ST STOD13AS User Manual

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

■ Minimum 250 mA output current

■ 4.6 V fixed positive output voltage

■ Programmable negative voltage by S

WIRE

from

-2.4 V to -6.4 V at 100 mV steps

■ Typical efficiency: 85%

■ Pulse skipping mode in light load condition

■ 1.5 MHz PWM mode control switching

frequency

■ TDMA noise high immunity

■ Enable pin for shutdown mode

■ Low quiescent current in shutdown mode

■ Soft-start with inrush current protection

■ Overtemperature protection

■ Temperature range: -40 °C to 85 °C

■ True-shutdown mode

■ Fast discharge outputs of the circuits after

shutdown

■ Short-circuit protection

■ Package DFN12L (3 x 3 mm) 0.6 mm height

Applications

■ Active matrix AMOLED power supply in

portable devices

■ Cellular phones

■ Camcorders and digital still cameras

Table 1. Device summary

STOD13AS

250 mA dual DC-DC converter

for powering AMOLED displays

DFN12L (3 x 3 mm)

■ Multimedia players

Description

The STOD13AS is a dual DC-DC converter for AMOLED display panels. It integrates a step-up and an inverting DC-DC converter making it particularly suitable for battery operated products, in which the major concern is overall system efficiency. It works in pulse skipping mode during low load conditions and PWM-MODE at 1.5 MHz frequency for medium/high load conditions. The high frequency allows the value and size of external components to be reduced. The Enable pin allows the device to be turned off, therefore reducing the current consumption to less than 1 µA. The negative output voltage can be programmed by an MCU through a dedicated pin which implements single-wire protocol. Soft-start with controlled inrush current limit, thermal shutdown, and short-circuit protection are integrated functions of the device.

Order code Positive voltage Negative voltage Package Packaging

STOD13ASTPUR 4.6V -2.4V to -6.4V DFN12L (3 x 3mm) 3000 parts per reel

January 2012 Doc ID 022733 Rev 1 1/25

www.st.com

Contents STOD13AS

Contents

1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.1 S

6.1.1 S

6.1.2

6.1.3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

WIRE

features and benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

WIRE

protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

WIRE

basic operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

WIRE

6.2 Negative output voltage levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.3 Enable, S

and FD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

WIRE

7 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.1 External passive components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.1.1 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.1.2 Input and output capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.2 Recommended PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1.1 Multiple operation modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1.2 Pulse skipping operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1.3 Discontinuous conduction mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1.4 Continuous conduction mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.1.5 Enable pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8.1.6 Soft-start and inrush current limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8.1.7 Undervoltage lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8.1.8 Overtemperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

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STOD13AS Contents

8.1.9 Short-circuit protection during soft-start (SSD) . . . . . . . . . . . . . . . . . . . 18

8.1.10 Overload protection (OLP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8.1.11 Short-circuit protection (SCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

8.1.12 Fast discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

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Schematic STOD13AS

1 Schematic

Figure 1. Application schematic

VBAT

LX1

CIN

S-WIRE

VINP

VINA

S-WIRE

LX1

VMID

STOD13AS

CREF

Table 2. Typical external components

Comp. Manufacturer Part number Value Size Ratings

VREF

PGND

AGND

VO2

LX2

CMID

CO2

AM10459v1

(1)

(2)

MID

REF

1. A 250 mA load can be provided with inductor saturation current as a minimum of 0.9 A.

2. At -6.4 V, a 250 mA load can be provided with inductor saturation current as a minimum of 1.5 A. See

CoilCraft

Murata

CoilCraft

Murata

Taiyo YudeN

Murata

Taiyo YudeN

Murata

Taiyo YudeN

Murata

Taiyo YudeN

LPS4012-472ML

LQH3NPN4R7MM0

LPS4012-472ML

LQH3NPN4R7MM0

GRM219R61A106KE44

LMK212BJ106KD-T

GRM219R61A106KE44

LMK212BJ106KD-T

GRM219R61A106KE44

LMK212BJ106KD-T

GRM185R60J105KE26

JMK107BJ105KK-T

4.7µH

2 x 10µF 0805

10µF

2 x 10µF

1µF

4.0 x 4.0 x 1.2

3.0 x 3.0 x 1.5

4.0 x 4.0 x 1.2

3.0 x 3.0 x 1.5

0805 0805

0603 0603

±20%, I = 1.7A, R = 0.175Ω ±20%, I = 1.25A, R = 0.13Ω

±20%, I = 1.7A, R = 0.175Ω

±20%, I = 1.25A, R = 0.13Ω

±10%, X5R, 10V ±10%, X5R, 10V

±10%, X5R, 6.3V ±10%, X5R, 6.3V

Section 7.1.1

Note: All the above components refer to the typical application performance characteristics.

Operation of the device is not limited to the choice of these external components. Inductor values ranging from 3.3 µH to 6.8 µH can be used together with the STOD13AS.

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STOD13AS Schematic

UVLO

LOGIC CONTROL

OTP

S-WIRE

RING

KILLER

VREF

OSC

STEP-UP

CONTROL

FAST

DISCHARGE

DMD

INVERTING

CONTROL

FAST

DISCHARGE

DMD

s s

INA

WIRE

REF

AGND

PGND

VREF

S-WIRE control

INP

MID

P1A

P1B

SSD SCP OLP

VO2

CURRENT

SENSE

VINP

Figure 2. Block schematic

AM10458v1

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Pin configuration STOD13AS

2 Pin configuration

Figure 3. Pin configuration (top view)

Table 3. Pin description

Pin name Pin n° Description

1 Boost converter switching node

PGND 2 Power ground pin

MID

FD 4

3 Boost converter output voltage

Fast discharge control pin. When pulled LOW, the fast discharge after shutdown is active. When pulled HIGH, the fast discharge is OFF

AGND 5 Signal ground pin. This pin must be connected to the power ground layer

REF

WIRE

7 Negative voltage setting pin

EN 8

IN A

12 Power input supply voltage

IN P

9 Inverting converter output voltage

10 Inverting converter switching node

11 Analogic input supply voltage

Exposed

pad

Voltage reference output. 1 µF bypass capacitor must be connected between this pin and AGND

Enable control pin. High = converter on; Low = converter in shutdown mode

Internally connected to AGND. Exposed pad must be connected to ground layers in the PCB layout in order to guarantee proper operation of the device

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STOD13AS Maximum ratings

3 Maximum ratings

Table 4. Absolute maximum ratings

Symbol Parameter Value Unit

, V

INA

EN, S

WIRE

FD Logic input pin -0.3 to V

MID

REF

STG

DC supply voltage -0.3 to 6 V

INP

Logic input pins -0.3 to 4.6 V

+0.3 V

INA

Inverting converter switching current Internally limited A

Inverting converter switching node voltage -10 to V

+ 0.3 V

INP

Inverting converter output voltage -10 to AGND + 0.3 V

Step-up converter and LDO output voltage -0.3 to 6 V

Step-up converter switching node voltage -0.3 to V

+ 0.3 V

MID

Step-up converter 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

Human body model protection ±2 kV

ESD

Machine body model protection 200 V

Note: Absolute maximum ratings are those values beyond which damage to the device may occur.

Functional operation under these condition is not implied.

The Lx1 and Lx2 have high slew rate and they can be over the absolute maximum rating during operation due to the parasitic inductance in the PCB and scope probe. An absolute maximum rating of Lx1 and Lx2 is related to voltage supplied by an external source so the internally generated Lx1 and Lx2 voltage during normal operation doesn't damage the chipset.

Table 5. Thermal data

Symbol Parameter Value Unit

thJA

thJC

1. The package is mounted on a 4-layer (2S2P) JEDEC board as per JESD51-7.

Thermal resistance junction-ambient 33 °C/W

Thermal resistance junction-case (FR-4 PCB)

(1)

2.12 °C/W

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Electrical characteristics STOD13AS

4 Electrical characteristics

TJ = 25 °C, V C

= 2 x 10 µF, C

INA

= V

= 3.7 V, I

INP

= 1 µF, L1 = L2 = 4.7 µH, V

REF

MID,O2

= 30 mA, C

= 2 x 10 µF, C

= 2 V, V

= 4.6 V, V

MID

= 10 µF,

= -4.9 V unless

otherwise specified.

Table 6. Electrical characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

General section

INA, VINP

UVLO_H Under voltage lockout HIGH V

UVLO_L Under voltage lockout LOW V

Q_SH

fs Switching frequency PWM mode 1.35 1.5 1.65 MHz

REF

Supply input voltage 2.5 3.7 4.5 V

rising 2.22 2.25 V

INA

falling 1.9 2.18 V

INA

Input current No load condition 1.7 2.1 mA

= VSW = GND

Shutdown current

H Enable high threshold

= -40°C to +85°C

=2.5V to 4.5V,

INA

= -40°C to +85°C

1.2 V

L Enable low threshold 0.4

Enable input current

H Fast discharge high threshold

EN=VINA

= -40°C to +85°C

INA

= -40°C to +85°C

=4.5V;

=2.5V to 4.5V,

1.2 V

L Fast discharge low threshold 0.4

=4.5V;

=10 to 30mA,

=4.6V, VO2=-4.9V

=30 to 150mA,

=4.6V, VO2=-4.9V

=150 to 250mA,

=4.6V, VO2=-4.9V

=10µA 1.208 1.220 1.232 V

100 µA

MAX

Fast discharge input current

FD=VINA

= -40°C to +85°C

Step-up maximum duty cycle No load 87 %

Inverting maximum duty cycle No load 87 %

MID,O2

MID

Total system efficiency

Reference voltage I

Reference current capability

MID,O2

MID

MID,O2

MID

REF

@ 98.5% of no load reference voltage

1µA

50 µA

Step-up converter section

Positive output voltage 4.6 V

MID

Positive output voltage total variation

INA=VINP

MID

load T

=2.9V to 4.5V;

=5mA to 250mA, IO2 no

= -40°C to +85°C

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