参数资料
| 型号： | LT1738EG#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM CM 20-SSOP |
| 标准包装： | 66 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 250kHz |
| 占空比： | 93.5% |
| 电源电压： | 2.55 V ~ 20 V |
| 降压： | 无 |
| 升压： | 是 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 是 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 20-SSOP（0.209"，5.30mm 宽） |
| 包装： | 管件 |
| 产品目录页面： | 1328 (CN2011-ZH PDF) |
LT1738
OPERATIO
Table 1. Safety and Protection Features
FEATURE
FUNCTION
EFFECT on GATE DRIVER
SLEW CONTROL EFFECT on V C , SS
Maximum Current Fault
Turn Off FET at Maximum
Immediately Goes Low
Overridden
None
Switch Current (V SENSE = 0.1)
Short-Circuit Fault
Turn Off FET and Reset V C
Immediately Goes Low
Overridden
Discharge V C , SS
for Short-Circuit (V SENSE = 0.22)
to GND
Overvoltage Fault
Turn Off Driver If FB > V REG + 0.22V
Immediately Goes Low
Overridden
None
(Output Overvoltage)
GCL Clamp
Set Max Gate Voltage to Prevent
Limits Max Voltage
None
None
FET Gate Breakdown
Gate Drive
Disable Gate Drive When V IN
Immediately Goes Low
Overridden
None
Undervoltage Lockout
Is Too Low. Set Via GCL Pin
Thermal Shutdown
Turn Off Driver If Chip
Immediately Goes Low
Overridden
None
Temperature Is Too Hot
V IN Undervoltage Lockout
Gate Drive Source and Sink Current Limit
V5 Source/Sink Current Limit
Disable Part When V IN ? 2.55V
Limit Gate Drive Current
Limit Current from V5
Immediately Goes Low
Limit Drive Current
None
Overridden
None
None
None
None
None
Shutdown
Disable Part When SHDN <1.3V
APPLICATIO S I FOR ATIO
Reducing EMI from switching power supplies has tradi-
tionally invoked fear in designers. Many switchers are
designed solely on efficiency and as such produce wave-
forms filled with high frequency harmonics that then
propagate through the rest of the system.
The LT1738 provides control over two of the more impor-
tant variables for controlling EMI with switching inductive
loads: switch voltage slew rate and switch current slew
rate. The use of this part will reduce noise and EMI over
to ensure oscillator frequency stability. The oscillator is of
a sawtooth design. A current defined by external resistor
R T is used to charge and discharge the capacitor C T . The
discharge rate is approximately ten times the charge rate.
By allowing the user to have control over both compo-
nents, trimming of oscillator frequency can be more easily
achieved.
The external capacitance C T is chosen by:
conventional switch mode controllers. Because these
variables are under control, a supply built with this part will
exhibit far less tendency to create EMI and less chance of
C T ( nF ) =
2180
f ( kHz ) ? R T ( k ? )
encountering problems during production.
It is beyond the scope of this data sheet to get into EMI
where f is the desired oscillator frequency in kHz. For R T
equal to 16.9k, this simplifies to:
fundamentals. Application Note 70 contains much infor-
mation concerning noise in switching regulators and
should be consulted.
C T ( nF ) =
129
f ( kHz )
e.g., C T = 1.29nF for f = 100kHz
Oscillator Frequency
The oscillator determines the switching frequency and
therefore the fundamental positioning of all harmonics.
The use of good quality external components is important
Nominally R T should be 16.9k. Since it sets up current, its
temperature coefficient should be selected to compliment
the capacitor. Ideally, both should have low temperature
coefficients.
1738fa
11
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相关代理商/技术参数 |
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| LT1738IG | 功能描述:IC REG CTRLR PWM CM 20-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 |
| LT1738IG#PBF | 功能描述:IC REG CTRLR PWM CM 20-SSOP 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: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 |
| LT1738IG#PBF | 制造商:Linear Technology 功能描述:ICSMPS CONTROLLERCURRENT-MODESSOP20P 制造商:Linear Technology 功能描述:IC,SMPS CONTROLLER,CURRENT-MODE,SSOP,20P |
| LT1738IG#TR | 功能描述:IC REG CTRLR PWM CM 20-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 |
| LT1738IG#TRPBF | 功能描述:IC REG CTRLR PWM CM 20-SSOP 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: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 |
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