参数资料
型号: LT3692IUH#PBF
厂商: LINEAR TECHNOLOGY CORP
元件分类: 稳压器
英文描述: 5.8 A DUAL SWITCHING CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PQCC32
封装: 5 X 5 MM, LEAD FREE, PLASTIC, MO-220WHHD, QFN-32
文件页数: 8/36页
文件大小: 526K
代理商: LT3692IUH#PBF
LT3692
16
3692f
APPLICATIONS INFORMATION
You can also use electrolytic capacitors. The ESRs of most
aluminum electrolytics are too large to deliver low output
ripple. Tantalum and newer, lower ESR organic electrolytic
capacitors intended for power supply use, are suitable
and the manufacturers will specify the ESR. The choice of
capacitor value will be based on the ESR required for low
ripple. Because the volume of the capacitor determines
its ESR, both the size and the value will be larger than a
ceramic capacitor that would give you similar ripple per-
formance. One benefit is that the larger capacitance may
give better transient response for large changes in load
current. Table 3 lists several capacitor vendors.
Table 3
VENDOR
TYPE
SERIES
Taiyo Yuden
Ceramic X5R, X7R
AVX
Ceramic X5R, X7R
Tantalum
Kemet
Tantalum
TA Organic
AL Organic
T491, T494, T495
T520
A700
Sanyo
TA/AL Orgainic
POSCAP
Panasonic
AL Organic
SP CAP
TDK
Ceramic X5R, X7R
Catch Diode
The diode D1 conducts current only during switch off
time. Use a Schottky diode to limit forward voltage drop to
increase efficiency. The Schottky diode must have a peak
reverse voltage that is equal to regulator input voltage and
sized for average forward current in normal operation.
Average forward current can be calculated from:
ID(AVG) =
IOUT
VIN
VIN – VOUT
(
)
With a shorted condition, diode current will increase to the
typical value determined by the peak switch current limit
of the LT3692 set by the ILIM pin. This is safe for short
periods of time, but it would be prudent to check with the
diode manufacturer if continuous operation under these
conditions can be tolerated.
BST Pin Considerations
The capacitor and diode tied to the BST pin generate a
voltage that is higher than the input voltage. In most cases
a 0.47F capacitor and a small Schottky diode (such as the
CMDSH-4E)willworkwell.Toensureoptimalperformance
at duty cycles greater than 80%, use a 0.5A Schottky
diode (such as a PMEG4005). Almost any type of film or
ceramic capacitor is suitable, but the ESR should be <1
to ensure it can be fully recharged during the off time of
the switch. The capacitor value can be approximated by:
CBST =
IOUT(MAX) VOUT
5 VIN VOUT – 2
(
) f
where IOUT(MAX) is the maximum load current.
Figure 7 shows four ways to arrange the boost circuit. The
BST pin must be more than 3V above the SW pin for full
efficiency. Generally, for outputs of 3.3V and higher the
standard circuit (Figure 7a) is the best. For lower output
voltages the boost diode can be tied to the input (Fig-
ure 7b). The circuit in Figure 7a is more efficient because
the BST pin current comes from a lower voltage source.
Figure 7c shows the boost voltage source from available
DC sources that are greater than 3V. The highest efficiency
is attained by choosing the lowest boost voltage above 3V.
For example, if you are generating 3.3V and 1.8V and the
3.3V is on whenever the 1.8V is on, the 1.8V boost diode
can be connected to the 3.3V output. In any case, you
must also be sure that the maximum voltage at the BST
pin is less than the maximum specified in the Absolute
Maximum Ratings section.
The boost circuit can also run directly from a DC voltage
that is higher than the input voltage by more than 3V, as
in Figure 7d. The diode is used to prevent damage to the
LT3692 in case VX is held low while VIN is present. The
circuit saves several components (both BST pins can be
tied to D2). However, efficiency may be lower and dissipa-
tion in the LT3692 may be higher. Also, if VX is absent, the
LT3692 will still attempt to regulate the output, but will do
so with very low efficiency and high dissipation because
相关PDF资料
PDF描述
LT3692EUH#PBF 5.8 A DUAL SWITCHING CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PQCC32
LT3724MPFE#TR SWITCHING CONTROLLER, 225 kHz SWITCHING FREQ-MAX, PDSO16
LT3740EDHC 0.14 A SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDSO16
LT3741EFE#PBF SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PDSO20
LT3741IFE#TRPBF SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PDSO20
相关代理商/技术参数
参数描述
LT3693 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic Dual Tracking
LT36931DD#PBF 制造商:Linear Technology 功能描述:
LT3693EDD#PBF 功能描述:IC REG BUCK ADJ 3.5A 10DFN 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
LT3693EDD#TRPBF 功能描述:IC REG BUCK ADJ 3.5A 10DFN 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
LT3693EDDPBF 制造商:Linear Technology 功能描述:DC-DC Converter Step-Down 3.6-36V DFN10