®
SPX4041
Precision 1.24V Shunt Voltage Reference
FEATURES
N/C 1
8 CATHODE
■
Voltage Tolerance........................1% and 2%
SPX4041
N/C 2
7 N/C
■
Wide Operating Curren..........100µA to 15mA
8 Pin nSOIC
■
Low Temperature Coefficient.........50ppm/°C
N/C 3
6 N/C
■
Fixed Reverse Breakdown Voltage.......1.24V
5 N/C
ANODE 4
■
No Output Capacitance Required
■
Two Terminal "Zener" Operation
Now Available in Lead Free Packaging
■
Improved Replacement for TL431
APPLICATIONS
■
Constant Current Source
■
Digital Voltmeter
■
Power Management
■
Precision Regulators
■
■
■
■
Battery Powered Equipment
Instrumentation
Automotive Electronics
Data Acquisition Systems
DESCRIPTION
The SPX4041 is a 2-terminal, temperature compensated, band-gap voltage reference which
provides a fixed 1.24V output for input currents between 160µA and 15mA. The bandgap voltage
(1.24V) is independently laser trimmed from the output voltage to achieve a very low temperature
coefficient, then the output voltage is trimmed to 1.24V. This trimming technique and the low
temperature coefficient (A grade: 50 ppm/°C) thin film resistor process gives a very stable device
over the full temperature range. The SPX4041 is available in the sub miniature 3 pin SOT-23,
3 pin TO-92 or 8 pin NSOIC packages. The operating temperature is -40°C to 85°C. The
SPX4041 advanced design eliminates the need for an external stabilized capacitor while insuring
stability with any capacitive load, making it easy to use.
TYPICAL APPLICATIONS CIRCUIT
Cathode (K)
+
-
1.24V
Anode (A)
Figure 1: Block Diagram
Date: 11/29/04
SPX4041 Precision 1.24V Shunt Voltage Reference
© Copyright 2004 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
Stresses greater than those listed under ABSOLUTE
MAXIMUM RATINGS may cause permanent damage
to the device. This is a stress rating only and functional
operation of the device at these or any other conditions
above those indicated in the operational sections of this
specification is not implied. Exposure to absolute maxi-
mum rating conditions for extended periods may affect
reliability.
Reverse Current (I
KA
)) ...................................... 20mA
Forward Current (I
AK
) ....................................... 10mA
Operating Temperature Range (T
A
) ...... -40 to +85°C
Junction Temperature (T
J
) .............................. 150°C
Storage Temperature (T
STG
) ................ - 65 to 150°C
Lead Temperature (Soldering 10 sec.), T
L .........
300°C
ELECTRICAL CHARACTERISTICS
PARAMETER
Reverse Breakdown Voltage
Reverse Breakdown
Tolerance
Dynamic Output Impedance
Noise Voltage
Temperature Coefficient
Turn-on Setting
Temperature Range (T
A
)
Operating Current Range
Thermal Resistance
TO-92
Θ
JA
TO-92
Θ
JC
SOIC-8
Θ
JA
SOIC-8
Θ
JC
SOT-23
Θ
JA
SOT-23
Θ
JC
I
IN
= 1000µA, T
A
= 25°C, unless otherwise specified.
SPX4041A
CONDITIONS
I
R
=500µA
I
R
=500µA
-40°C≤T
A
≤85°C
0.60
0.1kHz≤f≤10Hz
Note 1
0.1% of V
OUT
-40
0.5
160
80
175
45
575
150
30
85
5.0
15.0
-40
0.5
15
100
MIN.
TYP.
1.24
±12
±29
2.00
MAX
MIN.
SPX4041
TYP.
1.24
±25
±49
0.60
15
100
30
85
5.0
15.0
160
80
175
45
575
150
2.00
MAX.
UNIT
V
mV
Ω
µV
PP
ppm/°c
µs
°C
mA
°C/W
Note 1. Three-point measurement guarantees the error band over the specified temperature range.
*CALCULATING AVERAGE TEMPERATURE COEFFICIENT (TC)
ppm
0
%
0
mV
0
∆V
KA
TC in mV/°C =
∆T
∆V
KA
(mV)
∆T
A
-5
5000
0.5
TC in % /°C =
(
∆V
KA
∆V
KA
at 25°C
∆T
A
)
x 100
0
15
30
45
60
75
90
105
TC in ppm/°C =
(
∆V
KA
∆V
KA
at 25°C
∆T
A
)
x 10
6
Junction Temperature (°C)
0.033 mV/°C
0.0027 %/°C
27 ppm/°C
Figure 2. V
REF
vs. Temperature
Date: 11/29/04
SPX4041 Precision 1.24V Shunt Voltage Reference
© Copyright 2004 Sipex Corporation
2
TYPICAL PERFORMANCE CHARACTERISTICS
15.0
Temperature Range: 0°C to 105°C
12.5
V
IN
V
KA
I
K
- Cathode Current (mA)
10.0
7.5
5.0
2.5
I
K
0
-2.5
-5.0
-7.5
-10.0
-2
-1
0
1 1.24
2
3
V
KA
- Cathode Voltage (V)
Figure 3. Test Circuit for V
KA
=V
REF
Figure 4. High Current Operating Characteristics
900
I
K
= 10mA
1.26
800
700
600
=
V
KA
= V
REF
Temperature Range: 0°C to 105°C
1.25
V
REF
- Reference Voltage (V)
I
K
- Cathode Current (µA)
500
400
105 °C
300
25 °C
200
-0 °C
100
0
1.24
1.23
1.22
1.21
1.20
-100
-200
1.24
∫∫
-1.0
-0.5
0
0.25
0.5
0.75
1.0
1.25
1.5
-60
-30
0
30
60
90
T
A
- Ambient Temperature (°C)
V
KA
- Cathode Voltage (V)
Figure 5. Reference Voltage vs. Ambient Temperature
70
Figure 6. Low Current Operating Characteristics
0.150
I
KA
= 160µA to 15mA
f
≤
1kHz
60
0.125
50
Z
KA
Dynamic Impedance (Ω)
I
K
= 10mA
T
A
= 25°C
0.100
40
Noise Voltage nV/√Hz
0.075
30
0.050
20
0.025
10
0.0
-60
-30
0
30
60
90
120
100
1k
10 k
100 k
0
10
f - Frequency (Hz)
T
A
- Free Air Temperature
Figure 7. Noise Voltage vs Frequency
Date: 11/29/04
Figure 8. Low Frequency Dynamic Ouput Impedance
vs T
A
SPX4041 Precision 1.24V Shunt Voltage Reference
© Copyright 2004 Sipex Corporation
3
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
180Ω
V
OUT
I
K
f
p
= 100kHz
50Ω
GND
Figure 9. Frequency=100kHz, I
K
=10mA, T
A
=25°C
Figure 10. Test Circuit for Pulse Response
APPLICATION INFORMATION
This device is designed for stable opera-
tion and has no need of an external
capacitor. The reference remains stable if
a bypass capacitor is used.
SOT-23
The SPX4041 in the SOT-23 package has
a parasitic Schottky diode between pin 3
and pin 1. Pin 1 of SOT-23 must float or
be connected to pin 3.
Conventional Shunt Regulator
In a conventional shunt regulator applica-
tion (see Figure 11), an external series
resister (R
S
) is connected between the
supply voltage and the SPX4041. R
S
determines the current that flows through
the load (I
L
) and the reference (I
Q
). Since
load current and supply voltage may vary,
R
S
should be small enough to supply at
least the minimum acceptable I
Q
to the
reference 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
L
is at its
minimum, R
S
should be large enough so
that the current flowing through the
SPX4041 is less than 15mA.
R
S
is determined by the supply voltage
(V
S
), the load and operating current (I
L
and
I
Q
), reference’s reverse breakdown voltage
(V
R
).
R
S
= (V
S
- V
R
)/(I
L
+I
Q
)
V
S
V
IN
R
S
I
Q
+ I
L
3k
V
OUT
SPX4041
V
R
I
L
V
OUT
I
Q
SPX4041
Figure 11. SPX4041 Fixed Shunt Regulator
Date: 11/29/04
Figure 12 1.24V Reference Circuit
© Copyright 2004 Sipex Corporation
SPX4041 Precision 1.24V Shunt Voltage Reference
4
V
IN
= 12V to 20V
86.7 k
500 k
LO = Battery Low
1M
7
3 +
2 LM4250
12V
+
6
8
22 M
3.5 M
150 pF
-
500 k
150 pF
SPX4041
SPX4041
-
4
500 k
Figure 13. Low Battery Detector
Figure 14. Micropower 10V Reference
PACKAGE PINOUTS
8-Pin SOIC (S)
N/C
N/C
N/C
1
2
3
4
8
7
6
5
+
N/C
N/C
N/C
SOT-23-3 (M)
1
1
TO-92 (N)
+
2
-
3
+
2
-
3
Bottom View
Top View
-
Top View
Date: 11/29/04
SPX4041 Precision 1.24V Shunt Voltage Reference
© Copyright 2004 Sipex Corporation
5
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