ST STCS05 User Manual
Features
■ Up to 40 V input voltage
■ Less than 0.5 V voltage overhead
■ Up to 0.5 A output current
■ PWM dimming pin
■ Shutdown pin
■ LED disconnection diagnostic
Applications
STCS05
0.5 A max constant current LED driver
SO-8
■ LED constant current supplying for varying
input voltages
■ Low voltage lighting
■ Small appliances LED lighting
■ Car LED lights
Description
The STCS05 is a BiCMOS constant current
source designed to provide a precise constant
current starting from a varying input voltage
source. The main target is to replace discrete
components solution for driving LEDs in low
voltage applications such as 5 V, 12 V or 24 V
giving benefits in terms of precision, integration
and reliability.
The current is set with external resistor up to 0.5
A with a ± 10 % precision; a dedicated pin allows
implementing PWM dimming.
An open-drain pin output provides information on
load disconnection condition.
Table 1. Device summary
Order code Package Packaging
STCS05DR SO-8 2500 parts per reel
July 2008 Rev 4 1/16
www.st.com
16
STCS05
Contents
1 Application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7 Detail description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1 Current setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.2 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.3 PWM dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.4 Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1 Reverse polarity protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.2 Thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2/16
STCS05 Application diagram
Application diagram
Figure 1. Typical application diagram for 0.5 A LED current
V
V
IN
IN
4.5V to 40V
4.5V to 40V
BAT46ZFILM
BAT46ZFILM
RIN100 ohm
RIN100 ohm
OFF
OFF
OFF
OFF
C
C
BYP
BYP
0.1µF
0.1µF
ON
ON
ON
ON
Load disconnection
Load disconnection
(Open Drain output)
(Open Drain output)
V
V
PWM
PWM
EN
EN
CC
CC
DISC
DISC
STCS05
STCS05
GND
GND
DRAIN
DRAIN
FB
FB
R
R
FB
FB
0.2 ohm
0.2 ohm
C
C
DRAIN
DRAIN
0.47µF
0.47µF
3/16
Pin configuration STCS05
1 Pin configuration
Figure 2. Pin connections (top view)
Table 2. Pin description
Pin n° Symbol Note
1V
2 PWM PWM dimming input
3 EN Shutdown pin
4 DRAIN Internal N-MOSFET drain
5 FB External resistor connection for current set (N-MOSFET source)
6 GND Ground
7 N.C. In order to guarantee the device works properly it is mandatory to leave this pin floating
8 DISC Load disconnection flag (open drain)
CC
Supply voltage
4/16
STCS05 Maximum ratings
2 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
CC
V
D
PWM, EN, DISC Logic pins -0.3 to + V
DC supply voltage -0.3 to +45
Drain voltage -0.3 to +45
CC
V
+ 0.3 V
FB Configuration pins -0.3 to + 3.3 V
ESD Human body model (all pins) ±2 kV
(1)
T
J
T
STG
1. TJ is calculated from the ambient temperature TA and the power dissipation PD according the following formula:
= TA + (PD x R
T
J
Junction temperature -40 to 150 °C
Storage temperature range -55 to 150 °C
). See Figure 12 for details of max power dissipation for ambient temperatures higher than 25°C.
thJA
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these conditions is not implied.
Table 4. Thermal data
Symbol Parameter SO-8 Unit
R
thJC
R
thJA
1. This value depends from thermal design of PCB on which the device is mounted.
Thermal resistance junction-case 20 °C/W
Thermal resistance junction-ambient
(1)
100 °C/W
5/16
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