Datasheet LT1260, LT1259 Datasheet (Linear Technology)

FEATURES

■

90MHz Bandwidth on ±5V

■

0.1dB Gain Flatness >30MHz

■

Completely Off in Shutdown, 0µA Supply Current

■

High Slew Rate: 1600V/µs

■

Wide Supply Range: ±2V(4V) to ±15V(30V)

■

60mA Output Current

■

Low Supply Current: 5mA/Amplifier

■

Differential Gain: 0.016%

■

Differential Phase: 0.075°

■

Fast Turn-On Time: 100ns

■

Fast Turn-Off Time: 40ns

■

14-Pin and 16-Pin Narrow SO Packages

U

APPLICATIO S

LT1259/LT1260

Low Cost Dual and Triple

130MHz Current Feedback

Amplifiers with Shutdown

U

DESCRIPTIO

The LT®1259 contains two independent 130MHz current
feedback amplifiers, each with a shutdown pin. These
amplifiers are designed for excellent linearity while driving
cables and other low impedance loads. The LT1260 is a
triple version especially suited to RGB video applications.
These amplifiers operate on all supplies from single 5V to
±15V and draw only 5mA per amplifier when active.

When shut down, the LT1259/LT1260 amplifiers draw
zero supply current and their outputs become high
impedance. Only two LT1260s are required to make a
complete 2-input RGB MUX and cable driver. These
amplifiers turn on in only 100ns and turn off in 40ns,
making them ideal in spread spectrum and portable
equipment applications.

■

RGB Cable Drivers

■

Spread Spectrum Amplifiers

■

MUX Amplifiers

■

Composite Video Cable Drivers

■

Portable Equipment

TYPICAL APPLICATIO

CHANNEL

A

SELECT

V

IN A

R

G

1.6k

V

IN B

R

G

1.6k

EN A

+

1/2 LT1259

–

EN B

+

1/2 LT1259

–

R

1.6k

R

1.6k

B

F

F

U

75Ω

75Ω

LT1259/60 • TA01

75Ω
CABLE

75Ω

The LT1259/LT1260 amplifiers are manufactured on
Linear Technology’s proprietary complementary bipolar
process.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Square Wave Response2-Input Video MUX Cable Driver

V

OUT

CABLE OUTPUT

RL = 150Ω
f = 30MHz

LT1259/50 • TA02

1

LT1259/LT1260

WWWU

ABSOLUTE AXI U RATI GS

Supply Voltage ..................................................... ±18V

Input Current ..................................................... ±15mA

Output Short-Circuit Duration (Note 1).........Continuous

Specified Temperature Range (Note 2)....... 0°C to 70°C

UU

W

PACKAGE/ORDER I FOR ATIO

TOP VIEW

1

–IN A

2

+IN A

3

GND

4

GND

5

GND

6

+IN B

7

–IN B

N PACKAGE

14-LEAD PLASTIC DIP

T

= 150°C, θJA = 70°C/W (N)

JMAX

T

= 150°C, θJA = 110°C/W (S)

JMAX

EN A

A

B

14

OUT A

13

+

V

12

GND

11

–

V

10

OUT B

9

EN B

8

S PACKAGE

14-LEAD PLASTIC SOIC

ORDER PART

NUMBER

LT1259CN
LT1259CS
LT1259IN
LT1259IS

Operating Temperature Range ............... –40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Junction Temperature (Note 4)............................ 150°C

Lead Temperature (Soldering, 10 sec).................. 300°C

TOP VIEW

1

–IN R

2

+IN R

3

GND

4

–IN G

5

+IN G

6

GND

7

+IN B

8

–IN B

N PACKAGE

16-LEAD PLASTIC DIP

T

= 150°C, θJA = 70°C/W (N)

JMAX

= 150°C, θJA = 100°C/W (S)

T

JMAX

EN R

R

G

B

16

OUT R

15

+

V

14

EN G

13

OUT G

12

–

V

11

OUT B

10

EN B

9

S PACKAGE

16-LEAD PLASTIC SOIC

ORDER PART

NUMBER

LT1260CN
LT1260CS
LT1260IN
LT1260IS

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS

0°C ≤ TA ≤ 70°C, each amplifier VCM = 0V, ±5V ≤ VS ≤ ±15V, EN pins = 0V, pulse tested, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

I

I

e
+i
–i
R

C

C
V

IN

IN

n

OS

+

–

n
n

IN

IN

OUT
IN

Input Offset Voltage TA = 25°C212mV

● 16 mV

Input Offset Voltage Drift ● 30 µV/°C
Noninverting Input Current TA = 25°C 0.5 3 µA

● 6 µA

Inverting Input Current TA = 25°C2090µA

● 120 µA

Input Noise Voltage Density f = 1kHz, RF = 1k, RG = 10Ω, RS = 0Ω 3.6 nV/√Hz
Noninverting Input Noise Current Density f = 1kHz 1.3 pA/√Hz
Inverting Input Noise Current Density f = 1kHz 45 pA/√Hz
Input Resistance VIN = ±13V, VS = ±15V ● 217 MΩ

= ±3V, VS = ±5V ● 225 MΩ

V

IN

Input Capacitance Enabled 2 pF

Disabled 4 pF
Output Capacitance Disabled 4.4 pF
Input Voltage Range VS = ±15V, TA = 25°C ±13 ±13.5 V

● ±12 V

VS = ±5V, TA = 25°C ±3 ±3.5 V

● ±2V

2

LT1259/LT1260

LECTRICAL C CHARA TERIST

E

0°C ≤ TA ≤ 70°C, each amplifier VCM = 0V, ±5V ≤ VS ≤ ±15V, EN pins = 0V, pulse tested, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OUT

CMRR Common-Mode Rejection Ratio VS = ±15V, VCM = ±13V, TA = 25°C5569 dB

PSRR Power Supply Rejection Ratio VS = ±2V to ±15V, EN Pins at V–, TA = 25°C6080 dB

A

V

R

OL

I

OUT

I

S

SR Slew Rate (Note 6) TA = 25°C 900 1600 V/µs
t

ON

t

OFF

tr, t

f

t

S

Maximum Output Voltage Swing VS = ±15V, RL = 1k ● ±12.0 ±14.0 V

Inverting Input Current VS = ±15V, VCM = ±13V, TA = 25°C 3.5 10 µA/V
Common-Mode Rejection V

Noninverting Input Current VS = ±3V to ±15V, EN Pins at V–, TA = 25°C1565nA/V
Power Supply Rejection VS = ±3V to ±15V, EN Pins at V

Inverting Input Current VS = ±2V to ±15V, EN Pins at V–, TA = 25°C 0.1 5 µA/V
Power Supply Rejection V

Large-Signal Voltage Gain VS = ±15V, V

Transresistance, ∆V

OUT

/∆I

–

IN

Maximum Output Current RL = 0Ω, TA = 25°C3060mA
Supply Current per Amplifier VS = ±15V, V

(Note 5)

Disable Supply Current per Amplifier VS = ±15V, EN Pin Voltage = 14.5V, RL = 150Ω ● 3 16.7 µA

Enable Pin Current VS = ±15V, EN Pin Voltage = 0V, TA = 25°C 60 200 µA

Turn-On Delay Time (Note 7) AV = 10, TA = 25°C 100 400 ns
Turn-Off Delay Time (Note 7) AV = 10, TA = 25°C 40 150 ns
Small-Signal Rise and Fall Time VS = ±12V, RF = RG = 1.5k, RL = 150Ω 4.2 ns
Propagation Delay VS = ±12V, RF = RG = 1.5k, RL = 150Ω 4.7 ns
Small-Signal Overshoot VS = ±12V, RF = RG = 1.5k, RL = 150Ω 5%
Settling Time 0.1%, V
Differential Gain (Note 8) VS = ±12V, RF = RG = 1.5k, RL = 150Ω 0.016 %
Differential Phase (Note 8) VS = ±12V, RF = RG = 1.5k, RL = 150Ω 0.075 DEG

ICS

VS = ±5V, RL = 150Ω, TA = 25°C ±3.0 ±3.7 V

VS = ±15V, VCM = ±12V ● 55 dB

= ±5V, VCM = ±3V, TA = 25°C5263dB

V

S

= ±5V, VCM = ±2V ● 52 dB

V

S

= ±15V, VCM = ±12V ● 10 µA/V

S

= ±5V, VCM = ±3V, TA = 25°C 4.5 15 µA/V

V

S

VS = ±5V, VCM = ±2V ● 15 µA/V

= ±3V to ±15V, EN Pins at V

V

S

= ±3V to ±15V, EN Pins at V

S

= ±10V, RL = 1k ● 57 72 dB

= ±5V, V

V

S

VS = ±15V, V
VS = ±5V, V

VS = ±5V, V

= ±15V, Sink 1µA From EN Pin ● 1 2.7 µA

V

S

OUT

= ±2V, RL = 150Ω ● 57 69 dB

OUT

= ±10V, RL = 1k ● 120 300 kΩ

OUT

= ±2V, RL = 150Ω ● 100 200 kΩ

OUT

= 0V, TA = 25°C 5.0 7.5 mA

OUT

= 0V, TA = 25°C 4.5 6.7 mA

OUT

= 10V, RF = RG = 1.5k, RL = 1k 75 ns

OUT

–

–

–

● ±2.5 V

● 60 dB

● 75 nA/V

● 5 µA/V

● 7.9 mA

● 300 µA

–40°C ≤ TA ≤ 85°C, each amplifier VCM = 0V, ±5V ≤ VS ≤ ±15V, EN pins = 0V, pulse tested, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

+

I

IN

–

I

IN

R

IN

A

V

I

S

Input Offset Voltage ● 18 mV
Noninverting Input Current ● 7 µA
Inverting Input Current ● 130 µA
Input Resistance VIN = ±3V, VS = ±5V ● 1MΩ
Large-Signal Gain ● 55 dB
Disable Supply Current per Amplifier VS = ±15V, EN Pin Voltage = 14.5V, RL = 150Ω ● 19 µA
Enable Pin Current VS = ±15V, EN Pin Voltage = 0V ● 350 µA

3

LT1259/LT1260

ELECTRICAL CHARACTERISTICS

T

he ● denotes specifications which apply over the specified operating

temperature range.
Note 1: A heat sink may be required depending on the power supply

voltage and how many amplifiers have their outputs short circuited.
Note 2: Commercial grade parts are designed to operate over the

temperature range of –40°C to 85°C but are neither tested nor guaranteed
beyond 0°C to 70°C. Industrial grade parts specified and tested over
–40°C to 85°C are available on special request. Consult factory.

Note 3: Ground pins are not internally connected. For best
performance, connect to ground.

Note 4: T
power dissipation P

is calculated from the ambient temperature TA and the

J

according to the following formulas:

D

LT1259CN/LT1259IN: TJ = TA + (PD • 70°C/W)
LT1259CS/LT1259IS: T
LT1260CNLT1260IN/: T
LT1260CS/LT1260IS: T

= TA + (PD • 110°C/W)

J

= TA + (PD • 70°C/W)

J

= TA + (PD • 100°C/W)

J

Note 5: The supply current of the LT1259/LT1260 has a negative
temperature coefficient. See Typical Performance Characteristics.

Note 6: Slew rate is measured at ±5V on a ±10V output signal while
operating on ±15V supplies with R

= 1k, RG = 110Ω and RL = 1k.

F

Note 7: Turn-on delay time is measured while operating on ±5V
supplies with R

= 1k, RG = 110Ω and RL = 150Ω. The tON is measured

F

from control input to appearance of 0.5V at the output, for V
Likewise, turn-off delay time is measured from control input to
appearance of 0.5V on the output for VIN = 0.1V.

Note 8: Differential gain and phase are measured using a Tektronix
TSG120YC/NTSC signal generator and a Tektronix 1780R Video
Measurement Set. The resolution of this equipment is 0.1% and 0.1°.
Six identical amplifier stages were cascaded giving an effective
resolution of 0.016% and 0.016°.

WU

TYPICAL AC PERFOR A CE

SMALL SIGNAL SMALL SIGNAL SMALL SIGNAL

(V) A

V

S

V

±12 2 150 1.5k 1.5k 130 53 0.1

±5 2 150 1.1k 1.1k 93 40 0

±12 10 150 1.1k 121 69 20 0.13

±5 10 150 825 90.9 61 16 0

RL (Ω)R

(Ω)R

F

(Ω) – 3dB BW (MHz) 0.1dB BW (MHz) PEAKING (dB)

G

= 0.1V.

IN

UW

TYPICAL PERFOR A CE CHARACTERISTICS

±12V Frequency Response, AV = 2

12
11
10

9
8
7

GAIN (dB)

6
5
4
3

2

1

GAIN

VS = ±12V

= 150Ω

R

L

= RG = 1.5k

R

F

PHASE

10 100

FREQUENCY (MHz)

LT1259/60 • TPC01

0
–20
–40
–60
–80
–100
–120
–140
–160
–180
–200

PHASE (DEG)

26
25
24
23
22
21

GAIN (dB)

20
19

18
17
16

±12V Frequency Response, AV = 10

VS = ±12V
R

= 150Ω

L

= 1.1k

R

F

R

= 121Ω

PHASE

GAIN

1

10 100

FREQUENCY (MHz)

G

LT1259/60 • TPC01

0
–20
–40
–60
–80
–100
–120
–140
–160
–180
–200

PHASE (DEG)

4

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LT1259/LT1260

±5V Frequency Response, AV = 2

12
11
10

9
8

7

GAIN (dB)

6
5

4
3
2

VS = ±5V
R

L

R

F

1

GAIN

= 150Ω
= RG = 1.1k

Total Harmonic Distortion
vs Frequency

0.1
VS = ±12V
R

= 400Ω

L

R

= RG = 1.5k

F

VO = 6V

RMS

0.01
VO = 1V

TOTAL HARMONIC DISTORTION (%)

0.001
10

100 10k

1k 100k

FREQUENCY (Hz)

PHASE

10 100

FREQUENCY (MHz)

RMS

LT1259/60 • TPC05

LT1259/60 • TPC03

–20

–30

–40

–50

DISTORTION (dBc)

–60

–70

±5V Frequency Response, AV = 10

0
–20
–40
–60
–80
–100
–120
–140
–160
–180
–200

PHASE (DEG)

26
25
24
23
22
21

GAIN (dB)

20
19

18
17
16

1

VS = ±5V
R

L

R

= 825Ω

F

R

G

2nd and 3rd Harmonic Distortion
vs Frequency

VS = ±12V
V

= 2V

O

P-P

AV = 10dB
R

= 100Ω

L

R

= 1.5k

F

2ND 3RD

1

10 100

FREQUENCY (MHz)

LT12359/60 • TPC06

GAIN

= 150Ω
= 90.9Ω

PHASE

10 100

FREQUENCY (MHz)

LT1259/60 • TPC04

Maximum Undistorted Output
vs Frequency

25

20

)

P-P

15

10

OUTPUT VOLTAGE (V

5

0

1

AV = 1 AV = 2

FREQUENCY (MHz)

0
–20
–40
–60

PHASE (DEG)

–80
–100

–120
–140

–160
–180
–200

VS = ±15V

= 1k

R

L

R

= 2k

F

AV = 10

10 100

LT12359/60 • TPC07

Power Supply Rejection
vs Frequency

80

70

60

50

40

30

20

POWER SUPPLY REJECTION (dB)

10

0

10k

POSITIVE

100k 1M 10M

FREQUENCY (Hz)

VS = ±15V
R

= 1OOΩ

L

R

= RG = 1k

F

NEGATIVE

LTC1259/60 • TPC08

100M

Spot Noise Voltage and Current
vs Frequency Output Impedance vs Frequency

100

VS = ±15V

10

1

OUTPUT IMPEDANCE (Ω)

0.1
10k

100k 10M

RF = RG = 2k

1M 100M

FREQUENCY (Hz)

SPOT NOISE (nV/√Hz OR pA/√Hz)

100

–i

n

10

e

n

+i

n

1

10

100 10k

1k 100k

FREQUENCY (Hz)

LT1259/60 • TPC09

LT1259/60 • TPC10

5

LT1259/LT1260

TEMPERATURE (°C)

–50

OUTPUT SHORT-CIRCUIT CURRENT (mA)

60

70

150

LT1259/60 • TPC15

50

40

0

50

100

80

–25

25

75

125

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Output Impedance in Shutdown
vs Frequency

100

10

1

OUTPUT IMPEDANCE (kΩ)

0.1
100k

1M 10M 100M

FREQUENCY (Hz)

Output Saturation Voltage
vs Temperature

+

V

RL = ∞

≤ ±18V

±2V ≤ V

–0.5

–1.0

S

VS = ±15

= 1

A

V

= 1.5k

R

F

LT1259/60 • TPC11

Maximum Capacitive Load
vs Feedback Resistor

1000

VS = ±5V VS = ±15V

100

LOAD CAPACITANCE (pF)

10

265431

FEEDBACK RESISTOR (kΩ)

Input Common-Mode Limit
vs Temperature

+

V
–0.5
–1.0
–1.5
–2.0

V+ = 2V TO 18V

AV = 2

= 150Ω

R

L

PEAKING ≤ 5dB

LT1259/60 • TPC12

Supply Current vs Supply Voltage

7

6

5

4

3

2

SUPPLY CURRENT (mA)

1

0

218

46810

0

SUPPLY VOLTAGE (±V)

–55°C

25°C

125°C

12

Output Short-Circuit Current
vs Junction Temperature

14 16

LT1259/60 • TPC13

1.0

0.5

OUTPUT SATURATION VOLTAGE (V)

–

V

–50

–25 0

50 100 125

25 75

TEMPERATURE (°C)

LT1259/60 • TPC14

Settling Time to 10mV
vs Output Step

10

8
6
4
2
0

–2

OUTPUT STEP (V)

–4
–6
–8

–10

0

NONINVERTING

INVERTING

100 300

200

SETTLING TIME (ns)

400

500

2.0

1.5

COMMON-MODE RANGE (V)

1.0

0.5

–

V

–50

–25

VS = ±12V
R

= 1.5k

F

700

600

800

LT1259/60 • TPC17

V– = –2V TO –18V

50

25

0

TEMPERATURE (°C)

100

LT1259/60 • TPC16

125

75

Small-Signal Rise Time

R

VS = ±15V

= 2

A

V

= RG = 1.6k

F

= 150Ω

R

L

LT1259/60 G19

6

WW

SI PLIFIED SCHE ATIC

, each amplifier

LT1259/LT1260

+

V

+IN

EN

WUUU

APPLICATIO S I FOR ATIO

Feedback Resistor Selection

The small-signal bandwidth of the LT1259/ LT1260 are set
by the external feedback resistors and the internal junction
capacitors. As a result, the bandwidth is a function of the
supply voltage, the value of the feedback resistor, the
closed-loop gain and the load resistor. The LT1259/LT1260
have been optimized for ±5V supply operation and have a
– 3dB bandwidth of 90MHz. See resistor selection guide in
Typical AC Performance table.

Capacitance on the Inverting Input

Current feedback amplifiers require resistive feedback
from the output to the inverting input for stable operation.
Take care to minimize the stray capacitance between the
output and the inverting input. Capacitance on the invert­ing input to ground will cause peaking in the frequency
response (and overshoot in the transient response). See
the section on Demo Board Information.

Capacitive Loads

The LT1259/LT1260 can drive capacitive loads directly
when the proper value of feedback resistor is used. The
graph of Maximum Capacitive Load vs Feedback Resistor
should be used to select the appropriate value. The value
shown is for ≤5dB peaking when driving a 150Ω load at a
gain of 2. This is a worst case condition. The amplifier is

–IN

OUT

V

LT1259/60 • SS

–

more stable at higher gains. Alternatively, a small resistor
(10Ω to 20Ω) can be put in series with the output to isolate
the capacitive load from the amplifier output. This has the
advantage that the amplifier bandwidth is only reduced
when the capacitive load is present. The disadvantage is
that the gain is a function of the load resistance.

Power Supplies

The LT1259/LT1260 will operate from single or split
supplies from ±2V (4V total) to ±15V (30V total). It is not
necessary to use equal value split supplies, however the
offset voltage and inverting input bias current will change.
The offset voltage changes about 500µV per volt of
supply mismatch. The inverting bias current can change
as much as 5µA per volt of supply mismatch though
typically, the change is about 0.1µA per volt.

Slew Rate

The slew rate of a current feedback amplifier is not
independent of the amplifier gain configuration the way
slew rate is in a traditional op amp. This is because both the
input stage and the output stage have slew rate limitations.
In the inverting mode, and for higher gains in the nonin­verting mode, the signal amplitude between the input pins
is small and the overall slew rate is that of the output stage.
For gains less than ten in the noninverting mode, the
overall slew rate is limited by the input stage.

7

LT1259/LT1260

WUUU

APPLICATIO S I FOR ATIO

The input slew rate of the LT1259/LT1260 is approxi­mately 270V/µs and is set by internal currents and capaci-
tances. The output slew rate is set by the value of the
feedback resistors and internal capacitances. At a gain of
10 with at 1k feedback resistor and ±15V supplies, the
output slew rate is typically 1600V/µs. Larger feedback
resistors will reduce the slew rate as will lower supply
voltages, similar to the way the bandwidth is reduced.

The graph of Maximum Undistorted Output vs Frequency
relates the slew rate limitations to sinusoidal input for
various gains.

Large-Signal Transient Response, AV = 2

looks like a 4.4pF capacitor in parallel with a 75k resistor,
excluding feedback resistor effects. These amplifiers are
designed to operate with open drain logic: the EN pins have
internal pullups and the amplifiers draw zero current when
these pins are high. To activate an amplifier, its EN pin is
pulled to ground (or at least 2V below the positive supply).
The enable pin current is approximately 60µA when
activated. Input referred switching transients with no
input signal applied are only 35mV positive and 80mV
negative with RL = 100Ω.

Output Switching Transient

EN

OUTPUT

VS = ±15V

= RG = 1.6k

R

F

RL = 400Ω

LT1259/LT1260 • AI01

Large-Signal Transient Response, AV = 10

VS = ±15V

= 1k

R

F

RG = 110Ω

= 400Ω

R

L

LT1259/LT1260 • AI02

Enable/Disable

The LT1259/LT1260 amplifiers have a unique high imped­ance, zero supply current mode which is controlled by
independent EN pins. When disabled, an amplifier output

VS = ±5V

= 0V

V

IN

RF = RG = 1.6k

= 100Ω

R

L

LT1259/LT1260 • AI03

The enable/disable times are very fast when driven from
standard 5V logic. The amplifier enables in about 100ns
(50% point to 50% point) while operating on ±5V sup­plies. Likewise the disable time is approximately 40ns
(50% point to 50% point) or 75ns to 90% of the final
value. The output decay time is set by the output capaci­tance and load resistor.

Amplifier Enable Time, AV = 10

OUTPUT

EN

VS = ±5V

= 0.1V

V

IN

RF = 1k

= 110Ω

R

G

R

L

= 150Ω

LT1259/LT1260 • AI04

8

WUUU

APPLICATIO S I FOR ATIO

LT1259/LT1260

Amplifier Disable Time, AV = 10

EN

OUTPUT

VS = ±5V
V

= 0.1V

IN

RF = 1k

= 110Ω

R

G

R

L

= 150Ω

LT1259/LT1260 • AI05

Differential Input Signal Swing

The differential input swing is limited to about ±6V by an
ESD protection device connected between the inputs. In
normal operation, the differential voltage between the

U

TYPICAL APPLICATIO S

Amplifier Enable/Disable Time, AV = 2

EN

OUTPUT

VS = ±5V
V

= 2VPP at 2MHz

IN

R

= RG = 1.6k

F

= 100Ω

R

L

LT1259/LT1260 • AI06

input pins is small, so this clamp has no effect. In the
disabled mode however, the differential swing can be the
same as the input swing, and the clamp voltage will set the
maximum allowable input voltage.

2-Input Video MUX Cable Driver

The application on the first page shows a low cost, 2­input video MUX cable driver. The scope photo displays
the cable output of a 30MHz square wave driving 150Ω.
In this circuit the active amplifier is loaded by RF and R

G

of the disabled amplifier, but in this case it only causes a

1.2% gain error. The gain error can be eliminated by

2-Input Video MUX Switching Response

EN A

EN B

VS = ±5V
V

= V

IN A

= 2VPP at 2MHz

IN 2

R

= RG = 1.6k

F

R

= 100Ω

L

LT1259/LT1260 • TA03

configuring each amplifier as a unity-gain follower. The
switching time between channels is 100ns when both
EN A and EN B are driven.

2-Input RGB MUX Cable Driver Demonstration Board

A complete 2-input RGB MUX has been fabricated on PC
Demo Board #039A. The board incorporates two LT1260s
with outputs summed through 75Ω back termination
resistors as shown in the schematic. There are several
things to note about Demo Board #039A:

1. The feedback resistors of the disabled LT1260 load
the enabled amplifier and cause a small (1% to 2%)
gain error depending on the values of RF and RG.
Configure the amplifiers as unity-gain followers to
eliminate this error.

2. The feedback node has minimum trace length connect­ing RF and RG to minimize stray capacitance.

3. Ground plane is pulled away from RF and RG on both
sides of the board to minimize stray capacitance.

9

LT1259/LT1260

FREQUENCY (MHz)

1

–100

ALL HOSTILE CROSSTALK (dB)

–80

–60

–40

–20

10 100

LT1259/60 • TA06

0

VS = ±12V
R

L

= 100Ω

R

F

= RG = 1.6k

R

S

= 10Ω

G

B

R

TYPICAL APPLICATIO S

U

4. Capacitors C1 and C6 are optional and only needed to
reduce overshoot when EN 1 or EN 2 are activated with
a long inductive ground wire.

5. The R, G and B amplifiers have slightly different
frequency responses due to different output trace
routing to RF (between pins 3 and 4). All amplifiers
have slightly less bandwidth in PCB #039 than when
measured alone as shown in the Typical AC Perfor­mance table.

6. Part-to-part variation can change the peaking by
±0.25dB.

RGB Demo Board Gain vs Frequency

4

VS = ±12V

= 150Ω

R

L

= RG = 1.6k

R

F

2

R

G

B

LT1259/60 • TA04

R, B

G

LT1259/60 • TA05

0

GAIN (dB)

–2

–4

–6

1

10 100

FREQUENCY (MHz)

RGB Demo Board Gain vs Frequency

4

VS = ±5V
R

= 150Ω

L

= RG = 1.1k

R

F

2

0

GAIN (dB)

–2

–4

–6

1

10 100

FREQUENCY (MHz)

RGB Demo Board All Hostile Crosstalk

P-DIP PC Board #039

EN1EN2

R1

G1

B1

R2

G2

B2

R10

R11

R2

R3
R4

R5

R8

R9

R1

R6

R7

R12

C1

C6

U1

R13

C2

R14

C3

R15

U2

C5

R16

C7

R17

C8

R18

[phone]
LT1260 RGB AMPLIFIER
DEMONSTRATION BOARD

C4

GNDV–V+

R

G

B

LT1259/60 • TA07

10

PACKAGE DESCRIPTIO

0.300 – 0.325

(7.620 – 8.255)

0.009 – 0.015

(0.229 – 0.381)

+0.025

0.325

–0.015
+0.635

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

0.300 – 0.325

(7.620 – 8.255)

0.009 – 0.015

(0.229 – 0.381)

+0.025

0.325

–0.015

+0.635

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

**

DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

**

DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

× 45°

0.016 – 0.050

0.406 – 1.270

× 45°

0.016 – 0.050

0.406 – 1.270

0.015

(0.380)

MIN

0.015

(0.381)

MIN

0° – 8° TYP

(1.346 – 1.752)

0° – 8° TYP

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

0.053 – 0.069

0.014 – 0.019

(0.355 – 0.483)

U

Dimensions in inches (millimeters) unless otherwise noted.

N Package

14-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.045 – 0.065

(1.143 – 1.651)

0.255 ± 0.015*

0.065

(6.477 ± 0.381)

(1.651)

TYP

0.005

(0.125)

MIN

0.100 ± 0.010

(2.540 ± 0.254)

0.018 ± 0.003

(0.457 ± 0.076)

N Package

16-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.045 – 0.065

(1.143 – 1.651)

0.255 ± 0.015*
(6.477 ± 0.381)

0.065

(1.651)

TYP

0.005

(0.127)

MIN

0.100 ± 0.010

(2.540 ± 0.254)

0.018 ± 0.003

(0.457 ± 0.076)

S Package

14-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.004 – 0.010

(0.101 – 0.254)

0.228 – 0.244

0.050

(1.270)

TYP

(5.791 – 6.197)

S Package

16-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.004 – 0.010

(0.101 – 0.254)

0.228 – 0.244

0.050

(1.270)

TYP

(5.791 – 6.197)

14

16

1

13

14

1

2

16

1

14

15

3

2

LT1259/LT1260

0.770*
(19.558)

MAX

11

1213

31

2

14

15

2

3

0.337 – 0.344*
(8.560 – 8.738)

12

11

3

0.386 – 0.394*

(9.804 – 10.008)

13

4

4

13

12

5

4

0.770*

(19.558)

MAX

4

10

5

5

6

12

11

6

5

8

9

7

6

11

10

7

6

8910

7

N14 0695

910

8

7

N16 0695

0.150 – 0.157**
(3.810 – 3.988)

9

0.150 – 0.157**
(3.810 – 3.988)

8

S14 0695

S16 0695

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen­tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

11

LT1259/LT1260

TYPICAL APPLICATIO

U

Demonstration PC Board Schematic #039

EN 1

16

15

14

13

12

11

10

9

C6*

0.01µF

16

15

14

13

12

11

10

9

EN 2

C1*

0.01µF

R1 R2

1

–

R

+

LT1260

–

G

+

+

B

–

–

R

+

LT1260

–

G

+

+

B

–

R4

R10

2

3

4

5

6

7

8

R5

1

2

3

4

5

6

7

8

R11

R1

R3

G1

B1

R6

R7 R8

R2

R9

G2

B2

R12

+

V

C7

0.1µF

–

V

GND

R13

C2

0.1µF

C3

0.1µF

C4

4.7µF

75Ω

R14
75Ω

R15
75Ω

V

RED

OUT

V

GREEN

OUT

V

BLUE

OUT

+

+

C5

4.7µF

R16
75Ω

R17
75Ω

C8

0.1µF

R18
75Ω

LT1259/60 • TA08

*OPTIONAL

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1203/LT1205 150MHz Video Multiplexers 2:1 and Dual 2:1 MUXes with 25ns Switch Time
LT1204 4-Input Video MUX with Current Feedback Amplifier Cascadable Enable 64:1 Multiplexing
LT1227 140MHz Current Feedback Amplifier 1100V/µs Slew Rate, Shutdown Mode
LT1252/LT1253/LT1254 Low Cost Video Amplifiers Single, Dual and Quad Current Feedback Amplifiers

125960fas, sn125960 LT/TP 1197 REV A 4K • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1993

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● [phone]
FAX: [phone]

●

TELEX: 499-3977 ● www.linear-tech.com