Functional Block Diagram

Applications Information

The LM9140 is a precision micro-power curvature-corrected

bandgap shunt voltage reference. The LM9140 has been de-

signed for stable operation without the need of an external

capacitor connected between the “+” pin and the “−” pin. If,

however, a bypass capacitor is used, the LM9140 remains

stable. Reducing design effort is the availability of several

fixed reverse breakdown voltages: 2.500V, 4.096V, 5.000V,

and 10.000V. The minimum operating current increases from

60 µA for the LM9140-2.5 to 100 µA for the LM9140-10.0. All

versions have a maximum operating current of 15 mA.

The 4.096V version allows single +5V 12-bit ADCs or DACs

to operate with an LSB equal to 1 mV. For 12-bit ADCs or

DACs that operate on supplies of 10V or greater, the 8.192V

version gives 2 mV per LSB.

In a conventional shunt regulator application (

Figure 1), an

external series resistor (R

ply voltage and the LM9140. R

flows through the load (I

current and supply voltage may vary, R

enough to supply at least the minimum acceptable I

LM9140 even when the supply voltage is at its minimum and

the load current is at its maximum value. When the supply

voltage is at its maximum and I

be large enough so that the current flowing through the

LM9140 is less than 15 mA.

R

operating current, (I

breakdown voltage, V

Typical Applications

DS011393-12

DS011393-20

FIGURE 1. Shunt Regulator

7

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