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参数资料
| 型号： | MAX15021EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/24页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR MAX15021 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 0.6 V ~ 5.5 V |
| 电流 - 输出： | 4A，2A |
| 输入电压： | 2.5 V ~ 5.5 V |
| 稳压器拓扑结构： | 降压 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX15021 |
MAX15021
Dual, 4A/2A, 4MHz, Step-Down DC-DC
Regulator with Tracking/Sequencing Capability
Effective Input-Voltage Range
Although the MAX15021’s regulators can operate from
input supplies ranging from 2.5V to 5.5V, the input-volt-
age range can be effectively limited by the
MAX15021’s duty-cycle limitations for a given output
voltage (V OUT_ ). The maximum input voltage
(V PVIN_MAX ) can be effectively limited by the control-
lable minimum on-time (t ON(MIN) ):
where V PVIN_ is the input supply voltage, V OUT_ is the
regulator output voltage, and f SW is the switching fre-
quency. Use typical values for V PVIN_ and V OUT_ so
that efficiency is optimum for typical conditions. The
switching frequency (f SW ) is programmable between
500kHz and 4MHz (see the Oscillator section).
The peak-to-peak inductor current ( Δ I P-P ), which
reflects the peak-to-peak output ripple, is largest at the
V PVIN_MAX [V] ≤
V OUT_ [V]
t ON(MIN) [ μ s] × f SW [MHz]
maximum input voltage. See the Output-Capacitor
Selection section to verify that the worst-case output
current ripple is acceptable.
where t ON(MIN) is 0.06μs (typ).
The minimum input voltage (V PVIN_MIN ) can be effec-
tively limited by the maximum controllable duty cycle
and is calculated using the following equation:
Select an inductor with a saturation current, I SAT , high-
er than the maximum peak current to avoid runaway
current during continuous output short-circuit condi-
tions. Also, confirm that the inductor’s thermal perfor-
mances and projected temperature rise above ambient
does not exceed its thermal capacity. Many inductor
V PVIN_MIN [V] ≥
V OUT_ [V]
1 ? (t OFF(MIN) [ μ s] × f SW [MHz])
manufacturers provide bias/load current versus tem-
perature rise performance curves (or similar) to obtain
this information.
where V OUT_ is the regulator output voltage and
t OFF(MIN) is the 0.06μs (typ) controllable off-time.
Inductor Selection
Three key inductor parameters must be specified for
operation with the MAX15021: inductance value (L),
peak inductor current (I PEAK ), and inductor saturation
current (I SAT ). The minimum required inductance is a
function of operating frequency, input-to-output voltage
differential, and the peak-to-peak inductor current
( Δ I P-P ). Higher Δ I P-P allows for a lower inductor value. A
lower inductance minimizes size and cost and
improves large-signal and transient response.
However, efficiency is reduced due to higher peak cur-
Input-Capacitor Selection
The discontinuous input current of the buck converter
causes large input ripple currents and therefore, the
input capacitor must be carefully chosen to withstand
the input ripple current and keep the input-voltage rip-
ple within design requirements.
The input-voltage ripple is comprised of Δ V Q (caused by
the capacitor discharge) and Δ V ESR (caused by the ESR
of the input capacitor). The total voltage ripple is the
sum of Δ V Q and Δ V ESR which peaks at the end of the
on-cycle. Calculate the required input capacitance and
ESR for a specified ripple using the following equations:
? Δ I P ? P ?
? I LOAD(MAX) + ? [A]
rents and higher peak-to-peak output-voltage ripple for
the same output capacitor. A higher inductance
increases efficiency by reducing the ripple current;
however, resistive losses due to extra wire turns can
ESR [ m Ω ] =
? 2 ?
Δ V ESR [mV]
I LOAD(MAX) [A] × ? OUT_
? V PVIN_ [V] ?
C PVIN_ [ μ F ] =
( V PVIN_ ? V OUT_ ) [V] × V OUT_ [V]
Δ I P ? P [A] =
exceed the benefit gained from lower ripple current lev-
els especially when the inductance is increased without
also allowing for larger inductor dimensions. Choose
the inductor’s peak-to-peak current, Δ I P-P, in the range
of 20% to 50% of the full load current; as a rule of
thumb 30% is typical.
Calculate the inductance, L, using the following equation:
? V [V] ?
?
Δ V Q [V] × f SW [MHz]
V PVIN_ [V] × f SW [MHz] × L [ μ H ]
L [ μ H ] =
Maxim Integrated
V OUT_ [V] × (V PVIN_ [V] ? V OUT_ [V])
V PVIN_ [V] × f SW [MHz] × Δ I P ? P [ A ]
I LOAD(MAX) is the maximum output current, Δ I P-P is the
peak-to-peak inductor current, and V PVIN_ is the input
supply voltage, V OUT_ is the regulator output voltage,
and f SW is the switching frequency.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX15021EVKIT+ | 功能描述:电源管理IC开发工具 MAX15021 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 |
| MAX15022ATI+ | 功能描述:直流/直流开关调节器 Dual 4A/2A 4MHz w/Dual LDO Ctlr 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 |
| MAX15022ATI+T | 功能描述:直流/直流开关调节器 Dual 4A/2A 4MHz w/Dual LDO Ctlr 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 |
| MAX15022EVKIT+ | 功能描述:电源管理IC开发工具 MAX15022 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 |
| MAX15023ETG/V+ | 功能描述:DC/DC 开关控制器 4.5-28V Input Dual Out Synch Buck 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 |
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