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参数资料
| 型号： | LTC3828EG |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | Dual 2-Phase Step-Down Controller with Tracking |
| 中文描述： | 3 A DUAL SWITCHING CONTROLLER, 590 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封装： | 5.30 MM, PLASTIC, SSOP-28 |
| 文件页数： | 18/32页 |
| 文件大小： | 396K |
| 代理商： | LTC3828EG |
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LTC3828
3828f
APPLICATIOU
highest efficiency battery operated systems. Also con-
sider parallel ceramic and high quality electrolytic capaci-
tors as an effective means of achieving ESR and bulk
capacitance goals.
In continuous mode, the source current of the top N-chan-
nel MOSFET is a square wave of duty cycle V
OUT
/V
IN
. To
prevent large voltage transients, a low ESR input capacitor
sized for the maximum RMS current of one channel must
be used. The maximum RMS capacitor current is given by:
W
U
U
C
quiredI
Re
I
V
V
V
V
IN
RMS
MAX
OUT
IN
OUT
IN
/
≈
(
)
[
]
1 2
This formula has a maximum at V
IN
= 2V
OUT
, where
I
RMS
= I
OUT
/2. This simple worst case condition is com-
monly used for design because even significant deviations
do not offer much relief. Note that capacitor manufacturer’s
ripple current ratings are often based on only 2000 hours
of life. This makes it advisable to further derate the
capacitor, or to choose a capacitor rated at a higher
temperature than required. Several capacitors may also be
paralleled to meet size or height requirements in the
design. Always consult the manufacturer if there is any
question.
The benefit of the LTC3828 multiphase clocking can be
calculated by using the equation above for the higher
power controller and then calculating the loss that would
have resulted if both controller channels switched on at
the same time. The total RMS power lost is lower when
both controllers are operating due to the interleaving of
current pulses through the input capacitor’s ESR. This is
why the input capacitor’s requirement calculated above
for the worst-case controller is adequate for the dual
controller design. Remember that input protection fuse
resistance, battery resistance and PC board trace resis-
tance losses are also reduced due to the reduced peak
currents in a multiphase system. The overall benefit of a
multiphase design will only be fully realized when the
source mpedance of the power supply/battery s ncluded
in he efficiency esting.The drains of the two top MOSFETS
should be placed within 1cm of each other and share a
common C
IN
(s). Separating the drains and C
IN
may pro-
duce undesirable voltage and current resonances at V
IN
.
The selection of C
OUT
is driven by the required output
voltage ripple and load transient response. Both the ca-
pacitor effective series resistance (ESR) and capacitance
determine the output ripple:
V
I
ESR
fC
OUT
L
OUT
≈
+
1
8
Where f = operating frequency, C
OUT
= output capacitance
and
I
L
= ripple current in the inductor. The output ripple
is highest at maximum input voltage since
I
L
increases
with input voltage.
Usually, ceramic capacitors are used to minimize the
output voltage ripple because of their ultralow ESR. Cur-
rently, multilayer ceramic capacitors have capacitor val-
ues up to hundreds of
μ
F. However, the capacitance of the
ceramic capacitors usually decreases with increased DC
bias voltage and ambient temperature. In general, X5R or
X7R type capacitors are recommended for high perfor-
mance solutions. The OPTI-LOOP current mode control of
LTC3828 provides stable, high performance transient
response even with all ceramic output capacitors. Manu-
factures such as TDK, Taiyo Yuden, Murata and AVX
provide high performance ceramic capacitors.
When high capacitance is needed, especially for load
transient requirement, low ESR polymerized electrolytic
capacitors such as Sanyo POSCAP or Panasonic SP
capacitor can be used in parallel with ceramic capacitors.
Other high performance electolytic capacitor manufactur-
ers include AVX, KEMET and NEC. With LTC3828, a
combination of ceramic and low ESR electrolytic capaci-
tors can provide a low ripple, fast transient, high density
and cost-effective solution. Consult manufacturers for
specific recommendations.
INTV
CC
Regulator
An internal P-channel low dropout regulator produces 5V
at the INTV
CC
pin from the V
IN
supply pin. INTV
CC
powers
the drivers and internal circuitry within the IC. The INTV
CC
pin regulator can supply a peak current of 50mA and
must be bypassed to ground with a minimum of 4.7
μ
F
tantalum, 10
μ
F special polymer, or low ESR type electro-
lytic capacitor. A 1
μ
F ceramic capacitor placed directly
adjacent to the INTV
CC
and PGND IC pins is highly
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3828EG#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
| LTC3828EG#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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 |
| LTC3828EUH | 制造商:Linear Technology 功能描述:DC DC Cntrlr Dual-OUT Sync Step Down 4.5V to 28V Input 32-Pin QFN EP |
| LTC3828EUH#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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 |
| LTC3828EUH#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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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