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参数资料
| 型号： | MAX8702ETP+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/14页 |
| 文件大小： | 0K |
| 描述： | IC DRVR MOSFET DUAL 20-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 配置： | 高端和低端，同步 |
| 输入类型： | PWM |
| 延迟时间： | 25ns |
| 电流 - 峰： | 1.5A |
| 配置数： | 4 |
| 输出数： | 4 |
| 电源电压： | 4.5 V ~ 28 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-WFQFN 裸露焊盘 |
| 供应商设备封装： | 20-TQFN-EP（4x4） |
| 包装： | 带卷 (TR) |
Dual-Phase MOSFET Drivers
with Temperature Sensor
? V
? ? I
?
PD ( N H RESISTIVE ) = ? OUT ? ? LOAD ? R DS ( ON )
PD ( N H IN ( MAX ) ) 2 ? RSS SW ? ? LOAD ?
SWITCHING ) = ( V
A 10 ° C hysteresis keeps the output from oscillating
when the temperature is close to the threshold. The
thermal trip point is programmable up to +160 ° C
through an external resistor between TSET and AGND.
Use the following equation to determine the value of
the resistor:
R TSET = (85,210 / T) – (745,200 / T 2 ) – 195
where R TSET is the value of the set-point resistor in k ?
and T is the trip-point temperature in Kelvin.
The MAX8702 and MAX8703 include a thermal-shut-
down circuit that is independent of the temperature
sensor. The thermal shutdown has a fixed threshold of
+160 ° C (typ) with 10 ° C of thermal hysteresis. When the
die temperature exceeds +160 ° C, DH is pulled low and
DL is pulled high. The driver automatically resets when
the die temperature drops by +10 ° C.
Applications Information
Power MOSFET Selection
Most of the following MOSFET guidelines focus on the
challenge of obtaining high load-current capability
when using high-voltage (>20V) AC adapters. Low-cur-
rent applications usually require less attention.
The high-side MOSFET (N H ) must be able to dissipate
the resistive losses plus the switching losses at both
V IN(MIN) and V IN(MAX) . Calculate both of these sums.
Ideally, the losses at V IN(MIN) should be roughly equal
to losses at V IN(MAX) , with lower losses in between. If
the losses at V IN(MIN) are significantly higher than the
losses at V IN(MAX) , consider increasing the size of N H
(reducing R DS(ON) but increasing C GATE ). Conversely,
if the losses at V IN(MAX) are significantly higher than the
losses at V IN(MIN) , consider reducing the size of N H
(increasing R DS(ON) but reducing C GATE ). If V IN does
not vary over a wide range, the minimum power dissi-
pation occurs where the resistive losses equal the
switching losses.
Choose a low-side MOSFET that has the lowest possi-
ble on-resistance (R DS(ON) ), comes in a moderate-
sized package (i.e., one or two SO-8s, DPAK, or
D 2 PAK), and is reasonably priced. Ensure that the DL
gate driver can supply sufficient current to support the
case power dissipation due to resistance occurs at the
minimum input voltage:
2
? V IN ? ? n TOTAL ?
where n TOTAL is the total number of phases.
Generally, a small high-side MOSFET is desired to
reduce switching losses at high input voltages.
However, the R DS(ON) required to stay within package
power dissipation often limits how small the MOSFETs
can be. Again, the optimum occurs when the switching
losses equal the conduction (R DS(ON) ) losses. High-
side switching losses do not usually become an issue
until the input is greater than approximately 15V.
Calculating the power dissipation in high-side
MOSFETs (N H ) due to switching losses is difficult since
it must allow for difficult quantifying factors that influ-
ence the turn-on and turn-off times. These factors
include the internal gate resistance, gate charge,
threshold voltage, source inductance, and PC board
layout characteristics. The following switching-loss cal-
culation provides only a very rough estimate and is no
substitute for breadboard evaluation, preferably includ-
ing verification using a thermocouple mounted on N H :
? C f ? ? I ?
? I GATE ? ? n TOTAL ?
where C RSS is the reverse transfer capacitance of N H
and I GATE is the peak gate-drive source/sink current
(5A typ).
Switching losses in the high-side MOSFET can
become an insidious heat problem when maximum AC
adapter voltages are applied, due to the squared term
in the C × V IN 2 × f SW switching-loss equation. If the
high-side MOSFET chosen for adequate R DS(ON) at
low battery voltages becomes extraordinarily hot when
biased from V IN(MAX) , consider choosing another
MOSFET with lower parasitic capacitance.
For the low-side MOSFET (N L ), the worst-case power
dissipation always occurs at the maximum input voltage:
PD ( N L RESISTIVE ) = ? 1 ? ?
? V IN ( MAX ) ? ?
? I LOAD ?
? n TOTAL ?
gate charge and the current injected into the parasitic
gate-to-drain capacitor caused by the high-side MOS-
FET turning on; otherwise, cross-conduction problems
can occur.
? ? V OUT ? ?
?
? ?
? ? R DS ( ON )
2
MOSFET Power Dissipation
Worst-case conduction losses occur at the duty factor
extremes. For the high-side MOSFET (N H ), the worst-
The worst case for MOSFET power dissipation occurs
under heavy overloads that are greater than
I LOAD(MAX) but are not quite high enough to exceed
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8703ETP | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX8703ETP+T | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX8703ETP-T | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX8704EUB | 功能描述:低压差稳压器 - LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| MAX8704EUB+ | 功能描述:线性稳压器 - 标准 High current Low Voltage LDO RoHS:否 制造商:STMicroelectronics 输出类型: 极性: 输出电压:1.8 V 输出电流:150 mA 负载调节: 最大输入电压:5.5 V 线路调整率: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-323-5L |
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