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| 型号： | MAX17409GTI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 26/32页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR NVIDIA CPU 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 系列： | Quick-PWM™ |
| 应用： | 处理器 |
| 电流 - 电源： | 1.5mA |
| 电源电压： | 4.5 V ~ 5.5 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 带卷 (TR) |
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1-Phase Quick-PWM GPU Controller
capacitor selection, inductor saturation rating, and
the design of the current-limit circuit. The continu-
ous load current (I LOAD ) determines the thermal
stresses and thus drives the selection of input
capacitors, MOSFETs, and other critical heat-con-
output sag is also a function of the maximum duty fac-
tor, which can be calculated from the on-time and mini-
mum off-time. The worst-case output sag voltage can
be determined by:
(
) 2
? ? + t OFF (M IN ) ?
? ? V OUT t SW ? ?
? ?
? ? ( V IN OUT ) t SW ? ?
2 C OUT OUT ? ? ? - t OFF ( MIN ) ?
? ? ?
? ?
?
tributing components. Modern notebook CPUs gen-
erally exhibit I LOAD = I LOAD(MAX) x 80%.
Switching frequency: This choice determines the
basic trade-off between size and efficiency. The
optimal frequency is largely a function of maximum
input voltage, due to MOSFET switching losses that
V SAG =
L ? I LOAD(MAX) ? ? M
V
V IN ?
- V
V IN
are proportional to frequency and V IN 2 . The opti-
mum frequency is also a moving target, due to
rapid improvements in MOSFET technology that are
making higher frequencies more practical.
where t OFF(MIN) is the minimum off-time (see the
Electrical Characteristics table).
The amount of overshoot due to stored inductor energy
?
Inductor operating point: This choice provides
trade-offs between size vs. efficiency and transient
response vs. output noise. Low inductor values pro-
vide better transient response and smaller physical
can be calculated as:
V SOAR
≈
( ? I LOAD ( MAX ) ) 2 L
2 C OUT V OUT
size, but also result in lower efficiency and higher
output noise due to increased ripple current. The
? ? ? V OUT ?
V IN OUT
L = ?
? f SW LOAD ( MAX ) LIR ? ? V IN ?
V LIMIT = REF ILIM
minimum practical inductor value is one that causes
the circuit to operate at the edge of critical conduc-
tion (where the inductor current just touches zero
with every cycle at maximum load). Inductor values
lower than this grant no further size-reduction bene-
fit. The optimum operating point is usually found
between 20% and 50% ripple current.
Inductor Selection
The switching frequency and operating point (% ripple
current or LIR) determine the inductor value as follows:
- V
I ? ? ?
Find a low-loss inductor having the lowest possible DC
resistance that fits in the allotted dimensions. Ferrite
and molded iron cores are often the best choice,
although powdered iron is inexpensive and can work
well at 200kHz. The core must be large enough not to
saturate at the peak inductor current (I PEAK ):
Current-Limit Control (ILIM)
REF and ILIM are used to set the current limit. REF reg-
ulates to a fixed 2.0V and the REF-to-ILIM voltage
determines the valley current-sense threshold. When
ILIM = V CC , the controller uses the preset 22.5mV cur-
rent-limit threshold. In an adjustable design, ILIM is
connected to a resistive voltage-divider connected
between REF and ground. The differential voltage
between REF and ILIM sets the current-limit threshold
(V LIMIT ), so the valley current-sense threshold is:
V - V
10
This allows design flexibility since the DCR sense circuit
or sense resistor does not have to be adjusted to meet
the current limit as long as the current-sense voltage
never exceeds 50mV. Keeping V LIMIT between 20mV to
40mV leaves room for future current-limit adjustment.
The minimum current-limit threshold must be high
I PEAK LOAD ( MAX ) ? 1 +
= I
2 ?
?
?
LIR ?
?
enough to support the maximum load current when the
current limit is at the minimum tolerance value. The val-
ley of the inductor current occurs at I LOAD(MAX) minus
half the ripple current; therefore:
> I
I VALLEY LOAD ( MAX ) ? 1 -
2 ?
Transient Response
The inductor ripple current impacts transient-response
performance, especially at low V IN - V OUT differentials.
Low inductor values allow the inductor current to slew
faster, replenishing charge removed from the output fil-
ter capacitors by a sudden load step. The amount of
?
?
LIR ?
?
26
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1740EUB | 功能描述:转换 - 电压电平 Integrated Circuits (ICs) RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB+ | 功能描述:转换 - 电压电平 SIM/Smart Card Level Translator RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB+T | 功能描述:转换 - 电压电平 SIM/Smart Card Level Translator RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB-T | 功能描述:转换 - 电压电平 RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX17410EVKIT+ | 功能描述:电源管理IC开发工具 MAX17410 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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