參數(shù)資料
型號： MAX1965TEEP
廠商： MAXIM INTEGRATED PRODUCTS INC
元件分類： 穩(wěn)壓器
英文描述： Tracking/Sequencing Triple/Quintuple Power-Supply Controllers
中文描述： 0.05 A SWITCHING CONTROLLER, 240 kHz SWITCHING FREQ-MAX, PDSO20
封裝： 0.150 INCH, 0.025 INCH PITCH, QSOP-20
文件頁數(shù)： 25/30頁
文件大小： 475K
代理商： MAX1965TEEP
shown in Figure 8, a series RC snubber circuit at the
diode increases the damping factor, allowing the ring-
ing to settle quickly. Applications with multiple trans-
former windings require only one snubber circuit on the
highest output voltage.
The diode
’
s parasitic capacitance can be estimated
using the diode
’
s reverse voltage rating (V
RRM
), current
capability (I
O
), and recovery time (t
RR
). A rough
approximation is:
For the EC10QS10 Nihon diode used in Figure 8, the
capacitance is roughly 15pF. The output snubber only
needs to dampen the ringing, so the initial turn-on spike
that occurs during the blanking period is still present. A
100pF capacitor works well in most applications.
Larger capacitance values require more charge, there-
by increasing the power dissipation.
The snubber
’
s time constant (t
SNUB
) must be smaller
than the 60ns blanking time. A typical RC time constant
of approximately 30ns was chosen for Figure 8:
Minimum Load Requirements (Linear Regulators)
Under no-load conditions, leakage currents from the
pass transistors supply the output capacitor, even
when the transistor is off. Generally, this is not a prob-
lem since the feedback resistors
’
current drain the
excess charge. However, charge may build up on the
output capacitor over temperature, making V
LDO
rise
above its set point. Care must be taken to ensure that
the feedback resistors
’
current exceeds the pass tran-
sistor
’
s leakage current over the entire temperature
range.
Applications Information
PC Board Layout Guidelines
Careful PC board layout is critical to achieve low
switching losses and clean, stable operation. The
switching power stage requires particular attention.
Follow these guidelines for good PC board layout:
1) Place the power components first, with ground ter-
minals adjacent (NL source, C
IN
, C
OUT
). If possi-
ble, make all these connections on the top layer
with wide, copper-filled areas. Keep these high-cur-
rent paths short, especially at ground terminals.
2) Mount the MAX1964/MAX1965 adjacent to the
switching MOSFETs in order to keep IN-LX current-
sense lines, LX-GND current-limit sense lines, and
the driver lines (DL and DH) short and wide. The
current-sense amplifier inputs are connected
between IN and LX, so these pins must be connect-
ed as close as possible to the high-side MOSFET.
The current-limit comparator inputs are connected
between LX and GND, but accuracy is not as
important, so give priority to the high-side MOSFET
connections. The IN, LX, and GND connections to
the MOSFETs must be made using Kelvin sense
connections to guarantee current-sense and cur-
rent-limit accuracy.
3) Group the gate-drive components (BST diode and
capacitor, IN bypass capacitor) together near the
MAX1964/MAX1965.
4) All analog grounding must be done to a separate
solid copper ground plane, which connects to the
MAX1964/MAX1965 at the GND pin. This includes
the VL bypass capacitor, feedback resistors, com-
pensation components (R
COMP
, C
COMP
), and
adjustable current-limit threshold resistors connect-
ed to ILIM.
5) Ensure all feedback connections are short and
direct. Place the feedback resistors as close to the
MAX1964/MAX1965 as possible.
6) When trade-offs in trace lengths must be made, it
’
s
preferable to allow the inductor charging path to be
made longer than the discharge path. For example,
it is better to allow some extra distance between the
input capacitors and the high-side MOSFET than to
allow distance between the inductor and low-side
MOSFET.
7) Route high-speed switching nodes away from sen-
sitive analog areas (B_, FB_, COMP, ILIM).
Regulating High Voltage
The linear regulator controllers can be configured to
regulate high output voltages by adding a cascode
transistor to buffer the base-drive output. For example,
to generate an output voltage between 30V and 60V,
add a 2N5550 high-voltage NPN transistor as shown in
Figure 9A where VBIAS is a DC voltage between 3V
and 20V that can source at least 1mA. R
DROP
protects
the cascode transistor by decreasing the voltage
across the transistor when the pass transistor saturates.
Similarly, to regulate a negative output voltage between
-20V and -120V, add a 2N5401 high-voltage PNP tran-
sistor as shown in Figure 9B.
R
t
C
ns
C
SNUB
SNUB
SNUB
SNUB
=
=
30
C
I
t
V
DIODE
RR
RRM
=
×
0
M
Tracking/Sequencing Triple/Quintuple
Power-Supply Controllers
______________________________________________________________________________________
25
相關PDF資料
PDF描述
MAX1966 Low-Cost Voltage-Mode PWM Step-Down Controllers
MAX1967EUB Low-Cost Voltage-Mode PWM Step-Down Controllers
MAX1966-MAX1967 Low-Cost Voltage-Mode PWM Step-Down Controllers
MAX1966ESA Low-Cost Voltage-Mode PWM Step-Down Controllers
MAX2003 NiCd/NiMH Battery Fast-Charge Controllers
相關代理商/技術參數(shù)
參數(shù)描述
MAX1965TEEP-T 功能描述:電流和電力監(jiān)控器、調節(jié)器 RoHS:否 制造商:STMicroelectronics 產品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel
MAX1966ESA 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
MAX1966ESA+ 功能描述:電壓模式 PWM 控制器 Voltage-Mode PWM Step-Down RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
MAX1966ESA+T 功能描述:電壓模式 PWM 控制器 Voltage-Mode PWM Step-Down RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
MAX1966ESA-T 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
發(fā)布緊急采購，3分鐘左右您將得到回復。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*