ST STOD2540 User Manual
Features
■ Inductor switches boost controller
■ PFM mode control
■ High efficiency over wide range of load (1 mA
to 40 mA)
■ Integrated load disconnect switch
■ Over voltage protection with automatic restart
■ Soft start with adjustable peak current limit
■ Enable pin
■ Low shutdown current
■ Small external inductor
■ Supply voltage from 3.0 V to 5.5 V
Application
■ PMOLED display driver
Description
STOD2540
PMOLED display power supply
QFN8 (3 x 3 mm)
In this state-of-the-art boost converter, a DC
current path exists between the battery source
and the load. In order to reduce the consumption
in shutdown mode, a high-side load isolation
switch is necessary to cut this DC current path in
standby mode. The load disconnect switch (LDS)
act as an isolation switch in shutdown mode.
STOD2540 is dedicated to passive matrix OLED
(PMOLED) displays for portable handsets and
provides the pre-charge and biasing voltage of
the column matrix driver as shown in figure 3. The
current capability of STOD2540 allows feeding a
1", 1.3" or 1.5" color PMOLED. STOD2540 is a
boost converter that operates from 3.0 V to 5.5 V
and can provide an output voltage as high as 25
V. The output current capability is maximum 40
mA up to 25 V output voltage. The regulation is
performed by a resistor divider network (figure 3)
that detects the output voltage.
Table 1. Device summary
Order code Package Packaging
STOD2540PUR QFN8 (3 x 3 mm) 3000 parts per reel
July 2010 Doc ID 12204 Rev 10 1/20
www.st.com
20
Contents STOD2540
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 Boost controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Adjustable peak inductor current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.3 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.4 OVP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.5 Load isolation switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.6 Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.7 Under voltage lockout (UVLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2/20 Doc ID 12204 Rev 10
STOD2540 Diagram
1 Diagram
Figure 1. Block diagram
Doc ID 12204 Rev 10 3/20
Pin configuration STOD2540
2 Pin configuration
Figure 2. Pin connections (top through view)
Table 2. Pin description
Pin n° Symbol Note
1V
2R
SET
Supply voltage
I
Peak inductor current adjust
3 AGND Analog ground
4 FB Feedback for the LED current regulation
5V
6V
O
CAP
Output voltage for LED supply
Load disconnect switch input
7 EN IC enable signal
8V
SW
Boost switch drain
PGND Power ground
4/20 Doc ID 12204 Rev 10
STOD2540 Maximum ratings
3 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
VB
SW, VBO
V
I
R
SET
EN Enable pin V
V
ESD
T
STG
T
OP
Breakdown voltage at OUT and SW pin 40 V
Supply voltage range 6 V
R
pin VI + 0.3 V
SET
+ 0.3 V
I
ESD ratings, HBM MIL STD 883C 2 kV
Storage temperature range - 65 to 150 °C
Operating junction temperature range - 40 to 85 °C
Table 4. Thermal data
Symbol Parameter Value Unit
R
thJA
Thermal resistance junction-ambient 52 °C/W
Doc ID 12204 Rev 10 5/20
Electrical characteristics STOD2540
4 Electrical characteristics
TJ = 40 °C to 85 °C, VI = 3.6 V, VEN = 3V, CI = CO = 4.7 µF, L = 4.7 µH, R1 = 180 kΩ,
R
= 10 kΩ, VO = 24 V, Typ. values @ 25 °C, unless otherwise specified.
2
Table 5. Electrical characteristics
Symbol Parameter Test condition Min. Typ. Max. Unit
V
V
V
OVP
I
I
SD
I
R
DSON-SW
O
O
Q
Input voltage range 3.0 5.5 V
I
= 3 V to 5.5 V VI + 0.5
Regulated output voltage
Over voltage protection on
output
Continuous output current
Stand-by current
Quiescent current consumption
Boost switch R
DSON
(1)
V
I
= 25 V
V
O
V
= Low, VI = 3.6 V
EN
V
= Low, VI = 3 V to 4.2 V
EN
V
= 3 V to 4.2 V @ 25 °C
I
= 5.5 V @ 25 °C
V
I
VI = 4.2 V, ISW = 100 mA
35 V
140mA
25 35 V
0.4 0.8
0.8 1.2
0.4 Ω
BVDS Breakdown voltage 40 V
R
DSON-
LDS
R
DSON
(1)
VO = 25 V, IO = 30 mA
2 Ω
BVDS Breakdown voltage 40 V
I
LIM-ADJ
I
LIM-MAX
Peak inductor limit range
Maximum peak inductor current
(1)
(1)
R
= 10 kΩ to 100 kΩ
SET
VI = 3 V to 5.5 V, R
SET
= V
0.2 1.1 A
I
0.75 1.2 A
FB Feedback voltage 5% @ 25 °C 1.18 1.24 1.30 V
T
ON_MAX
T
OFF_MIN
Maximum ON time
Minimum OFF time
Efficiency, V
= 3.6 V
I
Eff
Efficiency, V
= 4.2 V
I
Ripple Output ripple and noise
OV
HYST
Over-voltage hysteresis 2 V
(1)
(1)
= 4.2 V
V
I
= 4.2 V
V
I
IO = 1 mA to 5 mA
= 5 mA to 40 mA
I
O
IO = 1 mA to 5 mA
I
= 5 mA to 40 mA
O
V
= 3.6 V, IO = 5 mA, VO = 24 V
I
V
= 3.6 V, IO = 30 mA, VO = 24 V
I
V
= 4.2 V, IO = 5 mA, VO = 24 V
I
= 4.2 V, IO = 30 mA, VO = 24 V
V
I
5.5 µs
300 ns
65
70
65
70
1.3
1.3
1.3
1.3
3
µA
10
mA
%
%
6/20 Doc ID 12204 Rev 10
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