®
RT6154A/B
High Efficiency Single Inductor Buck-Boost Converter
General Description
The RT6154A/B is a high efficiency single inductor Buck-
Boost Converter which can operate with wide input voltage
such as battery which is higher or lower than the output
voltage and it can supply the load current up to 4A. The
maximum peak current in the switches is limited to a
typical value of 5A.
The RT6154A/B feedback loop is internally compensated
for both Buck and Boost operation and it provides seamless
transition between Buck and Boost modes and optimal
transient response. The RT6154A/B operates at 2.4MHz
typical switching frequency in full synchronous operation.
The RT6154A/B operates in Pulse Skipped Modulation
(PSM) mode for increasing efficiency during low power
RF transmission modes. The Power Save Mode can be
disabled, forcing the RT6154A/B to operate at a fixed
switching frequency operation at 2.4MHz. The RT6154A/
B can also be synchronized with external frequency from
2.2MHz to 2.6MHz. The RT6154A output voltage is
programmable using an external resistor divider, and the
RT6154B is fixed internally to 3.3V.
Features
Operates from a Single Li-ion Cell : 1.8V to 5.5V
Adjustable Output Voltage : 1.8V to 5.5V
3A Maximum Load Capability for V
IN
> 3.6V,
V
OUT
= 3.3V
Power Save Mode (PSM) for Improving Low Output
Power Efficiency
Fixed Frequency Operation at 2.4MHz and
Synchronization Possible from 2.2MHz to 2.6MHz
Up to 96% Efficiency
Input Current Limit
Internal Compensation
RoHS Compliant and Halogen Free
Applications
Cellular Phones
Portable Hard Disk Drives
PDAs
Pin Configurations
(TOP VIEW)
VINA
GND
FB
VOUT
VOUT
LX2
LX2
1
2
3
4
5
6
7
14
13
12
11
10
9
8
PGND
15
PGOOD
PS/SYNC
EN
VIN
VIN
LX1
LX1
WDFN-14AL 4x3
Simplified Application Circuit
LX1
V
IN
VIN
LX2
VOUT
V
OUT
RT6154A
VINA
FB
Enable
EN
PGOOD
Power Good
Output
PS/SYNC
GND
PGND
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6154A/B-01 May 2014
www.richtek.com
1
RT6154A/B
Ordering Information
RT6154A/B
Package Type
QW : WDFN-14AL 4x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
RT6154A Adjustable Output Voltage
RT6154B Fixed 3.3V Output Voltage
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
RT6154BGQW
0D= : Product Code
Marking Information
RT6154AGQW
0E= : Product Code
YMDNN : Date Code
0E=YM
DNN
0D=YM
DNN
YMDNN : Date Code
Functional Pin Description
Pin No.
1
2
3
4, 5
6, 7
8, 9
10, 11
12
13
14
15
(Exposed Pad)
Pin Name
VINA
GND
FB
VOUT
LX2
LX1
VIN
EN
PS/SYNC
PGOOD
PGND
Supply Voltage Input.
Analog Ground.
Voltage Feedback of Adjustable Versions, must be connected to VOUT on
fixed output voltage versions.
Buck-Boost Converter Output.
Second Switch Node.
First Switch Node.
Power Input.
Enable Control Input (1 Enabled, 0 Disabled). Must not be left open.
Enable/Disable Control Input for Power Save Mode (1 disabled, 0 enabled,
clock signal for synchronization). Must not be left open.
Power Good Indicator Output. (1 good, 0 failure; open drain).
Power Ground. The exposed pad must be soldered to a large PCB and
connected to PGND for maximum power dissipation.
Pin Function
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS6154A/B-01 May 2014
RT6154A/B
Function Block Diagram
RT6154A (Adjustable Output Voltage)
LX1
LX2
VIN
VOUT
VINA
Gate DRV
OCP
PWM
CTRL
+
EN
PS/SYNC
PGOOD
Digital
CTRL
AMP
V
REF
OSC
OTP
UVLO
RT6154B (Fixed 3.3V Output Voltage)
LX1
LX2
VIN
VINA
Gate DRV
OCP
PWM
CTRL
-
EN
PS/SYNC
PGOOD
Digital
CTRL
AMP
+
V
REF
OSC
OTP
UVLO
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6154A/B-01 May 2014
-
FB
PGND
GND
VOUT
FB
R
FB1
R
FB2
PGND
GND
www.richtek.com
3
RT6154A/B
Operation
The RT6154A/B is a synchronous current-mode switching
Buck-Boost converter designed to an adjustable output
voltage from an input supply that can be above, equal, or
below the output voltage. The average inductor current is
regulated by a fast current regulator which is controlled
by a voltage control loop. The voltage error amplifier gets
its feedback input from the FB pin. The output voltage of
the RT6154A is adjustable, and can be set by the external
divider resistor value. For the RT6154B, the output voltage
is fixed at 3.3V. When VIN is greater than VOUT, the
device operates in Buck mode. When VIN is lower than
VOUT, the device operates in Boost mode. When VIN is
close to VOUT, the RT6154A/B automatically enters Buck
or Boost mode. In that case, the converter will maintain
the regulation for output voltage and keep a minimum
current ripple in the inductor to guarantee good
performance.
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS6154A/B-01 May 2014
RT6154A/B
Absolute Maximum Ratings
(Note 1)
VIN, VINA to GND ------------------------------------------------------------------
−0.2V
to 6V
VOUT to GND -----------------------------------------------------------------------
−0.2V
to 6.5V
EN, PS/SYNC to GND ------------------------------------------------------------
−0.2V
to (PVIN + 0.2V) with 6V max.
FB to PGND -------------------------------------------------------------------------
−0.2V
to (PVIN + 0.2V) with 6V max.
LX1 ------------------------------------------------------------------------------------- (PGND
−
0.2V) to (PVIN + 0.2V) with 6V max.
LX2 ------------------------------------------------------------------------------------- (PGND
−
0.2V) to (PVIN + 0.2V) with 6.5V max.
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-14AL 4x3 -------------------------------------------------------------------- 3.49W
Package Thermal Resistance (Note 2)
WDFN-14AL 4x3,
θ
JA
-------------------------------------------------------------- 28.6°C/W
WDFN-14AL 4x3,
θ
JC
-------------------------------------------------------------- 3.2°C/W
Lead Temperature (Soldering, 10 sec.) ---------------------------------------- 260°C
Junction Temperature -------------------------------------------------------------- 150°C
Storage Temperature Range -----------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ------------------------------------------------------- 2kV
MM (Machine Model) -------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 4)
Input Voltage Range ---------------------------------------------------------------
1.8V to 5.5V
Output Voltage Range -------------------------------------------------------------
1.8V to 5.5V
Junction Temperature Range -----------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range -----------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
IN
= 3.6V, T
A
= 25°C, unless otherwise specified.)
Parameter
Symbol
Test Conditions
Min
1.6
1.5
1.5
Typ
1.7
1.6
1.8
0.5
3.3
0.1
2.4
2.4
5
50
50
Max
1.8
1.7
2.0
0.505
3.333
1
2.6
2.6
--
--
--
Unit
V
V
V
V
V
μA
MHz
MHz
A
mΩ
mΩ
Under-Voltage Lockout Rising
UVLO_R
Threshold
Under-Voltage Lockout
Falling Threshold
Minimum Input Voltage for
Start-Up
FB Voltage
VOUT Voltage
Shutdown Current
Switching Frequency
Frequency Range for
Synchronization
Current Limit
High-Side Switch R
DS(ON)
Low-Side Switch R
DS(ON)
I
OC
V
IN
= V
INA
= 3.6V
V
IN
= V
INA
= 3.6V
V
IN
= V
INA
= 3.6V
V
FB
V
OUT
I
SHDN
f
SW
Force PWM (RT6154A)
Force PWM (RT6154B)
EN = 0V, PS/SYNC = 0V,
PGOOD = 0V
UVLO_F
0.495
3.267
--
2.2
2.2
--
--
--
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6154A/B-01 May 2014
www.richtek.com
5
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