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| 型号： | ADM8690ANZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 11/24页 |
| 文件大小： | 0K |
| 描述： | IC SUPERVISOR MPU 4.65V 8DIP |
| 标准包装： | 50 |
| 类型： | 备用电池电路 |
| 监视电压数目： | 1 |
| 输出： | 推挽式，图腾柱 |
| 复位： | 低有效 |
| 复位超时： | 最小为 35 ms |
| 电压 - 阀值： | 4.65V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-PDIP |
| 包装： | 管件 |
Data Sheet
CIRCUIT INFORMATION
BATTERY SWITCHOVER SECTION
The battery switchover circuit compares V CC to the V BATT
input and connects V OUT to whichever is higher. Switchover
occurs when V CC is 50 mV higher than V BATT as V CC falls, and
when V CC is 70 mV greater than V BATT as V CC rises. This 20 mV
hysteresis prevents repeated rapid switching if V CC falls very
slowly or remains nearly equal to the battery voltage.
ADM8690/ADM8691/ADM8695
If the battery switchover section is not used, V BATT should be
connected to GND and V OUT should be connected to V CC .
POWER-FAIL RESET OUTPUT
RESET is an active low output that provides a RESET signal to
the microprocessor whenever V CC is at an invalid level. When
V CC falls below the reset threshold, the RESET output is forced
low. The nominal reset voltage threshold is 4.65 V.
V CC
V OUT
V CC
V2
V1
V2
V1
V BATT
GATE DRIVE
100
mV
INTERNAL
SHUTDOWN SIGNAL
BATT ON
(ADM8691,
ADM8695)
RESET
LOW LINE
t 1
t 1
700
mV
WHEN
V BATT > (V CC + 0.7V)
t1 = RESET TIME
V1 = RESET VOLTAGE THRESHOLD LOW
V2 = RESET VOLTAGE THRESHOLD HIGH
Figure 14. Battery Switchover Schematic
During normal operation, with V CC higher than V BATT , V CC
is internally switched to V OUT through an internal PMOS tran-
sistor switch. This switch has a typical on resistance of 0.7 Ω
and can supply up to 100 mA at the V OUT terminal. V OUT is
normally used to drive a RAM memory bank, requiring
instantaneous currents of greater than 100 mA. If this is the
case, a bypass capacitor should be connected to V OUT . The
capacitor provides the peak current transients to the RAM.
A capacitance value of 0.1 μF or greater can be used.
If the continuous output current requirements at V OUT exceed
100 mA or if a lower V CC ? V OUT voltage differential is desired,
an external PNP pass transistor can be connected in parallel
(see Figure 24).
A 7 Ω MOSFET switch connects the V BATT input to V OUT during
battery backup. This MOSFET has very low input-to-output
differential (dropout voltage) at the low current levels required
for battery backup of CMOS RAM or other low power CMOS
circuitry. The supply current in battery backup is typically 0.4 μA.
The ADM8690 / ADM8691 / ADM8695 operate with battery
voltages from 2.0 V to 4.25 V. High value capacitors, either standard
electrolytic or the farad-size, double-layer capacitors, can also be
HYSTERESIS = V2 – V1
Figure 15. Power-Fail Reset Timing
On power-up, RESET remains low for 50 ms (200 ms for the
old. This allows time for the power supply and microprocessor
to stabilize. On power-down, the RESET output remains low
with V CC as low as 1 V. This ensures that the microprocessor is
held in a stable shutdown condition.
ADM8695 by using an external oscillator or by connecting an
The guaranteed minimum and maximum reset thresholds for
the ADM8690 / ADM8691 / ADM8695 are 4.5 V and 4.73 V. The
5 V supplies with a +10%, ?5% tolerance. The reset threshold
comparator typically has 40 mV of hysteresis. The response time
of the reset voltage comparator is less than 1 μs. If glitches are
present on the V CC line that could cause spurious reset pulses,
V CC should be decoupled close to the device.
In addition to RESET, the ADM8691 / ADM8695 provide an
active high RESET output. This output is the complement of
RESET and is intended for processors that require an active
high reset signal.
used for short-term memory backup. A small charging current
of typically 10 nA (0.1 μA maximum) flows out of the V BATT
terminal. This current is useful for maintaining rechargeable
batteries in a fully charged condition. This extends the life of the
backup battery by compensating for its self-discharge current.
Also note that this current poses no problem when lithium
batteries are used for backup because the maximum charging
current (0.1 μA) is safe for even the smallest lithium cells.
Rev. C | Page 11 of 24
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| ADM8690ARN | 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:1 系列:- 类型:简单复位/加电复位 监视电压数目:1 输出:开路漏极或开路集电极 复位:高有效 复位超时:- 电压 - 阀值:1.8V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:6-TSOP（0.059"，1.50mm 宽）5 引线 供应商设备封装:5-TSOP 包装:剪切带 (CT) 其它名称:NCP301HSN18T1GOSCT |
| ADM8690ARN-REEL | 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC TR RoHS:否 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:1 系列:- 类型:简单复位/加电复位 监视电压数目:1 输出:开路漏极或开路集电极 复位:高有效 复位超时:- 电压 - 阀值:1.8V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:6-TSOP（0.059"，1.50mm 宽）5 引线 供应商设备封装:5-TSOP 包装:剪切带 (CT) 其它名称:NCP301HSN18T1GOSCT |
| ADM8690ARNZ | 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 其它有关文件:STM6717 View All Specifications 标准包装:1 系列:- 类型:多压监控器 监视电压数目:2 输出:开路漏极或开路集电极 复位:低有效 复位超时:最小为 600 ms 电压 - 阀值:1.11V，3.075V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:Digi-Reel® 产品目录页面:1194 (CN2011-ZH PDF) 其它名称:497-7019-6 |
| ADM8691 | 制造商:AD 制造商全称:Analog Devices 功能描述:Microprocessor Supervisory Circuits |
| ADM8691AN | 制造商:Analog Devices 功能描述:Processor Supervisor 4.65V 4.75V to 5.5V 16-Pin PDIP 制造商:Rochester Electronics LLC 功能描述:IMPROVED ADM691 I.C. - Bulk 制造商:Analog Devices 功能描述:IC SUPERVISORY CCT 8691 DIP16 |
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