参数资料
型号: LT1374CR#PBF
厂商: Linear Technology
文件页数: 22/32页
文件大小: 0K
描述: IC REG BUCK ADJ 4.5A D2PAK
标准包装: 50
类型: 降压(降压)
输出类型: 可调式
输出数: 1
输出电压: 2.42 V ~ 21.5 V
输入电压: 5 V ~ 25 V
PWM 型: 电流模式
频率 - 开关: 500kHz
电流 - 输出: 4.5A
同步整流器:
工作温度: 0°C ~ 125°C
安装类型: 表面贴装
封装/外壳: TO-263-8,D²Pak(7 引线+接片),TO-263CA
包装: 管件
供应商设备封装: D2PAK-7
产品目录页面: 1327 (CN2011-ZH PDF)
LT1374
APPLICATIO N S I N FOR M ATIO N
Error amplifier transconductance phase and gain are
shown in Figure 11. The error amplifier can be modeled
as a transconductance of 2000 μ Mho, with an output
impedance of 200k ? in parallel with 12pF. In all practical
applications, the compensation network from V C pin to
ground has a much lower impedance than the output
impedance of the amplifier at frequencies above 500Hz.
This means that the error amplifier characteristics them-
selves do not contribute excess phase shift to the loop, and
the phase/gain characteristics of the error amplifier sec-
tion are completely controlled by the external compensa-
tion network.
In Figure 12, full loop phase/gain characteristics are
shown with a compensation capacitor of 1.5nF, giving the
error amplifier a pole at 530Hz, with phase rolling off to 90 °
and staying there. The overall loop has a gain of 74dB at
low frequency, rolling off to unity-gain at 100kHz. Phase
shows a two-pole characteristic until the ESR of the output
capacitor brings it back above 10kHz. Phase margin is
about 75 ° at unity-gain.
Analog experts will note that around 4.4kHz, phase dips
very close to the zero phase margin line. This is typical of
switching regulators, especially those that operate over a
wide range of loads. This region of low phase is not a
problem as long as it does not occur near unity-gain. In
practice, the variability of output capacitor ESR tends to
dominate all other effects with respect to loop response.
Variations in ESR will cause unity-gain to move around,
but at the same time phase moves with it so that adequate
phase margin is maintained over a very wide range of ESR
( ≥ ± 3:1).
LT1374
3000
200
CURRENT MODE
POWER STAGE
g m = 5.3A/V
ERROR
AMPLIFIER
V SW
R1
OUTPUT
2500
PHASE
150
FB
2000
GAIN
100
GND
V C
2.42V
+
ESR
C1
1500
V FB ( 2 × 10 –3 )
R OUT
200k
V C
C OUT
12pF
50
C F
R C
R2
1000
ERROR AMPLIFIER EQUIVALENT CIRCUIT
R LOAD = 50 ?
0
C C
500
100
1k
10k 100k
1M
–50
10M
FREQUENCY (Hz)
Figure 9. Model for Loop Response
1374 F09
1374 F11
Figure 11. Error Amplifier Gain and Phase
40
V IN = 10V
40
80
200
GAIN
V OUT = 5V
I OUT = 2A
60
GAIN
150
20
0
40
100
0
–40
20
PHASE
50
PHASE
–20
–80
0
V IN = 10V
V OUT = 5V, I OUT = 2A
0
C OUT = 100 μ F, 10V, AVX TPS
–40
10
100
1k 10k
100k
–120
1M
–20
10
C C = 1.5nF, R C = 0, L = 10 μ H
100 1k 10k
100k
–50
1M
FREQUENCY (Hz)
1374 F10
Figure 10. Response from V C Pin to Output
FREQUENCY (Hz)
1374 F12
Figure 12. Overall Loop Characteristics
1374fd
22
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相关代理商/技术参数
参数描述
LT1374CRSYNC 制造商:Linear Technology 功能描述:
LT1374CR-SYNC 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
LT1374CR-SYNC#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:- 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
LT1374CR-SYNC#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
LT1374CR-SYNC#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