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参数资料
| 型号： | MAX1830-MAX1831 |
| 厂商： | Maxim Integrated Products, Inc. |
| 英文描述： | 3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal Switches |
| 中文描述： | 第3A，1MHz的，低电压，降压型稳压器与同步整流和内部开关 |
| 文件页数： | 6/13页 |
| 文件大小： | 278K |
| 代理商： | MAX1830-MAX1831 |
M
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
6
_______________________________________________________________________________________
_______________Detailed Description
The MAX1830/MAX1831 synchronous, current-mode,
constant-off-time, PWM DC-DC converters step down
input voltages of +3V to +5.5V to preset output voltages,
or to an adjustable output voltage from +1.1V to V
IN
. The
MAX1830 has preset outputs +2.5V, +1.8V, and +1.5V.
The MAX1831 has preset outputs of +3.3V, +2.5V or
+1.5V. Both devices deliver up to 3A of continuous output
current. Internal switches composed of a 45m
PMOS
power switch and a 55m
NMOS synchronous rectifier
switch improve efficiency, reduce component count, and
eliminate the need for an external Schottky diode.
The MAX1830/MAX1831 optimize efficiency by operat-
ing in constant-off-time mode under heavy loads and in
Maxim
’
s proprietary Idle Mode under light loads. A sin-
gle 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 con-
tinuously 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 MAX1830/MAX1831 current-mode, constant-off-
time PWM architecture regulates the output voltage by
changing the PMOS switch on-time relative to the con-
stant off-time. Increasing the on-time increases the
peak inductor current and the amount of energy trans-
ferred 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), or
Idle Mode (for load currents less than half the Idle
Mode threshold). Current sense is achieved through a
proprietary architecture that eliminates current-sensing
I
2
R losses.
Constant-Off-Time Mode
Constant-off-time operation occurs when the current
through the PMOS switch is greater than the Idle Mode
threshold current (which corresponds to a load current
of half the Idle Mode threshold). In this mode, the regu-
Pin Description
PIN
NAME
FUNCTION
1, 3, 14, 16
LX
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.
2, 4
IN
Supply Voltage Input for the internal PMOS power switch
5
SHDN
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.
Integrator Compensation. Connect a capacitor from COMP to V
CC
for integrator compensation. See
Integrator Amplifier
section.
6
COMP
7
TOFF
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.
8
FB
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.
9
GND
Analog Ground
10
REF
Reference Output. Bypass REF to GND with a 1μF capacitor.
11
FBSEL
Feedback Select Input. Selects output voltage. See Table 3 for programming instructions.
12
V
CC
Analog Supply Voltage Input. Supplies internal analog circuitry. Bypass V
CC
with a 10
and 2.2μF
lowpass filter (Figure 1).
13, 15
PGND
Power Ground. Internally connected to the internal NMOS synchronous-rectifier switch.
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1830 | Replaced by TMS320BC52 : |
| MAX1831EEE | 3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal Switches |
| MAX1833ETT30-T | High-Efficiency Step-Up Converters with Reverse Battery Protection |
| MAX1834 | High-Efficiency Step-Up Converters with Reverse Battery Protection |
| MAX1832EUT-T | High-Efficiency Step-Up Converters with Reverse Battery Protection |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1831EEE | 功能描述:直流/直流开关调节器 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 |
| MAX1831EEE+ | 功能描述:直流/直流开关调节器 3A 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 |
| MAX1831EEE+T | 功能描述:直流/直流开关调节器 3A 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 |
| MAX1831EEE-T | 功能描述:直流/直流开关调节器 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 |
| MAX1832EUT | 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY STEP-UP CONVERTER - Rail/Tube |
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