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參數(shù)資料
| 型號(hào)： | LTC1516IS8 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類(lèi)： | 穩(wěn)壓器 |
| 英文描述： | Dual, Micropower, LinCMOS(TM) Voltage Comparator 8-SOIC -40 to 85 |
| 中文描述： | SWITCHED CAPACITOR REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | 0.150 INCH, PLASTIC, SO-8 |
| 文件頁(yè)數(shù)： | 5/8頁(yè) |
| 文件大小： | 105K |
| 代理商： | LTC1516IS8 |
5
LTC 1516
APPLICATIO
S I
FOR
ATIO
U
Short-Circuit/Thermal Protection
W
U
U
higher ripple due to higher output voltage dV/dt. High ESR
capacitors (ESR > 0.5
) on the output pin cause high
frequency voltage spikes on V
OUT
with every clock cycle.
There are several ways to reduce the output voltage ripple.
A larger C
OUT
capacitor (22
μ
F or greater) will reduce both
the low and high frequency ripple due to the lower C
OUT
charging and discharging dV/dt and the lower ESR typi-
cally found with higher value (larger case size) capacitors.
A low ESR ceramic output capacitor will minimize the high
frequency ripple, but will not reduce the low frequency
ripple unless a high capacitance value is chosen. A reason-
able compromise is to use a 10
μ
F to 22
μ
F tantalum
capacitor in parallel with a 1
μ
F to 3.3
μ
F ceramic capacitor
on V
OUT
to reduce both the low and high frequency ripple.
An RC filter may also be used to reduce high frequency
voltage spikes (see Figure 2).
In low load or high V
IN
applications, smaller values for C1
and C2 may be used to reduce output ripple. The smaller
C1 and C2 flying capacitors (0.022
μ
F to 0.1
μ
F) deliver less
charge per clock cycle to the output capacitor resulting in
lower output ripple. However, the smaller value flying caps
also reduce the maximum I
OUT
capability as well as
efficiency.
During short-circuit conditions, the LTC1516 will draw
between 200mA and 400mA from V
IN
causing a rise in
the junction temperature. On-chip thermal shutdown
circuitry disables the charge pump once the junction
temperature exceeds 135
°
C, and reenables the charge
pump once the junction temperature falls back to 115
°
C.
The LTC1516 will cycle in and out of thermal shutdown
indefinitely without latchup or damage until the V
OUT
short
is removed.
Capacitor Selection
For best performance, it is recommended that low ESR
capacitors be used for both C
IN
and C
OUT
to reduce noise
and ripple. The C
IN
and C
OUT
capacitors should be either
ceramic or tantalum and should be 10
μ
F or greater. If the
input source impedance is very low, C
IN
may not be
needed. Increasing the size of C
OUT
to 22
μ
F or greater will
reduce output voltage ripple.
Ceramic or tantalum capacitors are recommended for the
flying caps C1 and C2 with values in the range of 0.1
μ
F to
1
μ
F. Note that large value flying caps (>0.22
μ
F) will
increase output ripple unless C
OUT
is also increased. For
very low load applications, C1 and C2 may be reduced to
0.01
μ
F to 0.047
μ
F. This will reduce output ripple at the
expense of efficiency and maximum output current.
Output Ripple
Normal LTC1516 operation produces voltage ripple on the
V
OUT
pin. Output voltage ripple is required for the LTC1516
to regulate. Low frequency ripple exists due to the hyster-
esis in the sense comparator and propagation delays in the
charge pump enable/disable circuits. High frequency ripple
is also present mainly due to ESR (Equivalent Series
Resistance) in the output capacitor. Typical output ripple
under maximum load is 100mV
P-P
with a low ESR 10
μ
F
output capacitor.
The magnitude of the ripple voltage depends on several
factors. High input voltages (V
IN
> 3.3V) increase the output
ripple since more charge is delivered to C
OUT
per clock
cycle. Large C1 and C2 flying capacitors (>0.22
μ
F) also
increase ripple for the same reason. Large output current
load and/or a small output capacitor (<10
μ
F) results in
Inrush Currents
During normal operation, V
IN
will experience current tran-
sients in the 100mA to 200mA range whenever the charge
pump is enabled. During start-up, these inrush currents
may approach 500mA. For this reason, it is important to
minimize the source resistance between the input supply
and the V
IN
pin to prevent start-up problems and large
input voltage transients.
V
OUT
5V
LTC1516
V
OUT
3
15
μ
F
TANTALUM
1
μ
F
CERAMIC
V
OUT
5V
+
LTC1516
V
OUT
3
1516 F02
2
10
μ
F
+
10
μ
F
+
Figure 2. Output Ripple Reduction Techniques
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相關(guān)代理商/技術(shù)參數(shù) |
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| LTC1516IS8#PBF | 功能描述:IC REG SWITCHED CAP DBL 5V 8SOIC RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類(lèi)型:降壓（降壓） 輸出類(lèi)型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤(pán) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤(pán) |
| LTC1516IS8#TR | 功能描述:IC REG SWITCHED CAP DBL 5V 8SOIC RoHS:否 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類(lèi)型:降壓（降壓） 輸出類(lèi)型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤(pán) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤(pán) |
| LTC1516IS8#TRPBF | 功能描述:IC REG SWITCHED CAP DBL 5V 8SOIC RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類(lèi)型:降壓（降壓） 輸出類(lèi)型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤(pán) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤(pán) |
| LTC1517CS5-3.3 | 制造商:Linear Technology 功能描述:Charge Pump STPUP 3.3V 15mA 5-Pin TSOT-23 |
| LTC1517CS5-3.3#TR | 功能描述:IC REG SWITCHED CAP 3.3V SOT23-5 RoHS:否 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類(lèi)型:升壓（升壓） 輸出類(lèi)型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開(kāi)關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無(wú) 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
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