參數(shù)資料
型號: MAX792R
廠商: Maxim Integrated Products, Inc.
英文描述: Microprocessor and Non-Volatile Memory Supervisory Circuits(復位門限2.61V,微處理器和非易失存儲器監(jiān)控電路)
中文描述: 微處理器及非易失存儲器監(jiān)控電路
文件頁數(shù): 14/16頁
文件大小: 182K
代理商: MAX792R
M
Mic roproc essor and Non-Volatile
Memory S upervisory Circ uits
14
______________________________________________________________________________________
Alternative Chip-Enable Gating
Using memory devices with both CE and
CE
inputs
allows the MAX792/MAX820 CE propagation delay
to be bypassed. To do this, connect
CE
IN to ground,
pull up
CE
OUT to V
CC
, and connect
CE
OUT to the
CE
input of each memory device (Figure 11). The CE input
of each memory device then connects directly to the
chip-select logic, which does not have to be gated by
the MAX792/MAX820.
Interfac ing to μPs with Bidirec tional
Reset Inputs
μPs with bidirectional reset pins, such as the Motorola
68HC11 series, can contend with the MAX792/MAX820
RESET
output. If, for example, the MAX792/MAX820
RESET
output is asserted high and the μP wants to pull it
low, indeterminate logic levels may result. To avoid
this, connect a 4.7k
resistor between the
MAX792/MAX820
RESET
output and the μP reset I/O, as
in Figure 12. Buffer the MAX792/MAX820
RESET
output
to other system components.
Negative-Going V
CC
T ransients
While issuing resets to the μP during power-up, power-
down, and brownout conditions, these supervisors are
relatively immune to short-duration negative-going V
CC
transients (glitches). It is usually undesirable to reset
the μP when V
CC
experiences only small glitches.
Figure 13 shows maximum transient duration vs. reset-
comparator overdrive, for which reset pulses are
not
generated. The graph was produced using negative-
going V
CC
pulses, starting at 5V and ending below the
reset threshold by the magnitude indicated (reset-
comparator overdrive). The graph shows the maximum
pulse width a negative-going V
CC
transient may typi-
cally have without causing a reset pulse to be issued.
As the amplitude of the transient increases (i.e., goes
farther below the reset threshold), the maximum allow-
able pulse width decreases. Typically, a V
CC
transient
that goes 100mV below the reset threshold and lasts for
30μs or less will not cause a reset pulse to be issued.
A 100nF bypass capacitor mounted close to the V
CC
pin provides additional transient immunity.
MAX792
MAX820
CE IN
13
14
12
+5V
GND
3
V
CC
CE OUT
CE
CE
CE
CE
CE
CE
CE
CE
RAM 1
RAM 2
RAM 3
RAM 4
ACTIVE-HIGH CE
LINES FROM LOGIC
MAXIMUM R
VALUE DEPENDS ON
THE NUMBER OF RAMS.
MINIMUM R
P
VALUE IS 1k
*
R
P
*
Figure 11. Alternate CE Gating
V
CC
V
CC
V
CC
μ
P
BUFFER
TOOTHER
SYSTEM RESET
INPUTS
4.7k
1
RESET
RESET
GND
GND
12
MAX792
MAX820
3
Figure 12. Interfacing to μPs with Bidirectional
RESET
Pins
Figure 13. Maximum Transient Duration without Causing a
Reset Pulse vs. Reset-Comparator Overdrive
100
0
10
100
10,000
40
20
80
60
M
RESET COMPARATOR OVERDRIVE, (V
TH
- V
CC
) (mV)
M
1000
V
CC
= 5V
T
A
= +25°C
相關(guān)PDF資料
PDF描述
MAX792S Microprocessor and Non-Volatile Memory Supervisory Circuits(復位門限1.91V,微處理器和非易失存儲器監(jiān)控電路)
MAX792T Microprocessor and Non-Volatile Memory Supervisory Circuits(復位門限3.06V,微處理器和非易失存儲器監(jiān)控電路)
MAX793 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits(具有監(jiān)控器、芯片使能和支持備用電池的復位器)
MAX794 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits(具有可調(diào)閾值監(jiān)控器、芯片使能和支持備用電池的復位器)
MAX796 Step-Down Controllers with Synchronous Rectifier for CPU Power(3.3V/5V/可調(diào),帶有同步整流器的PWM步降控制器,用于筆記本電腦)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX792RC/D 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX792RCPE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX792RCPE+ 功能描述:監(jiān)控電路 MPU & NV Memory Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX792RCSE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX792RCSE+ 功能描述:監(jiān)控電路 MPU & NV Memory Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel