- 您现在的位置：买卖IC网 > PDF目录16049 > MIC2778-2YM5 TR (Micrel Inc)IC SUPERVISOR ADJ HYSTER SOT23-5 PDF资料下载
参数资料
| 型号： | MIC2778-2YM5 TR |
| 厂商： | Micrel Inc |
| 文件页数： | 5/6页 |
| 文件大小： | 0K |
| 描述： | IC SUPERVISOR ADJ HYSTER SOT23-5 |
| 标准包装： | 1 |
| 类型： | 简单复位/加电复位 |
| 监视电压数目： | 1 |
| 输出： | 开路漏极或开路集电极 |
| 复位： | 低有效 |
| 复位超时： | 最小为 140 ms |
| 电压 - 阀值： | 可调节/可选择 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SC-74A，SOT-753 |
| 供应商设备封装： | SOT-23-5 |
| 包装： | 标准包装 |
| 产品目录页面： | 1112 (CN2011-ZH PDF) |
| 其它名称： | 576-2691-6 |
V BAT(LO) = V REF ?
? R1 + R2 + R3 ?
?
?
R2 + R3
V BAT(HI) = V REF ?
? R1 + R2 + R3 ?
?
?
V BAT(LO) = 3.1V = 1.24 ?
? 1M ? ?
? R2 + 344K ?
MIC2778
Applications Information
Output
Since the MIC2778 output is an open-drain MOSFET, most
applications will require a pull-up resistor. The value of the
resistor should not be too large or leakage effects may domi-
nate. 470kΩ is the maximum recommended value.
Programming the Thresholds
The low-voltage threshold is calculated using:
?
The high-voltage threshold is calculated using:
?
R3
where, for both equations:
V REF = 1.240V
In order to provide the additional criteria needed to solve
for the resistor values, the resistors can be selected such
that they have a given total value, that is, R1 + R2 + R3 =
R TOTAL . A value such as 1MΩ for R TOTAL is a reasonable
value because it draws minimum battery current but has no
signi?cant effect on accuracy.
When working with large resistors, a small amount of leak-
age current can cause voltage offsets that degrade system
accuracy. The maximum recommended total resistance from
V BAT to ground is 3MΩ.
V BATT
Micrel
of the two remaining resistor values.
?
R2 = 56K ?
R1 = 1M ? ? R2 ? R3
R1 = 600K ?
The accuracy of the resistors can be chosen based upon the
accuracy required by the system.
Input Transients
The MIC2778 is inherently immune to very short negative-
going “glitches.” Very brief transients may exceed the V BAT(lo)
threshold without tripping the output.
As shown in Figure 2, the narrower the transient, the deeper
the threshold overdrive that will be ignored by the MIC2778.
The graph represents the typical allowable transient dura-
tion for a given amount of threshold overdrive that will not
generate a reset.
INPUT T RANS IENT
R ES PONS E
140
120
100
80
60
40
20
R1
604K
1%
MIC2778
VDD R ST
470K
0
1 10 100 1000
RESET COMP. OVERDRIVE, V REF –V LTH (MV)
HTH
GND
56K
1%
340K
1%
LTH
R2
R3
Figure 1. Example Circuit
Once the desired trip points are determined, set the V BAT(hi)
threshold ?rst.
Figure 2. Input Transient Response
Interfacing to Processors
With Bidirectional Reset Pins
Some microprocessors have reset signal pins that are bidi-
rectional, rather than input only. The Motorola 68HC11 family
is one example. Because the MIC2778’s output is open drain,
it can be connected directly to the processor ’s reset pin using
only the pull-up resistor normally required. See Figure 3.
V BATT
MICROPROCESSOR
V BAT(HI) = 1.24 ?
? 1M ? ?
? R3 ?
Forexample,useatotalof1MΩ=R1+R2+R3.Foratypical
single-cell lithium ion battery, 3.6V is a good “high threshold”
because at 3.6V the battery is moderately charged. Solving
for R3:
?
R1
R2
R3
604K
1%
56K
1%
340K
1%
MIC2778
VDD R ST
LTH
HTH GND
100K
SUPPLY IN
RESET IN
GND
R3 = 344K ?
Once R3 is determined, the equation for V BAT(lo) can be
used to determine R2. A single lithium-ion cell should not be
discharged below 2.5V. Many applications limit the drain to
3.1V. Using 3.1V for the V BAT(lo) threshold allows calculation
Figure 3. Interfacing to Bidirectional Reset Pin
January 2005
5
M9999-011405
相关PDF资料 |
PDF描述 |
|---|---|
| CCSMA-MM-LL142-24 | RF CABLE SMA M/M LOW LOSS 18GHZ |
| ECE-V1HA470P | CAP ALUM 47UF 50V 20% SMD |
| CCSMA-MM-SS402-36 | RF COAX CABLE 18GHZ 50 OHM 36" |
| LHL10NB272J | INDUCTOR 2700UH .24A RADIAL |
| CCSMA-MM-SS402-24 | RF COAX CABLE 18GHZ 50 OHM 24" |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC2779H-1BM5 TR | 功能描述:IC SUPERVISOR ADJ HYSTER SOT23-5 RoHS:否 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:1 系列:- 类型:简单复位/加电复位 监视电压数目:1 输出:开路漏极或开路集电极 复位:低有效 复位超时:标准传输延迟为 60 µs 电压 - 阀值:3V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:Digi-Reel® 其它名称:LM8364BALMF30DKR |
| MIC2779H-1BM5TR | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel 制造商:RF Micro Devices Inc 功能描述: |
| MIC2779H-1YM5 | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC2779H-1YM5 TR | 功能描述:监控电路 V-Supervisor w/Adj. Hysteresis, Active-High Ouput, 1% Accuracy (Lead Free) RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| MIC2779H-1YM5-TR | 功能描述:Supervisor Push-Pull, Totem Pole 2 Channel SOT-23-5 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:停产 类型:多压监控器 受监控电压数:2 输出:推挽式，图腾柱 复位:高有效 复位超时:最小为 140 ms 电压 - 阈值:可调节/可选择 工作温度:-40°C ~ 85°C（TA） 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商器件封装:SOT-23-5 标准包装:1 |
发布紧急采购，3分钟左右您将得到回复。