STCS2ASPR STMicroelectronics, STCS2ASPR Datasheet - Page 12

• Manufacturer Part Number: STCS2ASPR
• Description: IC LED DRVR PWM CONTROL PWRSO-10
• Manufacturer: STMicroelectronics
• Type: PWM Controlr

Specifications of STCS2ASPR

• Constant Current: Yes
• Topology: PWM
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Automotive
• Type - Secondary: White LED
• Voltage - Supply: 4.5 V ~ 40 V
• Mounting Type: Surface Mount
• Package / Case: PowerSO-10 Exposed Bottom Pad
• Operating Temperature: -40°C ~ 150°C
• Current - Output / Channel: 2A
• Internal Switch(s): Yes
• Low Level Output Current: 1 mA
• High Level Output Current: 2000 mA
• Operating Supply Voltage: 4.5 V
• Maximum Supply Current: 3 uA
• Maximum Operating Temperature: + 150 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Frequency: -
• Efficiency: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-6917-2; STCS2ASPR

8
8.1
Figure 15. Reverse polarity condition
8.2
12/18
Application information
Reverse polarity protection
STCS2A must be protected from reverse connection of the supply voltage. Since the current
sunk from V
protect the chip. Care must be taken for the whole application circuit, especially for the
LEDs, in fact, in case a negative voltage is applied between V
voltage will be applied to the LED string that must have a total breakdown voltage higher
than the negative applied voltage in order to avoid any damage.
Thermal considerations
The STCS2A is able to control a LED current up to 2 A and able to sustain a voltage on the
drain pin up to 40 V. Those operating conditions are however limited by thermal constraints.
The poor thermal conduction of epoxy FR4 boards does not permit to benefit of the
outstanding thermal performance of the PowerSO-10.
In any case one way to improve the thermal conduction is the use of large heat spreader
areas at the copper layer of the PC board. This leads to a reduction of thermal resistance to
30 - 36 °C/W for 3 to 6 cm
Use of copper-filled through holes on conventional FR4 techniques increases the
metallization and decreases thermal resistance accordingly. Using a configuration with 16
holes under the spreader of the package with a pitch of 1.8 mm and a diameter of 0.7 mm,
the thermal resistance (junction - heatsink) can be reduced to 12 °C/W.
The thermal resistances shown in the Error! Reference source not found. section are the
typical ones.
The power dissipation in the device can be calculated as follow:
V
V
IN
IN
CC
+
+
BAT46
BAT46
or similar
or similar
pin is in the range of 450 µA a small diode connected to V
2
on-board heatsink.
C
C
SLOPE
SLOPE
PWM
PWM
EN
EN
EN
EN
EN
EN
EN
EN
V
V
SLOPE
SLOPE
CC
CC
GND
GND
FB
FB
SOURCE
SOURCE
DRAIN
DRAIN
R
R
IN
SENSE
SENSE
and GND, a negative
DISC
DISC
CC
is able to