- 您现在的位置：买卖IC网 > PDF目录13971 > LT1507CS8-3.3#TR (Linear Technology)IC REG BUCK 3.3V 1.5A 8SOIC PDF资料下载
参数资料
| 型号： | LT1507CS8-3.3#TR |
| 厂商： | Linear Technology |
| 文件页数： | 11/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 3.3V 1.5A 8SOIC |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 3.3V |
| 输入电压： | 4 V ~ 15 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 500kHz |
| 电流 - 输出： | 1.5A |
| 同步整流器： | 无 |
| 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 |
LT1507
APPLICATIO N S I N FOR M ATIO N
Table 2. Surface Mount Solid Tantalum Capacitor ESR
and Ripple Current
E CASE SIZE ESR (MAX ? ) RIPPLE CURRENT (A)
appropriate for input bypassing because of their high
ripple current ratings and tolerance of turn-on surges.
AVX TPS, Sprague 593D
AVX TAJ
D CASE SIZE
AVX TPS, Sprague 593D
AVX TAJ
0.1 to 0.3
0.7 to 0.9
0.1 to 0.3
0.9 to 2.0
0.7 to 1.1
0.4
0.7 to 1.1
0.36 to 0.24
OUTPUT RIPPLE VOLTAGE
Ripple voltage is determined by the high frequency imped-
ance of the output capacitor and ripple current through the
inductor. Ripple current is triangular (continuous mode)
I P-P =
= 0 . 45 P-P
I P-P =
5 ? 5 10 500
C CASE SIZE
AVX TPS 0.2 (Typ) 0.5 (Typ)
AVX TAJ 1.8 to 3.0 0.22 to 0.17
Many engineers have heard that solid tantalum capacitors
are prone to failure if they undergo high surge currents.
This is historically true, and type TPS capacitors are
specially tested for surge capability, but surge rugged-
ness is not a critical issue with the output capacitor. Solid
tantalum capacitors fail during very high turn-on surges
which do not occur at the output of regulators. High
discharge surges, such as when the regulator output is
dead shorted, do not harm the capacitors.
Unlike the input capacitor, RMS ripple current in the
output capacitor is normally low enough that ripple cur-
rent rating is not an issue. The current waveform is
triangular with a typical value of 200mA RMS. The formula
to calculate this is:
Output Capacitor Ripple Current (RMS)
with a peak-to-peak value of:
( V OUT )( V IN ? V OUT )
( V IN )( L )( f )
Output ripple voltage is also triangular with peak-to-peak
amplitude of:
V RIPPLE = (I P–P )(ESR) (peak-to-peak)
Example: with V IN = 5V, V OUT = 3.3V, L = 5 μ H, ESR = 0.1 ? ;
( 3 . 3 )( 5 ? 3 . 3 )
? ? ?
? ? ? 6 ? ? ? ? 10 3 ? ?
? ? ? ? ? ? ? ?
V RIPPLE = ( 0 . 45 A )( 0 . 1 ? ) = 45 mV P-P
MAXIMUM OUTPUT LOAD CURRENT
Maximum load current will be less than the 1.5A rating of
the LT1507, especially with lower inductor values. Induc-
I RIPPLE ( RMS ) =
0.29 (V OUT )(V IN – V OUT )
( L )( f )( V IN )
tor ripple current must be taken into account as well as
reduced switch current at high duty cycles. Maximum
switch current rating (I P ) of the LT1507 is 1.5A up to 50%
duty cycle (DC), decreasing to 1.35A at 80% duty cycle,
I P = 1 . 5 A for OUT ≤ 0 . 5
0 . 5 ( V OUT ) V
Ceramic Capacitors
Higher value, lower cost ceramic capacitors are now
becoming available in smaller case sizes. These are tempt-
ing for switching regulator use because of their very low
ESR. Unfortunately, the ESR is so low that it can cause
loop stability problems when ceramic is used for the
output capacitor. Solid tantalum capacitor ESR generates
a loop “zero” at 5kHz to 50kHz that is instrumental in
giving acceptable loop phase margin. Ceramic capacitors
remain capacitive to beyond 300kHz and usually resonate
with their ESL before ESR becomes effective. They are
shown graphically in Typical Performance Characteristics
and as a formula below. Current rating decreases with
duty cycle because the LT1507 has internal slope com-
pensation to prevent current mode subharmonic switch-
ing. For more details on subharmonic oscillation read
Application Note 19. Peak guaranteed switch current (I P )
is found from:
V
V IN
I P = 1 . 75 A ? for OUT ≥ 0 . 5
V IN V IN
11
相关PDF资料 |
PDF描述 |
|---|---|
| GEM15DTBN-S273 | CONN EDGECARD 30POS R/A .156 SLD |
| LT1376CS8-5#TRPBF | IC REG BUCK 5V 1.5A 8SOIC |
| LT1376CS8-5#TR | IC REG BUCK 5V 1.5A 8SOIC |
| LT3433EFE#TRPBF | IC REG BUCK BST ADJ 0.5A 16TSSOP |
| HM61-20270LFTR13 | INJECTION MOULDED INDUCTORS |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1507CS8PBF | 制造商:Linear Technology 功能描述:LT1507CS8PBF |
| LT1507G | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:1.5A GLASS PASSIVATED RECTIFIER |
| LT1507I | 制造商:LINER 制造商全称:Linear Technology 功能描述:500kHz Monolithic Buck Mode Switching Regulator |
| LT1507IN8 | 功能描述:IC REG BUCK ADJ 1.5A 8DIP 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 |
| LT1507IN8#PBF | 功能描述:IC REG BUCK ADJ 1.5A 8DIP 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 |
发布紧急采购，3分钟左右您将得到回复。