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参数资料
| 型号： | MAX6887QETE |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 电源管理 |
| 英文描述： | Hex/Quad, Power-Supply Supervisory Circuits |
| 中文描述： | 6-CHANNEL POWER SUPPLY MANAGEMENT CKT, QCC16 |
| 封装： | 5 X 5 MM, 0.80 MM HEIGHT, MO-220WHHB, TQFN-16 |
| 文件页数： | 11/13页 |
| 文件大小： | 132K |
| 代理商： | MAX6887QETE |
MAX6887/MAX6888
Hex/Quad, Power-Supply Supervisory Circuits
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7
Detailed Description
The MAX6887/MAX6888 provide several supply-detector
inputs, one watchdog input, and three outputs for power-
supply monitoring applications. The MAX6887 offers six
voltage-detector inputs, while the MAX6888 offers four.
Each voltage-detector input offers both an undervoltage
and overvoltage threshold.
The undervoltage and overvoltage thresholds are facto-
ry-set for monitoring standard supply voltages (see the
Selector Guide). Inputs in the Selector Guide that con-
tain “Adj” allow an external voltage-divider to be con-
nected to set a user-defined threshold.
RESET goes low when any input voltage drops below
its undervoltage threshold or when MR is brought low.
RESET stays low for 200ms after all assertion-causing
conditions have been cleared. OV goes low when an
input voltage rises above its overvoltage threshold. OV
typically stays low for 25s (typ) after all inputs fall
back under their overvoltage thresholds.
The MAX6887/MAX6888 offer a watchdog timer with
initial and normal timeout periods of 102.4s and 1.6s,
respectively. WDO goes low when the watchdog timer
expires and deasserts when WDI transitions from low-
to-high or high-to-low.
Powering the MAX6887/MAX6888
The MAX6887/MAX6888 derive power from the voltage-
detector inputs IN1–IN4 or through an externally sup-
plied VCC. A virtual diode-ORing scheme selects the
positive input that supplies power to the device (see
the
Functional Diagram). The highest input voltage on
IN1–IN4 supplies power to the device. One of IN1–IN4
must be at least 2.7V to ensure proper operation.
Internal hysteresis ensures that the supply input that
initially powered the device continues to power the
device when multiple input voltages are within 50mV of
each other.
VCC powers the analog circuitry and is the bypass con-
nection for the MAX6887/MAX6888 internal supply.
Bypass VCC to GND with a 1F ceramic capacitor
installed as close to the device as possible. The inter-
nal supply voltage, measured at VCC, equals the maxi-
mum of IN1–IN4. If VCC is externally supplied, VCC
must be at least 200mV higher than any voltage
applied to IN1–IN4 and VCC must be brought up first.
VCC always powers the device when all IN_ are factory
set as “Adj.” Do not use the internally generated VCC to
provide power to external circuitry.
The MAX6887/MAX6888 generate a supply voltage at
BP for the internal logic circuitry. Bypass BP to GND with
a 1F ceramic capacitor installed as close to the device
as possible. The nominal BP output voltage is +2.55V.
Do not use BP to provide power to external circuitry.
Inputs
The MAX6887 offers six voltage-detector inputs, while
the MAX6888 offers four voltage-detector inputs. Each
voltage-detector input offers an undervoltage and over-
voltage threshold set at the factory to monitor standard
supply voltages (see the
Selector Guide). The 5% and
10% tolerances are based on maximum and minimum
threshold
values.
Actual
thresholds
for
the
MAX6887/MAX6888 are shown in Tables 1 and 2.
Inputs in the
Selector Guide listing “Adj” allow an exter-
nal voltage-divider to be connected to set a user-
defined threshold.
Adjustable Threshold Inputs
Inputs listed in the
Selector Guide containing “Adj” for
inputs allow external resistor voltage-dividers to be
connected at the voltage-detector inputs. These inputs
monitor any voltage supply higher than 0.6V (see
Figure 1). Use the following equation to set a voltage-
MAX6887
MAX6888
VIN
IN_
R1
R2
*VREFUV
*VREFOV AND VREFUV ARE REFERENCED
TO 0.6V ACCORDING TO THE DEVICE'S TOLERANCE
*VREFOV
Figure 1. Adjusting the Monitored Threshold
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PDF描述 |
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| MAX6887QETE-T | Hex/Quad, Power-Supply Supervisory Circuits |
| MAX6887RETE | Hex/Quad, Power-Supply Supervisory Circuits |
| MAX6887RETE-T | Hex/Quad, Power-Supply Supervisory Circuits |
| MAX6888AETE | Hex/Quad, Power-Supply Supervisory Circuits |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6887QETE+ | 功能描述:监控电路 Hex Power-Supply Supervisor 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 |
| MAX6887QETE+T | 功能描述:监控电路 Hex Power-Supply Supervisor 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 |
| MAX6887QETE-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 |
| MAX6887RETE | 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 |
| MAX6887RETE+ | 功能描述:监控电路 Hex Power-Supply Supervisor 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 |
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