TL431AILPG ON Semiconductor, TL431AILPG Datasheet - Page 11

• Manufacturer Part Number: TL431AILPG
• Description: IC REF PREC PROGR 2.5V TO-92
• Manufacturer: ON Semiconductor
• Type: Voltage Referencer

Specifications of TL431AILPG

• Reference Type: Shunt, Adjustable
• Voltage - Output: 2.495 ~ 36 V
• Tolerance: ±1%
• Temperature Coefficient: 50ppm/°C
• Number Of Channels: 1
• Current - Cathode: 1mA
• Current - Output: 100mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: TO-92-3 (Standard Body), TO-226
• Current, Supply: 1 to 100 mA
• Package Type: TO-92
• Power Dissipation: 0.7 W
• Regulator Type: Shunt
• Resistance, Thermal, Junction To Case: 83 °C/W
• Temperature, Operating, Range: -40 to +85 °C
• Voltage, Input: 2.495 V
• Voltage, Supply: 36 V
• Product: Voltage References
• Topology: Shunt References
• Output Voltage: Adjustable
• Initial Accuracy: 1 %
• Average Temperature Coefficient (typ): 50 PPM / C
• Series Vref - Input Voltage (max): 37 V
• Shunt Current (max): 100 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: Through Hole
• Shunt Current (min): 1 mA
• Fixed / Adjust / Prog: Adjust
• Output Voltage (max): 2.495 to 36V
• Reference Voltage Accuracy (max): 1
• Input Voltage (max): 37V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Current - Quiescent: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device
• Other names: TL431AILPGOS

is used in a variety of ways. It serves as a reference voltage
in circuits where a non−standard reference voltage is
needed. Other uses include feedback control for driving an
optocoupler in power supplies, voltage monitor, constant
current source, constant current sink and series pass
regulator. In each of these applications, it is critical to
maintain stability of the device at various operating currents
and load capacitances. In some cases the circuit designer can
estimate the stabilization capacitance from the stability
boundary conditions curve provided in Figure 15. However,
these typical curves only provide stability information at
specific cathode voltages and at a specific load condition.
Additional information is needed to determine the
capacitance needed to optimize phase margin or allow for
process variation.
When tested for stability boundaries, the load resistance is
150 W. The model reference input consists of an input
transistor and a dc emitter resistance connected to the device
anode. A dependent current source, Gm, develops a current
whose amplitude is determined by the difference between
the 1.78 V internal reference voltage source and the input
transistor emitter voltage. A portion of Gm flows through
compensation capacitance, C
drives the output dependent current source, Go, which is
connected across the device cathode and anode.
where I
model. Process tolerances are ±20% for resistors, ±10% for
capacitors, and ±40% for transconductances.
of circuit poles and zeroes:
P1 +
The TL431 is a programmable precision reference which
A simplified model of the TL431 is shown in Figure 31.
Model component values are:
V
Gm = 0.3 + 2.7 exp (−I
Go = 1.25 (V
Resistor and capacitor typical values are shown on the
An examination of the device model reveals the location
ref
= 1.78 V
C
2p R
is the device cathode current and Gm is in mhos
GM
1
cp
C
2) mmhos.
P1
+
2p * 1.0 M * 20 pF
C
/26 mA)
P2
. The voltage across C
1
+ 7.96 kHz
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P2
11
load:
Example 1:
Figure 32. The asymptotic plot may be expressed as the
following equation:
approximately 600 kHz. The phase margin, calculated from
the equation, would be 55.9 degrees. This model matches the
Open−Loop Bode Plot of Figure 12. The total loop would
have a unity gain frequency of about 300 kHz with a phase
margin of about 44 degrees.
I
C
P2 +
In addition, there is an external circuit pole defined by the
Also, the transfer dc voltage gain of the TL431 is:
The DC gain is:
The resulting transfer function Bode plot is shown in
The Bode plot shows a unity gain crossover frequency of
+ 10 mA, R
Z1 +
Loop gain + G
(2.138)(1.0 M)(1.25 m)(230) + 615 + 56 dB
2p R
2p R
Av + 615
P2
Z1
1
L
1
+ 230 W, C
C
C
P2
P1
G + G
G + G
+
+
1 )
P
8.25 k ) 15 k
L
2p * 10 M * 0.265 pF
2p * 15.9 k * 20 pF
M
+
M
8.25 k
8.0 kHz
L
R
R
2p R
+ 0. Define the transfer gain.
1 )
GM
GM
jf
1
GoR
GoR
1
L
500 kHz
1
C
L
+ 218 + 47 dB
jf
1 )
L
L
+
60 kHz
+ 500 kHz
jf
+ 60 kHz