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參數(shù)資料
| 型號： | S-816A33 |
| 廠商： | Seiko Instruments Inc. |
| 英文描述： | 3.3V±2.0% External Transistor Type Voltage Regulators(輸出電壓3.3V±2.0%，外部晶體管型穩(wěn)壓器) |
| 中文描述： | 3.3 ± 2.0％外部晶體管式電壓調(diào)節(jié)器（輸出電壓為3.3V ± 2.0％，外部晶體管型穩(wěn)壓器） |
| 文件頁數(shù)： | 10/21頁 |
| 文件大?。?/td> | 200K |
| 代理商： | S-816A33 |
External Transistor Type Voltage Regulators
Rev.3.0
S-816 Series
Seiko Instruments Inc.
9
The overcurrent detection value (Iout_max) is represented by the following equation:
Iout_max = |VBE1| / Rs
In this case, Rs denotes the resistance value of the sense resistance, and VBE1 denotes the base-emitter saturation voltage
of Tr.1.
For the PNP transistor (Tr.1) and the NPN transistor (Tr.2), try to select those of small-signal type that offer a sufficient
withstand voltage against the input voltage (VIN).
The on-time (Ton) and the off-time (Toff) of the intermittent operation are broadly expressed by the following equations:
Ton = -1
′
C2
′
R2
′
Ln( 1 - ( VBE2
′
( 1 + R2 / R3 ) ) / ( VIN - VBE1 ) )
Toff = -1
′
C1
′
R1
′
Ln( 1 - VSH / VIN )
In this case, VBE2 denotes the base-emitter saturation voltage of Tr.2, VIN denotes the input voltage, and VSH denotes the
inversion voltage (L
H) of the power-off terminal.
Set the on-time value that does not cause the overcurrent protection to be activated by a rush current to the load capacitor.
Then, compute the ratio between the on-time and the off-time from the maximum input voltage of the appropriate application
and the power dissipation of the external PNP transistor, and decide the off-time with reference to the on-time established
earlier.
Take the equation above as a rough guide, because the actual on-time (Ton) and off-time (Toff) should be defined and
checked using the utilizing components.
2. External adjustment of output voltage
The S-816 Series allows you to adjust the output voltage or to set its value over the output voltage range (6V) of the products
of this series, when external resistances RA, RB and capacitor CC are added, as illustrated in Figure 11. Moreover, a
temperature gradient can be obtained by inserting a thermistor or other element in series with external resistances RA and RB.
Error
amplifier
R2
R1
CC
RB
RA
Vref
EXT
V
OUT
V
SS
ON/OFF
V
IN
OUT
+
-
CL
+
-
VIN
CIN
Figure 11
The S-816 Series has an internal impedance resulting from R1 and R2 between the V
OUT
and the Vss terminal, as shown in
Figure 11. Therefore, the influence of the internal resistances (R1, R2) of the IC has to be taken into consideration in defining
the output voltage (OUT).
The output voltage (OUT) is expressed by the following equation:
OUT = VOUT + VOUT
′
RA
( RB // RI ) (Note: // denotes a combined resistance in parallel.)
In this case, VOUT is the output voltage value of the S-816 Series, RA and RB is the resistance values of the external
resistances, and RI is the resistance value (R1+R2) of the internal resistances in the IC.
The accuracy of the output voltage (OUT) is determined by the absolute accuracy of external connecting resistances RA and
RB, the output voltage accuracy (VOUT
±
2.0%) of the S-816 Series, and deviations in the absolute value of the internal
resistance (RI) in the IC.
The maximum value (OUTmax) and the minimum value (OUTmin) of the output voltage (OUT), including deviations, are
expressed by the following equations:
OUTmax = VOUT
′
1.02 + VOUT
′
1.02
′
RAmax
( RBmin // RImin )
OUTmin = VOUT
′
0.98 + VOUT
′
0.98
′
RAmin
( RBmax // RImax )
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相關代理商/技術參數(shù) |
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| S-816A33AMC-BAI-T2 | 功能描述:低壓差穩(wěn)壓器 - LDO 2.5V 1uA 2.0% 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 |
| S-816A33AMC-BAIT2G | 功能描述:低壓差穩(wěn)壓器 - LDO 2.5V 1uA 2.0% 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 |
| S-816A33AMC-BAIT2U | 功能描述:IC REG LINEAR 1A SOT23-5 制造商:ablic u.s.a. inc. 系列:* 包裝:剪切帶（CT） 零件狀態(tài):在售 穩(wěn)壓器數(shù):1 電流 - 輸出:1A 工作溫度:-40°C ~ 85°C（TA） 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應商器件封裝:SOT-23-5 標準包裝:1 |
| S-816A34AMC-BAI-T2 | 功能描述:低壓差穩(wěn)壓器 - LDO 2.5V 1uA 2.0% 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 |
| S-816A34AMC-BAIT2G | 功能描述:低壓差穩(wěn)壓器 - LDO 2.5V 1uA 2.0% 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 |
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