- 您现在的位置：买卖IC网 > PDF目录14136 > LTC1627CS8#TR (Linear Technology)IC REG BUCK SYNC ADJ 0.5A 8SOIC PDF资料下载
参数资料
| 型号： | LTC1627CS8#TR |
| 厂商： | Linear Technology |
| 文件页数： | 7/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 0.5A 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： | 0.8 V ~ 8.5 V |
| 输入电压： | 2.65 V ~ 8.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 35kHz ~ 350kHz |
| 电流 - 输出： | 500mA |
| 同步整流器： | 是 |
| 工作温度： | 0°C ~ 70°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 |
LTC1627
OPERATIO
load slightly allows constant frequency PWM operation
to resume.
Frequency synchronization is inhibited when the feedback
V DR
LTC1627 V IN
D1 L1
C1
0.1 μ F
V IN < 4.5V
voltage V FB is below 0.6V. This prevents the external clock
from interfering with the frequency foldback for short-
SW
C2
0.1 μ F
+
C OUT
100 μ F
V OUT
circuit protection.
D2
1627 F02
Dropout Operation
When the input supply voltage decreases toward the out-
put voltage, the duty cycle increases toward the maximum
on-time. Further reduction of the supply voltage forces the
main switch to remain on for more than one cycle until it
reaches 100% duty cycle. The output voltage will then be
determined by the input voltage minus the voltage drop
across the P-channel MOSFET and the inductor.
In Burst Mode operation or pulse skipping mode operation
(externally synchronized) with the output lightly loaded,
the LTC1627 transitions through continuous mode as it
enters dropout.
Undervoltage Lockout
A precision undervoltage lockout shuts down the LTC1627
when V IN drops below 2.5V, making it ideal for single
lithium-ion battery applications. In lockout, the LTC1627
draws only several microamperes, which is low enough to
prevent deep discharge and possible damage to the lithium-
ion battery nearing its end of charge. A 150mV hysteresis
ensures reliable operation with noisy supplies.
Low Supply Operation
The LTC1627 is designed to operate down to 2.65V supply
Figure 2. Using a Charge Pump to Bias V DR
the charge pump at V IN ≥ 4.5V is not recommended to
ensure that (V IN – V DR ) does not exceed its absolute
maximum voltage.
When V IN decreases to a voltage close to V OUT , the loop
may enter dropout and attempt to turn on the P-channel
MOSFET continuously. When the V DR charge pump is
enabled, a dropout detector counts the number of oscilla-
tor cycles that the P-channel MOSFET remains on, and
periodically forces a brief off period to allow C1 to
recharge. 100% duty cycle is allowed when V DR is grounded.
Slope Compensation and Inductor Peak Current
Slope compensation provides stability by preventing
subharmonic oscillations. It works by internally adding a
ramp to the inductor current signal at duty cycles in excess
of 40%. As a result, the maximum inductor peak current
is lower for V OUT /V IN > 0.4 than when V OUT /V IN < 0.4. See
the inductor peak current as a function of duty cycle graph
in Figure 3. The worst-case peak current reduction occurs
with the oscillator synchronized at its minimum frequency,
i.e., to a clock just above the oscillator free-running
950
voltage. At this voltage the converter is most likely to be
900
WITHOUT
running at high duty cycles or in dropout where the main
switch is on continuously. Hence, the I 2 R loss is due
mainly to the R DS(ON) of the P-channel MOSFET. See
Efficiency Considerations in the Applications Information
section.
When V IN is low (< 4.5V) the R DS(ON) of the P-channel
MOSFET can be lowered by driving its gate below ground.
The top P-channel MOSFET driver makes use of a floating
850
800
750
700
650
600
550
500
V IN = 5V
WORST CASE
EXTERNAL
CLOCK SYNC
EXTERNAL
CLOCK SYNC
return pin, V DR , to allow biasing below GND. A simple
charge pump bootstrapped to the SW pin realizes a
negative voltage at the V DR pin as shown in Figure 2. Using
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
1627 F03
Figure 3. Maximum Inductor Peak Current vs Duty Cycle
7
相关PDF资料 |
PDF描述 |
|---|---|
| LTC1503IS8-2#TRPBF | IC REG BUCK SWITCHD CAP 2V 8SOIC |
| LTC1503IS8-2#TR | IC REG BUCK SWITCHD CAP 2V 8SOIC |
| LTC1503IS8-1.8#TR | IC REG BUCK SWITCHED CAP 8SOIC |
| HSM18DRXI | CONN EDGECARD 36POS DIP .156 SLD |
| HMM18DRXI | CONN EDGECARD 36POS DIP .156 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1627IS8 | 功能描述:IC REG BUCK SYNC ADJ 0.5A 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 |
| LTC1627IS8#PBF | 功能描述:IC REG BUCK SYNC ADJ 0.5A 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: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 |
| LTC1627IS8#TR | 功能描述:IC REG BUCK SYNC ADJ 0.5A 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 |
| LTC1627IS8#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 0.5A 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: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 |
| LTC1628CG | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP 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:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 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:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
发布紧急采购，3分钟左右您将得到回复。