- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄375723 > FAN5067 (Fairchild Semiconductor Corporation) ACPI Dual Switch Controller PDF資料下載
參數(shù)資料
| 型號： | FAN5067 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | ACPI Dual Switch Controller |
| 中文描述： | 符合ACPI雙開關(guān)控制器 |
| 文件頁數(shù)： | 10/14頁 |
| 文件大?。?/td> | 101K |
| 代理商： | FAN5067 |
FAN5067
PRODUCT SPECIFICATION
10
REV. 1.0.1 5/2/02
Figure 6. Recommended C vs. ESR for
Stable Operation of the Dual Output
Adjustable Dual Output
The adjustable dual output is intended to provide power to
SDRAM or DDR memory.
Adjustable dual is generated by one external NPN bipolar
acting as a linear regulator from +5V main, and one linear
regulator internal to the FAN5067 from +5V standby, as
shown in Figure 4, and in the block diagram on the front
page. When main power is present, the NPN Q3 linear regu-
lates, and when main power is absent, the internal linear reg-
ulator is on. Q3 cannot be substituted with a MOSFET. If
used in one direction, the MOSFET’s body diode would per-
mit back-feed; if used in the other direction, it would short-
circuit the linear regulator action.
The state of the external MOSFET and the internal linear
regulator is controlled by the SLP_S3
and PWROK lines,
and additionally the SLP_S5 line, as shown in Figure 3.
When SLP_S5 is de-asserted, both the external MOSFET
and the internal linear regulator are off, and there is no out-
put voltage on the 3.3V SDRAM line.
If the SLP_S5 line is asserted, the adjustable dual output is
on. In this condition, if either the SLP_S3
or the PWROK
line, or both, are de-asserted, the linear regulator is on and
the MOSFET is off. Only in the case if both the SLP_S3
and
the PWROK lines are asserted, the MOSFET is on and the
linear regulator is off.
In a typical system, it is anticipated that standby current will
be a maximum of 365mA, and full-power current may be as
high as 2A. This places some significant constraints on the
selection of Q3. Since its input may be as low as (5V – 5%)
= 4.75V, there is only 4.75V – 3.3V = 1.45mV of V
CE
head-
room for its operation as a linear regulator. For this reason
the FAN5067 can provide up to 200mA of steady-state base
current. The TIP41A device shown has a sufficiently low
V
CE, sat
to guarantee worst-case regulation even at 2A I
E
with
this base current.
The output voltage of the Adjustable Dual is set with two
resistors as shown in Figure 4, according to the equation.
Dynamic Change of Adjust Output
There may be circumstances under which it is desired to
dynamically change the output of the adjustable dual output.
For example, a circuit that switches from 2.5V to 3.3V is
shown in Figure 7.
Figure 7. Circuit for Dynamic Change of Output Voltage
of the Adjustable
A potential problem arises when using this circuit, however:
When the transistor is turned on, the voltage on the VADJFB
pin abruptly drops, until the output of the linear regulator can
charge up the output caps. If the voltage to which it drops is
less than about 80% of 1.25V, or 1.00V, the OC limit will trip
and shut down the IC. This happens in this example because
To avoide this problem, systems that intended to dynami-
cally change the output voltage of the adjustable dual output
should disable the OC protection with the circuit shown in
Figure 8.
Figure 8. Circuit to Disable OC Protection
100
47
330
100
200
C (
μ
F)
ESR (m
)
300
400
200
300
Vadj
1.25V
R
------------------
R
2
+
R
2
=
3.3V
VADJFB
VADJ
2.5V
R
R
)
R
2
R
3
(
R1
+
[
]
-----------------------------------------
0.94V
=
SS
C
SS
2N3906
500K
1N4148
1
μ
F
+
+5V_SB
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| FAN5068MPX | DDR-1/DDR-2 plus ACPI Regulator Combo |
| FAN5068 | DDR-1/DDR-2 plus ACPI Regulator Combo |
| FAN5068ACPI | FAN5068 Component calculation and simulation tools |
| FAN5068DDR | FAN5068 Component calculation and simulation tools |
| FAN5069MTCX | PWM and LDO Controller Combo |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| FAN5067M | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 aCPI Dual Switch Controller RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| FAN5067MX | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 aCPI Dual Switch Controller RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| FAN5068 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:DDR-1/DDR-2 plus ACPI Regulator Combo |
| FAN5068A WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5068ACPI | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:FAN5068 Component calculation and simulation tools |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。