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MAX1958

W-CDMA/N-CDMA Cellular Phone HBT PA Management ICs

Maxim Integrated 

W-CDMA/N-CDMA Cellular Phone HBT PA

Management ICs

VIN

2.6V TO 5.5V

R2

20Ω

C7

0.1µF

OFFSET

SHDN2

VCC

IN+

INP

MAX1958/

MAX1959

AOUT

IN-

VAOUT

= VIN+

×

1+

R6 

R7 

R6

6.8kΩ

R7

12kΩ

VREF

HBT PA

Figure 4. Op-Amp Configuration

tures must be mounted on, or close to, the object

whose temperature they are intended to measure.

There is a good thermal path between the exposed

paddle of the package and the IC die; therefore, the

MAX1958/MAX1959 can accurately measure the

temperature of the circuit board to which they are sol-

dered. If the sensor is intended to measure the temper-

ature of a heat-generating component on the circuit

board, it should be mounted as close as possible to

that component and should share supply and ground

traces (if they are not noisy) with that component where

possible. This maximizes the heat transfer from the

component to the sensor.

The thermal path between the plastic package and the

die is not as good as the path through the exposed

paddle, so the MAX1958/MAX1959, like all temperature

sensors in plastic packages, are less sensitive to the

temperature of the surrounding air than they are to the

temperature of its exposed paddle. They can be suc-

cessfully used to sense ambient temperature if the cir-

cuit board is designed to track the ambient

temperature.

As with any IC, the wiring and circuits must be kept

insulated and dry to avoid leakage and corrosion,

especially if the part is operated at cold temperatures

where condensation can occur.

MAX1958/

MAX1959

AOUT

IN-

RISO

100Ω

R6

R7

CLOAD

RLOAD

Figure 5. Configuration for Driving Larger Capacitive Loads

The junction-to-ambient thermal resistance (θJA) is the

parameter used to calculate the rise of a device junc-

tion temperature (TJ) due to its power dissipation. The

θJA for the 20-pin QFN package is +50°C/W. For the

MAX1958/MAX1959, use the following equation to

calculate the rise in die temperature:

( ) TJ = TA + Θ JA × PD(CONVERTER) + PD(OPAMP) + PD(TEMPSENSOR)

The power dissipated by the DC-to-DC converter domi-

nates in this equation. It is then reasonable to assume

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