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参数资料
| 型号： | LTC1983ES6-5#TR |
| 厂商： | Linear Technology |
| 文件页数： | 7/12页 |
| 文件大小： | 0K |
| 描述： | IC REG SWITCHD CAP INV -5V SOT23 |
| 标准包装： | 2,500 |
| 类型： | 切换式电容器（充电泵），反相 |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | -5V |
| 输入电压： | 2.3 V ~ 5.5 V |
| PWM 型： | Burst Mode? |
| 频率 - 开关： | 900kHz |
| 电流 - 输出： | 100mA |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SOT-23-6 细型，TSOT-23-6 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | TSOT-23-6 |
| 其它名称： | LTC1983ES6-5TR LTC1983ES65TR |
LTC1983-3/LTC1983-5
OPERATIO
(Refer to Block Diagram)
There are many aspects of the capacitors that must be
taken into account. First, the temperature stability of the
dielectric is a main concern. For ceramic capacitors, a
three character code specifies the temperature stability
(e.g. X7R, Y5V, etc.). The first two characters represent
the temperature range that the capacitor is specified and
the third represents the absolute tolerance that the ca-
pacitor is specified to over that temperature range. The
ceramic capacitor used for the flying and output capaci-
tors should be X5R or better . Second, the voltage coef-
ficient of capacitance for the capacitor must be checked
and the actual value usually needs to be derated for the
operating voltage (the actual value has to be larger than
the value needed to take into account the loss of capaci-
tance due to voltage bias across the capacitor). Third, the
frequency characteristics need to be taken into account
because capacitance goes down as the frequency of
oscillation goes up. Typically, the manufacturers have
capacitance vs frequency curves for their products. This
curve must be referenced to be sure the capacitance will
not be too small for the application. Finally, the capacitor
ESR and ESL must be low for reasons mentioned in the
following section.
Output Ripple
Normal LTC1983 operation produces voltage ripple on the
V OUT pin. Output voltage ripple is required for the LTC1983
results in higher ripple due to higher output voltage dV/dt.
High ESR capacitors (ESR > 0.1 ? ) 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 4.7 μ F ceramic capacitor
on V OUT to reduce both the low and high frequency ripple.
However, the best solution is to use 10 μ F to 22 μ F, X5R
ceramic capacitors which are available in 1206 package
sizes. An RC filter may also be used to reduce high
frequency voltage spikes (see Figure 1).
In low load or high V IN applications, smaller values for
C FLY may be used to reduce output ripple. A smaller flying
capacitor (0.01 μ F to 0.047 μ F) delivers 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.
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 of the output capacitor.
Typical output ripple under maximum load is 60mV P-P
with a low ESR 10 μ F output capacitor. The magnitude of
the ripple voltage depends on several factors. High input
voltage to negative output voltage differentials [(V IN +
V OUT ) >1V] increase the output ripple since more charge
LTC1983-X
V OUT
LTC1983-X
V OUT
3.9 ?
10 μ F
TANTALUM
15 μ F
TANTALUM
V OUT
10 μ F
TANTALUM
V OUT
1 μ F
CERAMIC
is delivered to C OUT per clock cycle. A large flying capacitor
(>1 μ F) also increases ripple for the same reason. Large
output current load and/or a small output capacitor (<10 μ F)
1983 F01
Figure 1. Output Ripple Reduction Techniques
1983fa
7
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1983ES65TRMPBF | 制造商:Linear Technology 功能描述: |
| LTC1983ES6-5TRMPBF | 制造商:Linear Technology 功能描述:Charge Pump Inv -5V/-5.5V 100mA TSOT23-6 |
| LTC1985ES5-1.8 | 制造商:Linear Technology 功能描述:Volt Supervisor Monitor 1.8V/3V 5-Pin TSOT-23 制造商:Linear Technology 功能描述:3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LTC1985ES5-1.8#PBF | 制造商:Linear Technology 功能描述:Volt Supervisor Monitor 1.8V/3V 5-Pin TSOT-23 制造商:Linear Technology 功能描述:MS-System Monitor/Supervisor, cut tape uP Triple Supply Monitor w Push-Pull |
| LTC1985ES5-1.8#TR | 功能描述:IC MON TRPL SUPPLY PREC TSOT23-5 RoHS:否 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:400 系列:- 类型:备用电池电路 监视电压数目:1 输出:开路漏极，推挽式 复位:高有效/低有效 复位超时:最小为 35 ms 电压 - 阀值:4.65V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 供应商设备封装:16-SOIC W 包装:带卷 (TR) 其它名称:ADM691ARZ-REEL7TR |
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