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| 型号： | MAX16955AUE/V+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 17/26页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 16TSSOP |
| 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： | 96 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 3.5 V ~ 36 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 ~ 125°C |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 包装： | 管件 |
MAX16955
36V, 1MHz Step-Down Controller
with Low Operating Current
load current. The switching frequency is set by R FOSC
(see the Setting the Switching Frequency section).
The core must be large enough not to saturate at the
peak inductor current (I PEAK ):
The MAX16955 uses internal frequency independent
slope compensation to ensure stable operation at duty
cycles above 50%. The maximum slope compensation
I PEAK = I LOAD ( MAX ) +
Δ I INDUCTOR
2
ramp voltage over a full clock period is 200mV. Use the
equation below to select the inductor value:
Transient Response
The inductor ripple current also impacts transient
V OUT [ V ]
L [ μ H ] × f SW [ MHz ]
= 1 ± 25 %
response performance, especially at low V SUP - V OUT
differentials. Low inductor values allow the inductor cur-
rent to slew faster, replenishing charge removed from
the output filter capacitors by a sudden load step. The
However, if it is necessary, higher inductor values can
be selected.
The exact inductor value is not critical and can be
total output voltage sag is the sum of the voltage sag
while the inductor is ramping up and the voltage sag
before the next pulse can occur:
( )
L Δ I LOAD ( MAX )
adjusted to make trade-offs among size, cost, efficien-
cy, and transient response requirements. Table 1
shows a comparison between small and large inductor
sizes.
V SAG =
2
2 C OUT ( ( V SUP × D MAX ) ? V OUT )
+
Δ I LOAD(MAX ) ( t ? Δ t )
C OUT
Table 1. Inductor Size Comparison
INDUCTOR SIZE
SMALLER LARGER
Lower price Smaller ripple
Smaller form factor Higher efficiency
where D MAX is the maximum duty factor, L is the induc-
tor value in μH, C OUT is the output capacitor value in
μF, t is the switching period (1/f SW ) in μs, and Δ t equals
(V OUT /V SUP ) × t when in fixed-frequency PWM mode, or
L × 0.2 × I MAX /(V SUP - V OUT ) when in skip mode. The
amount of overshoot (V SOAR ) during a full-load to no-
load transient due to stored inductor energy can be cal-
( Δ I LOAD ( MAX ) )
Larger fixed-frequency range
Faster load response
in skip mode
The minimum practical inductor value is one that caus-
es the circuit to operate at the edge of critical conduc-
culated as:
V SOAR
≈
2
2 C OUT V OUT
L
tion (where the inductor current just touches zero with
every cycle at maximum load). Inductor values lower
than this grant no further size-reduction benefit. The
optimum operating point is usually found between 25%
and 45% ripple current. When pulse skipping (FSYNC
low and light loads), the inductor value also determines
the load-current value at which PFM/PWM switchover
occurs.
For the selected inductance value, the actual peak-to-
peak inductor ripple current ( Δ I INDUCTOR ) is defined by:
Current Sensing
For the most accurate current sensing, use a current-
sense resistor (R SENSE ) between the inductor and the
output capacitor. Connect CS to the inductor side of
R SENSE , and OUT to the capacitor side. Dimension
R SENSE so its maximum current (I OC ) induces a voltage
of V LIMIT (72mV minimum) across R SENSE .
If a higher voltage drop across R SENSE must be tolerat-
ed, divide the voltage across the sense resistor with a
voltage-divider between CS and OUT to reach V LIMIT
Δ I INDUCTOR =
V OUT ( V SUP ? V OUT )
V SUP × f SW × L
(72mV minimum).
The current-sense method (Figure 4) and magnitude
determine the achievable current-limit accuracy and
where Δ I INDUCTOR is in mA, L is in μH, and f SW is in kHz.
Maxim Integrated
power loss. Typically, higher current-sense limits
provide tighter accuracy, but also dissipate more
power. For the best current-sense accuracy and over-
current protection, use a ±1% tolerance current-sense
resistor with low parasitic inductance between the
inductor and output as shown in Figure 4a.
17
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相关代理商/技术参数 |
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| MAX16955EVKIT# | 功能描述:电源管理IC开发工具 MAX16955 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 |
| MAX16955EVKIT+ | 功能描述:电源管理IC开发工具 MAX16955 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 |
| MAX16956AUBA/V+T | 制造商:Maxim Integrated Products 功能描述:36V, 300MA, MINI BUCK CONVERTER WITH 2UA IQ - Tape and Reel |
| MAX16958GEE/V+ | 功能描述:模数转换器 - ADC 500mA Hi-Speed USB Protector RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX16958GEE/V+T | 功能描述:模数转换器 - ADC 500mA Hi-Speed USB Protector RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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