Intersil Corporation HS-1245RH Datasheet

HS-1245RH

Data Sheet August 1999

Radiation Hardened, Dual, High Speed,
Low Power Video Operational Amplifier
with Output Disable

The HS-1245RH is a radiation hardened dual high speed,
low power current feedback amplifier built with Intersil’s
proprietary complementary bipolar UHF-1(DI bonded wafer)
process. These devices are QML approved and are
processed and screened in full compliance with
MIL-PRF-38535.

This amplifier features individual TTL/CMOS compatible
disable controls, which when pulled low, reduce the supply
current and force the output into a high impedance state.
This allows easy implementation of simple, low power video
switching and routing systems. Component and composite
video systems also benefit from this op amp’s excellent gain
flatness, and good differentialgain and phase specifications.
Multiplexed A/D applications will also find the HS-1245RH
useful as the A/D driver/multiplexer.

Specifications for Rad Hard QML devices are controlled
by the Defense Supply Center in Columbus (DSCC). The
SMD numbers listed here must be used when ordering.

Detailed Electrical Specifications for these devices are
contained in SMD 5962-96832. A “hot-link” is provided
on our homepage for downloading.
www.intersil.com/spacedefense/space.asp

File Number 4229.1

Features

• Electrically Screened to SMD # 5962-96832

• QML Qualified per MIL-PRF-38535 Requirements

• MIL-PRF-38535 Class V Compliant

• Low Supply Current . . . . . . . . . . . . . . . . . . . . 5.9mA (Typ)

• Wide -3dB Bandwidth. . . . . . . . . . . . . . . . . .530MHz (Typ)

• High Slew Rate. . . . . . . . . . . . . . . . . . . . . .1050V/µs (Typ)

• Excellent Gain Flatness (to 50MHz). . . . . . ±0.11dB (Typ)

• Excellent Differential Gain . . . . . . . . . . . . . . . 0.02% (Typ)

• Excellent Differential Phase . . . . . . . . . 0.03 Degree (Typ)

• High Output Current . . . . . . . . . . . . . . . . . . . .60mA (Typ)

• Individual Output Enable/Disable

• Output Enable / Disable Time. . . . . . . . . 160ns/20ns (Typ)

• Total Gamma Dose. . . . . . . . . . . . . . . . . . . . 300kRAD(Si)

• Latch Up. . . . . . . . . . . . . . . . . . . . . None (DI Technology)

Applications

• Multiplexed Flash A/D Driver

• RGB Multiplexers and Preamps

• Video Switching and Routing

Ordering Information

INTERNAL

ORDERING NUMBER

5962F9683201VCA HS1-1245RH-Q -55 to 125
5962F9683201VCC HS1B-1245RH-Q -55 to 125

MKT. NUMBER

TEMP. RANGE

(oC)

• Pulse and Video Amplifiers

• Wideband Amplifiers

• Hand Held and Miniaturized RF Equipment

• Battery Powered Communications

Pinout

HS-1245RH (CERDIP) GDIP1-T14

OR

HS-1245RH (SBDIP) CDIP2-T14

TOP VIEW

-IN1

+IN1

DISABLE 1

DISABLE 2

+IN2

-IN2

1

-

+

2
3

V-

4
5
6

+

-

7

14

OUT1

13

NC

12

GND

11

V+

10

NC

9

NC

8

OUT2

1

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 321-724-7143 | Copyright © Intersil Corporation 1999

HS-1245RH

Application Information

Optimum Feedback Resistor

Although a current feedback amplifier’s bandwidth
dependency on closed loop gain isn’t as severe as that of a
voltage feedback amplifier, there can be an appreciable
decrease in bandwidth at higher gains. This decrease may
be minimized by taking advantage of the current feedback
amplifier’s unique relationship between bandwidth and R

.

F

All current feedback amplifiers require a feedback resistor,
even for unity gain applications, and R

, in conjunction with

F

the internal compensation capacitor, sets the dominant pole
of the frequency response. Thus, the amplifier’sbandwidth is
inversely proportional to R
optimized for a 560Ω R

. The HS-1245RH design is

F

at a gain of +2. Decreasing R

F

F

decreases stability, resulting in excessive peaking and
overshoot (Note: Capacitive feedback will cause the same
problemsdue to the feedbackimpedance decrease at higher
frequencies). At higher gains the amplifier is more stable, so
R

can be decreased in a trade-off of stability for bandwidth.

F

The table below lists recommended RF values for v arious
gains, and the expected bandwidth. F or good channel-to­channel gain matching, it is recommended that all resistors
(termination as well as gain setting) be ±1% tolerance or better.
Note that a series input resistor,on +IN, is required for a gain of
+1, to reduce gain peaking and increase stability.

GAIN
(ACL)R

-1 510 230

+1 560 (+RS = 560Ω) 290
+2 560 530

F

(Ω)

BANDWIDTH

(MHz)

Non-Inverting Input Source Impedance

Forbest operation,the D.C.source impedance looking outof
the non-inverting input should be ≥50Ω. This is especially
important in inverting gain configurations where the non­inverting input would normally be connected directly to GND.

Optional GND Pin for TTL Compatibility

The HS-1245RH derives an internal GND reference for the
digital circuitry as long as the power supplies are
symmetrical about GND. The GND reference is used to
ensure the TTL compatibility of the
symmetrical supplies the GND pin (Pin 12) may be floated,
or connected directly to GND. If asymmetrical supplies (e.g.
+10V, 0V) are utilized, and TTL compatibility is desired, the
GND pin must be connected to GND.

DISABLE inputs. With

PC Board Layout

The frequency response of this amplifier depends greatly on
the amount of care taken in designing the PC board. The

use of low inductance components such as chip
resistors and chip capacitors is strongly recommended,
while a solid ground plane is a must!

Attention should be given to decoupling the power supplies.
A large value (10µF) tantalum in parallel with a small value
(0.1µF) chip capacitor works well in most cases.

Terminated microstrip signal lines are recommended at the
input and output of the device. Capacitance directly on the
output must be minimized, or isolated as discussed in the
next section.

Care must also be taken to minimize the capacitance to
ground seen by the amplifier’s inverting input (-IN). The
larger this capacitance, the worse the gain peaking, resulting
in pulse overshoot and possible instability. To this end, it is
recommended that the ground plane be removed under
traces connected to -IN, and connections to -IN should be
kept as short as possible.

Driving Capacitive Loads

Capacitive loads, such as an A/D input, or an improperly
terminated transmission line will degrade the amplifier’s
phase margin resulting in frequency response peaking and
possible oscillations. In most cases, the oscillation can be
avoided by placing a resistor (R
prior to the capacitance.

Figure 1 details starting points for the selection of this
resistor. The points on the curve indicate the R
combinations for the optimum bandwidth, stability, and
settling time, but experimental fine tuning is recommended.
Picking a point above or to the right of the curve yields an
overdampedresponse, while points belowor leftof the curve
indicate areas of underdamped performance.

R

and CLform a low pass network at the output, thus

S

limiting system bandwidth well below the amplifier
bandwidth of 290MHz (for A

increases (as illustrated in the curves), the maximum

C

L

bandwidth is obtained without sacrificing stability. Even so,
bandwidth does decrease as you move to the right along
the curve. For example, at A
the overall bandwidth is limited to 180MHz, and bandwidth
drops to 70MHz at A

50

40

30

20

10

SERIES OUTPUT RESISTANCE (Ω)

0

0 100 200 300 400

FIGURE 1. RECOMMENDED SERIES OUTPUT RESISTOR vs

LOAD CAPACITANCE

= +1, RS = 8Ω, CL = 400pF.

V

AV = +2

150 250 35050

LOAD CAPACITANCE (pF)

) in series with the output

S

and C

S

= +1). By decreasing RS as

V

= +1, RS = 62Ω, CL= 40pF,

V

AV = +1

L

2