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參數(shù)資料
| 型號(hào)： | DS21Q48N |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類(lèi)： | Digital Transmission Interface |
| 英文描述： | DATACOM, PCM TRANSCEIVER, PBGA144 |
| 封裝： | BGA-144 |
| 文件頁(yè)數(shù)： | 16/16頁(yè) |
| 文件大?。?/td> | 296K |
| 代理商： | DS21Q48N |
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MAX863
Dual, High-Efficiency, PFM, Step-Up
DC-DC Controller
_______________________________________________________________________________________
9
Low-Voltage Start-Up Oscillator
(BOOT Pin)
The MAX863 features a low-voltage start-up oscillator
that guarantees start-up in bootstrapped configuration
down to 1.5V. At these low supply voltages, the error
comparator and internal biasing of the IC are locked
out. The low-voltage oscillator switches the external
MOSFET with around 30% duty cycle until the voltage
at VDD rises above 2.7V. At this point, the error com-
parator and one-shot timing circuitry turn on. The low-
voltage oscillator is enabled by connecting the BOOT
pin to VDD. When BOOT is high, VDD must be connect-
ed to VOUT1.
Use the start-up oscillator in the bootstrapped configu-
ration only, since the MAX863 operates in an open-loop
state while the start-up oscillator is active. When using
a non-bootstrapped circuit configuration, connect
BOOT to GND to disable the start-up oscillator. This
prevents the output from rising too high when VDD is
between 1.5V and 2.7V, such as during power-up and
low-battery conditions.
Bootstrapped/Non-Bootstrapped Modes
Figures 2 and 4 show standard applications in boot-
strapped and non-bootstrapped modes. In boot-
strapped mode, the IC is powered from the output (VDD
is connected to OUT1, BOOT is connected to VDD).
Bootstrapped-mode operation is useful for increasing
the gate drive to the MOSFETs in low-input-voltage
applications, since EXT1 and EXT2 swing from VDD to
GND. Increasing the gate-drive voltage reduces MOS-
FET on-resistance, which improves efficiency and
increases the load range. For supply voltages below
5V, bootstrapped mode is recommended. In boot-
strapped mode, the output connected to VDD must not
exceed 11V. If BOOT is high, VDD must be connect-
ed to OUT1.
In non-bootstrapped mode, the IC is powered by a
direct connection from the input voltage to VDD. Since
the voltage swing applied to the gate of the external
MOSFET is derived from VDD, the external MOSFET on-
resistance increases at low input voltages. The mini-
mum input voltage is 2.7V. For operation down to 4V,
use logic-level MOSFETs. For lower input voltages, use
low-threshold logic-level MOSFETs. When both output
voltages are set above 11V, non-bootstrapped mode is
mandatory.
MAX863
EXT2
CS2
VOUT2 = 24V
VOUT1 = 12V
VIN = 2.7V TO 11V
N1.B
IRF7301
C7
0.1
F
R4
56k
1%
C6
15pF
C5
22
F
35V
0.1
R2
100m
R3
1M
1%
N1.A
R1
50m
R7
100k
C1
100
F
16V
≤0.1
R8
1M
1%
R9
115k
1%
D1
MBRS340T3
R6
R5
C8
10pF
D2
MBRS140
L1
10
H
2A
L2
10
H
1A
C3
100
F
20V
≤0.1
C4
100
F
20V
≤0.1
C2
0.1
F
FB2
SHDN1
EXT1
CS1
LBO
LOW-BATTERY
DETECTOR OUTPUT
FB1
VDD
PGND
LBI
GND
BOOT
SENSE1
SHDN2
REF
ON/OFF
C10
270pF
C9
82pF
Figure 4b. Adjustable Non-Bootstrapped Typical Operating Circuit
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS21Q48NB | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray |
| DS21Q50 | 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:Quad E1 Transceiver |
| DS21Q50L | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad E1 Transceiver RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray |
| DS21Q50L+ | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad E1 Transceiver RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray |
| DS21Q50L-C01 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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