参数资料
型号: TL7705BIDRG4
厂商: TEXAS INSTRUMENTS INC
元件分类: 电源管理
英文描述: 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8
封装: GREEN, PLASTIC, SOIC-8
文件页数: 21/21页
文件大小: 640K
代理商: TL7705BIDRG4
TL7702B, TL7705B, TL7733B
SUPPLY-VOLTAGE SUPERVISORS
SLVS037M – SEPTEMBER 1989 – REVISED MAY 2003
9
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
VS
10 k
0.1
F
SENSE
RESIN
GND
REF
RESET
VCC
CT
To System
RESET
RT
CT
System Supply
Reset Input
(from system)
To System
RESET
(see text)
7
2
1
3
5
6
8
4
10 k
Figure 8. System Reset Controller With Undervoltage Sensing
When the TL770xB SENSE terminal is used to monitor VCC, a current-limiting resistor in series with CT is
recommended. During normal operation, the timing capacitor is charged by the onboard current source to
approximately VCC or an internal voltage clamp (≈7.1-V Zener), whichever is less. When the circuit then is subjected
to an undervoltage condition during which VCC is rapidly slewed down, the voltage on CT exceeds that on VCC. This
forward biases a secondary path internally, which falsely activates the outputs. A fault is indicated when VCC drops
below V(CT), not when VSENSE falls below VT–.
Texas Instruments performs a 100% electrical screen to verify that the outputs do not switch with 1 mA forced into
the CT terminal. Adding the external resistor, RT, prevents false triggering. Its value is calculated as follows:
V
(CT) * VT–
R
T
Where:
V(CT) = VCC or 7.1 V, whichever is less
VT–
= 4.55 V (nom)
RT
= value of series resistor required
For VCC = 5 V:
5
* 4.55
R
T
t 1mA
Therefore,
R
T
u 450 W
Using a 20%-tolerance resistor, RT should be greater than 560 .
Adding this series resistor changes the duration of the reset pulse by no more than 10%. RT extends the discharge
of CT, but also skews the V(CT) threshold. These effects tend to cancel one another. The precise percentage change
can be derived theoretically, but the equation is complicated by this interaction and is dependent upon the duration
of the supply-voltage fault condition.
Both outputs of the TL770xB should be terminated with similar value resistors, even when only one is being used.
This prevents unwanted plateauing in either output waveform during switching, which may be interpreted as an
undefined state or delay system reset.
The TL7705BM is obsolete
and no longer is supplied.
相关PDF资料
PDF描述
TL7660CDGKR SWITCHED CAPACITOR CONVERTER, 9 kHz SWITCHING FREQ-MAX, PDSO8
TL7660ID SWITCHED CAPACITOR CONVERTER, 9 kHz SWITCHING FREQ-MAX, PDSO8
TPS65562RGTT 3 A BATTERY CHARGE CONTROLLER, PQCC16
TL431LP 1-OUTPUT THREE TERM VOLTAGE REFERENCE, BCY3
TC1232EOE723 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO16
相关代理商/技术参数
参数描述
TL7705BIP 功能描述:监控电路 4.55V Monitor 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
TL7705BIPE4 功能描述:监控电路 Sngl SVS f/5V System w/Prg Time Delay 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
TL7705BMFK 制造商:TI 制造商全称:Texas Instruments 功能描述:SUPPLY-VOLTAGE SUPERVISORS
TL7705BMFKB 制造商:TI 制造商全称:Texas Instruments 功能描述:SUPPLY-VOLTAGE SUPERVISORS
TL7705BMJG 制造商:TI 制造商全称:Texas Instruments 功能描述:SUPPLY-VOLTAGE SUPERVISORS