PSSI2021SAY
Constant current source in SOT353 package
Rev. 03 — 27 August 2009 Product data sheet
1. Product profile
1.1 General description
Resistor-equipped PNP transistor with two diodes on one chip in a SOT353 (SC-88A)
plastic package. Stabilized output current of between 15 µA and 50 mA by connection of
an external resistor between pins 4 and 5.
1.2 Features
n One chip integrated constant current source
n Output current setting by use of an external resistor
n Very small package
n Reduces component count and board space
1.3 Applications
n Automotive applications
n Generic constant current source
n Constant current LED driver
n Active bias control for audio amplifiers
1.4 Quick reference data
Table 1. Quick reference data
Symbol Parameter Conditions Min Typ Max Unit
I
out
V
S
output current 0.015 - 50 mA
supply voltage - - 75 V
NXP Semiconductors
2. Pinning information
Table 2. Pinning
Pin Symbol Description Simplified outline Symbol
1 n.c. not connected
2 IOUT output current
3 GND ground
4 REXT external resistor
5 VS supply voltage
3. Ordering information
Table 3. Ordering information
Type number Package
PSSI2021SAY SC-88A plastic surface mounted package; 5 leads SOT353
PSSI2021SAY
Constant current source in SOT353 package
45
132
Name Description Version
54
n.c.
1
23
sym049
4. Marking
Table 4. Marking codes
Type number Marking code
PSSI2021SAY S1*
[1] * = -: made in Hong Kong
* = t: made in Malaysia
* = W: made in China
[1]
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 2 of 12
NXP Semiconductors
5. Limiting values
Table 5. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter Conditions Min Max Unit
I
out
V
S
V
out
V
R
P
tot
T
stg
T
j
T
amb
[1] Between all terminals
[2] Device mounted on a FR4 printed-circuit board, single-sided copper, tin-plated, standard footprint
PSSI2021SAY
Constant current source in SOT353 package
stabilized output current see Figure 2 0.015 50 mA
supply voltage - 75 V
output voltage VS = 75 V - 73 V
reverse voltage
total power dissipation T
amb
≤ 25 °C
storage temperature −65 +150 °C
junction temperature - 150 °C
ambient temperature −65 +150 °C
[1]
- 0.5 V
[2]
- 335 mW
6. Thermal characteristics
Table 6. Thermal characteristics
Symbol Parameter Conditions Min Typ Max Unit
R
th(j-a)
thermal resistance from
in free air
[1]
- - 370 K/W
junction to ambient
[1] Device mounted on a FR4 printed-circuit board, single-sided copper, tin-plated, standard footprint
7. Characteristics
Table 7. Characteristics
T
= 25°C unless otherwise specified
amb
Symbol Parameter Conditions Min Typ Max Unit
I
I
∆I
∆I
R
out
S
stabilized output current VS=12V; R
V
= 0 V to 10 V;
out
see
Figure 2
supply current VS=12V; I
V
= 0 V to 10 V;
out
see
Figure 4
=75V; I
V
S
V
= 0 V; see Figure 4
out
/ (I
/ I
out
out
×∆T
out
out
int
) output current change over
amb
ambient temperature
load stability of stabilized
output current
VS=12V; V
T
= −55 °C to 150 °C
amb
VS= 12 V;
V
= 1 V to 10 V
out
internal resistor value - 48 - kΩ
ext
=15µA;
out
=15µA;
out
out
= open;
=1V;
10 15 20 µA
- 240 370 µA
- 1.5 2.2 mA
- 0.15 - %/K
- 0.5 - %
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 3 of 12
NXP Semiconductors
PSSI2021SAY
Constant current source in SOT353 package
2
10
I
out
(mA)
10
1
−1
10
−2
10
10 10
2
10
(1)
006aaa020
(2)
(3)
(4)
(5)
(6)
3
10
RL (Ω)
VS= 12 V
(1) I
= 20 mA
out
(2) I
= 10 mA
out
(3) I
= 1mA
out
(4) I
= 100 µA
out
(5) I
= 50 µA
out
(6) I
= 15 µA
out
Fig 1. Output current as a function of load
resistance; typical values
2
10
I
out
(mA)
10
1
−1
10
−2
4
10
0806020 40
(1) I
= 20 mA
out
(2) I
= 10 mA
out
(3) I
= 1mA
out
(4) I
= 100 µA
out
(5) I
= 50 µA
out
(6) I
= 15 µA
out
006aaa021
(1)
(2)
(3)
(4)
(5)
(6)
VS (V)
Fig 2. Output current as a function ofsupplyvoltage;
typical values
2
10
I
out
(mA)
10
1
−1
10
−2
10
10 10
2
10
3
10
4
10
006aaa022
5
10
R
ext
(Ω)
VS= 12 V; RL= 100 Ω R
Fig 3. Output current as a function of external
resistance; typical values
2.0
I
S
(mA)
1.5
1.0
0.5
6
0
0806020 40
=∞; RL= 100 Ω
ext
006aaa023
VS (V)
Fig 4. Supply current asafunction of supply voltage;
typical values
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 4 of 12
NXP Semiconductors
8. Application information
External resistor calculation
The output current can be set by connecting an external resistor between VS (pin 5) and
REXT (pin 4).
I
then calculates to:
out
Without an external resistor the output current will be typically 15 µA.
PSSI2021SAY
Constant current source in SOT353 package
out
0.617
-------------
R
ext
15 µA+=
I
Typical output currents versus supply voltage V
The applied supply voltage determines the output current. Table 8 gives typical I
S
values
out
at specified supply voltages, assuming that the working output current is 70% of the
maximum possible output current.
Table 8. Typical output currents at specified supply voltages
VS (V) I
56
12 18
24 38
36 60
out
(mA)
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 5 of 12
NXP Semiconductors
8.1 Typical application circuits
LED driver
Figure 5 shows a typical application circuit for an LED driver. The constant current
ensures a constant LED brightness.
PSSI2021SAY
Constant current source in SOT353 package
VS
REXT
IOUT
GND
V
CC
R
ext
I
out
LED
006aaa024
Fig 5. LED driver application diagram
Switching the current ON/OFF
The output can be switched ON and OFF by connecting a resistor-equipped transistor
(RET, e.g. PDTC124XU) as shown in Figure 6.
VS
REXT
V
CC
R
ext
IOUT
GND
OUT
IN/
OUT
GND
I
out
LED
006aaa025
Fig 6. Switching the current ON/OFF; application diagram
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 6 of 12
NXP Semiconductors
Voltage reference
The PSSI2021SAY supplies a constant current to the Zener diode regardless of supply
voltage variation, resulting in a constant reference voltage (see Figure 7).
PSSI2021SAY
Constant current source in SOT353 package
VS
REXT
IOUT
GND
Fig 7. Voltage reference application diagram
R
ext
I
out
006aaa026
V
CC
V
ref
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 7 of 12
NXP Semiconductors
PSSI2021SAY
Constant current source in SOT353 package
9. Package outline
Plastic surface-mounted package; 5 leads SOT353
D
y
132
e
1
e
E
H
E
AB
X
v M
A
45
Q
A
A
1
b
p
wBM
L
detail X
c
p
0 1 2 mm
scale
DIMENSIONS (mm are the original dimensions)
A
UNIT
mm
VERSION
A
1.1
0.8
OUTLINE
SOT353
max
0.1
1
b
cD
p
0.3
0.25
0.2
0.10
IEC JEDEC JEITA
2.2
1.8
(2)
E
1.35
1.3
1.15
REFERENCES
e
H
L
0.45
0.15
Qywv
p
0.25
0.15
0.2 0.10.2
EUROPEAN
PROJECTION
ISSUE DATE
04-11-16
06-03-16
e
0.65
1
SC-88A
E
2.2
2.0
Fig 8. Package outline SOT353 (SC-88A)
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 8 of 12
NXP Semiconductors
10. Packing information
PSSI2021SAY
Constant current source in SOT353 package
Table 9. Packing methods
The indicated -xxx are the last three digits of the 12NC ordering code.
Type number Package Description Packing quantity
PSSI2021SAY SOT353 4 mm pitch, 8 mm tape and reel -115
[1] For further information and the availability of packing methods, seeSection 13.
[1]
3000
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 9 of 12
NXP Semiconductors
Constant current source in SOT353 package
PSSI2021SAY
11. Revision history
Table 10. Revision history
Document ID Release date Data sheet status Change notice Supersedes
PSSI2021SAY_3 20090827 Product data sheet - PSSI2021SAY_2
Modifications:
PSSI2021SAY_2 20041020 Product data sheet - PSSI2021SAY_1
PSSI2021SAY_1 20010507 Product specification - -
• This data sheet was changed to reflect the new company name NXP Semiconductors,
including new legal definitions and disclaimers. No changes were made to the technical
content.
• Table 2 “Pinning”: amended
• Figure 8 “Package outline SOT353 (SC-88A)”: updated
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 10 of 12
NXP Semiconductors
12. Legal information
12.1 Data sheet status
PSSI2021SAY
Constant current source in SOT353 package
Document status
Objective [short] data sheet Development This document contains data from the objective specification for product development.
Preliminary [short] data sheet Qualification This document contains data from the preliminary specification.
Product [short] data sheet Production This document contains the product specification.
[1] Please consult the most recently issued document before initiating or completing a design.
[2] The term ‘short data sheet’ is explained in section “Definitions”.
[3] The productstatus ofdevice(s) described in this document may have changedsince this document was publishedand maydiffer in case of multipledevices. The latest product status
information is available on the Internet at URL
[1][2]
Product status
12.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein andshall haveno liabilityfor theconsequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with thesame producttype number(s)and title.A short datasheet is intended
for quick reference onlyand should notbe relied uponto contain detailedand
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
12.3 Disclaimers
General — Information in this document is believed to be accurate and
reliable. However,NXP Semiconductors doesnot give anyrepresentations or
warranties, expressed or implied,as to theaccuracy or completeness of such
information and shall have no liability for the consequences of use of such
information.
Right to make changes — NXP Semiconductorsreserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. Thisdocument supersedes andreplaces all informationsupplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
[3]
http://www.nxp.com.
Definition
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is at the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Limiting values — Stress above one or more limiting values (as defined in
the AbsoluteMaximum Ratings Systemof IEC 60134)may cause permanent
damage tothe device.Limiting valuesare stress ratingsonly andoperation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
Terms and conditions of sale — NXP Semiconductors products are sold
subject to thegeneral terms and conditions ofcommercial sale, as published
at
http://www.nxp.com/profile/terms, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
No offer to sell or license — Nothing in this document may be interpreted
or construed as an offer to sell products that is open for acceptance or the
grant, conveyance or implication of anylicense under anycopyrights, patents
or other industrial or intellectual property rights.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
Quick reference data — The Quick reference data is an extract of the
product data given in the Limiting values and Characteristics sections of this
document, and as such is not complete, exhaustive or legally binding.
12.4 Trademarks
Notice: All referenced brands, productnames, service namesand trademarks
are the property of their respective owners.
13. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
PSSI2021SAY_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 27 August 2009 11 of 12
NXP Semiconductors
14. Contents
1 Product profile . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 General description. . . . . . . . . . . . . . . . . . . . . . 1
1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.4 Quick reference data. . . . . . . . . . . . . . . . . . . . . 1
2 Pinning information. . . . . . . . . . . . . . . . . . . . . . 2
3 Ordering information. . . . . . . . . . . . . . . . . . . . . 2
4 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
5 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 3
6 Thermal characteristics. . . . . . . . . . . . . . . . . . . 3
7 Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 3
8 Application information. . . . . . . . . . . . . . . . . . . 5
8.1 Typical application circuits . . . . . . . . . . . . . . . . 6
9 Package outline . . . . . . . . . . . . . . . . . . . . . . . . . 8
10 Packing information. . . . . . . . . . . . . . . . . . . . . . 9
11 Revision history. . . . . . . . . . . . . . . . . . . . . . . . 10
12 Legal information. . . . . . . . . . . . . . . . . . . . . . . 11
12.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 11
12.2 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
12.3 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . 11
12.4 Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 11
13 Contact information. . . . . . . . . . . . . . . . . . . . . 11
14 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
PSSI2021SAY
Constant current source in SOT353 package
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2009. All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
Date of release: 27 August 2009
Document identifier: PSSI2021SAY_3
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