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参数资料
| 型号： | MAX5098AATJ+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/28页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BST ADJ 1A/2A 32TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 2 |
| 输出电压： | 0.8 V ~ 0.85 V，4.5 V ~ 28 V |
| 输入电压： | 4.5 V ~ 19 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 200kHz ~ 2.2MHz |
| 电流 - 输出： | 1A，2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
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Dual, 2.2MHz, Automotive Buck or Boost
Converter with 80V Load-Dump Protection
Inductor Selection
where
Three key inductor parameters must be specified for
operation with the MAX5098A: inductance value (L),
peak inductor current (I L ), and inductor saturation cur-
rent (I SAT ). The minimum required inductance is a func-
Δ I L =
( V IN ? V OUT ) × V OUT
V IN × f SW × L
tion of operating frequency, input-to-output voltage
differential and the peak-to-peak inductor current ( Δ I L ).
A good compromise is to choose Δ I L equal to 30% of
the full load current. To calculate the inductance, use
the following equation:
and
C IN =
I OUT × D ( 1 ? D )
Δ V Q × f SW
V OUT ( V IN ? V OUT )
× f
× Δ I
D = OUT
L =
V IN SW L
where V IN and V OUT are typical values (so that efficien-
where
V
V IN
ESR IN =
Δ I L
I OUT +
Δ V ESR
Δ I L
C OUT =
cy is optimum for typical conditions). The switching fre-
quency is set by R OSC (see the Setting the Switching
Frequency section). The peak-to-peak inductor current,
which reflects the peak-to-peak output ripple, is worse
at the maximum input voltage. See the Output
Capacitor section to verify that the worst-case output
ripple is acceptable. The inductor saturation current is
also important to avoid runaway current during output
overload and continuous short circuit. Select the I SAT to
be higher than the maximum peak current limits of 4.3A
and 2.6A for converter 1 and converter 2.
Input Capacitor
The discontinuous input current waveform of the buck
converter causes large ripple currents at the input. The
switching frequency, peak inductor current, and the
allowable peak-to-peak voltage ripple dictate the input
capacitance requirement. Note that the two converters
of the MAX5098A run 180° out-of-phase, thereby effec-
tively doubling the switching frequency at the input.
The input ripple waveform would be unsymmetrical due
to the difference in load current and duty cycle
between converter 1 and converter 2. The worst-case
mismatch is when one converter is at full load while the
other converter is at no load or in shutdown. The input
ripple is comprised of Δ V Q (caused by the capacitor
discharge) and Δ V ESR (caused by the ESR of the
capacitor). Use ceramic capacitors with high ripple-
current capability at the input, connected between
DRAIN_ and PGND_. Assume the contribution from the
ESR and capacitor discharge equal to 50%. Calculate
the input capacitance and ESR required for a specified
ripple using the following equations:
Δ V ESR
2
where I OUT is the maximum output current from either
converter 1 or converter 2, and D is the duty cycle for
that converter. The frequency of each individual con-
verter is f SW . For example, at V IN = 12V, V OUT = 3.3V at
I OUT = 2A, and with L = 3.3μH, the ESR and input
capacitance are calculated for a peak-to-peak input rip-
ple of 100mV or less, yielding an ESR and capacitance
value of 20m Ω and 6.8μF for 1.25MHz frequency. At low
input voltages, also add one electrolytic bulk capacitor
of at least 100μF on the converters’ input voltage rail.
This capacitor acts as an energy reservoir to avoid pos-
sible undershoot below the undervoltage lockout thresh-
old during power-on and transient loading.
Output Capacitor
The allowable output ripple voltage and the maximum
deviation of the output voltage during step load cur-
rents determines the output capacitance and its ESR.
The output ripple is comprised of Δ V Q (caused by the
capacitor discharge) and Δ V ESR (caused by the ESR of
the capacitor). Use low-ESR ceramic or aluminum elec-
trolytic capacitors at the output. For aluminum elec-
trolytic capacitors, the entire output ripple is
contributed by Δ V ESR . Use the ESR OUT equation to cal-
culate the ESR requirement and choose the capacitor
accordingly. If using ceramic capacitors, assume the
contribution to the output ripple voltage from the ESR
and the capacitor discharge are equal. Calculate the
output capacitance and ESR required for a specified
ripple using the following equations:
ESR OUT =
Δ I L
8 × Δ V Q × f SW
______________________________________________________________________________________
19
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相关代理商/技术参数 |
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| MAX5099 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Dual, 2.2MHz, Automotive Synchronous Buck Converter with 80V Load-Dump Protection |
| MAX5099ATJ | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Dual, 2.2MHz, Automotive Synchronous Buck Converter with 80V Load-Dump Protection |
| MAX5099ATJ+ | 功能描述:直流/直流开关转换器 Dual 2.2MHz Synch Buck Converter 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 |
| MAX5099ATJ+T | 功能描述:直流/直流开关转换器 Dual 2.2MHz Synch Buck Converter 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 |
| MAX5099EVKIT+ | 功能描述:电源管理IC开发工具 MAX5098A/99 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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