参数资料
型号: LT1576CS8-5#PBF
厂商: Linear Technology
文件页数: 20/28页
文件大小: 0K
描述: IC REG BUCK 5V 1.5A 8SOIC
标准包装: 100
类型: 降压(降压)
输出类型: 固定
输出数: 1
输出电压: 5V
输入电压: 5 V ~ 25 V
PWM 型: 电流模式
频率 - 开关: 200kHz
电流 - 输出: 1.5A
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: 8-SOIC(0.154",3.90mm 宽)
包装: 管件
供应商设备封装: 8-SOIC
LT1576/LT1576-5
APPLICATIO N S I N FOR M ATIO N
the output. Gain is set by the 1.5A/V transconductance of
the LT1576 power section and the effective complex
impedance from output to ground. Gain rolls off smoothly
above the 160Hz pole frequency set by the 100 μ F output
capacitor. Phase drop is limited to about 85 ° . Phase
recovers and gain levels off at the zero frequency ( ≈ 16kHz)
set by capacitor ESR (0.1 ? ).
Error amplifier transconductance phase and gain are shown
in Figure 11. The error amplifier can be modeled as a
transconductance of 1000 μ Mho, with an output imped-
ance of 570k ? in parallel with 2.4pF. 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 200Hz.
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 100pF, giving the
error amplifier a pole at 2.8kHz, with phase rolling off to
90 ° and staying there. The overall loop has a gain of 66dB
at low frequency, rolling off to unity-gain at 58kHz. Phase
shows a two-pole characteristic until the ESR of the output
capacitor brings it back above 16kHz. Phase margin is
about 77 ° at unity-gain.
LT1576
2000
200
CURRENT MODE
POWER STAGE
g m = 1.5A/V
ERROR
AMPLIFIER
V SW
R1
OUTPUT
1500
PHASE
150
FB
1000
GAIN
100
GND
V C
1.21V
+
ESR
C1
500
V FB ( 1 × 10 –3 )
R OUT
570k
V C
C OUT
2.4pF
50
0
ERROR AMPLIFIER EQUIVALENT CIRCUIT
0
C F
R C
C C
R2
–500
10
R LOAD = 50 ?
100
1k 10k
100k
–50
1M
FREQUENCY (Hz)
1576 F11
1576 F09
Figure 9. Model for Loop Response
Figure 11. Error Amplifier Gain and Phase
40
V IN = 10V
40
80
180
V OUT = 5V
20
I OUT = 500mA
0
60
135
GAIN
0
PHASE
–40
40
PHASE
90
–20
–80
20
0
V IN = 10V
V OUT = 5V
I OUT = 500mA
C OUT = 100 μ F
10V, AVX TPS
GAIN
45
0
–40
10
100
1k
10k
–120
100k
–20
10
C C = 100pF
L = 30 μ H
100
1k 10k
100k
–45
1M
20
FREQUENCY (Hz)
1576 F07
Figure 10. Response from V C Pin to Output
FREQUENCY (Hz)
1576 F12
Figure 12. Overall Loop Characteristics
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LT1576CS8-5SYNC#PBF 功能描述:IC REG BUCK 5V 1.5A 8SOIC 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:20 系列:SIMPLE SWITCHER® 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP(0.300",7.62mm) 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12
LT1576CS8-5SYNC#TR 功能描述:IC REG BUCK 5V 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:1.2V,1.5V,1.8V,2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽)裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘
LT1576CS8-5SYNC#TRPBF 功能描述:IC REG BUCK 5V 1.5A 8SOIC 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:20 系列:SIMPLE SWITCHER® 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP(0.300",7.62mm) 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12
LT1576CS8-SYNC 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压(升压) 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式,混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°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