Richtek RT8058AGQW Schematic [ru]
1.2MHz, 2A, High Efficiency PWM Step-Down
DC/DC Converter
RT8058A
General Description
The RT8058A is a current mode PWM step-down converter.
The chip is ideal for fixed frequency and low ripple
applications over full range of load conditions. Its input
voltage range is from 2.6V to 5.5V with a constant 1.2MHz
switching frequency that allows it to adopt tiny, low cost
capacitors and inductors with 2mm or less in height making
it ideal for single-cell Li-lon/polymer battery applications.
The low on resistance internal MOSFET can achieve high
efficiency without the need of external schottky diodes in
wide operating ranges and the output voltage is adjustable
from 0.6V to 5V that can provide up to 2A load current.
The RT8058A operates at 100% duty cycle for low dropout
operation that extends battery life in portable devices.
The RT8058A is available in a WDFN-10L 3x3 package.
Ordering Information
RT8058A
Package Type
QW : WDFN-10L 3x3 (W-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
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.
Marking Information
E9= : Product Code
YMDNN : Data Code
E9=YM
DNN
Features
zz
z 0.6V Reference Allows Low Output Voltage
zz
zz
z Low Dropout Operation : 100% Duty Cycle
zz
zz
z 2A Load Current
zz
μμ
zz
z <2
μA Shutdown Current
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μμ
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z Up to 95% Efficiency
zz
zz
z No Schottky Diode Required
zz
zz
z 1.2MHz Constant Switching Frequency
zz
zz
z Low R
zz
zz
z Internally Compensated
zz
zz
z Internal Soft-Start
zz
zz
z Over temperature Protection
zz
zz
z Short Circuit Protection
zz
zz
z Small 10-Lead WDFN Package
zz
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z RoHS Compliant and Halogen Free
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Internal Switches
DS(ON)
Applications
z Portable Instruments
z Microprocessors and DSP Core supplies
z Cellular Telephones
z Wireless and DSL Modems
z Digital Cameras
z PC Cards
Pin Configurations
(TOP VIEW)
1
PGND
2
PGND
3
FB
4
GND
5
POK
WDFN-10L 3x3
GND
LX
10
9
LX
8
PVDD
7
VDD
9
11
EN
DS8058A-02 April 2011 www.richtek.com
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RT8058A
Typical Application Circuit
2.6V to 5.5V
V
IN
C1
10µF
C2
1µF
PGOOD
R3
100k
8
6
7
5
RT8058A
PVDD
EN
VDD
POK
GND
4
9, 10
LX
3
FB
PGND
1, 2,
11 (Exposed Pad)
Functional Pin Description
Pin No. Pin Name Pin F unction
1, 2,
11 (Exposed Pad)
3 FB
4 GND
5 POK
6 EN
7 VDD
8 PVDD
9, 10 LX
PGND
Power Ground. Connect this pin close to the (–) terminal of C
pad should be soldered to PCB board and connected to GND.
Feedback Input Pin. Receives the feedback voltage from a resistive divider
connected across the output.
Signal Ground. Return the feedback resistive dividers to this ground, which in turn
connects to PGND at one point.
Power Good Indicator. Open-drain logic output that is opened when the output
voltage exceeds 90% of the regulation point.
Enable pin. A logical high level at this pin enables the converter, while a logical low
level causes the converter to shut down.
Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is
equal to PVDD.
Power Input Supply of converter power stage. Decouple this pin to PGND with a
capacitor.
Internal Power MOSFET Switches Output of converter. Connect this pin to the
inductor.
L1
3.3µH
R1
100k
R2
100k
C3
22µF
V
OUT
1.2V/2A
C4
1µF
and C
IN
. Ex po s e d
OU T
Function Block Diagram
0.6V
FB
0.533V
2
EA
Int-SS
OSC
Output
Clamp
0.3V
POK
UV
VREF
Slope
Com
POR
VDD
Current Sense
OC
Limit
Control
Logic
OTP
EN
PVDD
Driver
LX
PGND
GND
DS8058A-02 April 2011www.richtek.com
RT8058A
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage VDD, PVDD ------------------------------------------------------------------------------------- −0.3V to 6V
z LX Pin Switch Voltage ---------------------------------------------------------------------------------------------------- −0.3V to 6V
z Other I/O Pin Voltage ----------------------------------------------------------------------------------------------------- −0.3V to 6V
z Power Dissipation, P
WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------------- 1.429W
z Package Thermal Resistance (Note 2)
WDFN-10L 3x3, θJA------------------------------------------------------------------------------------------------------- 70°C/W
WDFN-10L 3x3, θJC------------------------------------------------------------------------------------------------------- 7.8°C/W
z Lead Temperature (Soldering, 10 sec.)------------------------------------------------------------------------------- 260°C
z Storage Temperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C
z Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage ------------------------------------------------------------------------------------------------------ 2.6V to 5.5V
z Junction Temperature Range --------------------------------------------------------------------------------------------
z Ambient Temperature Range --------------------------------------------------------------------------------------------
@ TA = 25°C
D
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(V
= V
DD
Input Voltage Range
Feedback Reference Voltage
DC Bias Current
(PVDD, VDD total)
Under voltage Lockout
Threshold
Oscillator Frequency
EN High-Level Input Voltage
EN Low-Level Input Voltage
Switch On Resistance, High
Switch On Resistance, Low R
Peak Current Limit I
Output Voltage Line Regulation
Output Voltage Load
PVDD
= 3.6V, T
= 25°C, unless otherwise specified)
A
Parameter Symbol Test Conditions Min Typ Max Unit
V
IN
V
REF
UVLO
f
OSC
V
EN_H
V
EN_L
R
DS(ON)_P
DS(ON)_N IOUT
2.2 3 -- A
LIM
2.6 - - 5.5 V
0.582 0.6 0.618 V
Active, No Load -- 3.4 -- mA
Active, Not Switching, VFB = 0.5V
-- 340 --
μA
Shutdown, EN = 0 -- -- 2 μA
VDD Rising
V
Hysteresis
DD
Switching Frequency
1.4 -- -- V
-- -- 0.4 V
I
OUT
= 200mA
= 200mA
= 2.6V to 5.5V, I
V
IN
= 0AÆ2A
I
OUT
OUT
= 0
2.3 2.43 2.55 V
-- 150 -- mV
1 1.2 1.4 MHz
-- 142 210 mΩ
--
--
96 160 mΩ
0.05 -- %/V
-- 1 -- %/A
DS8058A-02 April 2011 www.richtek.com
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RT8058A
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. 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 for extended
periods may remain possibility to affect device reliability.
Note 2. θ
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of
JA
JEDEC 51-7 thermal measurement standard. The case point of θ
is on the exposed pad of the package.
JC
DS8058A-02 April 2011www.richtek.com
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Typical Operating Characteristics
RT8058A
Output Voltage (V)
Efficiency vs. Output Current
100
90
80
70
60
50
40
Efficiency (%)
30
20
10
0
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2
V
= 1.2V, L = 3.3μH, C
OUT
Output Current (A)
Output Voltage vs. Input Voltage
1.200
1.199
1.198
1.197
1.196
1.195
1.194
1.193
1.192
1.191
1.190
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
VIN = 5V
VIN = 3.3V
= 22μF
OUT
I
= 0A
OUT
Output Voltage vs. Output Current
1.196
1.195
1.194
Output Voltage (V)
1.193
1.192
1.191
1.190
1.189
1.188
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2
VIN = 5V
VIN = 3.3V
V
= 1.2V, L = 3.3μH, C
OUT
Output Current (A)
FB Voltage v s. Temperature
0.600
0.598
0.596
0.594
0.592
0.590
0.588
FB Voltage (V)
0.586
0.584
0.582
0.580
-50 -25 0 25 50 75 100 125
Temperature
VIN = 3.3V, I
(°C)
OUT
OUT
= 22μF
= 0A
Switching Frequency vs. Input Voltage
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
Switching Frequency (MHz)
V
= 1.2V, I
1.00
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
OUT
= 300mA
OUT
Switching Frequency (MHz)
Switching Frequency vs. Temperature
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
VIN = 3.3V, V
-50 -25 0 25 50 75 100 125
Temperature
= 1.2V, I
OUT
(°C)
= 300mA
OUT
DS8058A-02 April 2011 www.richtek.com
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