ST STOD02 User Manual
Dual DC-DC converter for powering AMOLED display
Features
■ Step-up and inverter converters
■ Operating input voltage range from
2.5 V to 4.5 V
■ Synchronous rectification for both DC-DC
converters
■ 150 mA maximum output current
■ 4.6 V fixed positive output voltage
■ Programmable negative voltage by S-wire from
- 2.3 V to - 5.9 V
■ Typical efficiency: 85 %
■ Pulse skipping mode in light load condition
(I
< 10 mA)
O
■ 1.6 MHz PWM mode control switching
frequency (I
■ Enable pin for shutdown mode
■ Low quiescent current: < 1 µA in shutdown
mode
■ Soft-start with inrush current protection
■ Over temperature protection
■ Temperature range: -40 °C to 85 °C
■ True shutdown mode
■ Fast outputs discharge circuit after shutdown
■ Package: DFN 12 leads - (3 x 3 mm)
Applications
■ Active matrix organic LED power supply
(AMOLED)
■ Mobile phones
> 10 mA)
O
STOD02
DFN12L (3 x 3 mm)
■ PDAs
■ Camcorders and digital still cameras
Description
The STOD02 is a dual DC-DC converter meant to
power AMOLED displays. It integrates a step up
and an inverting DC-DC converter making it
particularly suitable for battery operated products,
where the major concern is the overall system
efficiency. STOD02 works in pulse skipping mode
during low load condition and in PWM-mode (at
1.6 MHz) for medium/high load condition. The
high frequency allows reducing the value and
number of external components just to 6
components needed. The enable pin allows
turning off the device so reducing the current
consumption to less that 1 µA. The negative
output voltage can be programmed by an MCU
through a dedicated pin which implements singlewire protocol. Soft-start with controlled inrush
current limit and thermal shutdown are integrated
functions of the device.
Table 1. Device summary
Order code Package Packaging
STOD02PUR DFN12L (3 x 3 x 0.8 mm) 3000 parts per reel
STOD02TPUR DFN12L (3 x 3 x 0.6 mm) 3000 parts per reel
June 2009 Doc ID 15245 Rev 3 1/23
www.st.com
23
Contents STOD02
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 S-wire protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2/23 Doc ID 15245 Rev 3
STOD02 Diagram
1 Diagram
Figure 1. Block diagram
Doc ID 15245 Rev 3 3/23
Pin configuration STOD02
2 Pin configuration
Figure 2. Pin connections (top view)
Table 2. Pin description
Pin n° Symbol Description
1L
X1
Switching node of the step up converter
2 PGND Power ground pin
3VO1Step up converter output voltage
4 NC Not connected
5 AGND Signal ground pin. This pin must be connected to power ground pin
6V
REF
External voltage reference
7 S-wire Negative voltage setting pin, uses S-wire protocol
8 EN Enable control pin. ON = V
9V
10 L
11 V
12 V
O2
X2
INA
INP
exposed
pad
Inverting converter output voltage
Switching node of the inverting converter
Analog input supply voltage
Power input supply voltage
Internally connected to AGND. Exposed pad must be connected to AGND and PGND in
the PCB layout in order to guarantee proper operation of the device.
. When pulled low, the device goes in shutdown mode
I
4/23 Doc ID 15245 Rev 3
STOD02 Maximum ratings
3 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
, V
INA
EN,S-wire Enable pin, S-wire pin -0.3 to 6 V
DC supply voltage -0.3 to 6 V
INP
V
IL
L
V
V
L
IL
X2
X2
O2
O1
X1
X1
REF
P
T
st
T
D
J
Inverting converter’s switching current Internally limited A
Inverting converter switching node -10 to V
+0.3 V
INP
Inverting converter output voltage -10 to GND+0.3 V
Step-up converter output voltage -0.3 to 6 V
Step-up converter switching node -0.3 to VO1+0.3 V
Step up converter’s switching current Internally limited A
Reference voltage -0.3 to 3 V
Power dissipation Internally limited mW
Storage temperature range -65 to 150 °C
Maximum junction temperature 150 °C
ESD ESD protection HBM 2 kV
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 4. Thermal data
Symbol Parameter Value Unit
R
R
thJA
thJC
Thermal resistance junction-ambient referred to FR-4 PCB 49.1 °C/W
Thermal resistance junction-case 4.216 °C/W
Doc ID 15245 Rev 3 5/23
Application STOD02
4 Application
Figure 3. Typical application circuit
AA
Table 5. Typical external components
Symbol Parameter Min. Typ. Max. Unit
L
1
L
2
C
IN
C
01, C02
C
ref
Ceramic capacitor SMD 4.7 µF
Ceramic capacitor SMD 4.7 µF
Ceramic capacitor SMD 1 µF
6/23 Doc ID 15245 Rev 3
Inductor 4.7 µH
Inductor 4.7 µH
STOD02 Electrical characteristics
5 Electrical characteristics
TJ = 25 °C, V
4.7 µH, L2 = 4.7 µH, V
Table 6. Electrical characteristics
INA
= V
= 3.7 V, I
INP
EN
= V
INA
= 30 mA, CI = 4.7 µF, C
O1,2
= V
, V
INP
= 4.6 V, VO2= -4.9 V unless otherwise specified.
O1
= 4.7 µF, C
O1,2
= 1 µF, L1 =
REF
Symbol Parameter Test conditions Min. Typ. Max. Unit
General section
V
UVLO_H
UVLO_L
I_V
I
V
EN
V
EN
I
EN
F
SW
D1
Operating input voltage
IN
range
Under voltage lockout
HIGH
Under voltage lockout
LOW
Input current No Load condition (I_VI = I
I
Shutdown current VEN = GND, (IS = I
S
H Enable high threshold V
L Enable low threshold V
Enable input current V
Frequency PWM mode, TJ = -40 to 85°C 1.35 1.6 1.85 MHz
Step-up maximum duty
MAX
cycle
V
=4.6V, TJ = -40 to 85°C 2.5 4.5 V
O1
rising, TJ = -40 to 85°C 2.40 2.50 V
V
INA
falling, TJ = -40 to 85°C 2.30 2.35 V
V
INA
+ I
INA
+ I
INA
= 2.5V to 4.5V, TJ = -40 to 85°C 1.2
INA
= 2.5V to 4.5V, TJ = -40 to 85°C 0.4
INA
= V
EN
I
)1µA
INP
)11.5mA
INP
90 %
1µA
V
D2
Inverting maximum
MAX
duty cycle
ν Total system efficiency
V
REF
I
REF
Voltage reference I
Voltage reference
current capability
Step-up converter section
V
ΔV
O1 SL
ΔV
O1 LT
Line/Load maximum
O1
output voltage variation
Static line regulation
Line transient
=10 to 30mA, VO1=4.6V, VO2=-4.9V 80
I
O1,2
I
=30 to 150mA, VO1=4.6V,
O1,2
VO2=-4.9V
=10µA 1.196 1.209 1.222 V
REF
= V
At V
V
INA
V
INA
=-40°C to 85°C
T
J
(1)
V
INA
REF
=2.5V to 4.5V, IO1=5mA to 100mA 4.55 4.6 4.65 V
=2.5V to 4.5V, IO1=5mA, IO2 no load;
=2.5V to 4.5V, IO1=100mA, IO2 no
– 1.5% 100 µA
REF
load, TJ=-40°C to 85°C
=3.5V to 3.0V, IO1=100mA
V
INA
=-40°C to 85°C, TR=TF=50µs output
T
J
voltage variation with respect to nominal
V
O1
90 %
%
85
0.5
%
0.5
-12 mV
Doc ID 15245 Rev 3 7/23
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