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参数资料
| 型号： | ADP2126-1.2-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 12/20页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR ADP2126 1.2VOUT |
| 标准包装： | 1 |
| 系列： | * |
ADP2126/ADP2127
SPREAD SPECTRUM OSCILLATOR
The ADP2126 / ADP2127 incorporate spread spectrum
functionality to modulate electromagnetic interference (EMI)
for EMI sensitive applications. A typical switching converter
with a regulated switching frequency has a narrow frequency
spectrum centered at the target switching frequency. This
results in a high spectral density around the target frequency
with peak emission levels that can exceed the regulatory levels
for EMI in many portable, cellular, and wireless applications.
To maintain acceptable levels of EMI, the ADP2126/ADP2127
employs spread spectrum via a controlled variance of the switching
frequency over a wider band of frequencies. Figure 25 shows the
variance of the frequency over time. This distribution of the
frequency content spreads the spectral density over a wider
bandwidth, resulting in lower peak emission levels.
MODE SELECTION
The ADP2126/ADP2127 have two modes of operation (PWM
mode and auto mode), determined by the state of the MODE pin.
Pull the MODE pin high to force the converter to operate in
PWM mode, regardless of the output current. Otherwise, set
MODE low to put the converter into auto mode and allow the
converter to automatically transition from PWM mode to the
power-saving PFM mode at light load currents. Do not leave
this pin floating.
Pulse-Width Modulation (PWM) Mode
The PWM mode forces the part to maintain a fixed frequency
of 6 MHz (maximum) under all load conditions. The ADP2126/
ADP2127 use a proprietary, hybrid voltage-mode control scheme
to control the duty cycle under all load current and line voltage
variations. This control scheme provides excellent stability,
transient response, and output regulation. PWM mode results
in lower efficiencies at light load currents.
Auto Mode (PFM and PWM Switching)
Auto mode is a power-saving feature that enables the converter
to switch between PWM and PFM in response to the output
load. Auto mode is enabled when the MODE pin is pulled low.
In auto mode, the ADP2126/ADP2127 operate in PFM mode for
light load currents and switch to PWM mode for medium and
heavy load currents.
Pulse Frequency Modulation (PFM) Mode
When the converter is operating under light load conditions,
the effective switching frequency and supply current are decreased
Data Sheet
When the upper level is reached, the output stage and most
control circuitry turn off to reduce the quiescent current. During
this stage, the output capacitor supplies the current to the load.
As the output capacitor discharges and the output voltage reaches
the lower PFM comparator threshold, switching resumes and the
process repeats.
Mode Transition
When the MODE pin is low, the converter switches between
PFM and PWM modes automatically to maintain optimal
transient response and efficiency. The mode transition point
depends on the input voltage. Hysteresis exists in the transition
point to prevent instability and decreased efficiencies that could
result if the converter were able to oscillate between PFM and
PWM for a fixed input voltage and load current. See Figure 9 for
the typical PFM and PWM mode boundaries of the
ADP2126/ADP2127.
A switch from PFM to PWM occurs when the output voltage dips
below the nominal value of the output voltage option. Switching
to PWM allows the converter to maintain efficiency and supply
a larger current to the load. The output voltage in PFM mode is
slightly higher to keep the ADP2126/ADP2127 from oscillating
between modes, ensuring stable operation.
The switch from PWM to PFM occurs when the output current
is below the PFM threshold for multiple consecutive switching
cycles. Switching to PFM allows the converter to save power by
supplying the lighter load current with fewer switching cycles.
INTERNAL CONTROL FEATURES
Synchronous Rectification
In addition to the P-channel MOSFET switch, the ADP2126/
ADP2127 include an N-channel MOSFET switch to build the
synchronous rectifier. The synchronous rectifier improves
efficiency, especially for small load currents, and reduces cost
and board space by eliminating the need for an external rectifier.
Soft Start
To prevent excessive input inrush current at startup, the ADP2126/
ADP2127 operate with an internal soft start. When EXTCLK
begins to oscillate, or when the part recovers from a fault (UVLO,
TSD, or SCP), a soft start timer begins. During this time, the
peak current limit is gradually increased to its maximum. The
output voltage increases in stages to ensure that the converter is
able to start up effectively and in proper sequence. After the soft
start period expires, the peak PMOS switch current limit remains
at 1 A (typical), and the part begins normal operation.
and varied using PFM to regulate the output voltage. This results in
improved efficiencies and lower quiescent currents. In PFM mode,
the converter only switches when necessary to keep the output
voltage within the PFM limits set by an internal comparator.
Switching stops when the upper limit is reached and resumes
when the lower limit is reached.
Rev. B | Page 12 of 20
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| ADP2126ACDZ-1.20R7 | 功能描述:IC REG BUCK SYNC 1.2V 0.5A DIE RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:High Efficiency Current Mode Switching Regulators CMOS LDO Regulators 特色产品:BD91x Series Step-Down Regulators 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:2 输出电压:3.3V，0.8 V ~ 2.5 V 输入电压:4.5 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:1MHz 电流 - 输出:1.5A 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:20-VFQFN 裸露焊盘 包装:带卷 (TR) 供应商设备封装:VQFN020V4040 产品目录页面:1373 (CN2011-ZH PDF) 其它名称:BD9152MUV-E2TR |
| ADP2127 | 制造商:AD 制造商全称:Analog Devices 功能描述:Ultralow Profile, 500 mA, 6 MHz, Synchronous, Step-Down, DC-to-DC Converters |
| ADP2127-1.26-EVALZ | 功能描述:BOARD EVAL FOR ADP2127 1.2VOUT RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ADP2127ACNZ-1.20R7 | 功能描述:IC REG BUCK SYNC 1.2V 0.5A 6EWLP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:500 系列:- 类型:切换式电容器（充电泵），反相 输出类型:固定 输出数:1 输出电压:-3V 输入电压:2.3 V ~ 5.5 V PWM 型:Burst Mode? 频率 - 开关:900kHz 电流 - 输出:100mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 细型，TSOT-23-6 包装:带卷 (TR) 供应商设备封装:TSOT-23-6 其它名称:LTC1983ES6-3#TRMTR |
| ADP2127ACNZ1.260R7 | 功能描述:IC REG BUCK SYNC 1.26V .5A 6EWLP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:High Efficiency Current Mode Switching Regulators CMOS LDO Regulators 特色产品:BD91x Series Step-Down Regulators 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:2 输出电压:3.3V，0.8 V ~ 2.5 V 输入电压:4.5 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:1MHz 电流 - 输出:1.5A 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:20-VFQFN 裸露焊盘 包装:带卷 (TR) 供应商设备封装:VQFN020V4040 产品目录页面:1373 (CN2011-ZH PDF) 其它名称:BD9152MUV-E2TR |
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