TS821
1.225V micropower shunt voltage reference
Features
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■
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1.225V typical output voltage
Ultra low operating current: 45μA maximum at
25°C
High precision @ 25°C
– +/- 2% (standard version)
– +/- 1% (A grade)
– +/- 0.5% (B grade)
High stability when used with capacitive loads
Industrial temperature range: -40°C to +85°C
120ppm/°C maximum temperature coefficient
Pin connections
(Top view)
L
SOT23-3L
(Plastic micropackage)
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■
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Applications
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■
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■
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Computers
Instrumentation
Battery chargers
Switch mode power supply
Battery operated equipment
Description
The TS821 is a low power shunt voltage reference
providing a stable 1.225V output voltage over the
industrial temperature range (-40°C to +85°C).
Availabe in SOT23-3 surface mount package, it
can be designed in applications where space
saving is critical.
The low operating current is a key advantage for
power restricted designs. In addition, the TS821 is
very stable and can be used in a broad range of
application conditions.
July 2007
Rev 2
1/9
www.st.com
9
Absolute maximum ratings and operating conditions
TS821
1
Absolute maximum ratings and operating conditions
Table 1.
Symbol
I
k
I
f
P
d
T
stg
ESD
T
lead
Absolute maximum ratings (AMR)
Parameter
Reverse breakdown current
Forward current
Power dissipation
(1)
SOT23-3
Storage temperature
Human body model (HBM)
(2)
Machine model (MM)
(3)
Lead temperature (soldering, 10 seconds)
Value
20
10
360
-65 to +150
2
200
260
Unit
mA
mA
mW
°C
kV
V
°C
1. P
d
is calculated with T
amb
= 25°C and T
j
= 150°C and R
thja
= 340°C/W for the SOT23-3L package.
2. Human body model: 100pF discharged through a 1.5kΩ resistor between two pins of the device, done for
all couples of pin combinations with other pins floating.
3. Machine model: a 200pF cap is charged to the specified voltage, then discharged directly between two pins
of the device with no external series resistor (internal resistor < 5Ω), done for all couples of pin
combinations with other pins floating.
Table 2.
Symbol
I
min
I
max
T
oper
Operating conditions
Parameter
Minimum operating current
Maximum operating current
Operating free air temperature range
Value
45
12
-40 to +85
Unit
μA
mA
°C
2/9
TS821
Electrical characteristics
2
Table 3.
Symbol
Electrical characteristics
TS821 (2% precision) T
amb
= 25°C
(1)
(unless otherwise specified)
Parameter
Reverse breakdown voltage
V
k
Reverse breakdown voltage
tolerance
Minimum operating current
Average temperature coefficient
Test conditions
I
k
= 100μA
I
k
= 100μA
-40°C < T
amb
< +85°C
T
amb
= 25°C
-40°C < T
amb
< +85°C
I
k
= 100μA
I
k-min
< I
k
< 1mA
-40°C < T
amb
< +85°C
1mA < I
k
< 12mA
-40°C < T
amb
< +85°C
ΔI
k
= 45µA to 1mA
I
k
= 100μA, t = 1000hrs
I
k
= 100μA, 10Hz < f < 10kHz
0.3
2.5
0.25
120
200
Min.
Typ.
Max.
Unit
V
mV
μA
ppm/°C
1.200 1.225 1.250
-25
+34
40
+25
+34
45
50
120
0.7
1
I
k-min
ΔV
ref
/ΔT
ΔV
k
/ΔI
k
Reverse breakdown voltage change
with operating current range
mV
8
10
0.5
Ω
ppm
nV/√Hz
R
ka
K
vh
En
Static impedance
Long term stability
Wide band noise
1. Limits are 100% production tested at 25°C. Behavior at the temperature range limits is guaranteed through correlation and
by design.
Table 4.
Symbol
TS821A (1% precision) T
amb
= 25°C
(1)
(unless otherwise specified)
Parameter
Reverse breakdown voltage
Test conditions
I
k
= 100μA
I
k
= 100μA
-40°C < T
amb
< +85°C
T
amb
= 25°C
-40°C < T
amb
< +85°C
Average temperature coefficient
I
k
= 100μA
I
k-min
< I
k
< 1mA
-40°C < T
amb
< +85°C
1mA < I
k
< 12mA
-40°C < T
amb
< +85°C
ΔI
k
= 45μA to 1mA
I
k
= 100μA, t = 1000hrs
I
k
= 100μA 10Hz < f < 10kHz
0.3
2.5
0.25
120
200
Min.
Typ.
Max.
Unit
V
mV
μA
ppm/°C
1.213 1.225 1.237
-12
-22
40
+12
+22
45
50
120
0.7
1
V
k
Reverse breakdown voltage
tolerance
Minimum operating current
I
k-min
ΔV
ref
/ΔT
ΔV
k
/ΔI
k
Reverse breakdown voltage change
with operating current range
mV
5
7
0.5
Ω
ppm
nV/√Hz
R
ka
K
vh
En
Static impedance
Long term stability
Wide band noise
1. Limits are 100% production tested at 25°C. Behavior at the temperature range limits is guaranteed through correlation and
by design.
3/9
Electrical characteristics
Table 5.
Symbol
TS821
TS821B (0.5% precision) T
amb
= 25°C
(1)
(unless otherwise specified)
Parameter
Reverse breakdown voltage
Test conditions
I
k
= 100μA
I
k
= 100μA
-40°C < T
amb
< +85°C
T
amb
= 25°C
-40°C < T
amb
< +85°C
Average temperature coefficient
I
k
= 100μA
I
k-min
< I
k
< 1mA
-40°C < T
amb
< +85°C
1mA < I
k
< 12mA
-40°C < T
amb
< +85°C
ΔI
k
= 45μA to 1mA
I
k
= 100μA, t = 1000hrs
I
k
= 100μA 10Hz < f < 10kHz
0.3
2.5
0.25
120
200
Min.
Typ.
Max.
Unit
V
mV
μA
ppm/°C
1.219 1.225 1.231
-6
-16
40
+6
+16
45
50
120
0.7
1
V
k
Reverse breakdown voltage
tolerance
Minimum operating current
I
k-min
ΔV
ref
/ΔT
ΔV
k
/ΔI
k
Reverse breakdown voltage change
with operating current range
mV
5
7
0.5
W
ppm
nV/√Hz
R
ka
K
vh
En
Static impedance
Long term stability
Wide band noise
1. Limits are 100% production tested at 25°C. Behavior at the temperature range limits is guaranteed through correlation and
by design.
4/9
TS821
Electrical characteristics
Figure 1.
12
8
4
0
-4
-8
Reference voltage versus cathode
current
Figure 2.
Reference voltage versus cathode
current
100
Cathode current (µA)
Cathode current (mA)
50
0
-50
-1
-0.5
0
0.5
1
1.5
-1
-0.5
Reference voltage (V)
1
0.5
Reference voltage (V)
0
1.5
Figure 3.
Test circuit
Figure 4.
1.26
Reference voltage versus
temperature
+2%
+1%
+0.5%
R
Cathode voltage (V)
1.25
Ik=(Vin-Vref)/R
Vout=Vref
1.24
1.23
1.22
1.21
1.2
1.19
-40
-20
0
20
40
60
80
Temperature (°C)
-0.5%
-1%
-2%
Figure 5.
Static impedance versus
temperature
0.25
Figure 6.
800
700
Noise voltage versus frequency
Static impedance (Ohms)
0.24
0.23
0.22
0.21
0.2
-40
Noise voltage (nV/VHz)
C
L
=10µF
600
500
400
300
200
C
L
=100µF
C
L
=0µF
100
-20
0
20
40
60
80
0
0
1
10
100
1,000
10,000
Frequency (Hz)
Temperature (°C)
5/9
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