EL5397ACS INTERSIL [Intersil Corporation], EL5397ACS Datasheet - Page 12

• Manufacturer Part Number: EL5397ACS
• Description: Triple 200MHz Fixed Gain Amplifier with Enable
• Manufacturer: INTERSIL [Intersil Corporation]

Applications Information
Product Description
The EL5397A is a triple channel fixed gain amplifier that
offers a wide -3dB bandwidth of 200MHz and a low supply
current of 4mA. The EL5397A works with supply voltages
ranging from a single 5V to 10V and they are also capable of
swinging to within 1V of either supply on the output. This
combination of high bandwidth and low power, together with
aggressive pricing make the EL5397A the ideal choice for
many low-power/high-bandwidth applications such as
portable, handheld, or battery-powered equipment.
For varying bandwidth and higher gains, consider the
EL5191 with 1GHz on a 9mA supply current or the EL5193
with 300MHz on a 4mA supply current. Versions include
single, dual, and triple amp packages with 5-pin SOT23, 16-
pin QSOP, and 8-pin or 16-pin SO outlines.
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, good printed circuit
board layout is necessary for optimum performance. Low
impedance ground plane construction is essential. Surface
mount components are recommended, but if leaded
components are used, lead lengths should be as short as
possible. The power supply pins must be well bypassed to
reduce the risk of oscillation. The combination of a 4.7µF
tantalum capacitor in parallel with a 0.01µF capacitor has
been shown to work well when placed at each supply pin.
Disable/Power-Down
The EL5397A amplifier can be disabled placing its output in
a high impedance state. When disabled, the amplifier supply
current is reduced to < 150µA. The EL5397A is disabled
when its CE pin is pulled up to within 1V of the positive
supply. Similarly, the amplifier is enabled by floating or
pulling its CE pin to at least 3V below the positive supply. For
±5V supply, this means that an EL5397A amplifier will be
enabled when CE is 2V or less, and disabled when CE is
above 4V. Although the logic levels are not standard TTL,
this choice of logic voltages allows the EL5397A to be
enabled by tying CE to ground, even in 5V single supply
applications. The CE pin can be driven from CMOS outputs.
Gain Setting
The EL5397A is built with internal feedback and gain
resistors. The internal feedback resistors have equal value;
as a result, the amplifier can be configured into gain of +1,
-1, and +2 without any external resistors. Figure 1 shows the
amplifier in gain of +2 configuration. The gain error is ±2%
maximum. Figure 2 shows the amplifier in gain of -1
configuration. For gain of +1, IN+ and IN- should be
connected together as shown in Figure 3. This configuration
avoids the effects of any parasitic capacitance on the IN- pin.
Since the internal feedback and gain resistors change with
12
EL5397A
temperature and process, external resistor should not be
used to adjust the gain settings.
Supply Voltage Range and Single-Supply
Operation
The EL5397A has been designed to operate with supply
voltages having a span of greater than or equal to 5V and
less than 11V. In practical terms, this means that the
EL5397A will operate on dual supplies ranging from ±2.5V to
±5V. With single-supply, the EL5397A will operate from 5V to
10V.
As supply voltages continue to decrease, it becomes
necessary to provide input and output voltage ranges that
can get as close as possible to the supply voltages. The
EL5397A has an input range which extends to within 2V of
either supply. So, for example, on ±5V supplies, the
EL5397A has an input range which spans ±3V. The output
range of the EL5397A is also quite large, extending to within
1V of the supply rail. On a ±5V supply, the output is therefore
capable of swinging from -4V to +4V. Single-supply output
range is larger because of the increased negative swing due
to the external pull-down resistor to ground. Figure 4 shows
IN-
IN-
IN+
FIGURE 1. A
IN-
FIGURE 3. A
FIGURE 2. A
400
400
IN+
400
IN+
V
V
V
+
-
+
+
-
-
400
400
400
= +2
= +1
= -1