LM4041CIM3-ADJ National Semiconductor, LM4041CIM3-ADJ Datasheet - Page 12

• Manufacturer Part Number: LM4041CIM3-ADJ
• Description: Voltage Reference
• Manufacturer: National Semiconductor

Specifications of LM4041CIM3-ADJ

• Reference Volt Tolerance ±%: 0.5%
• Mounting Type: Surface Mount
• Output Voltage Min: 1.24V
• Voltage Regulator Type: Adjustable Shunt
• Operating Temperature Max: 85°C
• Peak Reflow Compatible (260 C): No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Applications Information
The LM4041 is a precision micro-power curvature-corrected
bandgap shunt voltage reference. For space critical applica-
tions, the LM4041 is available in the sub-miniature SOT-23
surface-mount package. The LM4041 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 LM4041 remains stable. De-
sign effort is further reduced with the choice of either a fixed
1.2V or an adjustable reverse breakdown voltage. The mini-
mum operating current is 60 µA for the LM4041-1.2 and the
LM4041-ADJ. Both versions have a maximum operating cur-
rent of 12 mA.
LM4041s using the SOT-23 package have pin 3 connected
as the (-) output through the package’s die attach interface.
Therefore, the LM4041-1.2’s pin 3 must be left floating or
connected to pin 2 and the LM4041-ADJ’s pin 3 is the (-) out-
put.
In a conventional shunt regulator application (Figure 1) , an
external series resistor (R
ply voltage and the LM4041. R
flows through the load (I
current and supply voltage may vary, R
enough to supply at least the minimum acceptable I
LM4041 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
LM4041 is less than 12 mA.
R
desired load and operating current, (I
LM4041’s reverse breakdown voltage, V
The LM4041-ADJ’s output voltage can be adjusted to any
value in the range of 1.24V through 10V. It is a function of the
internal reference voltage (V
feedback resistors as shown in Figure 2 . The output voltage
is found using the equation
where V
nal V
mined by
S
should be selected based on the supply voltage, (V
REF
O
is a function of V
is the output voltage. The actual value of the inter-
V
O
= V
L
REF
) and the LM4041 (I
S
O
) is connected between the sup-
REF
. The “corrected” V
[(R2/R1) + 1]
L
S
) and the ratio of the external
is at its minimum, R
determines the current that
L
R
S
.
and I
should be small
Q
). Since load
REF
Q
), and the
S
is deter-
Q
should
S
to the
), the
(1)
12
where
typically −1.55 mV/V. You can get a more accurate indication
of the output voltage by replacing the value of V
tion (1) with the value found using equation (2).
Note that the actual output voltage can deviate from that pre-
dicted using the typical value of V
for C-grade parts, the worst-case V
For D-grade parts, the worst-case V
Typical Applications
V
V
O
REF
= V
/ V
REF
FIGURE 2. Adjustable Shunt Regulator
O
[(R2/R1) + 1]
is found in the Electrical Characteristics and is
V
FIGURE 1. Shunt Regulator
REF
= V
V
Y
V
O
= 1.240 V and
O
= (V
( V
O
REF
− V
DS011392-22
/ V
REF
Y
DS011392-34
REF
REF
)
O
/ V
) + V
/ V
/ V
O
O
Y
O
in equation (2):
is −2.5 mV/V.
is −3.0 mV/V.
REF
in equa-
(2)