|
|
PDF EUP3476DIR1 Data sheet ( Hoja de datos )
| Número de pieza | EUP3476DIR1 | |
| Descripción | 500kHz Synchronous Step-Down Converter | |
| Fabricantes | Eutech Microelectronics | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de EUP3476DIR1 (archivo pdf) en la parte inferior de esta página. Total 13 Páginas | ||
|
No Preview Available !
EUP3476
3A, 28V, 500kHz Synchronous
Step-Down Converter
DESCRIPTION
The EUP3476 is a 500KHz fixed frequency
synchronous current mode buck regulator. The device
integrates both 135mΩ high-side switch and 90mΩ
low-side switch that provide 3A of continuous load
current over a wide operating input voltage of 4.5V to
28V.The internal synchronous power switch increases
efficiency and eliminates the need for an external
Schottky diode. Current mode control provides fast
transient response and cycle-by-cycle current limit.
The EUP3476 features short circuit and thermal
protection circuits to increase system reliability.
Externally programmable soft-start allows for proper
power on sequencing with respect to other power
supllies and avoids input inrush current during startup.
In shutdown mode, the supply current drops below
1µA. The EUP3476 is available in SOP-8 package
with the exposed pad.
FEATURES
3A Continuous Output Current
110ns Minimum On Time
Integrated 135mΩ High Side Switch
Integrated 90mΩ Low Side Switch
Wide 4.5V to 28V Operating Input Range
Output Adjustable from 0.8V to 24V
Up to 95% Efficiency
Programmable Soft-Start
<1µA Shutdown Current
Available in 500KHz Fixed Switching
Frequency
Thermal Shutdown and Over Current Protection
Input Under Voltage Lockout
Available in SOP-8 (EP) Package
RoHS Compliant and 100% Lead (Pb)-Free
Halogen-Free
Typical Application Circuit
APPLICATIONS
Distributed Power Systems
Networking Systems
FPGA, DSP, ASIC Power Supplies
DS3476 Ver 1.6 May 2012
Figure 1.
1
1 page  
EUP3476Tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com
Absolute Maximum Ratings (1)
Supply Voltage (VIN) -------------------------------------------------------- -0.3V to +30V
EN Voltage (VEN) -------------------------------------------------------- -0.3V to +6V
Switch Voltages (VSW) ------------------------------------------------------ -1V to VIN +0.3V
Bootstrap Voltage (VBS) -------------------------------------------- VSW -0.3V to VSW +6V
All Other Pins ---------------------------------------------------------------------- -0.3V to +6V
Junction Temperature -------------------------------------------------------------------- 150°C
Lead Temperature ------------------------------------------------------------------------ 260°C
Storage Temperature -------------------------------------------------------- -65°C to 150°C
Output Voltage VOUT ----------------------------------------------------------- 0.9V to 26V
Thermal Resistance
θJA (SOP-8_EP) ------------------------------------------------------------------------- 60°C /W
ESD Ratings
Human Body Mode --------------------------------------------------------------------------- ±2kV
Recommend Operating Conditions (2)
Input Voltage (VIN) --------------------------------------------------------------- 4.5V to 28V
Operating Temperature Range ----------------------------------------------- -40°C to +85°C
Note (1): Stress beyond those listed under “Absolute Maximum Ratings” may damage the device.
Note (2): The device is not guaranteed to function outside the recommended operating conditions.
Electrical Characteristics
Unless otherwise specified, VIN=12V ,TA=+25°C.
Symbol
Parameter
Conditions
EUP3476
Min Typ Max.
Unit
ISHUT Shutdown Supply Current
VEN=0V
IQ Supply Current
VEN=2V, VCOMP=0.35V
VFB Feedback Voltage
4.5V≦VIN≦28V
0.784
AEA Error Amplifier Voltage Gain
GEA Error Amplifier Transconductance
∆IC = ±10µA
RDS(ON) 1 High-Side Switch On-Resistance
ISW=300mA
RDS(ON) 2 Low-Side Switch On-Resistance
ISW=300mA
ILEAKAGE High-Side Switch Leakage Current
VEN=0V, VSW=0V
ILIMIT Upper Switch Current Limit
Minimum Duty Cycle 3.6
INEG Low-side Switch Reverse Current Limit From Drain to Source
GCS COMP to Current Sense Transconductance
FOSC1 Oscillation Frequency
VFB=0.76V
400
FOSC2 Short Circuit Oscillation Frequency
VFB=0V
DMAX Maximum Duty Cycle
VFB=0.76V
TON Minimum On Time
VEN EN Shutdown Threshold Voltage
VEN Rising
1.1
VEHHYS EN Shutdown Threshold Voltage Hysterisis
VUVLO Input Under Voltage Lockout Threshold VIN Rising
3.8
VUVLOHYS
Input Under Voltage Lockout Threshold
Hysteresis
ISS Soft-Start Current
VSS=0V
TSS Soft-Start Period
CSS=0.1µ F
TSD Thermal Shutdown
TSDHYS Thermal Shutdown Hysteresis
0.1
1.1
0.800
400
400
135
90
0
4.8
-1
5.6
500
100
90
110
1.5
0.2
4.0
0.2
6
15
160
20
3
1.5
0.816
10
600
2
4.2
µA
mA
V
V/V
µ A/V
mΩ
µA
A
A/V
kHz
kHz
%
ns
V
µA
ms
°C
DS3476 Ver 1.6 May 2012
5
5 Page 
EUP3476Tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com
When using tantalum or electrolytic capacitors, the ESR
dominates the impedance at the switching frequency. For
simplification, the output ripple can be approximated to:
∆VOUT
=
VOUT × (1−
fS × L
VOUT
VIN
) × R ESR
The characteristics of the output capacitor also affect the
stability of the regulation system. The EUP3476 can be
optimized for a wide range of capacitance and ESR
values.
Compensation Components
EUP3476 employs current mode control for easy
compensation and fast transient response. The system
stability and transient response are controlled through
the COMP pin. COMP is the output of the internal
transconductance error amplifier. A series
capacitor-resistor combination sets a pole-zero
combination to govern the characteristics of the control
system. The DC gain of the voltage feedback loop is
given by:
A VDC
=
R LOAD
× G CS
× A VEA
×
VFB
VOUT
Where VFB is the feedback voltage (0.8V), AVEA is the
error amplifier voltage gain, GCS is the current sense
transconductance and RLOAD is the load resistor value.
The system has two poles of importance. One is due to
the compensation capacitor (CC) and the output resistor
of the error amplifier, and the other is due to the output
capacitor and the load resistor. These poles are located
at:
f P1
=
2π ×
G EA
CC ×
A VEA
fP2
=
2π ×
1
COUT
×
R LOAD
where GEA is the error amplifier transconductance.
The system has one zero of importance, due to the
compensation capacitor (CC) and the compensation
resistor (RC). This zero is located at:
f Z1
=
1
2π × CC
×RC
The system may have another zero of importance, if the
output capacitor has a large capacitance and/or a high
ESR value. The zero, due to the ESR and capacitance of
the output capacitor, is located at:
f ESR
=
1
2π × COUT
× R ESR
In this case, a third pole set by the compensation
capacitor (C2) and the compensation resistor (RC) is used
to compensate the effect of the ESR zero on the loop
gain. This pole is located at:
fP3
=
1
2π × C2
×
RC
The goal of compensation design is to shape the
converter transfer function to get a desired loop gain.
The system crossover frequency where the feedback
loop has the unity gain is important. Lower crossover
frequencies result in slower line and load transient
responses, while higher crossover frequencies could
cause the system instability. A good standard is to set the
crossover frequency below one-tenth of the switching
frequency.
To optimize the compensation components, the
following procedure can be used:
1. Choose the compensation resistor (RC) to set the
desired crossover frequency. Determine RC by the
following equation:
RC
=
2π × COUT × fC
G EA × G CS
× VOUT
VFB
<
2π × COUT × 0.1× fS × VOUT
G EA × G CS
VFB
Where fC is the desired crossover frequency, which is
typically below one tenth of the switching frequency.
2. Choose the compensation capacitor (CC) to achieve
the desired phase margin. For applications with
typical inductor values, setting the compensation zero
(fZ1) below one-forth of the crossover frequency
provides sufficient phase margin. Determine CC by
the following equation:
CC
>
4
2π ×RC×fC
where RC is the compensation resistor.
3. Determine if the second compensation capacitor (C2)
is required. It is required if the ESR zero of the output
capacitor is located at less than half of the switching
frequency, or the following relationship is valid:
1 < fS
2π × COUT × R ESR 2
If this is the case, then add the second compensation
capacitor (C2) to set the pole fP3 at the location of the
ESR zero. Determine C2 by the equation:
C2
=
COUT × R ESR
RC
Table 1. Recommended Component Selection
（4.5V ≤ VIN < 15V）
VOUT(V) R1(kΩ) R2(kΩ) RC(kΩ) CC(nF) COUT(µF) L(µH)
1.2 5 10 5 2.2 22
3
1.5 8.75 10 5 2.2 22
3
1.8 12.5 10 8 2.2 22 4.7
2.5 21.25 10 10 2.2 22 4.7
3.3 31.25 10 10 2.2 22 6.8
5 52.5 10 15 2.2 22 6.8
8 90 10 20 2.2 22 6.8
10 115 10 20 2.2 22 6.8
DS3476 Ver 1.6 May 2012
11
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet EUP3476DIR1.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| EUP3476DIR1 | 500kHz Synchronous Step-Down Converter | Eutech Microelectronics |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |