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參數資料
| 型號： | ADM1085 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Simple Sequencers in 6-Lead SC70 |
| 中文描述： | 簡單排序6引腳SC70 |
| 文件頁數： | 13/16頁 |
| 文件大小： | 299K |
| 代理商： | ADM1085 |
ADM1085/ADM1086/ADM1087/ADM1088
DUAL LOFO SEQUENCING
A power sequencing solution for a portable device, such as a
PDA, is shown in Figure 27. This solution requires that the
microprocessor’s power supply turn on before the LCD display
turns on, and that the LCD display power-down before the
microprocessor powers down. In other words, the
last
power
supply to turn
on
is the
first
one to turn
off
(LOFO).
Rev. 0 | Page 13 of 16
An RC network connects the battery and the SD input of the
ADP3333 voltage regulator. This causes power-up and power-
down transients to appear at the SD input when the battery is
connected and disconnected. The 3.3 V microprocessor supply
turns on quickly on power-up and turns off slowly on power-
down. This is due to two factors: Capacitor C1 charges up to 9 V
on power-up and charges down from 9 V on power-down, and
the SD pin has logic-high and logic-low input levels of 2 V and
0.4 V.
For the display power sequencing, the ADM1085 is equipped
with capacitor C2, which creates the delay between the micro-
processor and display power turning on. When the system is
powered down, the ADM1085 turns off the display power
immediately, while the 3.3 V regulator waits for C1 to discharge
to 0.4 V before switching off.
0
ADM1086
ENOUT
3.3V
C2
ENIN
CEXT
V
IN
C1
DISPLAY
POWER
ADP3333
5V
SD
9V
MICROPROCESSOR
POWER
ADP3333
2.5V
SD
9V
9V
SYSTEM
POWER SWITCH
SYSTEM
POWER
9V
0V
9V
0V
2.5V
0V
5V
0V
V
C1
MICROPROCESSOR
POWER
DISPLAY
POWER
Figure 27. Dual LOFO Power-Supply Sequencing
SIMULTANEOUS ENABLING
The enable output can drive multiple enable or shutdown
regulator inputs simultaneously.
0
3.3V
ADP3333
IN
OUT
SD
ADM1085
V
CC
ENOUT
3.3V
3.3V
ENIN
CEXT
V
IN
2.5V
ADP3333
IN
OUT
SD
ENABLE
CONTROL
12V
1.8V
ADP3333
IN
OUT
SD
12V
Figure 28. Enabling a Pair of Regulators from a Single ADM1085
POWER GOOD SIGNAL DELAYS
Sometimes sequencing is performed by asserting Power Good
signals when the voltage regulators are already on, rather than
sequencing the power supplies directly. In these scenarios, a
simple sequencer IC can provide variable delays so that
enabling separate circuit blocks can be staggered in time.
For example, in a notebook PC application, a dedicated
microcomputer asserts a Power Good signal for North Bridge
and South Bridge ICs. The ADM1086 delays the south bridge’s
signal, so that it is enabled after the north bridge.
0
ADM1086
SOUTH
BRIDGE
IC
ENOUT
EN
5V
ENIN
CEXT
V
IN
NORTH
BRIDGE
IC
EN
5V
MICROCOMPUTER
5V
3.3V
POWER_GOOD
Figure 29. Power Good Delay
相關PDF資料 |
PDF描述 |
|---|---|
| ADM1085AKS-REEL7 | Simple Sequencers in 6-Lead SC70 |
| ADM1086 | Simple Sequencers in 6-Lead SC70 |
| ADM1086AKS-REEL7 | Simple Sequencers in 6-Lead SC70 |
| ADM1087 | Simple Sequencers in 6-Lead SC70 |
| ADM1087AKS-REEL7 | Simple Sequencers in 6-Lead SC70 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ADM1085AKS-REEL7 | 制造商:Rochester Electronics LLC 功能描述:SIMPLE SEQUENCER OPEN DRAIN EN IC - Tape and Reel 制造商:Analog Devices 功能描述:IC VOLTAGE SEQUENCER |
| ADM1085AKS-U1 | 制造商:Analog Devices 功能描述:- Bulk |
| ADM1085AKSZ-REEL7 | 功能描述:IC SIMPLE SEQUENCER OD SC70-6 RoHS:是 類別:集成電路 (IC) >> PMIC - 監控器 系列:Simple Sequencers® 標準包裝:100 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極，開路漏極 復位:高有效/低有效 復位超時:最小為 250 ms 電壓 - 閥值:4.37V，4.62V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:8-SOIC 包裝:管件 產品目錄頁面:1337 (CN2011-ZH PDF) |
| ADM1085AKSZ-REEL7 | 制造商:Analog Devices 功能描述:IC VOLT SEQUENCER 10A 3.6V SC-70-6 |
| ADM1085AKSZ-REEL7CT-ND | 制造商:Analog Devices 功能描述:IC SIMPLE SEQUENCER OD SC70-6NIC* |
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