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EN63A0QI 参数 Datasheet PDF下载

EN63A0QI图片预览
型号: EN63A0QI
PDF下载: 下载PDF文件 查看货源
内容描述: 12A同步高度集成DC-DC PowerSoC [12A Synchronous Highly Integrated DC-DC PowerSoC]
分类和应用:
文件页数/大小: 24 页 / 1511 K
品牌: ENPIRION [ ENPIRION, INC. ]
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EN63A0QI  
Functional Description  
soft-start function to limit in-rush current during  
device power-up. When the part is initially powered  
up, the output voltage is gradually ramped to its  
final value. The gradual output ramp is achieved by  
increasing the reference voltage to the error  
amplifier. A constant current flowing into the soft-  
start capacitor provides the reference voltage ramp.  
When the voltage on the soft-start capacitor  
reaches 0.60V, the output has reached its  
programmed voltage. Once the output voltage has  
reached nominal voltage the soft-start capacitor will  
continue to charge to 1.5V (Typical). The output  
rise time can be controlled by the choice of soft-  
start capacitor value.  
The EN63A0QI is a synchronous, programmable  
buck power supply with integrated power MOSFET  
switches and integrated inductor. The switching  
supply uses voltage mode control and a low noise  
PWM topology. This provides superior impedance  
matching to ICs processed in sub 90nm process  
technologies. The nominal input voltage range is  
2.5 - 6.6 volts. The output voltage is programmed  
using an external resistor divider network. The  
feedback control loop incorporates a type IV  
voltage mode control design. Type IV voltage mode  
control maximizes control loop bandwidth and  
maintains excellent phase margin to improve  
transient performance. The EN63A0QI is designed  
to support up to 12A continuous output current  
operation. The operating switching frequency is  
between 0.9MHz and 1.5MHz and enables the use  
of small-size input and output capacitors.  
The rise time is defined as the time from when the  
ENABLE signal crosses the threshold and the input  
voltage crosses the upper UVLO threshold to the  
time when the output voltage reaches 95% of the  
programmed value. The rise time (tRISE) is given by  
the following equation:  
The power supply has the following features:  
Precision Enable Threshold  
Soft-Start  
tRISE [ms] = Css [nF] x 0.065  
The rise time (tRISE) is in milliseconds and the soft-  
start capacitor (CSS) is in nano-Farads. The soft-  
start capacitor should be between 10nF and 100nF.  
Pre-bias Start-Up  
Resistor Programmable Switching Frequency  
Phase-Lock Frequency Synchronization  
Parallel Operation  
Pre-Bias Start-up  
The EN63A0QI supports startup into a pre-biased  
load. A proprietary circuit ensures the output  
voltage rises up from the pre-bias value to the  
programmed output voltage. Start-up is guaranteed  
to be monotonic for pre-bias voltages in the range  
of 20% to 75% of the programmed output voltage  
with a minimum pre-bias voltage of 300mV. Outside  
of the 20% to 75% range, the output voltage rise  
will not be monotonic. The Pre-Bias feature is  
automatically engaged with an internal pull-up  
resistor. For this feature to work properly, VIN must  
be ramped up prior to ENABLE turning on the  
device. Tie VSENSE to VOUT if Pre-Bias is used.  
Tie EN_PB to ground and leave VSENSE floating  
to disable the Pre-Bias feature. Pre-Bias is  
supported for external clock synchronization, but  
not supported for parallel operations.  
Power OK  
Over-Current/Short Circuit Protection  
Thermal Shutdown with Hysteresis  
Under-Voltage Lockout  
Precision Enable  
The ENABLE threshold is a precision analog  
voltage rather than a digital logic threshold. A  
precision voltage reference and a comparator  
circuit are kept powered up even when ENABLE is  
de-asserted. The narrow voltage gap between  
ENABLE Logic Low and ENABLE Logic High  
allows the device to turn on at a precise enable  
voltage level. With the enable threshold pinpointed,  
a proper choice of soft-start capacitor helps to  
accurately sequence multiple power supplies in a  
system as desired. There is an ENABLE lockout  
time of 2ms that prevents the device from re-  
enabling immediately after it is disabled.  
Resistor Programmable Frequency  
The operation of the EN63A0QI can be optimized  
by a proper choice of the RFQADJ resistor. The  
frequency can be tuned to optimize dynamic  
performance and efficiency. Refer to Table 1 and  
Table 2 for recommended RFQADJ values based on  
maximum output current operations.  
Soft-Start  
The SS pin in conjunction with a small external  
capacitor between this pin and AGND provides a  
Enpirion 2012 all rights reserved, E&OE  
Enpirion Confidential  
www.enpirion.com, Page 14  
07077  
May 9, 2012  
Rev: C