MAX793T Datasheet

  • MAX793T

  • 3.0V/3.3V可调、微处理器监控电路, 微处理器监控电路, 提供备用...

  • 604.40KB

  • 20页

  • MAXIM

扫码查看芯片数据手册

上传产品规格书

PDF预览

3.0V/3.3V Adjustable Microprocessor
Supervisory Circuits
V
CC
V
CC
BATT
3.6V
pulled to V
CC
. Use LOWLINE to provide an NMI to the
碌P when power begins to fall.
In most battery-operated portable systems, reserve
energy in the battery provides ample time to complete
the shutdown routine once the low-line warning is
encountered and before reset asserts. If the system
must also contend with a more rapid V
CC
fall time, such
as when the main battery is disconnected or a high-
side switch is opened during normal operation, use
capacitance on the V
CC
line to provide time to execute
the shutdown routine (Figure 11).
50pF
C
L
*
MAX793/MAX794/MAX795
25鈩?EQUIVALENT
SOURCE IMPEDANCE
50鈩?CABLE
MAX793
MAX794
MAX795
CE IN
CE OUT
50鈩?/div>
50鈩?/div>
GND
*C
L
INCLUDES LOAD CAPACITANCE AND SCOPE PROBE CAPACITANCE.
Figure 9. CE Propagation Delay Test Circuit
through a voltage divider, with the power-fail compara-
tor output (PFO) providing the NMI to the 碌P (Figure
10). If there is no easy access to the unregulated sup-
ply, the LOWLINE output can be used to generate an
NMI to the 碌P (see
LOWLINE Output
section).
First, calculate the worst-case time required for the sys-
tem to perform its shutdown routine. Then, with the worst-
case shutdown time, the worst-case load current, and the
minimum low-line to reset threshold (V
LR
min), calculate
the amount of capacitance required to allow the shut-
down routine to complete before reset is asserted:
C
HOLD
> I
LOAD
x t
SHDN
/ V
LR
where I
LOAD
is the current being drained from the
capacitor, V
LR
is the low-line to reset threshold differ-
ence (V
LL
- V
RST
), and t
SHDN
is the time required for
the system to complete an orderly shutdown routine.
LOWLINE Output (MAX793/MAX794)
The low-line comparator monitors V
CC
with a threshold
voltage typically 45mV above the reset threshold (10mV
of hysteresis) for the MAX793, and 15mV above RESET
IN (4mV of hysteresis) for the MAX794. For normal
operation (V
CC
above the reset threshold), LOWLINE is
Power-Fail Comparator (MAX793/MAX794)
The MAX793/MAX794鈥檚 PFI input is compared to an
internal reference. If PFI is less than the power-fail
threshold (V
PFT
), PFO goes low. The power-fail com-
parator is intended for use as an undervoltage detector
to signal a failing power supply (Figure 12). However,
the comparator does not need to be dedicated to this
function because it is completely separate from the rest
of the circuitry.
UNREGULATED
SUPPLY
REGULATOR
3.0V OR 3.3V
3.0V OR 3.3V
REGULATOR
V
CC
C
HOLD
V
CC
LOWLINE
TO
碌P
NMI
R1
MAX793
MAX794
PFI
PFO
TO
碌P
NMI
C
HOLD
> I
LOAD
x t
SHDN
V
LR
MAX793
MAX794
R2
GND
GND
Figure 10. Using the Power-Fail Comparator to Generate
Power-Fail Warning
Figure 11. Using LOWLINE to Provide Power-Fail Warning
to the 碌P
13
______________________________________________________________________________________

MAX793T相关型号PDF文件下载

  • 型号
    版本
    描述
    厂商
    下载
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM [Max...
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM [Max...
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM [Max...
  • 英文版
    Low-Cost レP Supervisory Circuits with Battery Backup
    MAXIM
  • 英文版
    Low-Cost レP Supervisory Circuits with Battery Backup
    MAXIM [Max...
  • 英文版
    Low-Cost レP Supervisory Circuits with Battery Backup
    MAXIM
  • 英文版
    Low-Cost レP Supervisory Circuits with Battery Backup
    MAXIM [Max...
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM [Max...
  • 英文版
    +3V Voltage Monitoring, Low-Cost, レP Supervisory Circuits
    MAXIM
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM [Max...
  • 英文版
    +3V Voltage Monitoring, Low-Cost, レP Supervisory Circuits
    MAXIM [Max...
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM [Max...
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM
  • 英文版
    Low-Cost, uP Supervisory Circuits
    MAXIM [Max...
  • 英文版
    Power-Supply Monitor with Reset
    MAXIM

扫码下载APP,
一键连接广大的电子世界。

在线人工客服

买家服务:
卖家服务:

0571-85317607

客服在线时间周一至周五
9:00-17:30

关注官方微信号,
第一时间获取资讯。

建议反馈

联系人:

联系方式:

按住滑块,拖拽到最右边
>>
感谢您向阿库提出的宝贵意见,您的参与是维库提升服务的动力!意见一经采纳,将有感恩红包奉上哦!