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参数资料
| 型号： | LTC1983ES6-5#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 6/12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 |
LTC1983-3/LTC1983-5
OPERATIO
(Refer to Block Diagram)
The LTC1983-3/LTC1983-5 use a switched capacitor
charge pump to invert a positive input voltage to a regu-
lated –3V ± 4% (LTC1983-3) or –5 ± 4% (LTC1983-5)
output voltage. Regulation is achieved by sensing the
output voltage through an internal resistor divider and
enabling the charge pump when the output voltage droops
above the upper trip point of COMP1. When the charge
pump is enabled, a 2-phase, nonoverlapping clock con-
trols the charge pump switches. Clock 1 closes the S1
switches which enables the flying capacitor to charge up
to the V IN voltage. Clock 2 closes the S2 switches that
invert the V IN voltage and connect the bottom plate of C FLY
to the output capacitor at V OUT . This sequence of charging
and discharging continues at a free-running frequency of
900kHz (typ) until the output voltage has been pumped
down to the lower trip point of COMP1 and the charge
pump is disabled. When the charge pump is disabled, the
LTC1983 draws only 25 μ A (typ) from V IN which provides
high efficiency at low load conditions.
In shutdown mode, all circuitry is turned off and the part
draws less than 1 μ A from the V IN supply. V OUT is also
disconnected from V IN and C FLY . The SHDN pin has a
threshold of approximately 0.7V. The part enters shut-
down when a low is applied to the SHDN pin. The SHDN pin
should not be floated; it must be driven with a logic high
or low.
Open-Loop Operation
The LTC1983-3/LTC1983-5 inverting charge pumps regu-
late at –3V/–5V respectively, unless the input voltage is too
low or the output current is too high. The equations for
output voltage regulation are as follows:
V IN –5.06V > I OUT ? R OUT (LTC1983-5)
V IN –3.06V > I OUT ? R OUT (LTC1983-3)
If this condition is not met, then the part will run in open
loop mode and act as a low output impedance inverter for
which the output voltage will be:
V OUT = –[V IN –(I OUT ? R OUT )]
For all R OUT values, check the corresponding curves in
the Typical Performance Characteristics section (Note:
C FLY = 1 μ F for all R OUT curves). The R OUT value will be
different for different flying caps, as shown in the follow-
ing equation:
Short-Circuit/Thermal Protection
During short-circuit conditions, the LTC1983 will draw
several hundred milliamps from V IN causing a rise in the
junction temperature. On-chip thermal shutdown cir-
cuitry disables the charge pump once the junction tem-
perature exceeds ≈ 155 ° C, and reenables the charge pump
once the junction temperature falls back to ≈ 145 ° C. The
LTC1983 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 4.7 μ F or greater.
Aluminum electrolytic are not recommended because of
their high equivalent series resistance (ESR). If the source
impedance is very low, C IN may not be needed. Increasing
the size of C OUT to 10 μ F or greater will reduce output
voltage ripple. The flying capacitor and C OUT should also
have low equivalent series inductance (ESL). The board
layout is critical as well for inductance for the same reason
(the suggested board layout should be used).
A ceramic capacitor is recommended for the flying capaci-
tor with a value in the range of 0.1 μ F to 4.7 μ F. Note that
a large value flying cap (>1 μ F) will increase output ripple
unless C OUT is also increased. For very low load applica-
tions, C1 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.
1983fa
6
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
| LTC1985ES5-1.8#TRM | 功能描述:IC MON TRI SUPPLY 1.8V 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 |
| LTC1985ES5-1.8#TRMPBF | 功能描述:IC MON TRI SUPPLY 1.8V TSOT23-5 RoHS:是 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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