CYT432
Adjustable Precision Shunt Regulator
General Description
The CYT432 is a low voltage three terminal
adjustable shunt regulator with a guaranteed
thermal
stability
over
applicable
temperature
ranges. The output voltage can be set to any value
between V
REF
(approximately 1.24 V) to 8V with two
external resistors. This device has a typical output
impedance
of
0.30Ω.
Active
output
circuitry
provides a very sharp turn on characteristic, making
this device excellent replacement for Zener diodes
in many applications.
The CYT432 is characterized for operation
from -40
o
C to 105
o
C, and two package options
(SOT-23 and TO-92) allow the designer the
opportunity to select the proper package for their
applications.
Features
■
■
■
■
■
■
■
Low voltage operation (1.24V)
Adjustable output voltage V
0
=V
REF
to 8V
Wide operating current range 60µA to 100mA
Low dynamic output impedance 0.30Ω (Typ.)
Trimmed bandgap design up to + 0.5%.
ESD rating is 2.5KV(Per MIL-STD-883D)
100% Lead (Pb)-Free.
Application
■
■
■
■
■
■
Linear Regulators
Adjustable Supplies
Switching Power Supplies
Battery Operated Computers
Instrumentation
Computer Disk Drives
Pin Configuration
SOT-23-3
(Top View)
TO-92
(Top View)
Marking Information
Package
SOT-23-3
Marking
Production Batch Number
The last character is the batch number.
Lead-Free Package
Lead-free package is
indicated by a dot on
top of the last character.
CYT432
XXXX
XXXX is the batch number.
Lead-free
indicated
XXXX.
package
by
LF
is
after
CYT432x
TO-92
2008-9-8
Shen Zhen CYT IC Design CO,Ltd
1
CYT432
Absolute Maximum Rating
Parameter
Cathode Voltage
Continuous Cathode Current
Reference Current
Operating Junction Temperature Range
Storage Temperature Range
Thermal Resistance
Lead Temperature (Soldering) 10 seconds
Symbol
V
KA
I
KA
I
REF
T
J
T
STG
θ
JA
T
LEAD
Maximum
8
150
3
150
-45 to 150
230 (SOT-23-3)
220 (TO-92)
260
°C
Units
V
mA
mA
°C
°C
°C/W
Electrical Characteristics
Parameter
0.5%
Reference
Voltage
1.0%
1.5%
2.0%
1.25V 1%
(1)
Symbol
Test Conditions & Circuit
Min
1234
Typ
1240
1240
1240
1240
1250
Max
1246
1252
1259
1265
1263
Unit
V
REF
Test circuit #1
V
KA
= V
REF
, I
KA
= 10mA
1228
1221
1215
1237
mV
Deviation of Reference Voltage over
Full Temperature Range
Ratio of Change in Reference Voltage
to the Change in Cathode Voltage
Reference Current
Test circuit #1
V
I(DEV)
V
KA
= V
REF
, I
KA
= 10mA,
T
A
=-40°C - 105°C
∆V
REF
/∆VKA
Test circuit #2
I
KA
= 10mA,
∆V
KA
= 8V to V
REF
Test circuit #2
I
KA
= 10mA, R1=10kΩ, R2 =
∞
Test circuit #2
I
I(DEV)
I
KA
= 10mA, R1=10kΩ, R2 =
∞
T
A
= 0°C - 105°C
I
MIN
Test circuit #1
V
KA
= V
REF
Test circuit #3
V
KA
= 8V, V
REF
= 0
Test circuit #1
--
10
mV
--
-1.0
-2.7
mV/V
I
REF
--
0.15
2
µA
Deviation of Reference Current over
Full Temperature Range
Minimum Cathode Current for
Regulation
Off-state Cathode Current
--
0.10
µA
--
60
100
µA
I
OFF
--
0.04
0.8
µA
Dynamic Impedance
| Z
KA
|
I
KA
= 100µA - 80mA,
V
KA
= V
REF
, f
≤
1kHZ
--
0.30
1
Ω
Note 1:
Upon Customer Request.
2008-9-8
Shen Zhen CYT IC Design CO,Ltd
2
CYT432
Typical Performance Characteristics
Cathode Current VS Cathode Voltage
150
Cathode Current (mA)
100
50
0
-50
-100
-150
-1.5
-1
-0.5
0
0.5
1
1.5
Cathode Voltage (V)
2008-9-8
Shen Zhen CYT IC Design CO,Ltd
3
CYT432
Stability Boundary Condition
100
80
IKA (mA)
60
40
20
0
0.1
0.001
0.01
1
VKA=3V
CL (uF)
VKA=VREF (1.24V)
VKA=2V
The areas under the curves represent conditions that may cause the device to oscillate. For V
KA
= 2V and 3V
curves, R2 and V
BAT
were adjusted to establish the initial V
KA
and I
K
conditions with CL = 0. V
BAT
and C
L
then
were adjusted to determine the ranges of stability. As the graph suggested, CYT432 is unconditional stable
with I
K
from 0 to 100mA and with C
L
from 0.001uF to 1uF.
2008-9-8
Shen Zhen CYT IC Design CO,Ltd
4
CYT432
Symbol Diagram
Cathode
Ref
Block Diagram
Cathode
+
-
Ref
Vref
Anode
Anode
Test Circuits
Input
V
KA
Input
V
KA
Input
V
KA
I
KA
I
KA
I
off
R1
Iref
Vref
R2
Vref
R1
V
KA
= Vref (1+
) + Iref x R1
R2
Test Circuit 1:
V
KA
= V
REF
Test Circuit 2:
V
KA
> V
REF
Test Circuit 3:
Off State Current
Application Circuit
2008-9-8
Shen Zhen CYT IC Design CO,Ltd
5
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