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GB4550A の電気的特性と機能

GB4550AのメーカーはGennumです、この部品の機能は「Monolithic Video Buffer/Clamp」です。


製品の詳細 ( Datasheet PDF )

部品番号 GB4550A
部品説明 Monolithic Video Buffer/Clamp
メーカ Gennum
ロゴ Gennum ロゴ 




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GB4550A Datasheet, GB4550A PDF,ピン配置, 機能
GB4550 & GB4550A
Monolithic Video Buffer/Clamp
DATA SHEET
FEATURES
adjustable clamp level from -5.5 V to +5.5 V at ±10 V
supplies.
ultra low differential gain (0.02% typ.) and
differential phase (0.03° typ.)
wideband unity gain: GB4550 ±0.2 dB at 25 MHz
GB4550A ±0.1 dB at 25 MHz
both drive 150pF loads at full power, flat to 10 MHz.
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GB4550A — tight delay spread of ±0.15°at colorburst.
convenient 8 pin SIP packaging.
both can be configured as a gain stage with reduced
bandwidth.
PIN CONNECTIONS
GB4550 and GB4550A
1 2 3 4 5 67 8
DESCRIPTION
The GB4550 and GB4550A are high performance mono-
lithic video buffer/clamps made on Gennum's LSI process.
They feature a wideband differential amplifier that can be
configured as a gain stage. The output signal voltage is
limited to +2V above the clamp level in order to prevent
damage to crosspoints connected to the output.
The clamping level can be set for normal sync tip clamping
by connecting pin 4 to -0.286 volts. For other applications,
the clamping voltage level can be varied from -5.5 to +5.5
volts.
The GB4550A features a tight delay spread of only ±0.15
degrees while the GB4550 maintains a ± 1.5 degree delay
spread. Both devices operate from ± 9 to ±12 V power
supplies and will directly interface with Gennum's video
crosspoint switches.
The 8 pin SIP package is ideally suited for space restricted
board layouts.
APPLICATIONS
Input buffering and clamping to crosspoint switches
Inter - system video signal clamping
Pin No.
1
2
3
4
5
6
7
8
GB4550
+IN
VCC
COMP
VCL
CX
VEE
-IN
OUT
GB4550A
+IN
VCC
NC
VCL
CX
VEE
-IN
OUT
ORDERING INFORMATION
Function
non-inverting input
positive power supply
frequency compensation or NC
clamp voltage input
external capacitor
negative power supply
inverting input
output
CX
(NC on
GB4550A)
COMP
+IN
-IN
VCC
100k
+
-
(+2 V OUTPUT CLAMP)
30k
+
10pF
-
30k
7mA
Nominal
VEE
All resistors in ohms, all capacitors in microfarads unless otherwise stated
VCL
OUT
Part Number
GB4550 - CSA
GB4550ACSA
Package Type
8 pin SIP
8 pin SIP
Temperature Range
0 to 70oC
0 to 70oC
SIMPLIFIED CIRCUIT DIAGRAM
Revision Date: February 1994
Document No. 520 - 34 - 4
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 tel. (905) 632-2996 fax: (905) 632-5946
Japan Branch: A-302, Miyamae Village, 2-10-42 Miyamae, Suginami-ku, Tokyo 168, Japan tel. (03) 3334-7700 fax: (03) 3247-8839

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GB4550A pdf, ピン配列
DETAILED DESCRIPTION
The GB4550(A) is intended for video applications requiring
coarse DC restoration coupled with flat frequency response.
As shown in Figure 1, the signal path features a wide band
operational amplifier designed to be unity gain stable. While
this amplifer is not intended to drive 75 transmission lines,
it is ideal for applications where high capactive loads, up to
several hundred picofarads, must be driven, such as input
buffering and DC restoration of video signals.
Optimal frequency response for the GB4550(A) occurs with
load capacitances in the range of 80 pF to 100 pF as shown in
Figure 4. For smaller loads, an external capacitor can be
added to extend the bandwidth and improve the flatness of the
www.DataSheet4dUe.vciocme response.
The clamping function is achieved through the use of a simple
comparator. The inverting input of the comparator is connected
to the GB4550(A) output, while the non-inverting input is
connected to the clamp voltage reference. For output signal
voltages more positive than the clamp reference the comparator
output is essentially open-circuit, while signal voltages more
negative than the clamp reference result in the charging of CX.
The action of the comparator is to provide a positive current
which is fed back to the op-amp non-inverting input under
conditions where the op-amp output is more negative than the
clamp reference voltage. This negative feedback raises the
DC level of the input signal to the point where all signal
fluctuations occur at voltages above the clamp reference
level. This is the desired clamp action.
Under equilibrium conditions the average current supplied by
the comparator output is just sufficient to balance the current
discharging the input capacitor. This discharge current is
simply the input bias current of the op-amp, typically less than
20 µA . However, an external resistor can be added to increase
the pull down current. Under dynamic conditions, where the
system is adjusting for a change in the signal level, the
charging current may be in the milliamp range. Because the
corrective current is small under equilibrium conditions, the
error voltage at the comparator input is small also, so clamping
accuracy to within ± 7 mV is achievable.
The clamp circuit makes use of a "peak hold" capacitor, CX, at
the output of the comparator . This gives rise to a more
constant voltage at the comparator output which is translated
to a more constant corrective current by an internal 100 k
resistor connected between the comparator output and the
signal input.
To avoid excessive phase shift and consequent instability of
the clamp feedback loop, the peak hold capacitor needs to be
considerably smaller (e.g. 1000 times) than the input coupling
capacitor. If a faster clamp is desirable (e.g. for 60 Hz hum
elimination) the peak hold capacitor can be removed and a
smaller input coupling capacitor employed. In this application
some distortion of the signal "tip" is unavoidable.
The input to the op-amp must be AC coupled using an
appropriate size of capacitor, which then acts as a DC "reservoir"
for the corrective level shift.
CX (+2 V OUTPUT CLAMP)
(NC on
GB4550A)
COMP
+IN
-IN
100k
+
-
30k VCL
+
10pF
-
30k
VCC
7mA
Nominal
VEE
All resistors in ohms, all capacitors in microfarads unless otherwise stated.
OUT
Fig. 1 Simplfied Circuit Diagram
3
520 - 34 - 4


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共有リンク

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部品番号部品説明メーカ
GB4550

Monolithic Video Buffer/Clamp

Gennum
Gennum
GB4550A

Monolithic Video Buffer/Clamp

Gennum
Gennum


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