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| 型号： | MAX16975AEE/V+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/17页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 5V/ADJ 16QSOP |
| 其它有关文件： | Automotive Product Guide |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 类型： | 降压（降压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 5V，1 V ~ 10 V |
| 输入电压： | 3.5 V ~ 28 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 220kHz ~ 1MHz |
| 电流 - 输出： | 1.2A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 16-QSOP |
MAX16975
28V, 1.2A Automotive Step-Down Converter
with Low Operating Current
The inductor value must be chosen so that the maximum
inductor current does not reach the minimum current limit
of the device. The optimum operating point is usually
found between 15% and 35% ripple current. When pulse
skipping (light loads), the inductor value also determines
the load-current value at which PFM/PWM switchover
occurs.
The input-voltage ripple comprises D V Q (caused by the
capacitor discharge) and D V ESR (caused by the ESR
of the capacitor). Use low-ESR ceramic capacitors with
high ripple-current capability at the input. Assume the
contribution from D V Q and D V ESR to be 50%. Calculate
the input capacitance and ESR required for a specified
input-voltage ripple using the following equations:
? V ESR
ESR IN =
I OUT +
? I L = SUPSW OUT OUT
? I INDUCTOR =
C IN = OUT
Find a low-loss inductor having the lowest possible
DC resistance that fits in the allotted dimensions. Most
inductor manufacturers provide inductors in standard
values, such as 1.0 F H, 1.5 F H, 2.2 F H, 3.3 F H, etc. Also
look for nonstandard values, which can provide a better
compromise in LIR across the input voltage range. If
using a swinging inductor (where the no-load inductance
decreases linearly with increasing current), evaluate
the LIR with properly scaled inductance values. For
the selected inductance value, the actual peak-to-peak
inductor ripple current ( D I INDUCTOR ) is defined by:
V OUT (V SUPSW - V OUT )
V SUPSW × f SW × L
where:
and
and
? I L
2
(V - V ) × V
V SUPSW × f SW × L
I × D(1- D)
? V Q × f SW
where D I INDUCTOR is in A, L is in H, and f SW is in Hz.
Ferrite cores are often the best choices, although pow-
D =
V OUT
V SUPSW
dered iron is inexpensive and can work well at 220kHz.
The core must be large enough not to saturate at the
peak inductor current (I PEAK ):
I OUT is the maximum output current and D is the duty
cycle.
I PEAK
= I LOAD(MAX) +
? I INDUCTOR
2
Output Capacitor
The output filter capacitor must have low enough equiva-
lent series resistance (ESR) to meet output ripple and
Input Capacitor
The input filter capacitor reduces peak currents drawn
from the power source and reduces noise and voltage
ripple on the input caused by the circuit’s switching.
The input capacitor RMS current requirement (I RMS ) is
defined by the following equation:
load transient requirements, yet have high enough ESR
to satisfy stability requirements. The output capacitance
must be high enough to absorb the inductor energy while
transitioning from full-load to no-load conditions without
tripping the overvoltage fault protection. When using
high-capacitance, low-ESR capacitors, the filter capaci-
tor’s ESR dominates the output voltage ripple. So the size
I RMS = I LOAD(MAX)
V OUT (V SUPSW - V OUT )
V SUPSW
of the output capacitor depends on the maximum ESR
required to meet the output voltage ripple (V RIPPLE(P-P) )
specifications:
I RMS is at a maximum value when the input voltage
equals twice the output voltage (V SUPSW = 2V OUT ), so
I RMS(MAX) = I LOAD(MAX) /2.
Choose an input capacitor that exhibits less than +10 N C
self-heating temperature rise at the RMS input current for
optimal long-term reliability.
Maxim Integrated
ESR × I
V RIPPLE(P ? P) = LOAD(MAX) × LIR
The actual capacitance value required relates to the
physical size needed to achieve low ESR, as well as
to the chemistry of the capacitor technology. Thus, the
capacitor is usually selected by ESR and voltage rating
rather than by capacitance value.
13
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相关代理商/技术参数 |
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|---|---|
| MAX16975BAEE/V+ | 功能描述:直流/直流开关转换器 28V 1A 2MHz 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 |
| MAX16975BAEE/V+CG | 制造商:Maxim Integrated Products 功能描述:28V, 1.2A AUTOMOTIVE STEP-DOWN CONVERTER WITH LOW OPERATING - Rail/Tube 制造商:Maxim Integrated Products 功能描述:IC REG BUCK SYNC 5V/ADJ 16QSOP |
| MAX16975BAEE/V+T | 功能描述:直流/直流开关转换器 28V 1A 2MHz 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 |
| MAX16975BAEE/V+TCG | 制造商:Maxim Integrated Products 功能描述:28V, 1.2A AUTOMOTIVE STEP-DOWN CONVERTER WITH LOW OPERATING - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC REG BUCK SYNC 5V/ADJ 16QSOP |
| MAX16975BAEE+CFY | 制造商:Maxim Integrated Products 功能描述:28V, 1.2A AUTOMOTIVE STEP-DOWN CONVERTER WITH LOW OPERATING - Rail/Tube 制造商:Maxim Integrated Products 功能描述:IC REG BUCK SYNC 5V/ADJ 16QSOP |
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