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参数资料
| 型号： | LT1374IS8-SYNC#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 8.5 A SWITCHING REGULATOR, 560 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | 0.150 INCH, PLASTIC, SO-8 |
| 文件页数： | 15/32页 |
| 文件大小： | 698K |
| 代理商： | LT1374IS8-SYNC#TR |
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LT1374
1374fd
APPLICATIONS INFORMATION
WU
U
Error amplifier transconductance phase and gain are
shown in Figure 11. The error amplifier can be modeled
as a transconductance of 2000Mho, with an output
impedance of 200k in parallel with 12pF. In all practical
applications, the compensation network from VC 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).
Figure 10. Response from VC Pin to Output
FREQUENCY (Hz)
GAIN:
V
C
PIN
TO
OUTPUT
(dB)
PHASE:
V
C PIN
TO
OUTPUT
(DEG)
40
20
0
–20
–40
40
0
–40
–80
–120
10
1k
10k
1M
1374 F10
100
100k
GAIN
PHASE
VIN = 10V
VOUT = 5V
IOUT = 2A
Figure 11. Error Amplifier Gain and Phase
FREQUENCY (Hz)
GAIN
(
Mho)
PHASE
(DEG)
3000
2500
2000
1500
1000
500
200
150
100
50
0
–50
100
10k
100k
10M
1374 F11
1k
1M
GAIN
PHASE
ROUT
200k
COUT
12pF
VC
ERROR AMPLIFIER EQUIVALENT CIRCUIT
RLOAD = 50
VFB 2 × 10
–3
)
(
Figure 9. Model for Loop Response
–
+
2.42V
VSW
VC
LT1374
GND
1374 F09
R1
OUTPUT
ESR
CF
CC
RC
ERROR
AMPLIFIER
FB
R2
C1
CURRENT MODE
POWER STAGE
gm = 5.3A/V
+
FREQUENCY (Hz)
LOOP
GAIN
(dB)
LOOP
PHASE
(DEG)
80
60
40
20
0
–20
200
150
100
50
0
–50
10
1k
10k
1M
1374 F12
100
100k
GAIN
PHASE
VIN = 10V
VOUT = 5V, IOUT = 2A
COUT = 100F, 10V, AVX TPS
CC = 1.5nF, RC = 0, L = 10H
Figure 12. Overall Loop Characteristics
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相关代理商/技术参数 |
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| LT1374IT7 | 功能描述:IC REG BUCK ADJ 4.5A TO220-7 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 |
| LT1374IT7#PBF | 功能描述:IC REG BUCK ADJ 4.5A TO220-7 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 |
| LT1374IT7-5 | 功能描述:IC REG BUCK 5V 4.5A TO220-7 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 |
| LT1374IT7-5#PBF | 功能描述:IC REG BUCK 5V 4.5A TO220-7 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 |
| LT1375 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5A, 500kHz Step-Down Switching Regulators |
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