TLV71209DBVT datasheet(10/26 Pages) TI2

10 / 26 page

P =(V

)

OUT

TLV712xx

SBVS150A – SEPTEMBER 2010 – REVISED JANUARY 2011

www.ti.com

DROPOUT VOLTAGE

The internal protection circuitry of the TLV712xx has

been designed to protect against overload conditions.

The TLV712xx uses a PMOS pass transistor to

It was not intended to replace proper heatsinking.

achieve low dropout. For the complete output voltage

Continuously running the TLV712xx into thermal

range of 0.7 V to 1.2 V, the device can supply 300

shutdown degrades device reliability.

mA with a rated minimum input voltage of 2.0 V. Note

that the dropout voltage specification is not relevant

POWER DISSIPATION

for the TLV712xx family of devices because the

output voltage range of the device does not exceed

The ability to remove heat from the die is different for

1.2 V and the minimum input voltage for the device is

each

package

type,

presenting

different

2.0 V.

considerations in the printed circuit board (PCB)

layout. The PCB area around the device that is free

TRANSIENT RESPONSE

of other components moves the heat from the device

to the ambient air.

As with any regulator, increasing the size of the

output capacitor reduces over-/undershoot magnitude

Thermal

performance

data

for

TLV712xx

were

but increases the duration of the transient response.

gathered using the TLV700 evaluation module (EVM),

a two-layer board with two ounces of copper per side.

The dimensions and layout for the SOT23-5 package

UNDERVOLTAGE LOCKOUT (UVLO)

EVM are shown in Figure 19 and Figure 20.

The TLV712xx uses an undervoltage lockout circuit to

Corresponding thermal performance data are given in

keep the output shut off until internal circuitry is

Table 1. Note that this board has provision for

operating properly.

soldering not only the SOT23-5 package on the

bottom layer, but also an SC-70 package on the top

THERMAL INFORMATION

layer. The dimensions and layout of the SON-6 (DSE)

package EVM are shown in Figure 21 and Figure 22.

Thermal protection disables the output when the

Corresponding thermal performance data are given in

junction temperature rises to approximately +165°C,

Table

Using

heavier

copper

increases

the

allowing the device to cool. When the junction

effectiveness in removing heat from the device. The

temperature cools to approximately +145°C, the

addition of plated through-holes to heat-dissipating

output circuitry is again enabled. Depending on power

layers also improves heatsink effectiveness.

dissipation,

thermal

resistance,

and

ambient

temperature, the thermal protection circuit may cycle

Power dissipation depends on input voltage and load

on and off. This cycling limits the dissipation of the

conditions. Power dissipation (PD) is equal to the

regulator, protecting it from damage as a result of

product of the output current and the voltage drop

overheating.

across the output pass element, as shown in

Equation 2.

Any tendency to activate the thermal protection circuit

indicates

excessive

power

dissipation

(2)

inadequate heatsink. For reliable operation, junction

temperature should be limited to +125°C maximum.

PACKAGE MOUNTING

To estimate the margin of safety in a complete design

Solder

pad

footprint

recommendations

for

the

(including

heatsink),

increase

the

ambient

TLV712xx are available from the Texas Instruments

temperature until the thermal protection is triggered;

web site at www.ti.com. The recommended land

use worst-case loads and signal conditions.

pattern for the DBV and DSE packages are shown in

Figure 23 and Figure 24 respectively.

Table 1. EVM Dissipation Ratings

PACKAGE

RqJA

TA < +25°C

TA = +70°C

TA = +85°C

DBV

200°C/W

500 mW

275 mW

200 mW

DSE

180°C/W

555 mW

305 mW

222 mW

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