SIP32460DB-T2-GE1 Просмотр технического описания (PDF) - Vishay Semiconductors

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SIP32460DB-T2-GE1

50 mΩ, Slew Rate Controlled Load Switch in WCSP

Vishay Semiconductors 

www.vishay.com

DETAILED DESCRIPTION

SiP32460, SiP32461, and SiP32462 are high side, slew rate

controlled, load switches. They incorporate a negative

charge pump at the gate to keep the gate to source voltage

high when turned on. This keeps the on resistance low at

lower input voltages. SiP32460 and SiP32461 are designed

with slow slew rate to minimize inrush current during turn on.

These devices have a reverse blocking circuit, when

disabled, to prevent the current from going back to the input

when the output voltage is higher than the input voltage. The

SiP32460 and SiP32462 can be used as bi-directional

switches and can be turned ON and OFF when power is at

either IN or OUT. The SiP32461 has an output pull down

resistor to discharge the output capacitance when the

device is off.

APPLICATION INFORMATION

Input Capacitor

While a bypass capacitor on the input is not required, a

4.7 μF or larger capacitor for CIN is recommended in almost

all applications. The bypass capacitor should be placed as

physically close as possible to the input pin to be effective

in minimizing transients on the input. Ceramic capacitors are

recommended over tantalum because of their ability to

withstand input current surges from low impedance sources

such as batteries in portable devices.

Output Capacitor

A 0.1 μF capacitor across VOUT and GND is recommended

to insure proper slew operation. There is inrush current

through the output MOSFET and the magnitude of the

inrush current depends on the output capacitor, the bigger

the COUT the higher the inrush current. There is no ESR or

capacitor type requirement.

Enable

The EN pin is compatible with CMOS logic voltage levels. It

requires at least 0.4 V or below to fully shut down the device

and 1 V or above to fully turn on the device. There is a

2.6 MΩ resistor connected between EN pin and GND pin.

Protection Against Reverse Voltage Condition

This device contains a reverse blocking circuit. When

disabled (VEN less than 0.4 V) this circuit keeps the output

current from flowing back to the input when the output

voltage is higher than the input voltage.

Thermal Considerations

Due to physical limitations of the layout and assembly of the

device the maximum switch current is 1.2 A as stated in the

Absolute Maximum Ratings table. However, another limiting

SiP32460, SiP32461, SiP32462

Vishay Siliconix

characteristic for the safe operating load current is the

thermal power dissipation of the package.

The maximum power dissipation in any application is

dependent on the maximum junction temperature,

TJ(max.) = 125 °C, the junction-to-ambient thermal resistance,

θJ-A = 205 °C/W, and the ambient temperature, TA, which

may be expressed as:

P (max.) = TJ (max.) - TA

θJ- A

= 125 - TA

205

It then follows that, assuming an ambient temperature of

70 °C, the maximum power dissipation will be limited to

about 268 mW.

So long as the load current is below the 1.2 A limit, the

maximum continuous switch current becomes a function

two things: the package power dissipation and the RDS(ON)

at the ambient temperature.

As an example let us calculate the worst case maximum

load current at TA = 70 °C. The worst case RDS(ON) at 25 °C

is 120 mΩ at VIN = 1.5 V. The RDS(ON) at 70 °C can be

extrapolated from this data using the following formula:

RDS(ON) (at 70 °C) = RDS(ON) (at 25 °C) x (1 + TC x ΔT)

Where TC is 2800 ppm/°C. Continuing with the calculation

we have

RDS(ON) (at 70 °C) = 120 mΩ x (1 + 0.0028 x (70 °C - 25 °C))

= 135 mΩ

The maximum current limit is then determined by

I LOAD (max.) <

P (max.)

R DS(ON)

which in this case is 1.99 A. Under the stated input voltage

condition, if the 1.99 A current limit is exceeded the internal

die temperature will rise and eventually, possibly damage

the device.

To avoid possible permanent damage to the device and

keep a reasonable design margin, it is recommended to

operate the device maximum up to 1.2 A only as listed in the

Absolute Maximum Ratings table.

Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon

Technology and Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and

reliability data, see www.vishay.com/ppg?67754

S14-0842-Rev. D, 28-Apr-14

12

Document Number: 67754

For technical questions, contact: powerictechsupport@vishay.com

THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT

ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000

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