- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄361602 > UT7R995C-XCX (Aeroflex Inc.) RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer PDF資料下載
參數(shù)資料
| 型號： | UT7R995C-XCX |
| 廠商： | Aeroflex Inc. |
| 英文描述： | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| 中文描述： | RadHard 2.5V/3.3V的200MHz的高速多相PLL時(shí)鐘緩沖器 |
| 文件頁數(shù)： | 6/22頁 |
| 文件大?。?/td> | 185K |
| 代理商： | UT7R995C-XCX |
6
When the outputs are configured for low drive operation, they
will provide a minimum 12mA of drive current regardless of
the selected output power supply. If the outputs are configured
for high drive operation, they will provide a minimum 24mA of
drive current under a 3.3V power supply and 20mA when pow-
ered from a 2.5V supply.
The UT7R995/C features split power supply buses for Banks 1
and 2, Bank 3, and Bank 4. These independent power supplies
enable the user to obtain both 3.3V and 2.5V output signals
from one UT7R995/C device. The core power supply (V
DD
)
must run from a 3.3V power supply. Table 12 summarizes the
various power supply options available with the UT7R995/C.
Table 12: Power Supply Constraints
1
Notes:
1. V
DD
Q1/3/4 must not be set at a level higher than that of V
DD
.
1.4 Reference Clock Interfaces
When an external, LVCMOS/LVTTL, digital clock is used to
drive the UT7R995 and UT7R995C, the reference clock signal
should drive the XTAL1 input of the RadClock, while the
XTAL2 output should be left unconnected (see Figure 4).
Note,
for the UT7R995 only, the XTAL2 pin is defined as a no-
connect.
In addition to a digital clock reference, the UT7R995C can in-
terface to a quartz crystal. When interfacing to a quartz crystal,
XTAL1 and XTAL2 are the input and output, respectively, of
an inverting amplifier within the RadClock. This inverting am-
plifier provides the initial 180
o
phase shift of the reference
clock whose frequency, and subsequent 180
o
phase shift, is set
by the quartz crystal and its surrounding RLC network. Figure
5 shows a typical pierce-oscillator with tank-circuit that will
support reliable startup of fundamental and odd-harmonic, AT-
cut, quartz crystals.
V
DD
V
DD
Q1
V
DD
Q3
V
DD
Q4
3.3V
3.3V or 2.5V
3.3V or 2.5V
3.3V or 2.5V
N/C
External
Digital
Oscillator
NC/XTAL2
XTAL1
V
SS
Figure 4. External Digital Clock Oscillator Interface
Figure 5. Pierce Crystal Oscillator with Tank Circuit
Y1
Rdc
R1
C1
C2
L1
Cdc
XTAL1
XTAL2
UT7R995C
Fundamental Frequency Pierce Crystal Oscillator
Rdc = ~10M
Ω
;
L1 = Not Used;
Cdc = Not Used
C2 is used to tune the circuit for stable oscillation.
Typical values for C2 range from 30pF to 50pF.
R1 and C1 are selected to create a time constant that facilitates the funda-
mental frequency (f
F
) of the quartz crystal as defined in equation 2.
As an example, selecting a value of 100
Ω
for R1 and 80pF for C1 would fa-
cilitate the reliable operation of a 20MHz, AT-cut, quartz crystal.
Higher Frequency Pierce Crystal Oscillator
Rdc = ~10M
Ω
;
Cdc = ~1.5nF;
C2 = Tuning capacitor
similar to prior example
R1 and C1 are selected to create a time constant that facilitates the overtone
frequency (f
OT
) of the quartz crystal as shown in equation 3.
Additionally, L1 is selected such that its relationship with C1 facilitates a
frequency falling between the fundamental frequency (f
F
) and the specified
overtone frequency (f
OT
) of the quartz crystal as shown in equation 4.
As an example, selecting the following component values will result in a
50MHz Pierce Crystal Oscillator based upon an 3rd overtone, AT-cut,
quartz crystal having a fundamental frequency of 16.6666MHz.
Rdc = 10M
Ω
;
R1 = 50
Ω
;
f
F
= 16.6666MHz;
Cdc = 1.5nF;
C1 = 55pF;
f
OT
= 50MHz
C2 = 30pF;
L1 = 300nH
(
)
1
C
*
1
*
2
1
R
f
F
π
=
Equation 2.
Equation 3.
(
)
1
C
*
1
*
2
1
R
f
OT
π
=
(
)
1
C
*
1
*
2
1
L
f
M
π
=
Equation 4.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UT7R995C-XPA | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XPC | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XPX | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XWA | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XWC | RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UT7R995C-XPA | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XPC | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XPX | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XWA | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
| UT7R995C-XWC | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard 2.5V/3.3V 200MHz High-Speed Multi-phase PLL Clock Buffer |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。