- 您现在的位置：买卖IC网 > PDF目录13908 > LT1959CS8#TR (Linear Technology)IC REG BUCK ADJ 4.5A 8SOIC PDF资料下载
参数资料
| 型号： | LT1959CS8#TR |
| 厂商： | Linear Technology |
| 文件页数： | 23/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 4.5A 8SOIC |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.21 V ~ 38 V |
| 输入电压： | 4.3 V ~ 15 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 500kHz |
| 电流 - 输出： | 4.5A |
| 同步整流器： | 无 |
| 工作温度： | 0°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-SOIC |
LT1959
APPLICATIO N S I N FOR M ATIO N
Redundant Operation
The circuit shown in Figure 15 is fault tolerant when
operating at less than 8A of output current. If one device
fails, the output will remain in regulation. The feedback
loop will compensate by raising the voltage on the V C pin,
increasing switch current of the two remaining devices.
BUCK CONVERTER WITH ADJUSTABLE SOFT START
Large capacitive loads can cause high input currents at
start-up. Figure 16 shows a circuit that limits the dv/dt of
the output at start-up, controlling the capacitor charge
rate. The buck converter is a typical configuration with the
addition of R3, R4, C SS and Q1. As the output starts to rise,
Q1 turns on, regulating switch current via the V C pin to
maintain a constant dv/dt at the output. Output rise time is
controlled by the current through C SS defined by R4 and
Q1’s V BE . Once the output is in regulation, Q1 turns off and
the circuit operates normally. R3 is transient protection for
the base of Q1.
output current is unchanged. Variants of this circuit can be
used for sequencing multiple regulator outputs.
Dual Output SEPIC Converter
The circuit in Figure 17 generates both positive and
negative 5V outputs with a single piece of magnetics. The
two inductors shown are actually just two windings on a
standard B H Electronics inductor. The topology for the 5V
output is a standard buck converter. The – 5V topology
would be a simple flyback winding coupled to the buck
converter if C4 were not present. C4 creates a SEPIC
(Single-Ended Primary Inductance Converter) topology
whicn improves regulation and reduces ripple current in
L1. Without C4, the voltage swing on L1B compared to
L1A would vary due to relative loading and coupling
losses. C4 provides a low impedance path to maintain an
equal voltage swing in L1B, improving regulation. In a
flyback converter, during switch on time, all the converter’s
energy is stroed in L1A only, since no current flows in L1B.
At switch off, energy is transferred by magnetic coupling
RiseTime =
(R 4)(C SS )( V OUT )
( V BE )
into L1B, powering the – 5V rail. C4 pulls L1B positive
during switch on time, causing current to flow, and energy
to build in L1B and C4. At switch off, the energy stored in
RiseTime =
Using the values shown in Figure 16,
(47 ? 10 3 )(15 ? 10 – 9 )(2 .5)
0 . 7
= 2 . 5 ms
both L1B and C4 supply the –5V rail. This reduces the
current in L1A and changes L1B current waveform from
square to triangular. For details on this circuit see Design
Note 100.
The ramp is linear and rise times in the order of 100ms are
D2
1N914
possible. Since the circuit is voltage controlled, the ramp
rate is unaffected by load characteristics and maximum
D2
1N914
INPUT
6V TO 15V
V IN
BOOST
LT1959
C2
0.27 μ F
V SW
L1*
6.8 μ H
OUTPUT
5V
+
+
D1
INPUT
12V
+
C3
10 μ F
V IN
SHDN
BOOST
LT1959
GND V C
C2
0.33 μ F
V SW
D1
FB
C C
1.5nF
Q1
L1
5 μ H
C1
100 μ F
C SS
R3 15nF
2k
R4
47k
R1
2.67k
R2
2.49k
1959 F16
OUTPUT
2.5V
4A
SHDN FB
GND V C
C3
10 μ F C C
25V 1.5nF
CERAMIC
GND
C4**
4.7 μ F
* L1 IS A SINGLE CORE WITH TWO WINDINGS
BH ELECTRONICS #501-0726
** TOKIN IE475ZY5U-C304
? IF LOAD CAN GO TO ZERO, AN OPTIONAL
PRELOAD OF 1k TO 5k MAY BE USED TO
R1
7.87k
R2
2.49k
C5**
L1* 100 μ F
10V TANT
D3
+
+
C1**
100 μ F
10V TANT
OUTPUT
–5V ?
1959 F17
IMPROVE LOAD REGULATION
D1, D3: MBRD340
Figure 16. Buck Converter with Adjustable Soft Start
Figure 17. Dual Output SEPIC Converter
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
23
相关PDF资料 |
PDF描述 |
|---|---|
| ECM31DCST-S288 | CONN EDGECARD 62POS .156 EXTEND |
| 50YXH56MEFC6.3X11 | CAP ALUM 56UF 50V 20% RADIAL |
| LT1271CT#PBF | IC REG BUCK INV FLYBK 4A TO220-5 |
| 10YXG150MEFC6.3X11 | CAP ALUM 150UF 10V 20% RADIAL |
| RCB60DHRN-S621 | EDGECARD EXTEND 120PS .050 PCI32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1959I | 制造商:LINER 制造商全称:Linear Technology 功能描述:4.5A, 500kHz Step-Down Switching Regulator |
| LT1959IR | 功能描述:IC REG BUCK ADJ 4.5A D2PAK RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT1959IR#PBF | 功能描述:IC REG BUCK ADJ 4.5A D2PAK RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 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:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LT1959IR#TR | 功能描述:IC REG BUCK ADJ 4.5A D2PAK RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT1959IR#TRPBF | 功能描述:IC REG BUCK ADJ 4.5A D2PAK RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
发布紧急采购，3分钟左右您将得到回复。