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PDF DS6203B Data sheet ( Hoja de datos )
| Número de pieza | DS6203B | |
| Descripción | Synchronous Step-Down Converter | |
| Fabricantes | Richtek | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de DS6203B (archivo pdf) en la parte inferior de esta página. Total 22 Páginas | ||
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®
RT6203B
5A, 18V, 700kHz ACOTTM Synchronous Step-Down
Converter with VID Control
General Description
The RT6203B is an adaptive on-time mode synchronous
Buck converter. The main control loop of the RT6203B
uses an adaptive on-time mode control which provides a
very fast transient response with no external components.
The RT6203B operates from 4.5V to 18V VIN input. After
the initial power-up, the output voltage can be changed by
codes sent into the IC via an I2C compatible VID control
bus. There are special codes which can be used to program
current limit level and thermal shutdown level. Shutdown
and startup can be also programmed by special codes.
The device also features an adjustable soft-start time.
Output voltage is adjustable by resistor divider through
the FB pin between 0.8V to 8V.
Pin Configuration
(TOP VIEW)
Features
VID Control Range Via I2C Compatitable Interface :
0.72V to 1.48V in 10mV Steps
Adjustable Current Limit
Adjustable Thermal Shutdown
Fast Transient Response
Adjustable Output Voltage from 0.8V to 8V
Steady 700kHz Switching Frequency
Optimized for All Ceramic Capacitors
Externally-Adjustable, Pre-Biased Compatible Soft-
Start
Input Under-Voltage Lockout
Output Over- and Under-Voltage Protection
Power Good Output
Thermal Shutdown
RoHS Compliant and Halogen Free
20 19 18 17 16
PVCC
PGOOD
A0
A1
SCL
1
2
3
4
5
PGND
21
15 SW
14 SW
13 SW
12 PGND
11 PGND
6 7 8 9 10
Applications
Industrial and Commercial Low Power Systems
Computer Peripherals
LCD Monitors and TVs
Green Electronics/Appliances
Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
WQFN-20L 4x4
Simplified Application Circuit
VIN
Power Good
Enable
I2C Control
C1
R3
C3
RT6203B
VIN VS
VCC
SW
PGOOD BOOT
PVCC
FB
SS
EN
SCL
SDA
A0
A1
PGND AGND
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6203B-00 September 2016
L1
C4 C5
R1 CFF
VOUT
R2
CSS
Address
Selection
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
1 page  
RT6203B
Shutdown, Start-Up and Enable (EN)
The enable input (EN) has a logic-low level of 0.4V. When
VEN is below this level the IC enters shutdown mode and
supply current drops to less than 10μA. When VEN exceeds
its logic-high level of 2V the IC is fully operational. Unlike
many competing devices, EN is a high voltage input that
can be safely connected to VIN (up to 18V) for automatic
start-up.
Input Under-Voltage Lockout
In addition to the enable function, the RT6203B feature an
Under-Voltage Lockout (UVLO) function that monitors the
internal linear regulator output (PVCC). To prevent
operation without fully-enhanced internal MOSFET
switches, this function inhibits switching when VCC drops
below the UVLO falling threshold. The IC resumes
switching when VCC exceeds the UVLO rising threshold.
Soft-Start (SS)
The RT6203B soft-start uses an external pin (SS) to clamp
the output voltage and allow it to slowly rise. After VEN is
high and VIN exceeds its UVLO threshold, the IC begins
to source 6μA from the SS pin. An external capacitor at
SS is used to adjust the soft-start timing. Following below
equation to get the minimum capacitance range in order
to avoid UV occurs.
t=
COUT VOUT 0.75 1.2
ILIM Load Current 0.8
CSS
t 6A
VREF
Do not leave SS unconnected. During start-up the SS
capacitor is charged and the RT6203B operates in
discontinuous switching mode with very small pulses. This
prevents negative inductor currents and keeps the circuit
from sinking current. Therefore, the output voltage may
be pre-biased to some positive level before start-up. Once
the VSS ramp charges enough to raise the internal reference
above the feedback voltage, switching will begin and the
output voltage will smoothly rise from the pre-biased level
to its regulated level. After VSS rises above about 2.2V
output over- and under-voltage protections are enabled and
the RT6203B begins continuous-switching operation.
Internal Regulator (PVCC)
An internal linear regulator (PVCC) produces a 5V supply
from VIN. The 5V power supplies the internal control circuit,
such as internal gate drivers, PWM logic, reference, analog
circuitry, and other blocks. 1μF ceramic capacitor for
decoupling and stability is required.
Over-Temperature Protection
The RT6203B includes an Over-Temperature Protection
(OTP) circuitry to prevent overheating due to excessive
power dissipation. The OTP will shut down switching
operation when the junction temperature exceeds 150°C.
Once the junction temperature cools down by
approximately 20°C the IC will resume normal operation
with a complete soft-start. For continuous operation,
provide adequate cooling so that the junction temperature
does not exceed 150°C.
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6203B-00 September 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
5 Page 
Typical Operating Characteristics
100
90
80
70
60
50
40
30
20
10
0
0
Efficiency vs. Output Current
VIN = 4.5V
VIN = 12V
VIN = 18V
VOUT = 1.2V, L = 1.5μH
1234
Output Current (A)
5
1.220
Output Voltage vs. Temperature
1.215
1.210
1.205
1.200
1.195
VIN = 18V
VIN = 12V
VIN = 4.5V
1.190
1.185
1.180
-50
-25
VOUT = 1.2V, IOUT = 0A
0 25 50 75
Temperature (°C)
100 125
Choke Valley Current Limit vs. Input Voltage
8.00
7.50
7.00
OC = 7A
VIN = 12V, VOUT = 1.2V
6.50
6.00
5.50
OC = 5A
5.00
4.50
4.00
3.50 OC = 3A
3.00
2.50
4 6 8 10 12 14 16 18
Input Voltage (V)
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6203B-00 September 2016
RT6203B
1.210
Output Voltage vs. Input Voltage
1.205
1.200
1.195
IOUT = 0A
IOUT = 1A
IOUT = 2A
IOUT = 3A
IOUT = 4A
IOUT = 5A
1.190
VOUT = 1.2V
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Input Voltage (V)
1.210
Output Voltage vs. Output Current
1.205
1.200
1.195
VIN = 18V
VIN = 12V
VIN = 4.5V
1.190
0
VOUT = 1.2V
1234
Output Current (A)
5
I2C Shutdown Current vs. Input Voltage
150
140
130
120
110
100
90
80
70
60
50
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Input Voltage (V)
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
11 Page | ||
| Páginas | Total 22 Páginas | |
| PDF Descargar | [ Datasheet DS6203B.PDF ] | |
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