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参数资料
| 型号： | LM2635M/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 350 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封装： | PLASTIC, SOP-20 |
| 文件页数： | 1/13页 |
| 文件大小： | 734K |
| 代理商： | LM2635M/NOPB |
LM2635 5-Bit Programmable
Synchronous Buck Regulator Controller
General Description
The LM2635 is a high speed controller designed specifically
for use in synchronous DC/DC buck converters for the
Pentium II or Deschutes microprocessor. A 5-bit DAC ac-
cepts the VID code directly from the CPU and adjusts the
output voltage from 1.8V to 3.5V. It provides the power good,
over-voltage protection, and output enable features as re-
quired by Intel VRM specifications. Current limiting is
achieved by monitoring the voltage drop across the r
DS_ON
of the high side MOSFET, which eliminates an expensive
current sense resistor.
The LM2635 employs a fixed-frequency voltage mode PWM
architecture. To provide a faster response to a large and fast
load transient, two ultra-fast comparators are built in to moni-
tor the output voltage and override the primary control loop
when necessary. The PWM frequency is adjustable from 50
kHz to 1 MHz through an external resistor. The wide range of
PWM frequency gives the power supply designer the flexibil-
ity to make trade-offs between load transient response per-
formance, MOSFET cost and the overall efficiency. The
adaptive non-overlapping MOSFET gate drivers help avoid
any potential shoot-through problem while maintaining high
efficiency. BiCMOS gate drivers with rail-to-rail swing ensure
that no spurious turn-on occur. When only 5V is available, a
bootstrap structure can be employed to accommodate an
NMOS high side switch. The precision reference trimmed to
2% over temperature is available externally for use by other
regulators. Dynamic positioning of load voltage, which helps
cut the number of output capacitors, can also be imple-
mented easily.
Features
n
1.8V to 3.5V 5-bit programmable output voltage
n
Synchronous rectification
n
Power Good flag and output enable
n
Over-voltage protection
n
Initial Output Accuracy: 2% over temperature
n
Current limit without external sense resistor
n
Adaptive non-overlapping MOSFET gate drives
n
Adjustable switching frequency: 50 kHz to 1 MHz
n
Dynamic output voltage positioning
n
1.256V reference voltage available externally
n
Plastic SO-20 package
Applications
n
Motherboard power supply/VRM for Cyrix Gxm, Cyrix
Gxi, Cyrix MII, Pentium II, Deschutes, Pentium Pro,
6x86 and K6 processors
n
5V to 1.8V–3.5V high current power supplies
Typical Application
Pentium is a trademark of Intel Corporation.
10011901
FIGURE 1. 5V to 1.8V–3.5V, 14A Power Supply
March 2005
LM2635
5-Bit
Programmable
Synchronous
Buck
Regulator
Controller
2005 National Semiconductor Corporation
DS100119
www.national.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2635MX | 功能描述:IC REG SYNCH BUCK 5-BIT 20-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| LM2635MX/NOPB | 制造商:Texas Instruments 功能描述:Conv DC-DC Single Step Down 20-Pin SOIC W T/R |
| LM2636 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:5-Bit Programmable Synchronous Buck Regulator Controller |
| LM2636A E WAF | 制造商:Texas Instruments 功能描述: |
| LM2636AM E WAF | 制造商:Texas Instruments 功能描述: |
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