GND, or between OUT and GND as required.

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 hav e 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 V

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 V

≥ 1.5 V.

ORDERING INFORMATION

■

Part number Package Remarks

MB3842PFV MB3845PFV MB3845PFV-ER

20-pin Plastic SSOP

(FPT-20P-M03)

MB3842/MB3845

PACKAGE DIMENSION

■

20-pin plastic SSOP

(FPT-20P-M03)

6.50±0.10(.256±.004)

INDEX

0.65±0.12

(.0256±.0047)

5.85(.230)REF

0.22 .009

+0.10 –0.05

+.004 –.002

*: These dimensions do not include resin protrusion.

+0.20 –0.10

1.25 .049

"A"

0.15 .006

+.008 –.004

5.40(.213)4.40±0.10 6.40±0.20 NOM(.252±.008)(.173±.004)

+0.05 –0.02

+.002 –.001

(Mounting height)

0.10(.004)

Details of "A" part

0 10°

0.10±0.10(.004±.004) (STAND OFF)

0.50±0.20

(.020±.008)

1994 FUJITSU LIMITED F20012S-2C-4

Dimensions in mm (inches).

MB3842/MB3845

FUJITSU LIMITED

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



Fujitsu MB3845, MB3842 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

DESCRIPTION

FEATURES

PACKAGE

PIN ASSIGNMENT

PIN DESCRIPTION

BLOCK DIAGRAM (for 1 channel)

ABSOLUTE MAXIMUM RATINGS

RECOMMENDED OPERATING CONDITIONS

ELECTRICAL CHARACTERISTICS (per 1 ch)

DIAGRAM

TYPICAL CHARACTERISTICS

FUNCTIONAL DESCRIPTION

TYPICAL APPLICATION

APPLICATION EXAMPLE

USAGE PRECAUTION

ORDERING INFORMATION

PACKAGE DIMENSION