- 您现在的位置：买卖IC网 > PDF目录1841 > MAX1876EEG+T (Maxim Integrated Products)IC REG CTRLR BUCK PWM VM 24-QSOP PDF资料下载
参数资料
| 型号： | MAX1876EEG+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 17/21页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 660kHz |
| 占空比： | 90% |
| 电源电压： | 4.75 V ~ 23 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 ~ 85°C |
| 封装/外壳： | 24-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
Dual 180° Out-of-Phase PWM Step-
Down Controllers with POR
N L _ according to duty factor as shown in the equations
50
BODE PLOT FOR VOLTAGE-
MODE CONTROLLERS
below. Switching losses affect only the high-side
MOSFET, since the low-side MOSFET is a zero-voltage
switched device when used in the buck topology.
40
30
f LC
Calculate MOSFET temperature rise according to pack-
age thermal-resistance specifications to ensure that
20
10
f Z-COMP_A
f ESR
f CO
f SWITCH
both MOSFETs are within their maximum junction tem-
perature at high ambient temperature. The worst-case
dissipation for the high-side MOSFET (P NH ) occurs at
0
-10
both extremes of input voltage, and the worst-case dis-
sipation for the low-side MOSFET (P NL ) occurs at maxi-
-20
f COMP_B
mum input voltage.
P NH ( SWITCHING ) = IN LOAD OSC ? GS GD ?
-30
-40
0.001
0.01
0.1
1
V I f ? Q + Q ?
2 ? I GATE ?
FREQUENCY (MHz)
Figure 8. Voltage-Mode Loop Analysis
I GATE is the average DH driver output current capability
determined by:
? Minimum threshold voltage (V TH(MIN) )
? Total gate charge (Q g )
I GATE =
2 ( R DS ( ON ) DH + R GATE
V L
)
P NH ( CONDUCTION ) = I LOAD DS ( ON ) NH ? OUT ?
P NL = I LOAD R DS ( ON ) NL ? 1- ? OUT ? ?
? Reverse transfer capacitance (C RSS )
? Power dissipation
All four N-channel MOSFETs must be a logic-level type
with guaranteed on-resistance specifications at V GS ≥
4.5V. For maximum efficiency, choose a high-side
MOSFET (N H _) that has conduction losses equal to the
switching losses at the optimum input voltage. Check to
ensure that the conduction losses at minimum input
voltage do not exceed MOSFET package thermal limits,
or violate the overall thermal budget. Also, check to
ensure that the conduction losses plus switching losses
at the maximum input voltage do not exceed package
ratings or violate the overall thermal budget.
Ensure that the MAX1875/MAX1876 DL_ gate drivers
can drive N L _. In particular, check that the dv/dt
caused by N H _ turning on does not pull up the N L _
gate through N L _ ’ s drain-to-gate capacitance. This is
the most frequent cause of cross-conduction problems.
Gate-charge losses are dissipated by the driver and do
not heat the MOSFET. All MOSFETs must be selected
so that their total gate charge is low enough that V L can
power all four drivers without overheating the IC:
P VL = V IN × Q G _ TOTAL × f SW
MOSFET package power dissipation often becomes a
dominant design factor. I 2 R power losses are the great-
est heat contributor for both high-side and low-side
MOSFETs. I 2 R losses are distributed between N H _ and
where R DS(ON)DH is the high-side MOSFET driver ’ s on-
resistance (5 ? max), and R GATE is any series resis-
tance between DH and BST (Figure 3).
2 ? V ?
R
? V IN ?
P NH ( TOTAL ) = P NH ( SWITCHING ) + P NH ( CONDUCTION )
2 ? ? V ? ?
? ? V IN ? ?
where P NH(CONDUCTION) is the conduction power loss
in the high-side MOSFET, and P NL is the total low-side
power loss.
To reduce EMI caused by switching noise, add a 0.1μF
ceramic capacitor from the high-side switch drain to
the low-side switch source or add resistors in series
with DL_ and DH_ to increase the MOSFETs ’ turn-on
and turn-off times.
Applications Information
Dropout Performance
When working with low input voltages, the output-volt-
age adjustable range for continuous-conduction opera-
tion is restricted by the minimum off-time (t OFF(MIN) ).
For best dropout performance, use the lowest (100kHz)
switching-frequency setting. Manufacturing tolerances
and internal propagation delays introduce an error to
______________________________________________________________________________________
17
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1878ETC+ | IC REG BUCK BST SYNC ADJ 12TQFN |
| MAX1879EUA+T | IC CHARGER LI+ PULSE 8UMAX |
| MAX1880EUG+ | IC DC-DC CONV QUAD LCD 24TSSOP |
| MAX1889ETE+T | IC PWR SUP TRPL LCD 16-TQFN |
| MAX1896EUT#TG16 | IC REG BOOST ADJ 0.5A SOT23-6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1876EEG-TG05 | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1878EGC | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1878EGC-T | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1878EPD | 制造商:Maxim Integrated Products 功能描述: |
| MAX1878ETC+ | 功能描述:直流/直流开关转换器 Dual-Output Step-Down RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
发布紧急采购，3分钟左右您将得到回复。