SP6200EM5-2.7SLASHTR datasheet(8/17 Pages) SIPEX

8 / 17 page

Date:5/25/04

SP6200/6201 100/200mA CMOS LDO Regulator

equation:

PD = (VIN - VOUT)*IOUT + VIN*IGND

≅ (VIN - VOUT) * IOUT

Substituting PD(max) for PD and solving for the

operating conditions that are critical to the ap-

plication will give the maximum operating con-

ditions for the regulator circuit. For example, if

we are operating the SP6201- 3.0V at room

temperature, with a SOT-23-5 package on a 4

layer standard board we can determine the maxi-

mum input voltage for a set output current.

PD(max) =

(125

°C -25°C) = 1.1W

(90

°C/W)

To prevent the device from entering thermal

shutdown, maximum power dissipation can not

be exceeded. Using the output voltage of 3.0V

and an output current of 200 mA, the maximum

input voltage can be determined. Ground pin

current can be taken from the electrical spec’s-

table (I

GND=200uA at IOUT=200uA). The maxi-

mum input voltage is determined as follows:

1.1W = (VIN – 3.0V)*200mA + VIN*0.2mA

Solving for VIN, we get:

VIN =

(1.1W + 0.6W)

200.2mA

After calculations, we find that the maximum

input voltage of a 3.0V application at 200mA of

output current in an SOT-23-5 package is 8.4V.

Dual-Supply Operation

When used in dual supply systems where the

regulator load is returned to a negative supply,

the output voltage must be diode clamped to

ground.

THEORY OF OPERATION: Continued

SP6200EM5-2.7/TR Datasheet(PDF) 8 Page - Sipex Corporation