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参数资料
| 型号： | MAX17083ETG+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 5A 24TQFN |
| 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） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.75 V ~ 2.7 V |
| 输入电压： | 2.4 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 500kHz |
| 电流 - 输出： | 5A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 24-TQFN-EP（4x4） |
Low-Voltage, Internal Switch,
Step-Down Regulator
(I LOAD ) determines the thermal stresses and thus dri-
ves the selection of input capacitors, MOSFETs, and
the selected inductance value, the actual peak-to-peak
inductor ripple current ( Δ I INDUCTOR ) is defined by:
( V - V
Δ I INDUCTOR = OUT IN OUT
V IN OSC L
?
other critical heat-contributing components.
Switching Frequency. This choice determines the
basic trade-off between size and efficiency. The
optimal frequency is largely a function of maximum
V
f
)
input voltage due to MOSFET switching losses that
are proportional to frequency and the square of V IN .
The optimum frequency is also a moving target, due
to rapid improvements in MOSFET technology that
are making higher frequencies more practical.
Ferrite cores are often the best choice, although soft sat-
urating molded core inductors are inexpensive and can
work well at 500kHz. The core must be large enough not
to saturate at the peak inductor current (I PEAK ):
I PEAK = I LOAD ( MAX ) + ?
?
Inductor Operating Point. This choice provides
trade-offs between size and efficiency, and
between transient response and output ripple. Low
? Δ I INDUCTOR ?
?
? 2 ?
inductor values provide better transient response
and smaller physical size, but also result in lower
efficiency and higher output ripple due to increased
ripple currents. The minimum practical inductor
value is one that causes the circuit to operate at the
edge of critical conduction (where the inductor cur-
rent just touches zero with every cycle at maximum
load). Inductor values lower than this grant no fur-
ther size-reduction benefit. The optimum operating
point is usually found between 20% and 50% of rip-
ple current. When pulse skipping (at light loads),
the inductor value also determines the load-current
value at which PFM/PWM switchover occurs.
Step-Down Inductor Selection
The switching frequency and inductor operating point
determine the inductor value as follows:
SMPS Output-Capacitor Selection
The output filter capacitor selection requires careful
evaluation of several different design requirements—
stability, transient response, and output ripple volt-
age—that place limits on the output capacitance and
ESR. Based on these requirements, the typical applica-
tion requires a low-ESR polymer capacitor (lower cost
but higher output-ripple voltage) or bulk ceramic
capacitors (higher cost but low output-ripple voltage).
SMPS Loop Compensation
Voltage positioning dynamically lowers the output volt-
age in response to the load current, reducing the loop
gain. This reduces the output capacitance requirement
(stability and transient) and output power dissipation
requirements as well. The load-line is generated by
sensing the inductor current through the high-side
L =
V OUT × ( V IN - V OUT )
V IN × f OSC × I LOAD ( MAX ) × LIR
MOSFET on-resistance, and is internally preset to
-5mV/A (typ). The load-line ensures that the output volt-
age remains within the regulation window over the full-
load conditions.
Assuming 5A maximum load current, and an LIR of 0.3
yields:
The load line of the internal SMPS regulators also pro-
vides the AC ripple voltage required for stability. To
× ( V
L = OUT IN OUT
V - V
V IN × f OSC × 1 . 5
)
maintain stability, the output capacitive ripple must be
kept smaller than the internal AC ripple voltage, and
crossover must occur before the Nyquist pole occurs
(1 + duty)/(2f SW ). Based on these loop requirements, a
C OUT > ?
? ? ? 1 + V
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 1.0μH, 1.5μH, 2.2μH, 3.3μH, 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 induc-
tance decreases linearly with increasing current), evalu-
ate the LIR with properly scaled inductance values. For
minimum output capacitance can be determined from
the following:
? 1 ? ? V REF ? ? V OUT ?
? ? ?
? 2 f SW R DROOP ? ? V OUT ? I N ?
where R DROOP is 5mV/A as defined in the Electrical
Characteristics table and f SW is the switching frequen-
cy selected by the FREQ setting (see Table 1).
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17083EVKIT+ | 功能描述:电源管理IC开发工具 Low-Voltage Internal Switch Step-Down 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 |
| MAX17085BETL+ | 功能描述:电池管理 Dual Main Step-Down Controller RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17085BETL+T | 功能描述:电池管理 Dual Main Step-Down Controller RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17085BEVKIT+ | 制造商:Maxim Integrated Products 功能描述:STEP-DOWN REGULATOR - Boxed Product (Development Kits) |
| MAX17085GTL+ | 功能描述:电池管理 Dual Main Step-Down Controller RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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