LM4050AIM3X-2.5 National Semiconductor, LM4050AIM3X-2.5 Datasheet - Page 10

• Manufacturer Part Number: LM4050AIM3X-2.5
• Description: Precision Micropower Shunt Voltage Reference
• Manufacturer: National Semiconductor

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Applications Information
The LM4050 is a precision micro-power curvature-corrected
bandgap shunt voltage reference. For space critical applica-
tions, the LM4050 is available in the sub-miniature SSOT-23
surface-mount package. The LM4050 has been designed 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 LM4050 remains stable. Re-
ducing design effort is the availability of several fixed reverse
breakdown voltages: 2.500V, 4.096V, 5.000V, 8.192V, and
10.000V. The minimum operating current increases from
60 µA for the LM4050-2.5 to 100 µA for the LM4050-10.0. All
versions have a maximum operating current of 15 mA.
LM4050s in the SSOT-23 packages have a parasitic Schot-
tky diode between pin 2 (−) and pin 3 (Die attach interface
contact). Therefore, pin 3 of the SSOT-23 package must be
left floating or connected to pin 2.
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 LM4050. R
flows through the load (I
current and supply voltage may vary, R
enough to supply at least the maximum guaranteed I
L
) and the LM4050 (I
S
) is connected between the sup-
S
determines the current that
S
should be small
Q
). Since load
RMIN
10
(spec. table) to the LM4050 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
minimum, R
flowing through the LM4050 is less than 15 mA.
R
operating current, (I
breakdown voltage, V
Typical Applications
S
is determined by the supply voltage, (V
S
should be large enough so that the current
FIGURE 1. Shunt Regulator
L
R
and I
.
Q
), and the LM4050’s reverse
DS101045-15
S
), the load and
L
is at its