LM4040AIM3X-2.0 National Semiconductor, LM4040AIM3X-2.0 Datasheet - Page 26

• Manufacturer Part Number: LM4040AIM3X-2.0
• Description: IC SHUNT VREF HI PREC SOT23-3
• Manufacturer: National Semiconductor

Specifications of LM4040AIM3X-2.0

• Reference Type: Shunt
• Voltage - Output: 2.048V
• Tolerance: ±0.1%
• Temperature Coefficient: 100ppm/°C
• Number Of Channels: 1
• Current - Cathode: 60µA
• Current - Output: 15mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: TO-236-3, SC-59, SOT-23-3
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Input: -
• Current - Quiescent: -
• Other names: 8LM4040AIM3X-2.0

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Applications Information
The LM4040 is a precision micro-power curvature-corrected
bandgap shunt voltage reference. For space critical applica-
tions, the LM4040 is available in the sub-miniature SOT-23
and SC70 surface-mount package. The LM4040 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 LM4040 remains
stable. Reducing design effort is the availability of several
fixed reverse breakdown voltages: 2.048V, 2.500V, 3.000V,
4.096V, 5.000V, 6.000, 8.192V, and 10.000V. The minimum
operating current increases from 60 µA for the LM4040-2.048
and LM4040-2.5 to 100 μA for the LM4040-10.0. All versions
have a maximum operating current of 15 mA.
LM4040s in the SOT-23 packages have a parasitic Schottky
diode between pin 2 (−) and pin 3 (Die attach interface con-
tact). Therefore, pin 3 of the SOT-23 package must be left
floating or connected to pin 2.
LM4040s in the SC70 have a parasitic Schottky diode be-
tween pin 1 (−) and pin 2 (Die attach interface contact).
Therefore, pin 2 must be left floating or connected to pin1.
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.
The typical thermal hysteresis specification is defined as the
change in +25°C voltage measured after thermal cycling. The
Typical Applications
FIGURE 1. Shunt Regulator
26
device is thermal cycled to temperature -40°C and then mea-
sured at 25°C. Next the device is thermal cycled to tempera-
ture +125°C and again measured at 25°C. The resulting
V
hysteresis. Thermal hysteresis is common in precision refer-
ences and is induced by thermal-mechanical package stress.
Changes in environmental storage temperature, operating
temperature and board mounting temperature are all factors
that can contribute to thermal hysteresis.
In a conventional shunt regulator application
external series resistor (R
voltage and the LM4040. R
through the load (I
and supply voltage may vary, R
supply at least the minimum acceptable I
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
enough so that the current flowing through the LM4040 is less
than 15 mA.
R
operating current, (I
breakdown voltage, V
OUT
S
1132315
is determined by the supply voltage, (V
delta shift between the 25°C measurements is thermal
L
) and the LM4040 (I
L
L
R
is at its minimum, R
and I
.
S
) is connected between the supply
S
determines the current that flows
Q
), and the LM4040's reverse
S
should be small enough to
Q
). Since load current
S
Q
S
should be large
to the LM4040
), the load and
(Figure
1) , an