The AMS431L is a three-terminal adjustable shunt regulator with guaranteed temperature stability over the entire range of
operation. The output voltage can be set to any value between 1.24V (V
REF
) and 20V by adding two external resistors. The
AMS431L features 0.5% initial tolerance, low dynamic output impedance and operates over a wide current range. Due to the
sharp turn-on characteristics this device is an excellent replacement for zener diodes in many applications.
AMS431 is available in TO-92, SOT-89, 3 pin SOT-23 and 5 pin SOT-23 packages.
ORDERING INFORMATION:
TOL.
±0.5%
±1.0%
±2.0%
TO-92
AMS431LAN
AMS431LBN
AMS431LCN
PACKAGE TYPE
SOT-89
AMS431LAL
AMS431LBL
AMS431LCL
3 LEAD SOT-23
AMS431LAM
AMS431LBM
AMS431LCM
5 LEAD SOT-23
AMS431LAM1
AMS431LBM1
AMS431LCM1
OPERATING
TEMP. RANGE
-40 to +85° C
-40 to +85° C
-40 to +85° C
PIN CONNECTIONS
TO-92
Plastic Package (N)
SOT-89
(L)
3L SOT-23
(M)
5L SOT-23
(M1)
ANODE
1
2
3
N/C 1
N/C 2
5 ANODE
1
REF
ANODE
CATHODE
2
3
REF
CATHODE
CATHODE 3
4 REFERENCE
REF
ANODE CATHODE
Bottom View
Top View
Top View
Top View
1
Advanced Monolithic Systems http://www.ams-semitech.com
AMS431L
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Cathode Voltage (V
Z
)
Continuous Cathode Current (I
Z
)
Reference Input Current (I
REF
)
Junction Temperature (T
J
)
Storage temperature
Lead Temperature (Soldering, 10sec.)
20V
100mA
3mA
-40°C to +125°C
-65°C to +150°C
265°C
Internal Power Dissipation (P
D
)
TO-92 Package
SOT-89 Package
SOT-23-3 Package
SOT-23-5 Package
Thermal Resistance (θ
JA
)
TO-92 Package
SOT-89 Package
SOT-23-3 Package
SOT-23-5 Package
0.78W
0.91W
0.28W
0.3 W
160°C/W
110°C/W
410°C/W
410°C/W
Note 1 :
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics
.
The
guaranteed specifications apply only for the test conditions listed.
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at I
Z
=10 mA and T
A
= +25°C unless otherwise noted.
Parameter
Reference Voltage
Deviation of Reference
Input Voltage over
Temperature
Ratio of Change in
Reference Voltage to
Cathode Voltage
Reference Input Current
Reference Input Current
Deviation over
Temperature
Off State Cathode
Current
Dynamic Output
Impedance
Minimum Operating
Current
V
Z
= V
REF
(circuit 1)
T
A
= -40°C to +85°C
I
Z
= 10mA
∆V
= from V
REF
R1 =10kΩ, R2 =
∞Ω
(test circuit 2)
R1 =10kΩ, R2 =
∞Ω
T
A
= Full Range
(test circuit 2)
V
Z
= 6V, V
REF
= 0V
( test circuit 3)
f < 1KHz, V
Z
= V
REF
I
Z
=100µA to 100mA
(test circuit 1)
V
Z
= V
REF
(test circuit 1)
60
80
60
80
60
80
µA
0.15
0.5
0.15
0.5
0.15
0.5
µA
Conditions
AMS431LA
Min
Typ
Max
1.234
1.240
10
1.246
25
AMS431LB
Min
Typ
Max
1.228
1.240
10
1.252
25
AMS431LC
Min
Typ
Max
1.215
1.240
10
1.265
35
Units
V
mV
-0.5
-2.7
-0.5
-2.7
-0.5
-2.7
mV/V
0.1
0.4
0.1
0.4
0.1
0.4
µA
µA
Ω
0.04
0.25
0.1
0.4
0.04
0.25
0.1
0.4
0.04
0.25
0.1
0.4
RECOMMENDED OPERATING CONDITIONS:
Min
V
REF
80µA
Max
20 V
100mA
Cathode Voltage, (V
Z
)
Cathode Current, (I
Z
)
2
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AMS431L
TEST CIRCUITS
V
Z
= V
REF
V
Z
V
Z
V
IN
V
IN
V
IN
I
REF
I
Z
V
REF
R1
I
REF
I
Z
I
Z
OFF
R2
V
REF
Figure 1.
Test Circuit for V
Z
=V
REF
Figure 2.
Test Circuit for V
REF
vs I
Z
.
Test circuit for I
REF
.
Figure 3.
Test Circuit for Off-State Current
TYPICAL APPLICATIONS
V
IN
R1
V
REF
R2
GND
V
OUT
1) Set the V
OUT
according to the following equation:
R1
V
OUT
=
V
REF
1
+
+
I
REF
R1
R2
2) Choose the value of R as follows:
•
•
The maximum limit for R should be such that the cathode current, I
Z
is greater than the minimum operating current (80µA) at V
IN(min)
.
The minimum limit for R should b such that I
Z
does not exceed 100mA under all load conditions, and the instantaneous turn-on value for I
Z
does not exceed
150mA. Both of the following conditions must be met:
V
IN(max)
(
to limit instantane ous turn - on I
Z
)
150mA
R
min
≥
R
min
≥
V
IN(max)
- V
OUT
(
to limit I
Z
under normal operating conditions
)
I
OUT(min)
+
100mA
3
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AMS431L
TYPICAL PERFORMANCE CHARACTERISTICS
Cathode Current vs. Cathode Voltage
300
T
A
=25° C
Cathode Current vs. Cathode Voltage
150
T
A
=25° C
Reference Voltage vs.
Junction Temperature
1.248
REFERENCE VOLTAGE (V)
I
Z
= 100mA
200
100
0
-100
-200
-300
-1
V
R
= V
REF
CATHODE CURRENT (mA)
CATHODE CURRENT (µA)
100
50
0
-50
-100
V
R
= V
REF
1.246
1.244
1.242
1.240
1.238
1.236
I
R
= 60µA
-0.5
0.5
1
0
CATHODE VOLTAGE (V)
Reference Input Current vs.
Junction Temperature
1.5
-150
-1.5
-1
0
0.5
1
-0.5
CATHODE VOLTAGE (V)
1.5
1.234
-50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (° C)
Off State Cathode Current vs.
Junction Temperature
250
V
REF
= 0V
REFERENCE INPUT CURRENT (nA)
150
I
Z
= 10mA
R
1
= 10kΩ
R
2
=
∞
125
100
75
50
-50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (° C)
Ratio of Delta Reference Voltage to Delta
Cathode Voltage vs. Junction Temperature
1.2
1.1
I
Z
= 10mA
∆V
Z
= 16V to V
REF
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (° C)
CATHODE CURRENT(OFF STATE) (nA)
200
150
100
50
0
V
R
= 16V
∆V
REF
/∆V
Z
(-mV/V)
V
Z
= 6V
-50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (° C)
Reference Impedance vs.
Junction Temperature
0.50
REFERENCE IMPEDANCE (Ω)
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
-50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (° C)
REFERENCE IMPEDANCE (Ω)
I
Z
= 0.1 to 100mA
V
Z
= V
REF
f< 1kHz
Reference Impedance vs. Frequency
100
T
A
=25° C
10
1
0.1
0.01
1
100
1000
10
FREQUENCY (kHz)
100000
4
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AMS431L
TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
Small Signal Gain and Phase Shift
vs. Frequency
80
SMALL SIGNAL GAIN (dB)
70
60
50
40
30
20
10
0
-10
-20
100
1k
10k
100k
FREQUENCY (Hz)
1000k
-180
-225
-315
-360
PHASE SHIFT (deg)
-270
10µF
Small Signal Gain and Phase Shift
Test Circuit
OUT
I
Z
15k
232
+
8.25k
-
GND
Stability Boundary Condition
3.5
T
A
=25° C
Stability Circuit
CATHODE CURRENT (mA)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.001
V
Z
= 2V
V
Z
= V
REF
Stable
Stable
+
-
I
Z
R1
C
L
R2
0.01
0.1
1
LOAD CAPACITANCE (
µF)
10
5
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