Diodes ZXRE252 User Manual
ZXRE250/ZXRE252
A
A
A
A
VERY LOW CATHODE CURRENT ADJUSTABLE
PRECISION SHUNT REGULATOR
Description
The ZXRE250 and ZXRE252 are three terminal adjustable
shunt regulators offering excellent temperature stability and
output current handling capability up to 100mA. The output
voltage may be set to any chosen voltage between 2.5 and
36 volts by selection of two external divider resistors.
ZXRE250 has the same electrical specifications as the
industry standard ‘431 except that it features a very low
minimum cathode current for regulation. The typical value of
40µA makes the parts ideal for very low power applications.
The devices can be used as a replacement for zener diodes
in many applications requiring an improvement in zener
performance. The ZXRE250/2 is available in 2 grades with
initial tolerances of 1% and 0.5% for the A and B grades
respectively.
Features
NEW PRODUCT
• Minimum cathode current for regulation: 40μA (typ)
• Temperature range -40 to 125ºC
• Reference Voltage Tolerance at 25°C
o ZXRE250A: 2.495V ± 1.0%.
o ZXRE250B: 2.495V ± 0.5%
• Low Output Noise
• 0.2Ω Typical Output Impedance
• Sink Current Capability: 0.065mA to 100mA
• Adjustable Output Voltage: V
• SOT23 and SOT25: Available in “Green” Molding
Compound (No Br, Sb) and Lead Free Finish/ RoHS
Compliant (Note 1)
REF
to 36V
Pin Assignments
Leave floating or
Leave floating or
Applications
• Opto-Coupler Linearisers
• Shunt Regulators
• Improved Zener
• Variable Reference
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
NODE
NODE
NC ANODE
NC ANODE
connect to pin 5
connect to pin 5
CATHODE
CATHODE
NODE
NODE
ZXRE250
(Top View)
(Top View)
3REF
3REF
1
1
2
2
SOT23
SOT23
(Top View)
(Top View)
1
1
2
2
3
3
SOT25
SOT25
ZXRE252
(Top View)
(Top View)
1
1
SOT23
SOT23
CATHODE
CATHODE
5
5
REF
REF
4
4
CATHODE
CATHODE
3
3
REF
REF
2
2
ZXRE250/ZXRE252
Document number: DS35228 Rev. 3 - 2
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© Diodes Incorporated
ZXRE250/ZXRE252
Absolute Maximum Ratings (Note 2)
Symbol Parameter Rating Unit
VKA
IKA
I
REF
TJ
TST
PD
Notes: 2. Operation above the absolute maximum r ating may cause device failur e. Operation at the absolute maximum ratings, for extended periods, may
reduce device reliability. Unless otherwise stated voltages specified are relative to the ANODE pin.
3. T
4. Ratings apply to ambient temperature at 25°C.
Recommended Operating Conditions
NEW PRODUCT
Symbol Parameter Min Max Unit
VKA
IKA
TA
Cathode Voltage 40 V
Continuous Cathode Current 150 mA
Reference Input Current -0.050 to +10 mA
Operating Junction Temperature +150
Storage Temperature -55 to +150
Power Dissipation (Notes 3, 4)
, max =150°C.
J
Cathode Voltage
Cathode Current 0.065 100 mA
Operating Ambient Temperature -40 125 °C
VERY LOW CATHODE CURRENT ADJUSTABLE
PRECISION SHUNT REGULATOR
SOT23 330 mW
SOT25 500 mW
V
REF
36 V
°
C
°
C
ZXRE250/ZXRE252
Document number: DS35228 Rev. 3 - 2
2 of 14
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May 2011
© Diodes Incorporated
ZXRE250/ZXRE252
A
A
A
)
A
A
VERY LOW CATHODE CURRENT ADJUSTABLE
PRECISION SHUNT REGULATOR
Electrical Characteristics (T
= +25°C, unless otherwise noted)
A
Symbol Parameter Test Conditions Min Typ. Max Unit
V
= V
KA
V
V
ΔV
ΔV
Reference voltage
REF
Deviation of reference voltage over
DEV
full temperature range (Note 5)
Ratio of the change in reference
REF
voltage to the change in cathode
KA
I
V
I
I
= 10mA
KA
= V
KA
= 10mA
KA
= 10mA
KA
REF
REF
voltage
I
REF
ΔI
I
KA(MIN)
NEW PRODUCT
I
KA(OFF
|ZKA|
θ
Notes: 5. Deviation of V
The average temperature coefficient of the reference input voltage αV
Where:
T2 – T1 = full temperature change.
αV
positive or negative.
Notes: 6. The dynamic output impedance, R
When the device is programmed with two external resistors R1 and R2, the dynamic output
impedance of the overall circuit, is defined as:
Reference input current
I
deviation over full temperature
REF
REF
range (Note 5)
Minimum cathode current for
regulation
Off-state current
Dynamic output impedance (Note 6)
Thermal Resistance Junction to
JA
Ambient
, and ΔI
DEV
REF can be positive or negative depending on whether the slope is
are defined as the maximum variation of the values over the full temperature range.
REF
V
V
DEV
DEV
V
@ 25ºC
V
@ 25ºC
REF
αV
αV
REF
REF
REF
=
=
Z
Z
=
=
KA
KA
T2 – T1
T2 – T1
Z, is defined as:
ΔV
ΔV
ΔI
ΔI
IKA= 10mA, R1 = 10KΩ, R2 = ∞
I
= 10mA, R1
KA
= 10KΩ, R2 = ∞
V
= V
KA
REF
V
= 36V, V
K
V
= V
K
REF,
SOT23 380
SOT25 250
6
6
X 10
X 10
ppm/ºC
ppm/ºC
KA
KA
KA
KA
ZXRE250A 2.470 2.495 2.520 V
,
ZXRE250B 2.482 2.495 2.507 V
T
,
= 0 to 70 oC
TA = -40 to 85 oC
TA = -40 to 125 oC
= 10V to V
V
K
VKA = 36V to 10V
= 0 to 70 oC
T
TA = -40 to 85 oC
TA = -40 to 125 oC
= 0V
REF
f = 0Hz
is defined as:
REF
Vmax
Vmax
Vmin
Vmin
6 16 mV
14 34 mV
14 34 mV
REF
-1.4 -2.7 mV/V
-1 -2 mV/V
1 4 μA
0.8 1.2 μA
0.8 2.5 μA
0.8 2.5 μA
40 65 μA
0.05 0.5 μA
0.2 0.5 Ω
V
V
= Vmax - Vmin
= Vmax - Vmin
DEV
DEV
T1 T2
T1 T2
Temperature
Temperature
o
C/W
o
C/W
R1
R1
ΔV
ΔV
ΔV
Z’
Z’
Z’
=
=
=
ΔI
ΔI
ΔI
Z
Z
Z
≈
≈
KA
KA
KA
ZXRE250/ZXRE252
Document number: DS35228 Rev. 3 - 2
1 +
1 +
1 +
R1
R2
R2
R2
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Test Circuits
ZXRE250/ZXRE252
VERY LOW CATHODE CURRENT ADJUSTABLE
PRECISION SHUNT REGULATOR
NEW PRODUCT
Figure 1. Test circuit for VKA = V
Figure 2. Test circuit for VKA > V
REF
REF
ZXRE250/ZXRE252
Document number: DS35228 Rev. 3 - 2
Figure 3. Test circuit for I
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OFF
May 2011
© Diodes Incorporated
2
Typical Performance Characteristics
2600
2580
2560
2540
2520
I = 10mA
KA
V = V
KA RE F
T = 25C
A
ZXRE250/ZXRE252
VERY LOW CATHODE CURRENT ADJUSTABLE
PRECISION SHUNT REGULATOR
0.
R1 = 10K
Ω
R2 =
°
0.15
μ
∞
I = 10mA
KA
NEW PRODUCT
2500
2480
2460
REF
V Reference Voltage (mV)
2440
2420
2400
-55 -35 -15 5 25 45 65 85 105 125
T Free Air Temperature ( C)
A
°
Reference Voltage vs. Free Air Temperature
150
V = V
KA RE F
T = 25C
°
A
100
50
0
KA
I Cathode Current (mA)
-50
0.1
REF
0.05
I Reference Current ( A)
0
-55 -35 -15 5 25 45 65 85 105 125
T Free Air Temperature ( C)
A
°
Reference Current vs. Free Air Temperature
200
V = V
KA RE F
T = 25C
°
A
μ
100
I
KMIN
0
KA
I Cathode Current ( A)
-100
-2 -1
0
V Cathode Voltage (V)
KA
12
Cathode Current vs. Cathode Voltage
3
-100
-2 -1
0
V Cathode Voltage
KA
12
Cathode Current vs. Cathode Voltage
3
ZXRE250/ZXRE252
Document number: DS35228 Rev. 3 - 2
5 of 14
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May 2011
© Diodes Incorporated
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