TS4431
1.224V Open Collector Shunt Voltage Reference
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■
■
■
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Internal 1.224V ±0.5% precision
Low output saturation voltage
75 mV max between SINK and GND
Low current consumption: 250
µ
A
Industrial temperature range: -40 to +85°C
100ppm/°C temperature coefficient
Description
The TS4431 is a four-terminal device dedicated to low voltage Switch Mode Power Supplies (SMPS).
It integrates a 1.224V voltage reference, an amplifier, and an open collector output transistor in a single package. The TS4431’s operating mode is similar to the well-known standard voltage reference, the TL431. It maintains the desired feedback voltage at the REF pin in a closed loop configuration by sinking a current proportional to the error voltage at the REF pin.
TS4431 features an open collector transistor with an ultra-low saturation voltage, allowing it to be used in series with the optocoupler in an SMPS architecture to regulate low voltage SMPS.
SOT23-5L
(Plastic Micropackage)
Pin connections (top view)
1 Vc c
2 Gnd
3 Nc
Sink 5
Ref 4
Applications
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■
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Low voltage switch mode power supplies
Isolated DC/DC converter
Computers
Low voltage discrete regulator
Order Codes
Part Number
TS4431AILT
TS4431ILT
Accuracy Temperature Range
0.5%
1%
-40, +85°C
Package
SOT23-5
Packing
Tape & Reel
Marking
L288
L275
November 2005
Rev 2
1/8 www.st.com
8
Absolute Maximum Ratings
1 Absolute Maximum Ratings
Table 1.
Key parameters and their absolute maximum ratings
Symbol Parameter
I
SINK
V
CC
V
SINK
P
D
T
STD
Output sink current
Supply voltage
Output voltage
Power Dissipation
(1)
Storage Temperature
SOT23-5
ESD
Human Body Model (HBM)
Machine Model (MM)
T
LEAD
Lead Temperature (soldering, 10 seconds)
1.
P
D
Rth
Rth
has been calculated with T
AMB
= 25°C, T
Junction
JA
= 250°C/W for the SOT23-5 package
JC
= 81°C/W for the SOT23-5 package
=150°C and
Value
30
12
12
500
-65 to +150
2
200
250
Table 2.
Operating conditions
Symbol Parameter
T
OPER
V
CC
I
SINK
Operating temperature range
Supply voltage
Output sink current
Value
-40 to +85
1.5 to 10
20
TS4431
Unit mA
V
V mW
°C kV
V
°C
Unit
°C
V mA
2/8
Typical Application Schematic
Figure 1.
SMPS power supply: secondary side
D1
D2
L1
C1
R1
1
Vcc
Cd1
100nF
2
Gnd
Vref
U1
TS4431
Sink
5
R2
R3
3
Nc Ref
4
Vout
TS4431
3/8
Electrical Characteristics TS4431
Table 3.
Electrical characteristics for T amb
= 25°C, V
CC
= 1.8V, I
SINK
= 2mA unless otherwise specified
Symbol Parameter Test Condition Min.
Typ.
Max.
Unit
V
REF
V
REF
T
C
∆
V
-----------------
∆
V
CC
∆
V
∆
I
SIN K
I
CC
I
OFF
I
REF
V
SAT
I
OH
Reference voltage TS4431A 0.5%
-40°C < T < +85°C
Reference voltage TS4431 1%
-40°C < T < +85°C
Temperature coefficient
Change in V
REF
due to change in
V
CC
V
CC
=1.5 to 10V
-40°C < T < +85°C
Change in V
REF
due to change in
I
SINK
Supply current
I
SINK
=0.5 to 20mA
-40°C < T < +85°C
I
SINK
=2mA
-40°C < T < +85°C
OFF-State supply current
Reference input current
Output transistor saturation voltage
Output leakage current
Ref < 0.6V
-40°C < T < +85°C
0.1< I
SINK
< 10mA
-40°C < T < +85°C
I
SINK
=5mA
-40°C < T < +85°C
I
SINK
=20mA
-40°C < T < +85°C
V
SINK
=V
CC
-40°C < T < +85°C
1.218
1.224
1.230
V
1.209
1.239
1.212
1.224
1.236
1.203
V
1.245
100 ppm/°C
1
2
7
250
15
0.4
30
90
2
3
10
15
300
50
60
100
120
350
20
30
1
2
0.05
0.1
mV mV
µ
A
µA
µA mV
µA
Note: Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation and by design.
4/8
Electrical Characteristics
Figure 2.
Vref vs. temp. Isink=2mA
1.225
1.224
1.223
1.222
1.221
1.22
1.219
1.218
-40°C -20°C 0°C 25°C 50°C 85°C
Te m perature (°C)
Vcc=1.8V
Figure 4.
dVref/dVcc vs. temp. Isink=2mA
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-40°C -20°C 0°C 25°C 50°C 85°C
Te m perature (°C)
Vcc=1.5V to 10V
Figure 6.
Icc vs. temp. Isink=2mA
400
350
300
250
200
150
100
50
0
-40°C -20°C 0°C 25°C 50°C 85°C
Te m pe rature (°C)
Vcc=1.5V
Vcc=10V
TS4431
Figure 3.
Vref vs. temp. Isink=2mA
1.228
1.226
1.224
1.222
1.22
1.218
1.216
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Vcc=10V Vcc=1.5V
Figure 5.
Icc vs. temp. Isink=2mA
350
300
250
200
150
100
50
0
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Vcc=1.8V
Figure 7.
Vref vs. temp. Vcc=1.8V
1.235
1.23
1.225
1.22
1.215
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Isink=20mA Isink=0.5mA
5/8
Electrical Characteristics
Figure 8.
dVref/dIsink vs. temp. Vcc=1.8V
8
5
4
3
2
7
6
1
0
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Isink 0.5 to 20mA
Figure 10. Vsat vs. temp. Vcc=1.8V
100
80
60
40
20
0
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Isink=20mA Isink=5mA
TS4431
Figure 9.
Iref vs. temp. Vcc=1.8V
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40°C -20°C 0°C 25°C 50°C 85°C
Tem perature (°C)
Isink 0.1 to 10mA
6/8
TS4431
4 Package Mechanical Data
Package Mechanical Data
In order to meet environmental requirements, ST offers these devices in ECOPACK
®
packages.
These packages have a Lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC
Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com
.
C
D
E
E1
A
A1
A2 b e e1
L
SOT23-5L P ackage
SOT23-5L MECHANICAL DATA
DIM.
mm.
TYP
0.35
0.09
2.80
2.60
1.50
MIN.
0.90
0.00
0.90
0.50
0.20
3.00
3.00
1.75
MAX.
1.45
0.15
1.30
13.7
3.5
110.2
102.3
59.0
MIN.
35.4
0.0
35.4
0.35
0 .95
1.9
0.55
13.7
mils
TYP.
37.4
74.8
19.7
7.8
118.1
118.1
68.8
MAX.
57.1
5.9
51.2
21.6
7/8
Revision History TS4431
Date
March 2005
Nov. 2005
Revision
1
2
Changes
First release corresponding to Preliminary Data version of datasheet.
First release of fully mature product data sheet.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics.
All other names are the property of their respective owners
© 2005 STMicroelectronics - All rights reserved
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