欢迎访问ic37.com |
会员登录 免费注册
发布采购

G916-285T1UF 参数 Datasheet PDF下载

G916-285T1UF图片预览
型号: G916-285T1UF
PDF下载: 下载PDF文件 查看货源
内容描述: 300毫安高PSRR ,噪声低, LDO稳压器 [300mA High PSRR, Low Noise, LDO Regulators]
分类和应用: 稳压器
文件页数/大小: 13 页 / 480 K
品牌: GMT [ GLOBAL MIXED-MODE TECHNOLOGY INC ]
 浏览型号G916-285T1UF的Datasheet PDF文件第4页浏览型号G916-285T1UF的Datasheet PDF文件第5页浏览型号G916-285T1UF的Datasheet PDF文件第6页浏览型号G916-285T1UF的Datasheet PDF文件第7页浏览型号G916-285T1UF的Datasheet PDF文件第9页浏览型号G916-285T1UF的Datasheet PDF文件第10页浏览型号G916-285T1UF的Datasheet PDF文件第11页浏览型号G916-285T1UF的Datasheet PDF文件第12页  
Global Mixed-mode Technology Inc.  
Pin Description  
G916  
PIN  
G916-XXX  
NAME  
FUNCTION  
G916  
1
1
IN  
Regulator Input. Supply voltage can range from +2.5V to +6.0V. Bypass with 1µF to GND  
Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board  
ground plane to maximize thermal dissipation.  
2
3
2
GND  
Active-Low Shutdown Input. A logic low reduces the supply current to less than 1µA. Connect to IN  
for normal operation.  
SHDN  
3
Feedback Input for Setting the Output Voltage. Connect to GND to set the output voltage to  
4
SET the preset output voltage. Connect to an external resistor divider for adjustable-output op-  
eration.  
This is a reference bypass pin. It should connect external 10nF capacitor to GND to reduce  
4
5
BYP  
output noise. Bypass capacitor must be no less than 1nF. (CBYP1nF)  
Regulator Output. Sources up to 300mA. Bypass with a 1µF, 0.2Ω typical ESR capacitor  
5
OUT  
to GND.  
feedback voltage force to be the same as the 1.25V  
bandgap reference. The output voltage, VOUT, is then  
given by the following equation:  
Detailed Description  
The block diagram of the G916 is shown in Figure 1. It  
consists of an error amplifier, 1.25V bandgap reference,  
PMOS output transistor, internal feedback voltage divider,  
mode comparator, shutdown logic, over current protec-  
tion circuit, and over temperature protection circuit.  
VOUT = 1.25 (1 + R1/R2).  
(1)  
Alternatively, the relationship between R1 and R2 is  
given by:  
The mode comparator compares the SET pin voltage  
with an internal 350mV reference. If the SET pin volt-  
age is less than 350mV, the internal feedback voltage  
divider’s central tap is connected to the non-inverting  
input of the error amplifier. The error amplifier com-  
pares non-inverting input with the 1.25V bandgap ref-  
erence. If the feedback voltage is higher than 1.25V,  
the error amplifier’s output becomes higher so that the  
PMOS output transistor has a smaller gate-to-source  
voltage (VGS). This reduces the current carrying capa-  
bility of the PMOS output transistor, as a result the  
output voltage decreases until the feedback voltage is  
equal to 1.25V. Similarly, when the feedback voltage is  
less than 1.25V, the error amplifier causes the output  
PMOS to source more current to pull the feedback  
voltage up to 1.25V. Thus, through this feedback ac-  
tion, the error amplifier, output PMOS, and the voltage  
dividers effectively form a unity-gain amplifier with the  
R1 = R2 (VOUT /1.25 - 1).  
(2)  
For the reasons of reducing power dissipation and  
loop stability, R2 is chosen to be 100KΩ. For G916,  
R1 is 164K, and the pre-set VOUT is 3.30V.  
When external voltage divider is used, as shown in  
Figure 2, the SET pin voltage will be larger than  
350mV. The non-inverting input of the amplifier will be  
connected to the external voltage divider. However,  
the operation of the feedback loop is the same, so that  
the conditions of Equations 1 and 2 are still true. The  
output voltage is still given by Equation 1.  
For G916-XXX, adjust the internal reference and in-  
ternal voltage divider. It provides a fixed mode output  
ranging from 1.2V to 5V.  
TEL: 886-3-5788833  
http://www.gmt.com.tw  
Ver: 1.7  
Jan 25, 2006  
8