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参数资料
| 型号： | MAX1638EAG+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/16页 |
| 文件大小： | 0K |
| 描述： | IC STEP-DWN CTRLR HI-SPD 24-SSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,000 |
| 应用： | 控制器，Intel Pentium? II |
| 输入电压： | 4.5 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 1.3 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 24-SSOP |
| 包装： | 带卷 (TR) |
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
Synchronous-Rectifier Driver
Synchronous rectification reduces conduction losses in
the rectifier by shunting the normal Schottky diode or
MOSFET body diode with a low-on-resistance MOSFET
V IN = 5V
switch. The synchronous rectifier also ensures proper
start-up by precharging the boost-charge pump used
BST
D2
C1
for the high-side switch gate-drive circuit. Thus, if you
must omit the synchronous power MOSFET for cost or
other reasons, replace it with a small-signal MOSFET,
such as a 2N7002.
The DL drive waveform is simply the complement of
the DH high-side drive waveform (with typical con-
trolled dead time of 30ns to prevent cross-conduction
or shoot-through). The DL output’s on-resistance is
0.7 Ω (typ) and 2 Ω (max).
LEVEL
TRANSLATOR
CONTROL AND
DRIVE LOGIC
DH
LX
V DD
DL
R4
R3
N1
N2
C3
L1
BST High-Side Gate-Driver Supply
and MOSFET Drivers
PGND
Gate-drive voltage for the high-side N-channel switch
is generated using a flying-capacitor boost circuit
(Figure 3). The capacitor is alternately charged from
the +5V supply and placed in parallel with the high-
side MOSFET’s gate and source terminals.
MAX1638
R3 AND R4
ARE OPTIONAL
Gate-drive resistors (R3 and R4) can often be useful to
reduce jitter in the switching waveforms by slowing
down the fast-slewing LX node and reducing ground
bounce at the controller IC. However, switching loss
may increase. Low-value resistors from around 1 Ω to
5 Ω are sufficient for many applications.
GlitchCatcher
Current-Boost Driver
Drivers for an optional GlitchCatcher current-boost cir-
cuit are included in the MAX1638 to improve transient
response in applications where several amperes of
load current are required in a matter of a few tens of
nanoseconds. The GlitchCatcher can be used to offset
the fast drop in output voltage due to the ESR of the
output capacitance. The current-boost circuit improves
transient response by providing a direct path from the
input to the output that circumvents the buck inductor’s
filtering action. When the output drops out of regulation
by more than 2%, the P-channel or N-channel switch
turns on and injects current directly into the output from
V IN or ground, forcing the output back into regulation.
The driver’s response time is typically 75ns, and mini-
mum on-time is typically 100ns. GlitchCatcher provides
the greatest benefit when the output voltage is less
than 2V, and in applications using minimum output
capacitance.
Figure 3. Boost Supply for Gate Drivers
Current Sense and Overload
Current Limiting
The current-sense circuit resets the main PWM latch
and turns off the high-side MOSFET switch whenever
the voltage difference between CSH and CSL from cur-
rent through the sense resistor (R1) exceeds the peak
current limit (100mV typical).
Current-mode control provides cycle-by-cycle current-
limit capability for maximum overload protection.
During normal operation, the peak current limit set by
the current-sense resistor determines the maximum
output current. When the output is shorted, the peak
current may be higher than the set current limit due to
delays in the current-sense comparator. Thus, foldback
current limiting is employed where the set current-limit
point is reduced from 100mV to 38mV as the output
(feedback) voltage falls (Figure 4). When the short-cir-
cuit condition is removed, the feedback voltage will
rise and the current-limit voltage will revert to 100mV.
The foldback current-limit circuit is designed to ensure
startup into a resistive load.
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1638VRMEVKIT | 功能描述:DC/DC 开关控制器 High-Speed Step-Down Controller with Synchronous Rectification for CPU Power RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1639ESE | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1639ESE+ | 功能描述:DC/DC 开关控制器 High Speed Step Down RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1639ESE+T | 功能描述:DC/DC 开关控制器 High Speed Step Down RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1639ESE-T | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
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