ZL40123
High Speed, Current Feedback
Dual Operational Amplifier
Data Sheet
Features
•
•
•
•
•
•
450 MHz small signal bandwidth
1500V/µs slew rate
5.2 mA/channel static supply current
65 mA output current
120 MHz gain flatness to +/- 0.1 dB
8 pin SOIC
the ideal choice where a high density of high speed
devices is required.
The flat gain response to 120 MHz, 450 MHz small
signal bandwidth and 1500V/µs slew rate make the
device an excellent solution for video applications such
as driving video signals down significant cable lengths.
Other applications which may take advantage of the
ZL40123 superior dynamic performance features
include low cost high order active filters and twisted pair
driver/receivers.
ZL40123/DCA
ZL40123/DCB
ZL40123DCE1
ZL40123DCF1
Ordering Information
8 Pin SOIC
Tubes
8 Pin SOIC
Tape & Reel
8 Pin SOIC* Tubes, Bake & Drypack
8 Pin SOIC* Trays, Bake & Drypack
*Pb Free Matte Tin
-40°C to +85°C
March 2006
Applications
•
•
•
•
Video switchers/routers
Video line drivers
Twisted pair driver/receiver
Active filters
Description
The ZL40123 is a high speed, dual, current feedback
operational amplifier offering high performance at a
low cost. The device has a very high output current
drive capability of 65 mA while requiring only 5.2 mA of
static supply current. This feature makes the ZL40123
Out_1
1
8 V+
In_n_1 2
7 Out_2
1
In_p_1 3
6 In_n_2
2
V- 4
ZL40123
5 In_p_2
Figure 1 - Functional Block Diagram and Pin Connection
1
Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2003-2006, Zarlink Semiconductor Inc. All Rights Reserved.
ZL40123
Change Summary
Data Sheet
Changes from January 2005 Issue to March 2006 Issue. Page, section, figure and table numbers refer to this
current issue.
Page
1
Item
Change
Updated Ordering Information
Application Notes
Current Feedback Op Amps
Current feedback op amps offer several advantages over voltage feedback amplifiers:
•
•
•
AC bandwidth not dependent on closed loop gain
High Slew Rate
Fast settling time
The architecture of the current feedback opamp consists of a high impedance non-inverting input and a low
impedance inverting input which is always feedback connected. The error current is amplified by a transimpedance
amplifier which can be considered to have gain
Z
(
f
)
=
Z
o
f
1
+
j
f
o
where Z
o
is the DC gain.
It can be shown that the closed loop non-inverting gain is given by
Vout
=
Vin
Av
fR
f
1
+
j
f Z
o o
f
o
Z
o
GB
OL
=
R
f
R
f
where Av is the DC closed loop gain, R
f
is the feedback resistor. The closed loop bandwidth is therefore given by
BW
CL
=
and for low values of closed loop gain Av depends only on the feedback resistor R
f
and not the closed loop gain.
Increasing the value of R
f
•
•
•
•
•
Increases closed loop stability
Decreases loop gain
Decreases bandwidth
Reduces gain peaking
Reduces overshoot
Using a resistor value of R
f
=510
Ω
for Av=+2 V/V gives good stability and bandwidth. However since requirements
for stability and bandwidth vary it may be worth experimentation to find the optimal R
f
for a given application.
2
Zarlink Semiconductor Inc.
ZL40123
Layout Considerations
Data Sheet
Correct high frequency operation requires a considered PCB layout as stray capacitances have a strong influence
over high frequency operation for this device. The Zarlink evaluation board serves as a good example layout that
should be copied. The following guidelines should be followed:
•
•
•
Include 6.8 uF tantalum and 0.1 uF ceramic capacitors on both positive and negative supplies
Remove the ground plane under and around the part, especially near the input and output pins to reduce
parasitic capacitances
Minimize all trace lengths to reduce series inductance
3
Zarlink Semiconductor Inc.
ZL40123
Application Diagrams
Vcc
6.8uF
Data Sheet
Vin
0.1uF
Vout
½ ZL40123
Rin
Rf
Ra
0.1uF
Vout
Rf
=
Av
=
1
+
Vin
Ra
6.8uF
Vee
Figure 2 - Non-inverting Gain
Vcc
6.8uF
•
•
•
Rb
0.1uF
½ ZL40123
•
Vout
Rf
Vin
•
Ra
•
•
0.1uF
Rin
•
6.8uF
Vee
•
Vout
Rf
=
Av
= −
Vin
Ra
Figure 3 - Inverting Gain
4
Zarlink Semiconductor Inc.
ZL40123
Absolute Maximum Ratings
Parameter
Symbol
Min.
Max.
Data Sheet
Units
1
2
Vin Differential
Output Short Circuit Protection
V
IN
V
OS/C
±1.2
See Apps
Note in this
data sheet
±6.5
V-
V-
2
V+
V+
(see Note 3)
V
3
4
5
6
Supply voltage
Voltage at Input Pins
Voltage at Output Pins
EDS Protection
(HBM Human Body Model)
(see Note 2)
Storage Temperature
Latch-up test
Supply transient test
V+, V-
V
(+IN)
, V
(-IN)
V
O
V
V
V
kV
7
8
9
-55
+150
(see Note 4)
(see Note 5)
°C
±
100 mA
for 100 ms
20% pulse
for 100ms
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate
conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed
specifications and the test conditions, see the Electrical Characteristics.
Human body model, 1.5 kΩ in series with 100 pF. Machine model, 20
Ω
in series with 100 pF.
0.8 kV between the pairs of +INA, -INA and +INB pins only. 2kV between supply pins, OUTA or OUTB pins and any input pin.
±100 mA applied to input and output pins to force the device to go into "latch-up". The device passes this test to JEDEC spec
17.
Positive and Negative supply transient testing increases the supplies by 20% for 100 ms.
Note 2:
Note 3:
Note 4:
Note 5:
Operating Range
Characteristic
Min.
Typ.
Max.
Units
Comments
Supply Voltage (Vcc)
Operating Temperature (Ambient)
Junction to Ambient resistance
±4.0
-40
Rth(j-a)
150
±
6.0
+85
V
°C
°C
4 layer
FR4 board
°C
4 layer
FR4 board
Junction to Case resistance
Rth(j-c)
60
5
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