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参数资料
| 型号： | ADP1822ARQZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 12/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QSOP |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 720kHz |
| 电源电压： | 3.7 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 24-SSOP（0.154"，3.90mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 791 (CN2011-ZH PDF) |
| 配用： | ADP1822-EVAL-ND - BOARD EVALUATION FOR ADP1822 |
| 其它名称： | ADP1822ARQZ-R7DKR |
ADP1822
THEORY OF OPERATION
The ADP1822 is a versatile, economical, synchronous-rectified,
fixed frequency, voltage-mode, pulse-width modulated (PWM)
step-down controller capable of generating an output voltage as
low as 0.6 V. It is ideal for a wide range of high power applications,
such as DSP and processor core power in telecommunications,
medical imaging, and industrial applications. The ADP1822
controller runs from 3.7 V to 5.5 V and accepts a power input
voltage between 1.0 V and 24 V.
The ADP1822 includes circuitry to implement output voltage
margining and can track an external voltage, making it ideal for
high reliability applications with multiple dc-to-dc converters. It
operates at a fixed, internally set 300 kHz or 600 kHz switching
frequency that is controlled by the state of the FREQ input. The
high frequency reduces external component size and cost while
maintaining high efficiency. For noise sensitive applications
where the switching frequency needs to be more tightly con-
trolled, synchronize the ADP1822 to an external signal whose
frequency is between 300 kHz and 1.2 MHz.
The ADP1822 includes adjustable soft start with output reverse-
current protection, and a unique, adjustable, lossless current limit.
It operates over the ?40°C to +125°C junction temperature
range and is available in a space-saving, 24-lead QSOP package.
CURRENT-LIMIT SCHEME
The ADP1822 employs a unique, programmable cycle-by-cycle
lossless current-sensing scheme that uses an inexpensive
resistor to set the current limit. A 50 μA current source is forced
out of CSL to a programming resistor connected to SW. The
resulting voltage across the current sense resistor sets the
current-limit threshold. When on-state voltage of the low-side
MOSFET synchronous rectifier exceeds the programmed
threshold, the low-side MOSFET remains on, preventing
another on cycle and reducing the inductor current. Once the
MOSFET voltage, and thus the inductor current, is below the
current-sense threshold, the synchronous rectifier is allowed to
turn off, and another cycle begins.
When the ADP1822 senses an overcurrent condition, SS sinks
current from the soft start capacitor through an internal 2.5 k?
resistor, reducing the voltage at SS and thus reducing the regulated
output voltage. The output behaves like a constant current source
around the preset current limit in the event of an overcurrent
condition. The ADP1822 remains in this mode for as long as
the overcurrent condition persists. When the overcurrent
condition is removed, operation resumes in soft start mode.
This ensures that when the overload condition is removed, the
output voltage smoothly transitions back to regulation while
providing protection for overload and short-circuit conditions.
Data Sheet
OUTPUT VOLTAGE MARGINING
The ADP1822 features output voltage margining. MAR enables
voltage margining, and MSEL controls whether the voltage is
margined up or down.
The voltage is margined by switching a resistor from FB to GND
(for the high margin) or from FB to the output voltage (for the
low margin). The switches from FB are internal to the ADP1822
through the MUP and MDN terminals. Table 4 shows the states
of MAR and MSEL and the resulting voltage margin setting. See
the Setting the Voltage Margin section for more information.
Table 4. Voltage Margining Control
MSEL MAR Voltage Margin
X L None (FB not changed)
H H High margin (FB connected to MUP)
L H Low margin (FB connected to MDN)
OUTPUT VOLTAGE TRACKING
The ADP1822 features an internal comparator that forces the
output voltage to track an external voltage at startup, which
prevents the output voltage from exceeding the tracking voltage.
The comparator turns off the high-side switch if the positive
tracking (TRKP) input voltage exceeds the negative tracking
(TRKN) input voltage. Connect TRKP to the output voltage and
drive TRKN with the voltage to be tracked. If the voltage at
TRKN is below the regulation voltage, the output voltage is
limited to the voltage at TRKN. If the voltage at TRKN is above
the regulation voltage, the output voltage regulates the desired
voltage set by the voltage divider. For more information, see the
SOFT START
When powering up or resuming operation after shutdown,
overload, or short-circuit conditions, the ADP1822 employs an
adjustable soft start feature that reduces input current transients
and prevents output voltage overshoot at start-up and overload
conditions. The soft start period is set by the value of the soft
start capacitor, C SS , between SS and GND.
When starting the ADP1822, C SS is initially discharged. It is
enabled by either driving SHDN high or by bringing VCC
above the undervoltage lockout threshold, and C SS begins
charging to 0.8 V through an internal 100 k? resistor. As C SS
charges, the regulation voltage at FB is limited to the lesser of
either the voltage at SS or the internal 0.6 V reference voltage.
As the voltage at SS rises, the output voltage rises proportionally
until the voltage at SS exceeds 0.6 V. At this time, the output
voltage is regulated to the desired voltage.
The ADP1822 also offers a technique for implementing a
current limit foldback in the event of a short circuit with the use
section for more information.
Rev. D | Page 12 of 24
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1822-BL1-EVZ | 制造商:Analog Devices 功能描述:Evaluation Board For PWM, Step-Down DC-To-DC Controller With Margining And Tracking 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1822 - Boxed Product (Development Kits) |
| ADP1822-BL2-EVZ | 制造商:Analog Devices 功能描述:Evaluation Board For PWM, Step-Down DC-To-DC Controller With Margining And Tracking 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1822 - Boxed Product (Development Kits) |
| ADP1822-EVAL | 功能描述:BOARD EVALUATION FOR ADP1822 RoHS:否 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 |
| ADP1823 | 制造商:AD 制造商全称:Analog Devices 功能描述:Dual, Interleaved, Step-Down DC-to-DC Controller with Tracking |
| ADP1823ACPZ | 制造商:Analog Devices 功能描述:IC CONTROLLER STEP DOWN DUAL SMD |
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