参数资料
| 型号： | MIC2826-A0YMT TR |
| 厂商： | Micrel Inc |
| 文件页数： | 24/27页 |
| 文件大小： | 0K |
| 描述： | IC PWR MANAGER PROG 4OUT 14-TMLF |
| 特色产品： | MIC2826 Quad Output PMIC |
| 标准包装： | 1 |
| 应用： | 处理器 |
| 电源电压： | 2.7 V ~ 5.5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-UFQFN 裸露焊盘，14-TMLF? |
| 供应商设备封装： | 14-TMLF?（2.5x2.5） |
| 包装： | 标准包装 |
| 产品目录页面： | 1086 (CN2011-ZH PDF) |
| 其它名称： | 576-3529-6 |
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Micrel, Inc.
product of the quiescent (operating) current and the
supply voltage is another DC loss. The current required
driving the gates on and off at a constant 4MHz
frequency and the switching transitions make up the
switching losses.
Efficiency VOUT=1.8V
MIC2826
PMOS on and keeps it on for the duration of the
minimum-on-time. This increases the output voltage. If
the output voltage is over the regulation threshold, then
the error comparator turns the PMOS off for a minimum-
off-time until the output drops below the threshold. The
NMOS acts as an ideal rectifier that conducts when the
PMOS is off. Using a NMOS switch instead of a diode
allows for lower voltage drop across the switching device
100
VIN=3.6V
when it is on. The asynchronous switching combination
90
80
70
60
50
40
30
20
10
0
1
VIN=2.7V
VIN=4.2V
10 100
LOAD CURRENT (mA)
1000
between the PMOS and the NMOS allows the control
loop to work in discontinuous mode for light load
operations. In discontinuous mode, the MIC2826 works
in pulse frequency modulation (PFM) to regulate the
output. As the output current increases, the off-time
decreases, thus providing more energy to the output.
This switching scheme improves the efficiency of
MIC2826 during light load currents by only switching
when it is needed. As the load current increases, the
MIC2826 goes into continuous conduction mode (CCM)
and switches at a frequency centered at 4MHz. The
V OUT × I OUT
Efficiency Loss = ? 1 ? ? ? ? × 100
? ( V IN ? V OUT ) × D ?
I LOAD > ? ?
The Figure above shows an efficiency curve. From no
load to 100mA, efficiency losses are dominated by
quiescent current losses, gate drive and transition
losses. By using the HyperLight Load? mode the
MIC2826 is able to maintain high efficiency at low output
currents.
Over 100mA, efficiency loss is dominated by MOSFET
R DSON and inductor losses. Higher input supply voltages
will increase the Gate-to-Source threshold on the
internal MOSFETs, thereby reducing the internal R DSON .
This improves efficiency by reducing DC losses in the
device. All but the inductor losses are inherent to the
device. In which case, inductor selection becomes
increasingly critical in efficiency calculations. As the
inductors are reduced in size, the DC resistance (DCR)
can become quite significant. The DCR losses can be
calculated as follows:
DCR Loss = I OUT2 × DCR
From that, the loss in efficiency due to inductor
resistance can be calculated as follows:
? ? ? ?
? ?
? ? V OUT × I OUT + L_P D ? ?
equation to calculate the load when the MIC2826 goes
into continuous conduction mode may be approximated
by the following formula:
? 2L × f ?
As shown in the previous equation, the load at which
MIC2826 transitions from HyperLight Load? mode to
PWM mode is a function of the input voltage (V IN ), output
voltage (V OUT ), duty cycle (D), inductance (L) and
frequency (f). This is illustrated in the graph below. Since
the inductance range of MIC2826 is from 0.47μH to
4.7μH, the device may then be tailored to enter
HyperLight Load? mode or PWM mode at a specific
load current by selecting the appropriate inductance. For
example, in the graph below, when the inductance is
4.7μH the MIC2826 will transition into PWM mode at a
load of approximately 5mA. Under the same condition,
when the inductance is 1μH, the MIC2826 will transition
into PWM mode at approximately 70mA.
Switching Frequency
v s. Load Current
10
L=4.7μH
Efficiency loss due to DCR is minimal at light loads and
gains significance as the load is increased. Inductor
selection becomes a trade-off between efficiency and
size in this case.
HyperLight Load Mode?
The MIC2826 uses a minimum on and off time
1
0.1
L=2.2μH
L=1μH
proprietary control loop (patented by Micrel). When the
output voltage falls below the regulation threshold, the
0.01
1
10 100
LO AD CURRENT (mA)
1000
error comparator begins a switching cycle that turns the
July 2009
24
M9999-071609-A
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| MIC2826-D9YMT TR | 功能描述:直流/直流开关调节器 Single 500mA Step-Down and Triple 150mA LDOs with I2C Voltage Control & Sequencing 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 |
| MIC2826-D9YMT-TR | 功能描述:Processor PMIC 14-TMLF? (2.5x2.5) 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:停产 应用:处理器 电流 - 电源:- 电压 - 电源:2.7 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:14-UFQFN 裸露焊盘，14-TMLF? 供应商器件封装:14-TMLF?（2.5x2.5） 标准包装:1 |
| MIC2827-B2YMT TR | 功能描述:直流/直流开关调节器 Single 500mA Step-Down and Dual 150mA LDOs with I2C Voltage Control & Sequencing 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 |
| MIC2827-B2YMT-TR | 功能描述:Processor PMIC 14-TMLF? (2.5x2.5) 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:停产 应用:处理器 电流 - 电源:- 电压 - 电源:2.7 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:14-UFQFN 裸露焊盘，14-TMLF? 供应商器件封装:14-TMLF?（2.5x2.5） 标准包装:1 |
| MIC2827-E1YMT TR | 功能描述:直流/直流开关调节器 Single 500mA Step-Down and Dual 150mA LDOs with I2C Voltage Control & Sequencing 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 |
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