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参数资料
| 型号： | MAX6737XKZWD7-T |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 电源管理 |
| 英文描述： | Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| 封装： | EIAJ, SC-70, 5 PIN |
| 文件页数： | 4/16页 |
| 文件大小： | 658K |
| 代理商： | MAX6737XKZWD7-T |
MAX6736–MAX6745
Low-Power Dual-/Triple-Voltage SC70 P
Supervisory Circuits
12
______________________________________________________________________________________
Adding Hysteresis to the
Power-Fail Comparator
The power-fail comparator has a typical input hystere-
sis of 2.5mV. This is sufficient for most applications in
which a power-supply line is being monitored through
an external voltage-divider. If additional noise margin is
desired, connect a resistor between PFO and PFI, as
shown in Figure 6. Select the values of R1, R2, and R3
such that PFI sees VTH-PFI (488mV) when VEXT falls to
its power-fail trip point (VFAIL) and when VEXT rises to
its power-good trip point (VGOOD). The hysteresis win-
dow extends between the specified VFAIL and VGOOD
thresholds. R3 adds the additional hysteresis by sink-
ing current from the R1/R2 divider network when the
PFO output is logic low and sourcing current into the
network when PFO is logic high. R3 is typically an order
of magnitude greater than R1 or R2.
The current through R2 should be at least 1A to ensure
that the 10nA (max) PFI input current does not significant-
ly shift the trip points. Therefore, for most applications:
R2 < VTH-PFI / 1mA < 0.488V / 1mA < 488k
PFO is an open-drain output requiring an external
pullup resistor, R4. Select R4 to be less than 1% of R3.
VGOOD = DESIRED VEXT GOOD VOLTAGE THRESHOLD
VFAIL = DESIRED VEXT FAIL VOLTAGE THRESHOLD
VPU = VPULLUP (FOR OPEN-DRAIN PFO)
R2 = 488k
(FOR >1A R2 CURRENT)
R3 = (R1 x VPU) / (VGOOD - VFAIL)
R4
≤ 0.01 x R3
Power Sequencing Applications
Many dual-voltage processors/ASICs require specific
power-up/power-down sequences for the I/O and core
supplies.
RR
VV
V
GOOD
TH PFI
GOOD
FAIL
PU
TH
PFI
12
=
() ()
-
(
MAX6742
MAX6745
PFI
GND
VEXT_TH
A) VIN IS POSITIVE
R1
R2
PFO
VEXT_TH = VTH-PFI
R1 + R2
R2
()
MAX6742
MAX6745
PFI
GND
VEXT_TH
VCC
B) VIN IS NEGATIVE
R1
R2
PFO
VEXT_TH = R2
1
R1
1
R2
VCC
R1
+
(
()
)
-
(VTH-PFI)
VPFI = 488mV
Figure 4. Using Power-Fail Input to Monitor an Additional
Power Supply
MAX6737
MAX6739
MAX6743
MAX6744
MAX6745
GND
VCC1VCC2
VCC2
VCC1
RESET
RESET TO OTHER SYSTEM COMPONENTS
RESET
P
4.7k
Figure 5. Interfacing to Ps with Bidirectional Reset I/O
MAX6742
MAX6745
VEXT
R1
R4
R3
R2
PFI
GND
PFO
VGOOD = DESIRED VEXT GOOD VOLTAGE THRESHOLD
VFAIL = DESIRED VEXT FAIL VOLTAGE THRESHOLD
VOH = VCC1 (FOR PUSH-PULL PFO)
R2 = 200k
(FOR > 2.5A R2 CURRENT)
R1 = R2 ((VGOOD - VTH-PFI) - (VTH-PFI)(VGOOD - VFAIL) / VPU) / VTH-PFI
R3 = (R1 x VOH) / (VGOOD - VFAIL)
VGOOD
VFAIL
VIN
PFO
VPULLUP
Figure 6. Adding Hysteresis to Power Fail for Push-Pull PFO
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6738XKLD3 | 制造商:Maxim Integrated Products 功能描述:LOW-POWER DUAL-/TRIPLE-VOLTAGE SC70 - Rail/Tube |
| MAX6738XKLD3+ | 制造商:Maxim from Components Direct 功能描述:MAXIM MAX6738XKLD3+ PROCESSOR SUPERVISORS - Boxed Product (Development Kits) 制造商:Maxim Integrated Products 功能描述:LOW-POWER DUAL-/TRIPLE-VOLTAGE SC70 ?P SUPERVISORY CIRCUITS - Rail/Tube 制造商:Maxim 功能描述:Maxim MAX6738XKLD3+ Processor Supervisors |
| MAX6738XKLD3+T | 功能描述:监控电路 Fixed, R/C Adj A-Low O-Drain 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 |
| MAX6738XKLD3-T | 功能描述:监控电路 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 |
| MAX6738XKLD7 | 制造商:Maxim Integrated Products 功能描述:LOW-POWER DUAL-/TRIPLE-VOLTAGE SC70 - Rail/Tube |
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