参数资料
型号: IR3840MTR1PBF
厂商: International Rectifier
文件页数: 16/32页
文件大小: 0K
描述: IC REG BUCK SYNC ADJ 12A 15QFN
产品培训模块: SupIRBuck? Family and POL Design Tools Overview
标准包装: 1
系列: SupIRBuck™
类型: 降压(降压)
输出类型: 可调式
输出数: 1
输出电压: 0.7 V ~ 14.4 V
输入电压: 1.5 V ~ 16 V
PWM 型: 电压模式
频率 - 开关: 225kHz ~ 1.65MHz
电流 - 输出: 12A
同步整流器:
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 15-PowerVQFN
包装: 标准包装
供应商设备封装: PQFN(5x6)
产品目录页面: 1384 (CN2011-ZH PDF)
其它名称: IR3840MTR1PBFDKR
IR3840MPbF
Minimum on time Considerations
The minimum ON time is the shortest amount of
time for which the Control FET may be reliably
turned on, and this depends on the internal
timing delays. For the IR3840, the typical
minimum on-time is specified as 50 ns.
Any design or application using the IR3840 must
ensure operation with a pulse width that is higher
than this minimum on-time and preferably higher
than 100 ns. This is necessary for the circuit to
operate without jitter and pulse-skipping, which
can cause high inductor current ripple and high
output voltage ripple.
Maximum Duty Ratio Considerations
A fixed off-time of 200 ns maximum is specified
for the IR3840. This provides an upper limit on
the operating duty ratio at any given switching
frequency. It is clear, that higher the switching
frequency, the lower is the maximum duty ratio at
which the IR3840 can operate. To allow some
margin, the maximum operating duty ratio in any
application using the IR3840 should still
accommodate about 250 ns off-time. Fig 10.
shows a plot of the maximum duty ratio v/s the
switching frequency, with 250 ns off-time.
t on =
=
D
F s
V out
V in × F s
95
90
85
80
75
M a x Duty Cycle
In any application that uses the IR3840, the
following condition must be satisfied:
70
65
60
t on (min) ≤ t on
55
250
450
650
850
1050
1250
1450
1650
∴ t on (min) ≤
∴ V in × F s ≤
V out
V in × F s
V out
t on (min)
The minimum output voltage is limited by the
reference voltage and hence V out(min) = 0.7 V.
Therefore, for V out(min) = 0.7 V,
S w itching Frequency (kH z )
Fig. 10. Maximum duty cycle v/s switching
frequency.
∴ V in × F s ≤
V out (min)
t on (min)
∴ V in × F s ≤
0.7 V
100 ns
= 7 × 10 6 V/s
Therefore, at the maximum recommended input
voltage 16V and minimum output voltage, the
converter should be designed at a switching
frequency that does not exceed 440 kHz.
Conversely, for operation at the maximum
recommended operating frequency 1.65 MHz
and minimum output voltage, any voltage above
4.2 V may not be stepped down without pulse-
skipping.
06/18/09
16
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相关代理商/技术参数
参数描述
IR3840MTR1PBF 制造商:International Rectifier 功能描述:IC DC/DC SUPIRBUCK 12A 15QFN
IR3840MTRPBF 功能描述:直流/直流开关调节器 12A SupIRBuck Reg 250-1500kHz, 1.5-16V 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
IR3840WMPBF 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGHLY EFFICIENT INTEGRATED 12A SYNCHRONOUS BUCK REGULATOR
IR3840WMPBF_12 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGHLY EFFICIENT INTEGRATED 12A SYNCHRONOUS BUCK REGULATOR
IR3840WMTR1PBF 功能描述:直流/直流开关调节器 12A SupIRBuck Reg 250-1500kHz, 1.5-16V 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