- 您现在的位置：买卖IC网 > PDF目录67412 > FAN5361UMP10X (FAIRCHILD SEMICONDUCTOR CORP) SWITCHING REGULATOR, DSO6 PDF资料下载
参数资料
| 型号： | FAN5361UMP10X |
| 厂商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, DSO6 |
| 封装： | 2 X 2 MM, ROHS COMPLIANT, MO-229VCCC, UMLP-6 |
| 文件页数： | 4/17页 |
| 文件大小： | 1565K |
| 代理商： | FAN5361UMP10X |
2008 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FAN5361 Rev. 1.0.0
12
FAN5361
—
6MHz,
60
0mA
TinyBu
ck
Syn
c
hronous
Buck
Regu
lator
Operation Description
The FAN5361 is a 600mA, step-down, switching voltage
regulator that delivers a fixed output from an input voltage
supply of 2.3V to 5.5V. Using a proprietary architecture with
synchronous rectification, the FAN5361 is capable of
delivering a peak efficiency of 92%, while maintaining
efficiency over 80% at load currents as low as 1mA. The
regulator operates at a nominal frequency of 6MHz at full load,
which reduces the value of the external components to 470nH
for the inductor and 4.7F for the output capacitor.
Control Scheme
The FAN5361 uses a proprietary, non-linear, fixed-frequency
PWM modulator to deliver a fast load transient response,
while maintaining a constant switching frequency over a wide
range of operating conditions. The regulator performance is
independent of the output capacitor ESR, allowing for the use
of ceramic output capacitors. Although this type of operation
normally results in a switching frequency that varies with input
voltage and load current, an internal frequency loop holds the
switching frequency constant over a large range of input
voltages and load currents.
For very light loads, the FAN5361 operates in discontinuous
current (DCM) single-pulse PFM mode, which produces low
output ripple compared with other PFM architectures.
Transition between PWM and PFM is seamless, with a glitch
of less than 18mV at VOUT during the transition between DCM
and CCM modes.
Combined with exceptional transient response characteristics,
the very low quiescent current of the controller (35A)
maintains high efficiency; even at very light loads, while
preserving fast transient response for applications requiring
tight output regulation.
Enable and Soft-Start
Maintaining the EN pin LOW keeps the FAN5361 in non-
switching mode, in which all circuits are off and the part draws
~50nA of current. Increasing EN above its threshold voltage
activates the part and starts the soft-start cycle. The output
ramp during soft-start is a fixed slew rate of 50mV/
μs from 0 to
1VOUT, then 25mV/μs for 1.82VOUT or 12mV/s for 1.2VOUT
until the output reaches its setpoint.
MODE pin
Logic 1 on this pin forces the IC to stay in PWM mode. A logic
0 allows the IC to automatically switch to PFM during light
loads. If the MODE pin is toggled, the converter synchronizes
its switching frequency to four times the frequency on the
mode pin (fMODE). The mode pin must be held LOW for at least
10
μs or HIGH for 10μs to ensure that the converter does not
attempt to synchronize to this pin.
Current Limit, Fault Shutdown, and Restart
A heavy load or short circuit on the output causes the current
in the inductor to increase until a maximum current threshold
is reached in the high-side switch. Upon reaching this point,
the high-side switch turns off, preventing high currents from
causing damage. The regulator continues to limit the current
cycle-by-cycle. After 21s of current limit, the regulator
triggers an over-current fault, causing the regulator to shut
down for about 86
μs before attempting a restart.
If the fault was caused by short circuit, the soft-start circuit
attempts to restart at 33% of normal current limit and produces
an over-current fault after about 21
μs, which results in a duty
cycle of less than 25% providing current into a short.
Under-Voltage Lockout (UVLO)
When EN is high, the under-voltage lock-out keeps the part
from operating until the input supply voltage rises high enough
to properly operate. This ensures no misbehavior of the
regulator during start-up or shutdown.
Thermal Shutdown (TSD)
When the die temperature increases, due to a high load
condition and/or a high ambient temperature, the output
switching is disabled until the temperature on the die has
fallen sufficiently. The junction temperature at which the
thermal shutdown activates is nominally 150°C with a 15°C
hysteresis.
Minimum Off-Time Effect on Switching
Frequency
tOFF(MIN) is 50ns. This imposes constraints on the maximum
IN
OUT
V
that the FAN5361 can provide, while maintaining a
fixed switching frequency in PWM mode.
7
.
0
1
)
(
≈
≤
SW
MIN
OFF
IN
OUT
f
t
V
IN
OUT
IN
SW
V
ns
V
f
≈
50
The switching frequency drops when the regulator cannot
provide sufficient duty cycle at 6Mhz to maintain regulation.
This occurs when VOUT is 1.8V or 1.82V and VIN is below 3V at
high load currents (see Figure 13).
The calculation for switching frequency is given by:
=
ns
t
f
MAX
SW
6
.
166
1
,
1
min
)
(
where:
(1)
+
=
OUT
ON
OUT
IN
OFF
OUT
MAX
SW
V
R
I
V
R
I
V
ns
t
1
50
)
(
(2)
where:
OFF
R
=
L
N
DSON
DCR
R
+
_
ON
R
=
L
P
DSON
DCR
R
+
_
相关PDF资料 |
PDF描述 |
|---|---|
| FAN5361UC13X | SWITCHING REGULATOR, PBGA6 |
| FAN5361UC15X | SWITCHING REGULATOR, PBGA6 |
| FAN5361UMP12X | SWITCHING REGULATOR, DSO6 |
| FAN5361UC18X | SWITCHING REGULATOR, PBGA6 |
| FAN5361UC10X | SWITCHING REGULATOR, PBGA6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FAN5361UMP123X | 功能描述:直流/直流开关调节器 6MHz, 600mA / 750mA Synchronous Buck Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| FAN5361UMP12X | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:6MHz, 600mA TinyBuck⑩ Synchronous Buck Regulator |
| FAN5361UMP13X | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:6MHz, 600mA TinyBuck⑩ Synchronous Buck Regulator |
| FAN5361UMP15X | 功能描述:直流/直流开关调节器 6MHz;600mA;TinyBuck Syncronous Buck Reg. RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| FAN5361UMP182X | 功能描述:直流/直流开关调节器 6MHz, 600mA/750mA Sync Buck Regulator RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
发布紧急采购，3分钟左右您将得到回复。