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參數(shù)資料
| 型號： | REG104FA-2.7/500 |
| 元件分類： | 固定正電壓單路輸出LDO穩(wěn)壓器 |
| 英文描述： | 2.7 V FIXED POSITIVE LDO REGULATOR, 0.46 V DROPOUT, PSSO5 |
| 封裝： | D2PAK-5 |
| 文件頁數(shù)： | 3/14頁 |
| 文件大小： | 246K |
| 代理商： | REG104FA-2.7/500 |
REG104
11
SBVS025A
connected from the output to the adjust pin will reduce both
the output noise and the peak error from a load transient.
See Figure 7 for improved output noise performance for two
capacitor combinations.
FIGURE 7. Output Noise Density on Adjustable Versions.
FIGURE 8. Transient and DC Dropout.
For large step changes in load current, the REG104 requires
a larger voltage drop across it to avoid degraded transient
response. The boundary of this “transient dropout” region is
shown as the top line in Figure 8. Values of VIN to VOUT
voltage drop above this line insure normal transient re-
sponse.
In the transient dropout region between “DC” and “Tran-
sient”, transient response recovery time increases. The time
required to recover from a load transient is a function of both
the magnitude and rate of the step change in load current and
the available “headroom” VIN to VOUT voltage drop. Under
worst-case conditions (full-scale load change with VIN to
VOUT voltage drop close to DC dropout levels), the REG104
can take several hundred microseconds to re-enter the speci-
fied window of regulation.
TRANSIENT RESPONSE
The REG104 response to transient line and load conditions
improves at lower output voltages. The addition of a capaci-
tor (nominal value 10nF) from the output pin to ground may
improve the transient response. In the adjustable version, the
addition of a capacitor, CFB (nominal value 10nF), from the
output to the adjust pin will also improve the transient
response.
THERMAL PROTECTION
Power dissipated within the REG104 will cause the junc-
tion temperature to rise. The REG104 has thermal shut-
down circuitry that protects the regulator from damage.
The thermal protection circuitry disables the output when
the junction temperature reaches approximately 150
°C,
allowing the device to cool. When the junction temperature
cools to approximately 130
°C, the output circuitry is again
enabled. Depending on various conditions, the thermal
protection circuit may cycle on and off. This limits the
dissipation of the regulator, but may have an undesirable
effect on the load.
Any tendency to activate the thermal protection circuit
indicates excessive power dissipation or an inadequate heat
sink. For reliable operation, junction temperature should be
limited to 125
°C, maximum. To estimate the margin of
safety in a complete design (including heat sink), increase
the ambient temperature until the thermal protection is
triggered. Use worst-case loads and signal conditions. For
good reliability, thermal protection should trigger more than
35
°C above the maximum expected ambient condition of
your application. This produces a worst-case junction tem-
perature of 125
°C at the highest expected ambient tempera-
ture and worst-case load.
The internal protection circuitry of the REG104 has been
designed to protect against overload conditions. It was not
intended to replace proper heat sinking. Continuously run-
ning the REG104 into thermal shutdown will degrade reli-
ability.
250
200
150
100
50
0
Drop
Out
Voltage
(mV)
0
100
200
300
400
500
I
OUT (mA)
REG103 –3.3 at 25
°C
DC
Transient
100
10
1000
10000
100000
10.0
1.0
0.1
nV/
√Hz
Frequency
C
OUT = 0, CFB = 0
C
OUT = 0, CFB = 0.01F
C
OUT = 10F, CFB = 0.01F
The REG104 utilizes an internal charge pump to develop an
internal supply voltage sufficient to drive the gate of the
DMOS pass element above VIN. The charge-pump switch-
ing noise (nominal switching frequency = 2MHz) is not
measurable at the output of the regulator.
DROP-OUT VOLTAGE
The REG104 uses an N-channel DMOS as the “pass”
element. When the input voltage is within a few hundred
millivolts of the output voltage, the DMOS device behaves
like a resistor. Therefore, for low values of VIN to VOUT, the
regulator’s input-to-output resistance is the RdsON of the
DMOS pass element (typically 230m
). For static (DC)
loads, the REG104 will typically maintain regulation down
to VIN to VOUT voltage drop of 230mV at full rated output
current. In Figure 8, the bottom line (DC dropout) shows the
minimum VIN to VOUT voltage drop required to prevent
dropout under DC load conditions.
相關PDF資料 |
PDF描述 |
|---|---|
| REG104GA-2.7G4 | 2.7 V FIXED POSITIVE LDO REGULATOR, 0.4 V DROPOUT, PDSO6 |
| REG1117FA | ADJUSTABLE POSITIVE LDO REGULATOR, 1.55 V DROPOUT, PSSO3 |
| REG1117TR | ADJUSTABLE POSITIVE LDO REGULATOR, 1.2 V DROPOUT, PDSO4 |
| REG1118-2.85/2K5G4 | 2.85 V FIXED POSITIVE LDO REGULATOR, 1.3 V DROPOUT, PDSO4 |
| REG1118-2.85G4 | 2.85 V FIXED POSITIVE LDO REGULATOR, 1.3 V DROPOUT, PDSO4 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| REG104FA-3 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| REG104FA-3.3 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| REG104FA-3.3/500 | 功能描述:低壓差穩(wěn)壓器 - LDO DMOS 1A LDO Reg 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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| REG104FA-3.3/500G3 | 功能描述:低壓差穩(wěn)壓器 - LDO DMOS 1A LDO Reg 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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| REG104FA-3.3/KTTT | 制造商:TI 制造商全稱:Texas Instruments 功能描述:DMOS 1A Low-Dropout Regulator |
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