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參數(shù)資料
| 型號(hào)： | NCV8505D2T33 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Micropower 400 mA LDO Linear Regulators with ENABLE, DELAY, and RESET |
| 中文描述： | 3.3 V FIXED POSITIVE LDO REGULATOR, PSSO7 |
| 封裝： | D2PAK, 7 PIN |
| 文件頁數(shù)： | 10/12頁 |
| 文件大?。?/td> | 76K |
| 代理商： | NCV8505D2T33 |
NCV8505 Series
http://onsemi.com
10
APPLICATION NOTES
SETTING THE DELAY TIME
The delay time is controlled by the Reset Delay Low
Voltage, Delay Switching Threshold, and the Delay Charge
Current. The delay follows the equation:
[CDELAY(Vdt
Delay Charge Current
Example:
Using C
DELAY
= 33 nF.
Assume reset Delay Low Voltage = 0.
Use the typical value for V
dt
= 1.8 V (2.5 V, 3.3 V, and
5.0 V options).
Use the typical value for Delay Charge Current = 4.2
μ
A.
[33 nF(1.8
4.2 A
tDELAY
Reset Delay Low Voltage)]
tDELAY
0)]
14 ms
STABILITY CONSIDERATIONS
The output or compensation capacitor helps determine
three main characteristics of a linear regulator: startup
delay, load transient response and loop stability.
The capacitor value and type should be based on cost,
availability, size and temperature constraints. A tantalum or
aluminum electrolytic capacitor is best, since a film or
ceramic capacitor with almost zero ESR can cause
instability. The aluminum electrolytic capacitor is the least
expensive solution, but, if the circuit operates at low
temperatures (25
°
C to 40
°
C), both the value and ESR of
the capacitor will vary considerably. The capacitor
manufacturers data sheet usually provides this information.
The value for the output capacitor C
OUT
shown in Figure 16
should work for most applications, however it is not
necessarily the optimized solution.
Figure 16. Test and Application Circuit Showing
Output Compensation
V
IN
V
OUT
C
OUT
**
33
μ
F
R
RST
RESET
C
IN
*
0.1
μ
F
NCV8505
*C
IN
required if regulator is located far from the power supply
filter.
**C
OUT
required for stability. Capacitor must operate at minimum
temperature expected.
CALCULATING POWER DISSIPATION IN A
SINGLE OUTPUT LINEAR REGULATOR
The maximum power dissipation for a single output
regulator (Figure 17) is:
PD(max)
[VIN(max)
VIN(max)IQ
VOUT(min)]IOUT(max)
(1)
where:
V
IN(max)
is the maximum input voltage,
V
OUT(min)
is the minimum output voltage,
I
OUT(max)
is the maximum output current for the
application, and
I
Q
is the quiescent current the regulator consumes at
I
OUT(max)
.
Once the value of P
D(max)
is known, the maximum
permissible value of R
JA
can be calculated:
150
°
C
RJA
TA
PD
(2)
The value of R
JA
can then be compared with those in the
package section of the data sheet. Those packages with
R
JA
’s less than the calculated value in equation 2 will keep
the die temperature below 150
°
C.
In some cases, none of the packages will be sufficient to
dissipate the heat generated by the IC, and an external
heatsink will be required.
SMART
REGULATOR
I
Q
Control
Features
I
OUT
I
IN
Figure 17. Single Output Regulator with Key
Performance Parameters Labeled
V
IN
V
OUT
}
HEAT SINKS
A heat sink effectively increases the surface area of the
package to improve the flow of heat away from the IC and
into the surrounding air.
Each material in the heat flow path between the IC and the
outside environment will have a thermal resistance. Like
series electrical resistances, these resistances are summed to
determine the value of R
JA
:
RJA
RJC
RCS
where:
R
JC
= the junctiontocase thermal resistance,
R
CS
= the casetoheatsink thermal resistance, and
R
SA
= the heatsinktoambient thermal resistance.
R
JC
appears in the package section of the data sheet. Like
R
JA
, it too is a function of package type. R
CS
and R
SA
are
functions of the package type, heatsink and the interface
between them. These values appear in heat sink data sheets
of heat sink manufacturers.
RSA
(3)
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NCV8505D2T33G | 功能描述:低壓差穩(wěn)壓器 - LDO MICROPOWER 400 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(dòng)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 |
| NCV8505D2T33R4 | 功能描述:低壓差穩(wěn)壓器 - LDO 3.3V 400mA w/ENABLE 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(dòng)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 |
| NCV8505D2T33R4G | 功能描述:低壓差穩(wěn)壓器 - LDO MICROPOWER 400 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(dòng)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 |
| NCV8505D2T50 | 功能描述:低壓差穩(wěn)壓器 - LDO 5.0V 400mA w/ENABLE 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(dòng)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 |
| NCV8505D2T50G | 功能描述:低壓差穩(wěn)壓器 - LDO 5.0V 400mA w/ENABLE 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(dòng)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 |
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