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參數(shù)資料
| 型號(hào)： | DS21Q48N |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Digital Transmission Interface |
| 英文描述： | DATACOM, PCM TRANSCEIVER, PBGA144 |
| 封裝： | BGA-144 |
| 文件頁(yè)數(shù)： | 12/16頁(yè) |
| 文件大小： | 296K |
| 代理商： | DS21Q48N |
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MAX863
Dual, High-Efficiency, PFM, Step-Up
DC-DC Controller
_______________________________________________________________________________________
5
_______________Detailed Description
The MAX863 dual, bi-CMOS, step-up, switch-mode
power-supply controller provides preset 3.3V, 5V, or
adjustable outputs. Its pulse-frequency-modulated
(PFM) control scheme combines the advantages of low
supply current at light loads and high efficiency with
heavy loads. These attributes make the MAX863 ideal
for use in portable battery-powered systems where
small size and low cost are extremely important, and
where low quiescent current and high efficiency are
needed to maximize operational battery life. Use of
external current-sense resistors and MOSFETs allows
the designer to tailor the output current and voltage
capability for a diverse range of applications.
PFM Control Scheme
Each DC-DC controller in the MAX863 uses a one-shot-
sequenced, current-limited PFM design, as shown in
Figure 1. Referring to the Typical Operating Circuit
(Figure 2) and the switching waveforms (Figures 3a–3f),
the circuit works as follows. Output voltage is sensed
by the error comparator using either an internal voltage
divider connected to SENSE1 or an external voltage
divider connected to FB1. When the output voltage
drops, the error comparator sets an internal flip-flop.
The flip-flop turns on an external MOSFET, which allows
inductor current to ramp-up, storing energy in a mag-
netic field.
______________________________________________________________Pin Description
PIN
Feedback Input for DC-DC Controller 1 in Fixed-Output Mode
SENSE1
1
FUNCTION
NAME
IC Power-Supply Input
VDD
2
Bootstrap Low-Voltage-Oscillator Enable Input. BOOT is an active-high, logic-level input. It enables the
low-voltage oscillator to allow start-up from input voltages down to 1.5V while in a bootstrapped circuit
configuration. Connect BOOT to GND when in a non-bootstrapped configuration. If BOOT is high, VDD
must be connected to OUT1.
BOOT
4
Adjustable Feedback and Preset Output Voltage Selection Input for DC-DC Controller 1. Connect to VDD
for 3.3V preset output or to GND for 5V output. Connect a resistor voltage divider to adjust the output volt-
age. See the section Set the Output Voltage.
FB1
3
Gate-Drive Output of DC-DC Controller 1. Drives an external N-channel power MOSFET.
EXT1
6
High-Current Ground Return for Internal MOSFET Drivers
PGND
8
Analog Ground for Internal Reference, Feedback, and Control Circuits
GND
7
Input to the Current-Sense Comparator of DC-DC Controller 1
CS1
5
Input to the Current-Sense Amplifier of DC-DC Controller 2
CS2
10
Adjustable Feedback Input for DC-DC Controller 2. Connect a resistor voltage divider to adjust the output
voltage. See the section Set the Output Voltage.
FB2
12
Active-Low Shutdown Input for DC-DC Controller 1. Connect to VDD for normal operation.
SHDN1
11
Low-Battery Comparator Input. When the voltage on LBI drops below 1.25V, LBO sinks current. If unused,
connect to GND.
LBI
14
Reference Bypass Input. Connect a 0.1F ceramic capacitor from REF to GND.
REF
16
Active-Low Shutdown Input for DC-DC Controller 2. Connect to VDD for normal operation.
SHDN2
15
Low-Battery Output. An open-drain N-channel MOSFET output. Sinks current when the voltage on LBI
drops below 1.25V. If unused, connect to GND.
LBO
13
Gate-Drive Output of DC-DC Controller 2. Drives an external N-channel power MOSFET.
EXT2
9
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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: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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