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參數(shù)資料
| 型號： | MIC5319-8YD5 |
| 廠商： | Micrel Semiconductor,Inc. |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 500mA ?Cap Ultra-Low Dropout, High PSRR LDO Regulator |
| 中文描述： | 500mA的？第超低壓差，高PSRR LDO穩(wěn)壓器 |
| 文件頁數(shù)： | 8/10頁 |
| 文件大小： | 319K |
| 代理商： | MIC5319-8YD5 |
MIC5319
Micrel
October 2004
8
M9999-100604
Applications Information
Enable/Shutdown
The MIC5319 features an active-high enable pin that allows
the regulator to be disabled. Forcing the enable pin low
disables the regulator and sends it into a “zero” off-mode-
current state. In this state, current consumed by the regulator
goes nearly to zero. Forcing the enable pin high enables the
output voltage. The active-high enable pin uses CMOS
technology and the enable pin cannot be left floating, as this
may cause an indeterminate state on the output.
Input Capacitor
The MIC5319 is a high-performance, high bandwidth device.
Therefore, it requires a well-bypassed input supply for opti-
mal performance. A 1
μ
F capacitor is required from the input-
to-ground to provide stability. Low-ESR ceramic capacitors
provide optimal performance at a minimum of space. Addi-
tional high frequency capacitors, such as small-valued NPO
dielectric-type capacitors, help filter out high-frequency noise
and are good design practice in any RF-based circuit.
Output Capacitor
The MIC5319 requires an output capacitor of 2.2
μ
F or greater
to maintain stability. The design is optimized for use with low-
ESR ceramic chip capacitors. High ESR capacitors may
cause high frequency oscillation. The output capacitor can be
increased, but performance has been optimized for a 2.2
μ
F
ceramic output capacitor and does not improve significantly
with larger capacitance.
X7R/X5R dielectric-type ceramic capacitors are recom-
mended because of their temperature performance. X7R-
type capacitors change capacitance by 15% over their oper-
ating temperature range and are the most stable type of
ceramic capacitors. Z5U and Y5V dielectric capacitors change
value by as much as 50% and 60%, respectively, over their
operating temperature ranges. To use a ceramic chip capaci-
tor with Y5V dielectric, the value must be much higher than an
X7R ceramic capacitor to ensure the same minimum capaci-
tance over the equivalent operating temperature range.
Bypass Capacitor
A capacitor can be placed from the bypass pin-to-ground to
reduce output voltage noise. The capacitor bypasses the
internal reference. A 0.1
μ
F capacitor is recommended for
applications that require low-noise outputs. The bypass ca-
pacitor can be increased, further reducing noise and improv-
ing PSRR. Turn-on time increases slightly with respect to
bypass capacitance. A unique, quick-start circuit allows the
MIC5319 to drive a large capacitor on the bypass pin without
significantly slowing turn-on time. Refer to the “Typical Char-
acteristics” section for performance with different bypass
capacitors.
No-Load Stability
Unlike many other voltage regulators, the MIC5319 will
remain stable and in regulation with no load. This is especially
important in CMOS RAM keep-alive applications.
Adjustable Regulator Application
Adjustable regulators use the ratio of two resistors to multiply
the reference voltage to produce the desired output voltage.
The MIC5319 can be adjusted from 1.25V to 5.5V by using
two external resistors (Figure 1). The resistors set the output
voltage based on the following equation:
R1
R2
MIC5319BML
VOUT
VIN
ADJ
BYP
GND
V
IN
V
OUT
R1
2.2
μ
F
R2
1
μ
F
EN
Figure 1. Adjustable Voltage Application
Thermal Considerations
The MIC5319 is designed to provide 500mA of continuous
current in a very small MLF package. Maximum ambient
operating temperature can be calculated based on the output
current and the voltage drop across the part. Given an input
voltage of 3.3V, output voltage of 2.8V and output current =
500mA, the actual power dissipation of the regulator circuit
can be determined using the equation:
P
D
= (V
IN
– V
OUT
) I
OUT
+ V
IN
×
I
GND
Because this device is CMOS and the ground current is
typically <100
μ
A over the load range, the power dissipation
contributed by the ground current is < 1% and can be ignored
for this calculation.
P
D
= (3.3V – 2.8V)
×
500mA
P
D
= 0.25W
To determine the maximum ambient operating temperature
of the package, use the junction-to-ambient thermal resis-
tance of the device and the following basic equation:
T
J
(max) = 125
°
C, the maximum junction temperature of the die
θ
JA
thermal resistance = 93
°
C/W
V
V
1
V
1.25V
OUT
REF
REF
=
+
=
P (
T (max)– T
θ
A
JA
max)
=
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC5319BML | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC5319BML TR | 功能描述:IC REG LDO ADJ .5A 6MLF RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:- 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):正，固定式 輸出電壓:3.8V 輸入電壓:最高 16V 電壓 - 壓降（標(biāo)準(zhǔn)）:0.3V @ 80mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:80mA 電流 - 限制（最小）:- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應(yīng)商設(shè)備封裝:SOT-23-5 包裝:帶卷 (TR) 其它名稱:MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| MIC5319YML | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC5319YML TR | 功能描述:低壓差穩(wěn)壓器 - LDO 500mA Cap Ultra-Low Dropout, High PSRR LDO Regulator IN 2X2 MLF (Lead Free) RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| MIC5319YML-TR | 功能描述:Linear Voltage Regulator IC Positive Adjustable 1 Output 1.25 V ~ 5.5 V 500mA 6-MLF? (2x2) 制造商:microchip technology 系列:- 包裝:剪切帶（CT） 零件狀態(tài):有效 穩(wěn)壓器拓?fù)?正，可調(diào)式 電壓 - 輸出:1.25 V ~ 5.5 V 電流 - 輸出:500mA 電壓 - 跌落（典型值）:0.2V @ 500mA 穩(wěn)壓器數(shù):1 電壓 - 輸入:2.5 V ~ 5.5 V 電流 - 限制（最小值）:600mA 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-VQFN 裸露焊盤，6-MLF? 供應(yīng)商器件封裝:6-MLF?（2x2） 標(biāo)準(zhǔn)包裝:1 |
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