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| 型号： | MAX1843ETI+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/13页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 2.7A 28TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 类型： | 降压（降压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 1.5V，1.8V，2.5V，可调 |
| 输入电压： | 3 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 2.7A |
| 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： | 28-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
2.7A, 1MHz, Low-Voltage, Step-Down Regulator with
Synchronous Rectification in TQFN Package
Pin Description
PIN
1, 5, 10,
11, 12,
22, 24,
26, 28
2, 4
3, 18, 19,
23, 25
6
7
8
9
13, back-
side pad
14
15
16
17, 20, 21
27
NAME
N.C.
IN
LX
SS
COMP
TOFF
FB
GND
REF
FBSEL
V CC
PGND
SHDN
FUNCTION
Not Internally Connected
Supply Voltage Input—for the Internal pMOS Power Switch
Connection for the Drains of the pMOS Power Switch and nMOS Synchronous-Rectifier Switch. Connect
the inductor from this node to the output filter capacitor and load.
Soft-Start. Connect a capacitor from SS to GND to limit inrush current during startup.
Integrator Compensation. Connect a capacitor from COMP to V CC for integrator compensation. See
Integrator Amplifier section.
Off-Time Select Input. Sets the pMOS power switch off-time during constant-off-time operation. Connect a
resistor from TOFF to GND to adjust the PMOS switch off-time.
Feedback Input—for Both Preset-Output and Adjustable-Output Operating Modes. Connect directly to
output for fixed-voltage operation or to a resistive divider for adjustable operating modes.
Analog Ground. Connect exposed backside pad to pin 13.
Reference Output. Bypass REF to GND with a 1μF capacitor.
Feedback Select Input. Selects output voltage. See Table 2 for programming instructions.
Analog Supply Voltage Input. Supplies internal analog circuitry. Bypass V CC with a 10 ? and 2.2μF lowpass
filter. See Figure 1.
Power Ground. Internally connected to the internal nMOS synchronous-rectifier switch.
Shutdown Control Input. Drive SHDN low to disable the reference, control circuitry, and internal
MOSFETs. Drive high or connect to V CC for normal operation.
Detailed Description
The MAX1843 synchronous, current-mode, constant-off-
time, PWM DC-DC converter steps down input voltages
of +3V to +5.5V to a preset output voltage of +2.5V,
+1.8V, or +1.5V, or to an adjustable output voltage from
+1.1V to V IN . It delivers up to 2.7A of output current.
Internal switches composed of a 0.09 ? pMOS power
switch and a 0.07 ? nMOS synchronous-rectifier switch
improve efficiency, reduce component count, and elimi-
nate the need for an external Schottky diode.
The MAX1843 optimizes efficiency by operating in con-
stant-off-time mode under heavy loads and in Maxim’s
proprietary idle mode under light loads. A single resistor-
programmable constant-off-time control sets switching
frequencies up to 1MHz, allowing the user to optimize
performance trade-offs in efficiency, switching noise,
component size, and cost. Under low-dropout conditions,
the device operates in a 100% duty-cycle mode, where
the pMOS switch remains continuously on. Idle mode
enhances light-load efficiency by skipping cycles, thus
reducing transition and gate-charge losses.
When power is drawn from a regulated supply, constant-
off-time PWM architecture essentially provides constant-
frequency operation. This architecture has the inherent
advantage of quick response to line-and-load transients.
The MAX1843’s current-mode, constant-off-time PWM
architecture regulates the output voltage by changing
the pMOS switch on-time relative to the constant off-
time. Increasing the on-time increases the peak induc-
tor current and the amount of energy transferred to the
load per pulse.
Modes of Operation
The current through the pMOS switch determines the
mode of operation: constant-off-time mode (for load
currents greater than half the Idle Mode threshold, of
idle mode), or idle mode (for load currents less than
half the Idle-Mode threshold). Current sense is
achieved through a proprietary architecture that elimi-
nates current-sensing I 2 R losses.
6
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相关代理商/技术参数 |
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|---|---|
| MAX1843ETI+ | 功能描述:直流/直流开关调节器 2.7A 1MHz Step-Down RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1843ETI+T | 功能描述:直流/直流开关调节器 2.7A 1MHz Step-Down RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1844EEP | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1844EEP+ | 功能描述:电流型 PWM 控制器 Step-Down Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1844EEP+T | 功能描述:电流型 PWM 控制器 Step-Down Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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