STP4CMP
Low voltage 4-channel constant current
LED driver with charge pump
Datasheet - production data
Description
The STP4CMP is a charge-pump-based 4-
channel LED driver designed for RGB
illumination or LCD display backlighting. The
STP4CMP works off a battery with an input
voltage between 2.7 V and 5.5 V. The device
generates regulated current sinks with high
absolute and channel-to-channel accuracy to
drive up to 4 LEDs. It can support LEDs with
forward voltage as high as 3.8 V. The current
sink for each channel can be set with 4 individual
external resistors. Each channel is controlled
independently. The PWM control can be applied
directly to the 4 EN (enable) pins to provide
brightness control. When enabled, the charge
pump, which uses a small ceramic bucket
capacitor between C
1P
and C
1N
, operates to
regulate the V
OUT
with a clamping voltage at typ.
5 V. The tiny QFN20 (1.8x3.2 mm) package
allows the device to be also used for applications
with space limitations.
Table 1: Device summary
Oder code
STP4CMPQTR
Package
QFN20
(1.8x3.2 mm)
Packing
Tape and reel
QFN20 (1.8x3.2 mm)
Features
Operating voltage range: V
CC
2.7 V to 5.5 V
Full RGB function support
4-channel LED driver with individual
ON/OFF control directly from input pins
Individually programmable output current for
the 4 channels through 4 external resistors
with a max. capability of 30 mA
Absolute output current accuracy of max.
±7% and channel-to-channel mismatch of
max. ±4%
Selectable charge pump enable/disable
Thermal protection
Small QFN20 (1.8x3.2 mm) package
Applications
Mobile phone display backlighting
RGB LED indicator driver
April 2015
DocID15770 Rev 3
1/24
www.st.com
This is information on a product in full production.
Contents
STP4CMP
Contents
1
2
3
4
5
Application schematic .................................................................... 5
Pin configuration ............................................................................. 7
Maximum ratings ............................................................................. 8
Electrical characteristics ................................................................ 9
Detailed description ...................................................................... 11
5.1
5.2
5.3
5.4
5.5
Enable pin ....................................................................................... 11
LED turn-on pin (ONx) .................................................................... 11
Programmable output current.......................................................... 11
Charge pump .................................................................................. 11
Thermal protection .......................................................................... 11
6
7
Typical performance characteristics ........................................... 12
PCB layout ..................................................................................... 15
7.1
7.2
Recommended ................................................................................ 15
Evaluation board ............................................................................. 17
QFN20 (1.8x3.2 mm) package information ..................................... 19
Packing information ......................................................................... 21
8
Package information ..................................................................... 18
8.1
8.2
9
Revision history ............................................................................ 23
2/24
DocID15770 Rev 3
STP4CMP
List of tables
List of tables
Table 1: Device summary ........................................................................................................................... 1
Table 2: Typical external components ........................................................................................................ 5
Table 3: Pin description .............................................................................................................................. 7
Table 4: Absolute maximum ratings ........................................................................................................... 8
Table 5: Recommended operating conditions ............................................................................................ 8
Table 6: Thermal data ................................................................................................................................. 8
Table 7: Electrical characteristics ............................................................................................................... 9
Table 8: QFN20 (1.8x3.2 mm) package mechanical data ........................................................................ 20
Table 9: Document revision history .......................................................................................................... 23
DocID15770 Rev 3
3/24
List of figures
STP4CMP
List of figures
Figure 1: Application schematic .................................................................................................................. 5
Figure 2: Block schematic ........................................................................................................................... 6
Figure 3: Pin connections (top view) ........................................................................................................... 7
Figure 4: Efficiency vs. V
IN
, I
OUT
= 10 mA ................................................................................................. 12
Figure 5: Efficiency vs. V
IN
, I
OUT
= 60 mA ................................................................................................. 12
Figure 6: V
OUT
vs. V
IN
................................................................................................................................ 13
Figure 7: PWM modulation CH1-2 ............................................................................................................ 13
Figure 8: Output ripple .............................................................................................................................. 14
Figure 9: Top layer .................................................................................................................................... 15
Figure 10: Bottom layer............................................................................................................................. 16
Figure 11: Top overlay .............................................................................................................................. 16
Figure 12: Evaluation board ...................................................................................................................... 17
Figure 13: Evaluation board schematic .................................................................................................... 17
Figure 14: QFN20 (1.8x3.2 mm) package outline .................................................................................... 19
Figure 15: QFN20 (1.8x3.2 mm) recommended footprint ......................................................................... 20
Figure 16: QFN20 (1.8x3.2 mm) carrier tape outline ................................................................................ 21
Figure 17: QFN20 (1.8x3.2 mm) reel outline ............................................................................................ 22
4/24
DocID15770 Rev 3
STP4CMP
Application schematic
1
Application schematic
Figure 1: Application schematic
ON1
ON2
ON3
ON4
EN
R
SET1
R
SET2
R
SET3
R
SET4
I
SET1
I
SET2
I
SET3
GND
C
1N
C
1P
C1
C
OUT
V
OUT
V
CC
LED1
LED2
LED3
LED4
CP_Sel
C3
C2
LED1
LED2
LED3
LED4
I
SET4
GND
GIPG270320151334LM
The above figure shows the typical application diagram with the external components. To
ensure an optimal charge pump performance, it is highly recommended that the bucket
capacitor, C1, and the output capacitor, C
OUT
, to be placed as close as possible to the pins.
Table 2: Typical external components
Component
C
1
,C
OUT
C2
Manufacturer
Murata
TDK
Murata
TDK
Murata
TDK
(1)
(2)
Part number
GRM155R61A105KE15D
C1005X5R1A105MT
GRM188R60J106ME84
C1608X5R0J106MT
GRM155R60J104KA01D
C1005X5R1C104KT
CPF0402B976RE1
Value
1 µF/10 V
Size
0402
10 µF/6.3 V
0603
C3
R
SET1-4
100 nF
976 Ω
0402
0402
Tyco
LED1-4
Notes:
(1)
(2)
649 Ω to 7.87 kΩ according to the desired output current from each channel.
Forward voltage typ. 3.8 V.
All the above components refer to a typical application. Operation of the device is
not limited to the choice of these external components.
DocID15770 Rev 3
5/24
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