RT6213A/B
3A Peak, 18V, 500kHz, ACOT
TM
Step-Down Converter
General Description
The RT6213A/B is a high-efficiency, monolithic
synchronous step-down DC/DC converter that can
deliver up to 3A peak output current from a 4.5V to 18V
input supply. The RT6213A/B adopts ACOT
architecture to allow the transient response to be
improved and keep in constant frequency.
Cycle-by-cycle current limit provides protection against
shorted outputs and soft-start eliminates input current
surge during start-up. Fault conditions also include
output under voltage protection, output over current
protection, and thermal shutdown.
Features
Integrated 150m/70m MOSFETs
4.5V to 18V Supply Voltage Range
500kHz Switching Frequency
ACOT Control
0.8V
1.5% Voltage Reference
Internal Start-Up into Pre-biased Outputs
Compact Package: TSOT-23-6 pin
Input Under-Voltage Lockout
Over-Current Protection and Hiccup
Applications
Ordering Information
RT6213A/B
Package Type
J6F : TSOT-23-6 (FC)
Lead Plating System
G : Green (Halogen Free and Pb Free)
UVP Option
H : Hiccup
PSM/PWM
A : PSM Mode
B : PWM Mode
Note :
Richtek products are :
Set-Top Boxes
Portable TVs
Access Point Routers
DSL Modems
LCD TVs
Marking Information
RT6213AHGJ6F
09=DNN
09= : Product Code
DNN : Date Code
RT6213BHGJ6F
08=DNN
08= : Product Code
DNN : Date Code
RoHS compliant and compatible with the current
requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Simplified Application Circuit
V
IN
C
IN
LX
Enable
EN
GND
FB
R2
R1
C
FF
C
OUT
RT6213A/B
BOOT
VIN
C
BOOT
L
V
OUT
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6213A/B-02
September
2016
www.richtek.com
1
RT6213A/B
Pin Configurations
(TOP VIEW)
BOOT EN
6
5
FB
4
2
3
GND LX VIN
TSOT-23-6 (FC)
Functional Pin Description
Pin No.
1
2
3
4
5
6
Pin Name
GND
LX
VIN
FB
EN
BOOT
Pin Function
System Ground. Provides the ground return path for the control circuitry and
low-side power MOSFET.
Switch Node. LX is the switching node that supplies power to the output and
connect the output LC filter from LX to the output load.
Power Input. Supplies the power switches of the device.
Feedback Voltage Input. This pin is used to set the desired output voltage via
an external resistive divider. The feedback voltage is 0.8V typically.
Enable Control Input. Floating this pin or connecting this pin to GND can
disable the device and connecting this pin to logic high can enable the device.
Bootstrap Supply for High-Side Gate Driver. Connect a 100nF or greater
capacitor from LX to BOOT to power the high-side switch.
Function Block Diagram
BOOT
VIN
VIN
PVCC
Reg
Minoff
PVCC
VIBIAS
VREF
OC
UV &OV
PVCC
Ripple
Gen.
+
UGATE
Control
Driver
LGATE
GND LX
EN
VIN
On-Time
LX
--
LX
GND
EN
LX
Comparator
FB
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS6213A/B-02
September
2016
RT6213A/B
Operation
The RT6213A/B is a synchronous step-down converter
with advanced constant on-time control mode. Using
the ACOT
TM
control mode can reduce the output
capacitance and provide fast transient response. It can
minimize the component size without additional
external compensation network.
Current Protection
The inductor current is monitored via the internal
switches cycle-by-cycle. Once the output voltage drops
under UV threshold, the RT6213A/B will enter hiccup
mode.
UVLO Protection
To protect the chip from operating at insufficient supply
voltage, the UVLO is needed. When the input voltage
of VIN is lower than the UVLO falling threshold voltage,
the device will be lockout.
Thermal Shutdown
When the junction temperature exceeds the OTP
threshold value, the IC will shut down the switching
operation. Once the junction temperature cools down
and is lower than the OTP lower threshold, the
converter will autocratically resume switching.
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6213A/B-02
September
2016
www.richtek.com
3
RT6213A/B
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage ---------------------------------------------------------------------------------
0.3V
to 20V
Switch Node Voltage, LX ----------------------------------------------------------------------------
0.3V
to (V
IN
+ 0.3V)
BOOT Pin Voltage ------------------------------------------------------------------------------------
(V
LX
– 0.3V) to (V
IN
+ 6.3V)
Other Pins -----------------------------------------------------------------------------------------------
0.3V
to 6V
Power Dissipation, P
D
@ T
A
= 25C
TSOT-23-6 (FC) ---------------------------------------------------------------------------------------
1.667W
Package Thermal Resistance
(Note 2)
TSOT-23-6 (FC),
JA
---------------------------------------------------------------------------------
60C/W
TSOT-23-6 (FC),
JC
---------------------------------------------------------------------------------
8C/W
Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------
260C
Junction Temperature --------------------------------------------------------------------------------
150C
Storage Temperature Range -----------------------------------------------------------------------
65C
to 150C
ESD Susceptibility
(Note 3)
HBM (Human Body Model) -------------------------------------------------------------------------
2kV
Recommended Operating Conditions
(Note 4)
Supply Input Voltage ---------------------------------------------------------------------------------
4.5V
to 18V
Ambient Temperature Range-----------------------------------------------------------------------
40C
to 85C
Junction Temperature Range ----------------------------------------------------------------------
40C
to 125C
Electrical Characteristics
(V
IN
= 12V, T
A
= 25C, unless otherwise specified)
Parameter
Supply Voltage
VIN Supply Input Operating
Voltage
Under-Voltage Lockout
Threshold
Under-Voltage Lockout
Threshold Hysteresis
Shutdown Current
Quiescent Current
Soft-Start
Soft-Start Time
Enable Voltage
Enable Voltage Threshold
Symbol
Test Conditions
Min
Typ
Max
Unit
V
IN
V
UVLO
V
UVLO
I
SHDN
I
Q
V
EN
= 0V
V
EN
= 2V, V
FB
= 0.85V
4.5
3.6
--
--
--
--
3.9
340
--
0.5
18
V
4.2
--
5
--
mV
µA
mA
--
1000
--
µS
V
EN
Rising
V
EN
Falling
1.4
1.18
1.5
1.28
1.6
1.38
V
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS6213A/B-02
September
2016
RT6213A/B
Parameter
Feedback Voltage
Feedback Voltage Threshold
Internal MOSFET
High-Side On-Resistance
Low-Side On-Resistance
Current Limit
High-Side Switch Current Limit I
LIM_H
Low-Side Switch Valley Current
I
LIM_L
Limit
Switching Frequency
Switching Frequency
On-Time Timer Control
Maximum Duty Cycle
Minimum On Time
Minimum Off Time
D
MAX
t
ON(MIN)
t
OFF(MIN)
--
--
--
86
60
240
--
--
--
%
nS
f
OSC
400
500
--
kHz
--
3.1
5.8
3.8
--
--
A
R
DS(ON)_H
R
DS(ON)_L
V
BOOT
− V
LX
= 4.8V
--
--
150
70
--
--
mΩ
V
FB_TH
4.5V ≤ V
IN
≤ 18V
0.788
0.8
0.812
V
Symbol
Test Conditions
Min
Typ
Max
Unit
Output Under Voltage and Over Voltage Protections
OVP Trip Threshold
OVP Propagation Delay
UVP Trip Threshold
UVP Propagation Delay
Thermal Shutdown
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
T
SD
T
SD
--
--
150
20
--
--
°C
UVP Detect
Hysteresis
OVP Detect
--
--
45
--
--
125
10
50
10
5
--
--
55
--
--
%
µS
%
µS
Note 1.
Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect
device reliability.
Note 2.
JA
is measured at T
A
= 25C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. The first
layer of copper area is filled
JC
is measured at the exposed pad of the package.
Note 3.
Devices are ESD sensitive. Handling precaution recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6213A/B-02
September
2016
www.richtek.com
5