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PDF RT8079 Data sheet ( Hoja de datos )
| Número de pieza | RT8079 | |
| Descripción | Synchronous Step-Down Converter | |
| Fabricantes | Richtek | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de RT8079 (archivo pdf) en la parte inferior de esta página. Total 13 Páginas | ||
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®
RT8079
2.95V to 6V Input, 3A Output, 2MHz, Synchronous
Step-Down Converter
General Description
The RT8079 is a high efficiency step-down converter and
capable of delivering 3A output current over a wide input
voltage range from 2.95V to 6V.
The RT8079 provides accurate regulation for a variety of
loads with ±3% accuracy. For reducing inductor size, it
provides up to 2MHz switching frequency. The efficiency
is maximized through the integrated 45mΩ MOSFETs
and 550μA typical supply current.
Under voltage lockout voltage of the RT8079 is 2.7V, and
it also provides external setting by a resistor network on
the enable pin.
The RT8079 provides protections such as inductor current
limit under voltage lockout and thermal shutdown. The
over temperature threshold is 145°C.
The RT8079 is available in WQFN-16L 3x3 package.
Ordering Information
RT8079
Package Type
QW : WQFN-16L 3x3 (W-Type)
Note :
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
Features
z Integrated 45mΩ MOSFETs
z Input Range : 2.95V to 6V
z Adjustable PWM Frequency : 300kHz to 2MHz
z Output Current : 3A
z 95% Efficiency
z Adjustable Soft-Start
z Power Good Indicator
z Enable Control
z Under Voltage Lockout
z Current Limit
z Thermal Shutdown
z 16-Lead WQFN Package
z RoHS Compliant and Halogen Free
Applications
z Low-Voltage, High-Density Power Systems
z Distributed Power Systems
z Point-of-Load Conversions
Marking Information
62=YM
DNN
62= : Product Code
YMDNN : Date Code
Simplified Application Circuit
RT8079
VIN VIN SW
EN
PGOOD
SS/TR
RT/SYNC
BOOT
FB
COMP
GND
AGND
VOUT
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8079-01 February 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
1 page  
RT8079
Parameter
Symbol
Test Conditions
Min Typ Max Unit
Switching Frequency Setting and External Synchronization (RT/SYNC pin)
Switching Frequency Range in
RT Mode
fOSC
300 -- 2000 kHz
Oscillator Frequency
Switching Frequency Range in
ExtSYNC Mode
fSYNC
RRT = 180kΩ
-- 1000 -- kHz
300 -- 2000 kHz
MOSFET
High Side MOSFET Resistance
Low Side MOSFET Resistance
VBOOT − VSW = 5V
-- 45 -- mΩ
-- 42 -- mΩ
Current Limit
Current Limit Threshold
Over Temperature Protection
Thermal Shutdown
Temperature
Thermal Shutdown Hysteresis
IL IM
TSD
ΔTSD
4.2 6.6 -- A
-- 145 -- °C
-- 20 -- °C
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. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is
measured at the exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8079-01 February 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
5 Page 
RT8079
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TAis
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications, the
maximum junction temperature is 125°C. The junction to
ambient thermal resistance, θJA, is layout dependent. For
WQFN-16L 3x3 package, the thermal resistance, θJA, is
47°C/W on a standard JEDEC 51-7 four-layer thermal test
board. The maximum power dissipation at TA = 25°C can
be calculated by the following formula :
PD(MAX) = (125°C − 25°C) / (47°C/W) = 2.128W for
WQFN-16L 3x3 package
The maximum power dissipation depends on the operating
ambient temperature for fixed TJ(MAX) and thermal
resistance, θJA. The derating curve in Figure 2 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
2.4
Four-Layer PCB
2.0
1.6
1.2
0.8
0.4
0.0
0
25 50 75 100
Ambient Temperature (°C)
125
Figure 2. Derating Curve of Maximum Power Dissipation
Layout Considerations
For the best performance of the RT8079, the following
guidelines must be strictly followed.
` The input capacitor should be placed as close as possible
to the device pins (VIN and GND).
` The RT/SYNC pin is sensitive. The RT resistor should
be located as close as possible to the IC and minimal
lengths of trace.
` The SW node is with high frequency voltage swing. It
should be kept at a small area.
` Place the feedback components as close as possible
to the IC and keep away from the noisy devices.
` The GND and AGND should be connected to a strong
ground plane for heat sinking and noise protection.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8079-01 February 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet RT8079.PDF ] | |
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