参数资料
型号: LTC1266CS-3.3
厂商: Linear Technology
文件页数: 13/20页
文件大小: 0K
描述: IC REG CTRLR BST PWM CM 16-SOIC
标准包装: 50
PWM 型: 电流模式
输出数: 1
频率 - 最大: 400kHz
占空比: 100%
电源电压: 3.5 V ~ 18 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: 0°C ~ 70°C
封装/外壳: 16-SOIC(0.154",3.90mm 宽)
包装: 管件
产品目录页面: 1342 (CN2011-ZH PDF)
LTC1266
LTC1266-3.3/LTC1266-5
APPLICATIO S I FOR ATIO
600
500
V OUT = 3.3V
TOPSIDE
TOPSIDE
N-CHANNEL WITH
CHARGE PUMP
100
90
Burst Mode OPERATION
ENABLED
400
300
P-CHANNEL
80
Burst Mode OPERATION
200
TOPSIDE N-CHANNEL
70
INHIBITED
100
WITH POWER V IN = 12V
0
0
1
2
3
4
5
60
0.01
0.1
1
5
V IN
LOAD CURRENT
1266 F05
Figure 5. Comparison of Dropout Performance
LOAD CURRENT (A)
1266 F07
Figure 7. Effect of Disabling Burst Mode Operation on Efficiency
2. If the load is never expected to drop low enough to
R2
LTC1266
benefit from the efficiency advantages of Burst Mode
R1
1.25V
LB OUT
operation, the output capacitor ESR and minimum capaci-
tance requirements (which may falsely trigger Burst Mode
operation if not met) can be relaxed if Burst Mode opera-
tion is disabled.
REFERENCE
1266 F06
3. If an auxiliary winding is used. Disabling Burst Mode
Figure 6. Low-Battery Comparator
The divided down voltage at the “–” input to the comparator
is compared to an internal 1.25V reference. This reference
is separate from the 1.265V reference used by the voltage
comparator and current comparator for regulation and is
not disabled by the shutdown pin, therefore the low-battery
detection is operational even when the rest of the chip is
shut down. The comparator is functional down to an input
voltage of 2.5V. Thus, the output will provide a valid state
even when the rest of the chip does not have sufficient
voltage to operate. For best performance, the value of the
pull-up resistor should be high enough that the output is
pulled down to ground when sinking 200 μ A or less.
Suppressing Burst Mode Operation
Normally, enabling Burst Mode operation is desired due to
its superior efficiency at low load currents (see Figure 7).
However, in certain applications it may be desirable to
inhibit this feature. Some reasons for doing so are:
1. To eliminate audible noise from certain types of induc-
tors at light loads.
operation guarantees switching independent of the load
on the primary. This allows power to be taken from the
auxiliary winding independently.
4. Tighter load regulation (< 1%).
Burst Mode operation is disabled by applying a CMOS
logic high voltage (> 2.1V) to Pin 4. When it is disabled, the
voltage comparator limit is raised high enough so that it no
longer is involved in regulation; however it is still active
and is useful as a voltage clamp to keep the output from
overshooting.
Note that since the inductor current must reverse to
regulate the output at zero load when Burst Mode opera-
tion is disabled, the minimum inductance (L MIN ) specified
during Inductor Core Selection is no longer applicable.
Checking Transient Response
The regulator loop response can be checked by looking at
the load transient response. Switching regulators take
several cycles to respond to a step in DC (resistive) load
current. When a load step occurs, V OUT shifts by an
amount equal to ? I LOAD (ESR), where ESR is the effective
series resistance of C OUT . ? I LOAD also begins to charge or
13
相关PDF资料
PDF描述
VE-B7Y-EW-F3 CONVERTER MOD DC/DC 3.3V 66W
RMM15DRMN-S288 CONN EDGECARD 30POS .156 EXTEND
GBC25DRAS-S734 CONN EDGECARD 50POS .100 R/A SLD
UCA2W220MHD CAP ALUM 22UF 450V 20% RADIAL
LT3781EG#TRPBF IC REG CTRLR ISO PWM CM 20-SSOP
相关代理商/技术参数
参数描述
LTC1266CS-5 功能描述:IC REG CTRLR BST PWM CM 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC1266CS-5#PBF 功能描述:IC REG CTRLR BST PWM CM 16-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC1266CS-5#TR 功能描述:IC REG CTRLR BST PWM CM 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC1266CS-5#TRPBF 功能描述:IC REG CTRLR BST PWM CM 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC1266IS 功能描述:IC REG CTRLR BST PWM CM 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)