- 您现在的位置：买卖IC网 > PDF目录245264 > UZXCL280E5 (ZETEX PLC) 2.8 V FIXED POSITIVE LDO REGULATOR, 0.28 V DROPOUT, PDSO5 PDF资料下载
参数资料
| 型号： | UZXCL280E5 |
| 厂商： | ZETEX PLC |
| 元件分类： | 固定正电压单路输出LDO稳压器 |
| 英文描述： | 2.8 V FIXED POSITIVE LDO REGULATOR, 0.28 V DROPOUT, PDSO5 |
| 封装： | 2.80 X 2.90 MM, SOT-23, 5 PIN |
| 文件页数： | 11/11页 |
| 文件大小： | 277K |
| 代理商： | UZXCL280E5 |
APPLICATIONS INFORMATION (Cont)
Power Dissipation
The maximum allowable power dissipation of the
device for normal operation (Pmax), is a function of the
package junction to ambient thermal resistance (
θja),
maximum junction temperature (Tjmax), and ambient
temperature (Tamb), according to the expression:
Pmax = (Tjmax – Tamb) /
θja
The maximum output current (Imax) at a given value of
Input voltage (VIN) and output voltage (VOUT) is then
given by
Imax =Pmax / (VIN -VOUT )
The value of
θja is strongly dependent upon the type of
PC board used. Using the SC70 package it will range
from approximately 280 °C/W for a multi-layer board to
around 450°C/W for a single sided board. It will range
from 180°C/W to 300°C/W for the SOT23-5 package. To
avoid entering the thermal shutdown state, Tjmax
should be assumed to be 125°C and Imax less than the
over-current limit,(IOLIM). Power derating for the SC70
and SOT23-5 packages is shown in the following
graph.
Capacitor Selection and Regulator Stability
The device is designed to operate with all types of
output capacitor, including tantalum and low ESR
ceramic. For stability over the full operating range from
no load to maximum load, an output capacitor with a
minimum value of 1 F is recommended, although this
can be increased without limit to improve load
transient performance. Higher values of output
capacitor will also reduce output noise. Capacitors with
ESR less than 0.5
are recommended for best results.
The dielectric of the
ceramic capacitance is an
important consideration for the ZXCL Series operation
over temperature. Zetex recommends minimum
dielectric specification of X7R for the input and output
capacitors. For example a ceramic capacitor with X7R
dielectric will lose 20% of its capacitance over a -40 Cto
85 C temperature range, whereas a capacitor with a
Y5V dielectric loses 80% of its capacitance at -40 C and
75% at 85 C.
An input capacitor of 1 F (ceramic or tantalum) is
recommended to filter supply noise at the device input
and will improve ripple rejection.
The input and output capacitors should be positioned
close to the device, and a ground plane board layout
should be used to minimise the effects of parasitic track
resistance.
Dropout Voltage
The output pass transistor is a large PMOS device,
which acts like a resistor when the regulator enters the
dropout region. The dropout voltage is therefore
proportional to output current as shown in the typical
characteristics.
Ground Current
The use of a PMOS device ensures a low value of
ground current under all conditions including dropout,
start-up and maximum load.
Power Supply Rejection and Load Transient Response
Line and Load transient response graphs are shown in
the typical characteristics.
These show both the DC and dynamic shift in the
output voltage with step changes of input voltage and
load current, and how this is affected by the output
capacitor.
If improved transient response is required, then an
output capacitor with lower ESR value should be used.
Larger capacitors will reduce over/undershoot, but will
increase the settling time. Best results are obtained
using a ground plane layout to minimise board
parasitics.
ZXCL Series
ISSUE 7 - AUGUST 2002
9
-40
-20
0
20406080
100
0
100
200
300
400
500
SOT23
SC70
Derating Curve
Max
Power
D
issipation
(mW)
Temperature (°C)
相关PDF资料 |
PDF描述 |
|---|---|
| UZXCL280H5 | 2.8 V FIXED POSITIVE LDO REGULATOR, 0.28 V DROPOUT, PDSO5 |
| UT1028-AB3-C-R | 2.8 V FIXED POSITIVE LDO REGULATOR, PSSO3 |
| UT1028-T92-B-B | 2.8 V FIXED POSITIVE LDO REGULATOR, BCY3 |
| UT1028-T92-C-B | 2.8 V FIXED POSITIVE LDO REGULATOR, BCY3 |
| UT1028-T92-C-K | 2.8 V FIXED POSITIVE LDO REGULATOR, BCY3 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| UZXYY | 制造商:ANALOGICTECH 制造商全称:Advanced Analogic Technologies 功能描述:PCMCIA Current Limit Interface and Capacitor Charger |
| UZZ101 | 制造商:Panasonic Electric Works 功能描述: |
| UZZ102 | 制造商:Panasonic Electric Works 功能描述: |
| UZZ110 | 制造商:Panasonic Electric Works 功能描述: |
| UZZ1100 | 制造商:Panasonic Electric Works 功能描述: |
发布紧急采购，3分钟左右您将得到回复。