TL431BILPRM [MOTOROLA]
暂无描述;Order this document by TL431/D
The TL431, A, B integrated circuits are three–terminal programmable
shunt regulator diodes. These monolithic IC voltage references operate as a
PROGRAMMABLE
PRECISION REFERENCES
low temperature coefficient zener which is programmable from V to 36 V
ref
with two external resistors. These devices exhibit a wide operating current
range of 1.0 mA to 100 mA with a typical dynamic impedance of 0.22 Ω. The
characteristics of these references make them excellent replacements for
zener diodes in many applications such as digital voltmeters, power
supplies, and op amp circuitry. The 2.5 V reference makes it convenient to
obtain a stable reference from 5.0 V logic supplies, and since the TL431, A,
B operates as a shunt regulator, it can be used as either a positive or
negative voltage reference.
SEMICONDUCTOR
TECHNICAL DATA
LP SUFFIX
PLASTIC PACKAGE
CASE 29
• Programmable Output Voltage to 36 V
• Voltage Reference Tolerance: ±0.4%, Typ @ 25°C (TL431B)
• Low Dynamic Output Impedance, 0.22 Ω Typical
• Sink Current Capability of 1.0 mA to 100 mA
Pin 1. Reference
2. Anode
(TO–92)
3. Cathode
1
2
3
• Equivalent Full–Range Temperature Coefficient of 50 ppm/°C Typical
P SUFFIX
PLASTIC PACKAGE
CASE 626
• Temperature Compensated for Operation over Full Rated Operating
Temperature Range
8
• Low Output Noise Voltage
1
DM SUFFIX
PLASTIC PACKAGE
CASE 846A
8
1
(Micro–8)
1
2
3
4
8
7
6
5
Cathode
N/C
Reference
N/C
N/C
Anode
N/C
N/C
(Top View)
D SUFFIX
PLASTIC PACKAGE
CASE 751
8
1
(SOP–8)
ORDERING INFORMATION
Operating
1
8
Temperature Range
Device
Package
TO–92
Plastic
Cathode
Reference
Anode
2
7
6
5
TL431CLP, ACLP, BCLP
TL431CP, ACP, BCP
TL431CDM, ACDM, BCDM
TL431CD, ACD, BCD
TL431ILP, AILP, BILP
TL431IP, AIP, BIP
Anode
3
4
N/C
N/C
T
A
= 0° to +70°C
Micro–8
SOP–8
TO–92
Plastic
(Top View)
SOP–8 is an internally modified SO–8 package. Pins 2,
3, 6 and 7 are electrically common to the die attach flag.
This internal lead frame modification decreases power
dissipationcapability when appropriately mounted on a
printed circuit board. SOP–8 conforms to all external
dimensions of the standard SO–8 package.
T
A
= –40° to +85°C
TL431IDM, AIDM, BIDM
TL431ID, AID, BID
Micro–8
SOP–8
Motorola, Inc. 1998
Rev 6
TL431, A, B Series
Symbol
Representative Schematic Diagram
Component values are nominal
Cathode
(K)
Cathode (K)
Reference
(R)
800
800
Reference
(R)
Anode
(A)
20 pF
Representative Block Diagram
150
3.28 k
4.0 k
1.0 k
20 pF
Reference
(R)
Cathode
(K)
10 k
2.4 k
7.2 k
+
–
2.5 V
ref
800
Anode (A)
Anode (A)
This device contains 12 active transistors.
MAXIMUM RATINGS (Full operating ambient temperature range applies, unless
otherwise noted.)
Rating
Symbol
Value
37
Unit
V
Cathode to Anode Voltage
V
KA
Cathode Current Range, Continuous
Reference Input Current Range, Continuous
Operating Junction Temperature
I
–100 to +150
–0.05 to +10
150
mA
mA
°C
K
I
ref
T
J
Operating Ambient Temperature Range
TL431I, TL431AI, TL431BI
TL431C, TL431AC, TL431BC
T
A
°C
–40 to +85
0 to +70
Storage Temperature Range
T
stg
–65 to +150
°C
Total Power Dissipation @ T = 25°C
P
D
W
A
Derate above 25°C Ambient Temperature
D, LP Suffix Plastic Package
P Suffix Plastic Package
0.70
1.10
0.52
DM Suffix Plastic Package
Total Power Dissipation @ T = 25°C
P
D
W
C
Derate above 25°C Case Temperature
D, LP Suffix Plastic Package
P Suffix Plastic Package
1.5
3.0
NOTE: ESD data available upon request.
RECOMMENDED OPERATING CONDITIONS
Condition
Symbol
Min
Max
Unit
V
Cathode to Anode Voltage
Cathode Current
V
KA
V
ref
36
I
K
1.0
100
mA
THERMAL CHARACTERISTICS
D, LP Suffix
Package
P Suffix
Package
DM Suffix
Package
Characteristic
Symbol
Unit
°C/W
°C/W
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
R
R
178
83
114
41
240
–
θJA
θJC
2
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
ELECTRICAL CHARACTERISTICS (T = 25°C, unless otherwise noted.)
A
TL431I
Typ
TL431C
Typ
Characteristic
Symbol
Min
Max
Min
Max
Unit
Reference Input Voltage (Figure 1)
V
ref
V
V
KA
= V , I = 10 mA
ref
K
T
T
A
= 25°C
2.44
2.41
2.495
–
2.55
2.58
2.44
2.423
2.495
–
2.55
2.567
A
= T
to T (Note 1)
high
low
Reference Input Voltage Deviation Over
Temperature Range (Figure 1, Notes 1, 2)
∆V
ref
–
7.0
–
–
3.0
–
mV
V = V I = 10 mA
KA ref, K
Ratio of Change in Reference Input Voltage
to Change in Cathode to Anode Voltage
mV/V
V
V
ref
KA
I
K
= 10 mA (Figure 2),
∆V
∆V
= 10 V to V
= 36 V to 10 V
–
–
–1.4
–1.0
–2.7
–2.0
–
–
–1.4
–1.0
–2.7
–2.0
KA
KA
ref
Reference Input Current (Figure 2)
= 10 mA, R1 = 10 k, R2 = ∞
I
µA
µA
ref
I
K
T
A
= 25°C
–
–
1.8
–
4.0
6.5
–
–
1.8
–
4.0
5.2
T
A
= T
to T
(Note 1)
high
low
Reference Input Current Deviation Over
Temperature Range (Figure 2, Note 1, 4)
∆I
ref
–
0.8
2.5
–
0.4
1.2
I
K
= 10 mA, R1 = 10 k, R2 = ∞
Minimum Cathode Current For Regulation
= V (Figure 1)
I
–
–
–
0.5
260
0.22
1.0
1000
0.5
–
–
–
0.5
2.6
1.0
1000
0.5
mA
nA
Ω
min
V
KA
ref
Off–State Cathode Current (Figure 3)
= 36 V, V = 0 V
I
off
V
KA
ref
Dynamic Impedance (Figure 1, Note 3)
= V , ∆I = 1.0 mA to 100 mA
|Z
|
0.22
KA
V
KA
ref
K
f ≤ 1.0 kHz
NOTES: 1. T
= –40°C for TL431AIP TL431AILP, TL431IP, TL431ILP, TL431BID, TL431BIP, TL431BILP, TL431AIDM, TL431IDM, TL431BIDM
= 0°C for TL431ACP, TL431ACLP, TL431CP, TL431CLP, TL431CD, TL431ACD, TL431BCD, TL431BCP, TL431BCLP, TL431CDM,
TL431ACDM, TL431BCDM
low
T
= +85°C for TL431AIP, TL431AILP, TL431IP, TL431ILP, TL431BID, TL431BIP, TL431BILP, TL431IDM, TL431AIDM, TL431BIDM
= +70°C for TL431ACP, TL431ACLP, TL431CP, TL431ACD, TL431BCD, TL431BCP, TL431BCLP, TL431CDM, TL431ACDM, TL431BCDM
high
2. The deviation parameter ∆V is defined as the difference between the maximum and minimum values obtained over the full operating ambient
ref
temperature range that applies.
V
max
min
ref
∆
V
= V max
ref
ref
–V min
ref
T = T – T
A
∆
2
1
V
ref
T1
T2
Ambient Temperature
The average temperature coefficient of the reference input voltage, αV is defined as:
ref
V
ref
6
X 10
V
@ 25 C
6
V
x 10
ref
ppm
C
ref
(V
V
ref
T
A
T
@ 25 C)
A
ref
αV can be positive or negative depending on whether V Min or V Max occurs at the lower ambient temperature. (Refer to Figure 6.)
ref
ref
ref
Example :
V
V
8.0 mV and slope is positive,
ref
ref
6
0.008 x 10
70 (2.495)
@ 25 C
2.495 V,
T
70 C
V
45.8 ppm
C
A
ref
V
KA
3. The dynamic impedance Z
is defined as |Z
|
KA
KA
I
K
When the device is programmed with two external resistors, R1 and R2, (refer to Figure 2) the total dynamic impedance of the circuit is defined as:
R1
|Z
|
|Z
|
1
KA
KA
R2
3
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
ELECTRICAL CHARACTERISTICS (T = 25°C, unless otherwise noted.)
A
TL431AI
TL431AC
Typ
TL431B
Typ
Characteristic
Symbol Min
Typ
Max
Min
Max
Min
Max
Unit
Reference Input Voltage (Figure 1)
V
ref
V
V
KA
= V , I = 10 mA
ref
K
T
A
= 25°C
2.47 2.495 2.52 2.47 2.495 2.52 2.483 2.495 2.507
T
A
= T
to T
high
2.44
–
2.55 2.453
–
2.537 2.475 2.495 2.515
low
Reference Input Voltage Deviation Over
Temperature Range (Figure 1, Notes 1, 2)
∆V
ref
–
7.0
–
–
3.0
–
–
3.0
–
mV
V = V I = 10 mA
KA ref, K
Ratio of Change in Reference Input Voltage
to Change in Cathode to Anode Voltage
mV/V
V
ref
V
KA
I
K
= 10 mA (Figure 2),
∆V
∆V
= 10 V to V
= 36 V to 10 V
–
–
–1.4 –2.7
–1.0 –2.0
–
–
–1.4
–1.0
–2.7
–2.0
–
–
–1.4
–1.0
–2.7
–2.0
KA
KA
ref
Reference Input Current (Figure 2)
= 10 mA, R1 = 10 k, R2 = ∞
∆I
µA
µA
ref
I
K
T
A
= 25°C
–
–
1.8
–
4.0
6.5
–
–
1.8
–
4.0
5.2
–
–
1.1
–
2.0
4.0
T
A
= T
to T
(Note 1)
high
low
Reference Input Current Deviation Over
Temperature Range (Figure 2, Note 1)
∆I
ref
–
0.8
2.5
–
0.4
1.2
–
0.4
1.2
I
K
= 10 mA, R1 = 10 k, R2 = ∞
Minimum Cathode Current For Regulation
= V (Figure 1)
I
–
–
–
0.5
260
0.22
1.0
1000
0.5
–
–
–
0.5
260
0.22
1.0
1000
0.5
–
–
–
0.5
230
0.14
1.0
500
0.3
mA
nA
Ω
min
V
KA
ref
Off–State Cathode Current (Figure 3)
= 36 V, V = 0 V
I
off
V
KA
ref
Dynamic Impedance (Figure 1, Note 3)
= V , ∆I = 1.0 mA to 100 mA
|Z
|
KA
V
KA
ref
K
f ≤ 1.0 kHz
NOTES: 1. T
= –40°C for TL431AIP TL431AILP, TL431IP, TL431ILP, TL431BID, TL431BIP, TL431BILP, TL431AIDM, TL431IDM, TL431BIDM
= 0°C for TL431ACP, TL431ACLP, TL431CP, TL431CLP, TL431CD, TL431ACD, TL431BCD, TL431BCP, TL431BCLP, TL431CDM,
TL431ACDM, TL431BCDM
low
T
= +85°C for TL431AIP, TL431AILP, TL431IP, TL431ILP, TL431BID, TL431BIP, TL431BILP, TL431IDM, TL431AIDM, TL431BIDM
= +70°C for TL431ACP, TL431ACLP, TL431CP, TL431ACD, TL431BCD, TL431BCP, TL431BCLP, TL431CDM, TL431ACDM, TL431BCDM
high
2. The deviation parameter ∆V is defined as the difference between the maximum and minimum values obtained over the full operating ambient
ref
temperature range that applies.
V
max
min
ref
∆
V
= V max
ref
ref
–V min
ref
T = T – T
A
∆
2
1
V
ref
T1
T2
Ambient Temperature
The average temperature coefficient of the reference input voltage, αV is defined as:
ref
V
ref
6
X 10
V
@ 25 C
6
V
x 10
ref
ppm
C
ref
(V
V
ref
T
A
T
@ 25 C)
A
ref
αV can be positive or negative depending on whether V Min or V Max occurs at the lower ambient temperature. (Refer to Figure 6.)
ref
ref
ref
Example :
V
V
8.0 mV and slope is positive,
ref
ref
6
0.008 x 10
70 (2.495)
@ 25 C
2.495 V,
T
70 C
V
45.8 ppm
C
A
ref
V
KA
3. The dynamic impedance Z
is defined as |Z
|
KA
KA
I
K
When the device is programmed with two external resistors, R1 and R2, (refer to Figure 2) the total dynamic impedance of the circuit is defined as:
R1
|Z
|
|Z
|
1
KA
KA
R2
4
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 1. Test Circuit for V
= V
ref
Figure 2. Test Circuit for V
> V
Figure 3. Test Circuit for I
off
KA
KA
ref
Input
V
Input
V
KA
KA
Input
V
KA
I
I
off
K
I
K
I
R1
ref
V
ref
R2
R1
R2
V
V
1
I
R1
KA
ref
ref
V
ref
Figure 4. Cathode Current versus
Cathode Voltage
Figure 5. Cathode Current versus
Cathode Voltage
150
100
50
800
600
400
200
0
V
T
= V
°
V
T
= V
°
KA
= 25
ref
KA
= 25
ref
C
C
A
A
I
Input
V
KA
Min
Input
V
KA
K
I
K
I
0
–50
–100
–200
–1.0
–2.0
–1.0
0
1.0
2.0
3.0
0
1.0
, CATHODE VOLTAGE (V)
2.0
3.0
V
, CATHODE VOLTAGE (V)
V
KA
KA
Figure 6. Reference Input Voltage versus
Ambient Temperature
Figure 7. Reference Input Current versus
Ambient Temperature
2600
2580
2560
2540
2520
2500
3.0
V
Input
KA
I
V
= V
ref
K
KA
= 10 mA
V
Max = 2550 mV
ref
2.5
2.0
1.5
1.0
0.5
0
I
V
K
ref
V
Typ = 2495 mV
ref
I
= 10 mA
I
2480
2460
K
V
Input
10k
KA
I
K
ref
2440
V
Min = 2440 mV
100
ref
2420
2400
–55
–25
0
25
50
75
C)
125
–55
–25
0
25
50
75
C)
100
125
T , AMBIENT TEMPERATURE (
°
T , AMBIENT TEMPERATURE (
°
A
A
5
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 8. Change in Reference Input
Voltage versus Cathode Voltage
Figure 9. Off–State Cathode Current
versus Ambient Temperature
0
–8.0
–16
–24
–32
1.0 k
I
T
= 10 mA
= 25°C
K
A
100
10
V
= 36 V
= 0 V
KA
Input
R1
V
KA
V
ref
1.0
I
K
V
Input
KA
I
off
R2
V
0.1
ref
0.01
–55
–25
0
25
50
75
100
125
0
10
20
, CATHODE VOLTAGE (V)
30
40
V
T , AMBIENT TEMPERATURE (5C)
KA
A
Figure 10. Dynamic Impedance
versus Frequency
Figure 11. Dynamic Impedance
versus Ambient Temperature
100
0.320
0.300
T
∆
= 25 C
A
1.0 k
50
V
= V
ref
KA
K
Output
K
I = 1.0 mA to 100 mA
K
∆
f
I
= 1.0 mA to 100 mA
I
≤
1.0 kHz
–
+
Output
K
0.280
0.260
0.240
0.220
0.200
Gnd
10
1.0
0.1
1.0 k
I
50
–
+
Gnd
1.0 k
10 k
100 k
f, FREQUENCY (MHz)
1.0 M
10 M
–55
–25
0
25
50
75
100
125
T , AMBIENT TEMPERATURE ( C)
A
Figure 12. Open–Loop Voltage Gain
versus Frequency
Figure 13. Spectral Noise Density
80
60
40
20
0
60
Output
I
K
50
40
30
20
10
15 k
9.0 µF
230
8.25 k
Gnd
V
= V
ref
KA
I
T
= 10 mA
K
= 25°C
A
Input
Output
I
T
= 10 mA
= 25 C
K
A
I
K
0
–10
1.0 k
10 k
100 k
1.0 M
10 M
10
100
1.0 k
f, FREQUENCY (Hz)
10 k
100 k
f, FREQUENCY (MHz)
6
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 14. Pulse Response
Figure 15. Stability Boundary Conditions
140
T
= 25 C
A) V
= V
ref
Stable
A
KA
KA
KA
KA
Input
Monitor
3.0
2.0
1.0
B) V
C) V
D) V
= 5.0 V @ I = 10 mA
K
120
Output
Gnd
= 10 V @ I = 10 mA
K
220
50
A
A
= 15 V @ I = 10 mA
K
Output
Pulse
100
80
D) T = 25
°C
A
B
B
Generator
f = 100 kHz
Stable
C
60
40
D
0
5.0
0
Input
20
0
0
4.0
8.0
12
16
20
100 pF
1000 pF
0.01
µF
0.1
µ
F
1.0
µF
10 µF
t, TIME (µs)
C , LOAD CAPACITANCE
L
Figure 16. Test Circuit For Curve A
of Stability Boundary Conditions
Figure 17. Test Circuit For Curves B, C, And D
of Stability Boundary Conditions
150
150
I
I
K
K
10 k
V+
V+
C
C
L
L
TYPICAL APPLICATIONS
Figure 18. Shunt Regulator
Figure 19. High Current Shunt Regulator
V+
V
out
V+
V
out
R1
R1
R2
R2
R1
V
1
V
out
ref
R2
R1
R2
V
1
V
out
ref
7
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 20. Output Control for a
Three–Terminal Fixed Regulator
Figure 21. Series Pass Regulator
V+
V
out
MC7805
Out
Common
R1
R2
V+
V
out
In
R1
R2
R1
R2
V
V
1
V
out
out
ref
R1
R2
V
V
1
V
out
out
ref
5.0V
min
V
V
ref
be
min
V
ref
Figure 22. Constant Current Source
Figure 23. Constant Current Sink
R
CL
I
V+
sink
V+
I
out
V
ref
I
Sink
R
S
V
R
ref
CL
I
out
R
S
Figure 24. TRIAC Crowbar
Figure 25. SRC Crowbar
V+
V+
V
out
V
out
R1
R1
R2
V
R2
R1
R2
V
1
out(trip)
ref
R1
R2
V
1
V
out(trip)
ref
8
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 26. Voltage Monitor
Figure 27. Single–Supply Comparator with
Temperature–Compensated Threshold
V+
V
out
V+
l
R1
R2
R3
V
out
V
in
R4
V
V
out
V+
in
V
= V
L.E.D. indicator is ‘on’ when V+ is between the
upper and lower limits.
th ref
< V
> V
ref
ref
≈ 2.0 V
R1
Lower Limit
Upper Limit
1
1
V
V
ref
ref
R2
R3
R4
Figure 28. Linear Ohmmeter
Figure 29. Simple 400 mW Phono Amplifier
25 V
1N5305
38 V
2.0 mA
330
T = 330 to 8.0
Ω
l
T
5.0 k
1%
50 k
1%
10 k
500 k
1%
5.0 M
1%
10 k
Calibrate
I
+
470 µF
8.0
Ω
Ω
360 k
56 k
100 k
Ω
V
25 V
1.0 M
Ω
V
1.0 µF
1.0 k
Ω
–
V
*
V
LM11
+
V
Range
out
Volume
47 k
0.05 µF
Tone
*Thermalloy
*THM 6024
*Heatsink on
*LP Package
–5.0 V
Range
R
X
10 k
25 k
R
x
V
out
V
9
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 30. High Efficiency Step–Down Switching Converter
150 H @ 2.0 A
V
= 10 V to 20 V
in
TIP115
V
= 5.0 V
= 1.0 A
out
I
out
1.0 k
1N5823
4.7 k
4.7 k
100 k
470
MPSA20
4.7 k
0.01µF
+
2200 µF
+
µF
0.1 µF
2.2 k
10
51 k
Test
Conditions
= 10 V to 20 V, I = 1.0 A
Results
Line Regulation
Load Regulation
Output Ripple
Output Ripple
Efficiency
V
in
V
in
V
in
V
in
V
in
53 mV (1.1%)
25 mV (0.5%)
o
= 15 V, I = 0 A to 1.0 A
o
= 10 V, I = 1.0 A
50 mVpp P.A.R.D.
o
= 20 V, I = 1.0 A
100 mVpp P.A.R.D.
82%
o
= 15 V, I = 1.0 A
o
10
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
APPLICATIONS INFORMATION
The TL431 is a programmable precision reference which
1
1
P2
Z1
60 kHz
2
R
C
2 * 10 M * 0.265 pF
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.
A simplified model of the TL431 is shown in Figure 31.
When tested for stability boundaries, the load resistance is
150 . 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 amplidute 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
P2 P2
1
1
500 kHz
2
R
C
2 * 15.9 k * 20 pF
Z1 P1
In addition, there is an external circuit pole defined by the
load:
1
P
L
2
R C
L L
Also, the transfer dc voltage gain of the TL431 is:
G R GoR
G
M GM
L
Example 1:
10 mA, R
I
230 , C
0. Define the transfer gain.
C
L
L
The DC gain is:
G
G R
M GM
GoR
L
(2.138)(1.0 M)(1.25 )(230)
615
218
56 dB
47 dB
8.25 k
Loop gain
G
8.25 k 15 k
The resulting transfer function Bode plot is shown in
Figure 32. The asymptotic plot may be expressed as the
following equation:
compensation capacitance, C . The voltage across C
drives the output dependent current source, Go, which is
connected across the device cathode and anode.
P2
P2
1
jf
500 kHz
jf
8.0 kHz 60 kHz
Model component values are:
V
= 1.78 V
ref
Gm = 0.3 + 2.7 exp (–I /26 mA)
Av
615
1
1
jf
C
where I is the device cathode current and Gm is in mhos
C
The Bode plot shows a unity gain crossover frequency of
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.
Go = 1.25 (V 2) µmhos.
cp
Resistor and capacitor typical values are shown on the
model. Process tolerances are ±20% for resistors, ±10% for
capacitors, and ±40% for transconductances.
An examination of the device model reveals the location of
circuit poles and zeroes:
1
1
P1
7.96 kHz
2
R
C
2 * 1.0 M * 20 pF
GM P1
11
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Figure 31. Simplified TL431 Device Model
V
CC
R
L
C
L
Input
3
15 k
Cathode
9.0
F
Go
1.0 mho
R
10 M
P2
Ref
V
ref
1
1.78 V
C
G
P1
20 pF
M
C
+
P2
R
R
1.0 M
ref
16
GM
0.265 pF
R
15.9 k
Z1
500 k
–
8.25 k
Anode
2
Figure 32. Example 1
Circuit Open Loop Gain Plot
Note that the transfer function now has an extra pole
formed by the load capacitance and load resistance.
Note that the crossover frequency in this case is about
250 kHz, having a phase margin of about –46 degrees.
Therefore, instability of this circuit is likely.
TL431 OPEN–LOOP VOLTAGE GAIN VERSUS FREQUENCY
60
50
40
30
Figure 33. Example 2
Circuit Open Loop Gain Plot
TL431 OPEN–LOOP BODE PLOT WITH LOAD CAP
80
20
10
0
60
40
20
–10
–20
1
2
3
4
5
6
7
10
10
10
10
10
10
10
f, FREQUENCY (Hz)
Example 2.
= 7.5 mA, R = 2.2 k , C = 0.01 F. Cathode tied to
0
I
C
L
L
reference input pin. An examination of the data sheet stability
boundary curve (Figure 15) shows that this value of load
capacitance and cathode current is on the boundary. Define
the transfer gain.
–20
1
2
3
4
5
6
10
10
10
10
10
10
f, FREQUENCY (Hz)
With three poles, this system is unstable. The only hope
for stabilizing this circuit is to add a zero. However, that can
only be done by adding a series resistance to the output
capacitance, which will reduce its effectiveness as a noise
filter. Therefore, practically, in reference voltage applications,
the best solution appears to be to use a smaller value of
capacitance in low noise applications or a very large value to
provide noise filtering and a dominant pole rolloff of the
system.
The DC gain is:
G
G R
GoR
M GM
L
(2.323)(1.0 M)(1.25 )(2200)
6389
76 dB
The resulting open loop Bode plot is shown in Figure 33.
The asymptotic plot may be expressed as the following
equation:
1
jf
500 kHz
jf
8.0 kHz 60 kHz 7.2 kHz
Av
615
1
jf
1
1
jf
12
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
OUTLINE DIMENSIONS
LP SUFFIX
PLASTIC PACKAGE
CASE 29–04
(TO–92)
NOTES:
A
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
B
ISSUE AE
2. CONTROLLING DIMENSION: INCH.
3. CONTOUR OF PACKAGE BEYOND DIMENSION R
IS UNCONTROLLED.
R
4. DIMENSION F APPLIES BETWEEN P AND L.
DIMENSION D AND J APPLY BETWEEN L AND K
MINIMUM. LEAD DIMENSION IS UNCONTROLLED
IN P AND BEYOND DIMENSION K MINIMUM.
P
L
F
SEATING
PLANE
K
INCHES
MIN
MILLIMETERS
DIM
A
B
C
D
F
G
H
J
K
L
N
P
MAX
0.205
0.210
0.165
0.022
0.019
0.055
0.105
0.020
–––
MIN
4.45
4.32
3.18
0.41
0.41
1.15
2.42
0.39
12.70
6.35
2.04
–––
MAX
5.20
5.33
4.19
0.55
0.48
1.39
2.66
0.50
–––
0.175
0.170
0.125
0.016
0.016
0.045
0.095
0.015
0.500
0.250
0.080
–––
D
X X
G
J
H
V
C
–––
–––
SECTION X–X
0.105
0.100
–––
2.66
2.54
–––
1
N
R
V
0.115
0.135
2.93
3.43
N
–––
–––
P SUFFIX
PLASTIC PACKAGE
CASE 626–05
ISSUE K
8
5
NOTES:
1. DIMENSION L TO CENTER OF LEAD WHEN
FORMED PARALLEL.
2. PACKAGE CONTOUR OPTIONAL (ROUND OR
SQUARE CORNERS).
–B–
1
4
3. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
MILLIMETERS
INCHES
F
DIM
A
B
C
D
F
MIN
9.40
6.10
3.94
0.38
1.02
MAX
10.16
6.60
4.45
0.51
1.78
MIN
MAX
0.400
0.260
0.175
0.020
0.070
0.370
0.240
0.155
0.015
0.040
–A–
NOTE 2
L
G
H
J
K
L
2.54 BSC
0.100 BSC
C
0.76
0.20
2.92
1.27
0.30
3.43
0.030
0.008
0.115
0.050
0.012
0.135
J
–T–
SEATING
PLANE
7.62 BSC
0.300 BSC
N
M
N
–––
0.76
10
1.01
–––
0.030
10
0.040
M
D
K
G
H
M
M
M
0.13 (0.005)
T
A
B
13
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
OUTLINE DIMENSIONS
DM SUFFIX
PLASTIC PACKAGE
CASE 846A–02
(Micro–8)
NOTES:
6. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
–A–
ISSUE D
7. CONTROLLING DIMENSION: MILLIMETER.
8. DIMENSION A DOES NOT INCLUDE MOLD FLASH,
PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT
EXCEED 0.15 (0.006) PER SIDE.
9. DIMENSION B DOES NOT INCLUDE INTERLEAD
FLASH OR PROTRUSION. INTERLEAD FLASH OR
PROTRUSION SHALL NOT EXCEED 0.25 (0.010)
PER SIDE.
–B–
K
MILLIMETERS
INCHES
PIN 1 ID
G
DIM
A
B
C
D
MIN
2.90
2.90
–––
MAX
3.10
3.10
1.10
0.40
MIN
MAX
0.122
0.122
0.043
0.016
D 8 PL
0.08 (0.003)
0.114
0.114
–––
M
S
S
T
B
A
0.25
0.010
G
H
J
K
L
0.65 BSC
0.026 BSC
0.05
0.13
4.75
0.40
0.15
0.23
5.05
0.70
0.002
0.005
0.187
0.016
0.006
0.009
0.199
0.028
SEATING
PLANE
–T–
C
0.038 (0.0015)
L
J
H
D SUFFIX
PLASTIC PACKAGE
CASE 751–06
(SOP–8)
ISSUE T
NOTES:
D
A
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
C
2. DIMENSIONS ARE IN MILLIMETER.
3. DIMENSION D AND E DO NOT INCLUDE MOLD
PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.
5. DIMENSION B DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 TOTAL IN EXCESS
OF THE B DIMENSION AT MAXIMUM MATERIAL
CONDITION.
8
1
5
M
M
0.25
B
H
E
4
h X 45
MILLIMETERS
B
e
DIM
A
A1
B
C
D
E
e
H
h
MIN
1.35
0.10
0.35
0.19
4.80
3.80
MAX
1.75
0.25
0.49
0.25
5.00
4.00
A
C
SEATING
PLANE
L
1.27 BSC
0.10
5.80
0.25
0.40
0
6.20
0.50
1.25
7
A1
B
L
M
S
S
0.25
C
B
A
14
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and
specificallydisclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola
datasheetsand/orspecificationscananddovaryindifferentapplicationsandactualperformancemayvaryovertime. Alloperatingparameters,including“Typicals”
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applicationsintended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury
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and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees
arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that
Motorola was negligent regarding the design or manufacture of the part. Motorola and
Opportunity/Affirmative Action Employer.
are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal
15
MOTOROLA ANALOG IC DEVICE DATA
TL431, A, B Series
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