參數(shù)資料
型號(hào)： 74HCT7046APW-T
廠商： NXP SEMICONDUCTORS
元件分類： PLL合成/DDS/VCOs
英文描述： PHASE LOCKED LOOP, PDSO16
封裝： PLASTIC, TSSOP
文件頁數(shù)： 23/38頁
文件大?。?/td> 468K
代理商： 74HCT7046APW-T
December 1990
3
Philips Semiconductors
Product specication
Phase-locked-loop with lock detector
74HC/HCT7046A
waveforms for the PC1 loop locked at
fo are shown in Fig.7.
The frequency capture range (2fc) is
defined as the frequency range of
input signals on which the PLL will
lock if it was initially out-of-lock. The
frequency lock range (2fL) is defined
as the frequency range of input
signals on which the loop will stay
locked if it was initially in lock. The
capture range is smaller or equal to
the lock range.
With PC1, the capture range depends
on the low-pass filter characteristics
and can be made as large as the lock
range. This configuration retains lock
even with very noisy input signals.
Typical behaviour of this type of
phase comparator is that it can lock to
input frequencies close to the
harmonics of the VCO centre
frequency.
Phase comparator 2 (PC2)
This is a positive edge-triggered
phase and frequency detector. When
the PLL is using this comparator, the
loop is controlled by positive signal
transitions and the duty factors of
SIGIN and COMPIN are not important.
PC2 comprises two D-type flip-flops,
control-gating and a 3-state output
stage. The circuit functions as an
up-down counter (Fig.5) where SIGIN
causes an up-count and COMPIN a
down-count. The transfer function of
PC2, assuming ripple (fr =fi) is
suppressed,
is:
where VDEMOUT is the demodulator
output at pin 10;
VDEMOUT =VPC2OUT (via low-pass
filter).
V
DEMOUT
V
CC
4
π
-----------
φ
SIGIN
φ
COMPIN
–
()
=
The phase comparator gain is:
VDEMOUT is the resultant of the initial
phase differences of SIGIN and
COMPIN as shown in Fig.8. Typical
waveforms for the PC2 loop locked at
fo are shown in Fig.9.
When the frequencies of SIGIN and
COMPIN are equal but the phase of
SIGIN leads that of COMPIN, the
p-type output driver at PC2OUT is held
“ON” for a time corresponding to the
phase difference (
φ
DEMOUT). When
the phase of SIGIN lags that of
COMPIN, the n-type driver is held
“ON”.
When the frequency of SIGIN is higher
than that of COMPIN, the p-type
output driver is held “ON” for most of
the input signal cycle time, and for
the remainder of the cycle both n and
p- type drivers are “OFF” (3-state). If
the SIGIN frequency is lower than the
COMPIN frequency, then it is the
n-type driver that is held “ON” for
most of the cycle. Subsequently, the
voltage at the capacitor (C2) of the
low-pass filter connected to PC2OUT
varies until the signal and comparator
inputs are equal in both phase and
frequency. At this stable point the
voltage on C2 remains constant as
the PC2 output is in 3-state and the
VCO input at pin 9 is a high
impedance.
Thus, for PC2, no phase difference
exists between SIGIN and COMPIN
over the full frequency range of the
VCO. Moreover, the power
dissipation due to the low-pass filter is
reduced because both p and n-type
drivers are “OFF” for most of the
signal input cycle. It should be noted
that the PLL lock range for this type of
phase comparator is equal to the
capture range and is independent of
K
p
V
CC
4
π
----------- Vr
() .
=
the low-pass filter. With no signal
present at SIGIN the VCO adjusts, via
PC2, to its lowest frequency.
APPLICATIONS
FM modulation and demodulation
Frequency synthesis and
multiplication
Frequency discrimination
Tone decoding
Data synchronization and
conditioning
Voltage-to-frequency conversion
Motor-speed control
相關(guān)PDF資料
PDF描述
74HCT9046AP PHASE LOCKED LOOP, PDIP16
74HCT9046AT PHASE LOCKED LOOP, PDSO16
74HCT9046AT-T PHASE LOCKED LOOP, PDSO16
74LV4051PWDH-T 8-CHANNEL, SGL ENDED MULTIPLEXER, PDSO16
74LV4052PWDH-T DUAL 4-CHANNEL, DIFFERENTIAL MULTIPLEXER, PDSO16
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74HCT7273D,112 功能描述:觸發(fā)器 OCTAL D FF POS-EDGE RoHS:否 制造商:Texas Instruments 電路數(shù)量:2 邏輯系列:SN74 邏輯類型:D-Type Flip-Flop 極性:Inverting, Non-Inverting 輸入類型:CMOS 輸出類型: 傳播延遲時(shí)間:4.4 ns 高電平輸出電流:- 16 mA 低電平輸出電流:16 mA 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:X2SON-8 封裝:Reel
74HCT7273D,118 功能描述:觸發(fā)器 OCTAL D FLIP-FLOP RoHS:否 制造商:Texas Instruments 電路數(shù)量:2 邏輯系列:SN74 邏輯類型:D-Type Flip-Flop 極性:Inverting, Non-Inverting 輸入類型:CMOS 輸出類型: 傳播延遲時(shí)間:4.4 ns 高電平輸出電流:- 16 mA 低電平輸出電流:16 mA 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:X2SON-8 封裝:Reel
74HCT7273D-T 功能描述:觸發(fā)器 OCTAL D FLIP-FLOP RoHS:否 制造商:Texas Instruments 電路數(shù)量:2 邏輯系列:SN74 邏輯類型:D-Type Flip-Flop 極性:Inverting, Non-Inverting 輸入類型:CMOS 輸出類型: 傳播延遲時(shí)間:4.4 ns 高電平輸出電流:- 16 mA 低電平輸出電流:16 mA 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:X2SON-8 封裝:Reel
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