Datasheet LT1206 Datasheet (Linear Technology)

LT1206

250mA/60MHz Current

Feedback Amplifier

EATU

F

■

250mA Minimum Output Drive Current

■

60MHz Bandwidth, AV = 2, RL = 100Ω

■

900V/µs Slew Rate, AV = 2, RL = 50Ω

■

0.02% Differential Gain, AV = 2, RL = 30Ω

■

0.17° Differential Phase, AV = 2, RL = 30Ω

■

High Input Impedance, 10MΩ

■

Wide Supply Range, ±5V to ±15V

■

Shutdown Mode: IS < 200µA

■

Adjustable Supply Current

■

Stable with CL = 10,000pF

RE

S

U

APPLICATIO S

■

Video Amplifiers

■

Cable Drivers

■

RGB Amplifiers

■

Test Equipment Amplifiers

■

Buffers

DUESCRIPTIO

The LT1206 is a current feedback amplifier with high
output current drive capability and excellent video char­acteristics. The LT1206 is stable with large capacitive
loads, and can easily supply the large currents required
by the capacitive loading. A shutdown feature switches
the device into a high impedance, low current mode,
reducing dissipation when the device is not in use. For
lower bandwidth applications, the supply current can be
reduced with a single external resistor. The low differen­tial gain and phase, wide bandwidth, and the 250mA
minimum output current drive make the LT1206 well
suited to drive multiple cables in video systems.

The LT1206 is manufactured on Linear Technology’s
proprietary complementary bipolar process.

U

TYPICAL APPLICATIO S

Noninverting Amplifier with Shutdown

15V

V

ENABLE

+

IN

V

OUT



R

F

OPTIONAL, USE WITH CAPACITIVE LOADS

*

R

G

GROUND SHUTDOWN PIN FOR

**

NORMAL OPERATION

5V

LT1206



S/D**

–

74C906

–15V

15V

COMP

24k

C

COMP

0.01µF*

LT1206 • TA01

Large-Signal Response, CL = 10,000pF

VS = ±15V
R

= ∞

L

= RG = 3k

R

F

LT1206 • TA02

1

LT1206

A

W

O

LUTEXI T

S

A

WUW

ARB

U
G

I

S

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

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

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

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

WU

/

PACKAGE

NC

–IN

+IN

S/D*

FRONT VIEW

TAB IS

V

7-LEAD PLASTIC DD

O

RDER I FOR ATIO

TOP VIEW

1
2
3
4

N8 PACKAGE

8-LEAD PLASTIC DIP

θJA = 100°C/W

7
6
5
4
3

+

R PACKAGE

2
1

θJA ≈ 30°C/W

ORDER PART

+



V

8

OUT

7

–



V

6

COMP

5



NUMBER

LT1206CN8**

ORDER PART

OUT

–



V
COMP

+



V
S/D*
+IN
–IN

NUMBER

LT1206CR**

Operating Temperature Range

LT1206C ........................................... –40°C to 85°C

Junction Temperature......................................... 150°C

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

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

U

TAB IS

+

V

+

V

1



–IN

2

+IN

3

S/D*

4

8-LEAD PLASTIC SO

FRONT VIEW

Y PACKAGE

7-LEAD TO-220

TOP VIEW

S8 PACKAGE

θ

≈ 60°C/W

JA

7
6
5
4
3
2
1

θJC = 5°C/W

+

V



8

OUT

7

–

V



6

COMP

5

OUT

–

V
COMP

+

V
S/D*
+IN
–IN

ORDER PART

NUMBER

LT1206CS8**

PART MARKING

ORDER PART





NUMBER

LT1206CY**

1206

*Ground shutdown pin for normal operation **See Note 2

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

I

I

e
+i
–i
R

C

OS

+

IN

–

IN

n

n

n

IN

IN

Input Offset Voltage TA = 25°C ±3 ±10 mV

Input Offset Voltage Drift ● 10 µV/°C
Noninverting Input Current TA = 25°C ±2 ±5 µA

Inverting Input Current TA = 25°C ±10 ±60 µA

Input Noise Voltage Density f = 10kHz, RF = 1k, RG = 10Ω, RS = 0Ω 3.6 nV/√Hz
Input Noise Current Density f = 10kHz, RF = 1k, RG = 10Ω, RS = 10k 2 pA/√Hz
Input Noise Current Density f = 10kHz, RF = 1k, RG = 10Ω, RS = 10k 30 pA/√Hz
Input Resistance VIN = ±12V, VS = ±15V ● 1.5 10 MΩ

VIN = ±2V, VS = ±5V ● 0.5 5 MΩ
Input Capacitance VS = ±15V 2 pF
Input Voltage Range VS = ±15V ● ±12 ±13.5 V

VS = ±5V ● ±2 ±3.5 V

VCM = 0, ±5V ≤ VS ≤ ±15V, pulse tested, V

● ±15 mV

● ±20 µA

● ±100 µA

= 0V, unless otherwise noted.

S/D

2

LT1206

ELECTRICAL CHARACTERISTICS

VCM = 0, ±5V ≤ VS ≤ ±15V, pulse tested, V

= 0V, unless otherwise noted.

S/D

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

CMRR Common-Mode Rejection Ratio VS = ±15V, VCM = ±12V ● 55 62 dB

V

= ±5V, VCM = ±2V ● 50 60 dB

S

Inverting Input Current VS = ±15V, VCM = ±12V ● 0.1 10 µA/V
Common-Mode Rejection V

= ±5V, VCM = ±2V ● 0.1 10 µA/V

S

PSRR Power Supply Rejection Ratio VS = ±5V to ±15V ● 60 77 dB

Noninverting Input Current VS = ±5V to ±15V ● 30 500 nA/V
Power Supply Rejection

Inverting Input Current VS = ±5V to ±15V ● 0.7 5 µA/V
Power Supply Rejection

A

V

R

OL

V

OUT

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

V

= ±5V, V

S

VS = ±15V, V

Transresistance, ∆V

OUT

/∆I

–

IN

VS = ±5V, V

= ±10V, RL = 50Ω ● 55 71 dB

OUT

= ±2V, RL = 25Ω ● 55 68 dB

OUT

= ±10V, RL = 50Ω ● 100 260 kΩ

OUT

= ±2V, RL = 25Ω ● 75 200 kΩ

OUT

Maximum Output Voltage Swing VS = ±15V, RL = 50Ω, TA = 25°C ±11.5 ±12.5 V

● ±10.0 V

VS = ±5V, RL = 25Ω, TA = 25°C ±2.5 ±3.0 V

● ±2.0 V

I
I

OUT

S

Maximum Output Current RL = 1Ω ● 250 500 1200 mA
Supply Current VS = ±15V, V

Supply Current, R

= 51k (Note 3) VS = ±15V, TA = 25°C1217mA

S/D

Positive Supply Current, Shutdown VS = ±15V, V
Output Leakage Current, Shutdown VS = ±15V, V

= 0V, TA = 25°C2030mA

S/D

= 15V ● 200 µA

S/D

= 15V ● 10 µA

S/D

●35 mA

SR Slew Rate (Note 4) AV = 2, TA = 25°C 400 900 V/µs

Differential Gain (Note 5) VS = ±15V, RF = 560Ω, RG = 560Ω, RL = 30Ω 0.02 %
Differential Phase (Note 5) VS = ±15V, RF = 560Ω, RG = 560Ω, RL = 30Ω 0.17 DEG

BW Small-Signal Bandwidth VS = ±15V, Peaking ≤ 0.5dB 60 MHz

RF = RG = 620Ω, RL = 100Ω

VS = ±15V, Peaking ≤ 0.5dB 52 MHz

R

= RG = 649Ω, RL = 50Ω

F

VS = ±15V, Peaking ≤ 0.5dB 43 MHz

RF = RG = 698Ω, RL = 30Ω

VS = ±15V, Peaking ≤ 0.5dB 27 MHz

R

= RG = 825Ω, RL = 10Ω

F

● denotes specifications which apply for 0°C ≤ T

The
Note 1: Applies to short circuits to ground only. A short circuit between
the output and either supply may permanently damage the part when

operated on supplies greater than ±10V.
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

≤ 70°C.

A

beyond 0°C to 70°C. Industrial grade parts tested over –40°C to 85°C are
available on special request. Consult factory.

Note 3: R

is connected between the shutdown pin and ground.

S/D

Note 4: Slew rate is measured at ±5V on a ±10V output signal while
operating on ±15V supplies with R

= 1.5k, RG = 1.5k and RL = 400Ω.

F

Note 5: NTSC composite video with an output level of 2V.

3

LT1206

WU

U

S ALL-SIG AL BA DWIDTH

I

= 20mA Typical, Peaking ≤ 0.1dB

S

A

VS = ±5V, RSD = 0Ω

–1 150 562 562 48 21.4

1 150 619 – 54 22.3

2 150 576 576 48 20.7

10 150 442 48.7 40 19.2

R

V

30 649 649 34 17
10 732 732 22 12.5

30 715 – 36 17.5
10 806 – 22.4 11.5

30 649 649 35 18.1
10 750 750 22.4 11.7

30 511 56.2 31 16.5
10 649 71.5 20 10.2

R

L

R

F

G

IS = 10mA Typical, Peaking ≤ 0.1dB

A

VS = ±5V, RSD = 10.2k

–1 150 576 576 35 17

1 150 665 – 37 17.5

2 150 590 590 35 16.8

10 150 301 33.2 31 15.6

R

V

30 681 681 25 12.5
10 750 750 16.4 8.7

30 768 – 25 12.6
10 845 – 16.5 8.2

30 681 681 25 13.4
10 768 768 16.2 8.1

30 392 43.2 23 11.9
10 499 54.9 15 7.8

R

L

R

F

G

–3dB BW –0.1dB BW

(MHz) (MHz)

–3dB BW –0.1dB BW

(MHz) (MHz)

A

VS = ±5V, RSD = 0Ω

–1 150 681 681 50 19.2

10 150 487 536 44 20.7

A

VS = ±15V, RSD = 60.4k

–1 150 634 634 41 19.1

10 150 301 33.2 33 15.6

R

V

30 768 768 35 17
10 887 887 24 12.3

1 150 768 – 66 22.4

30 909 – 37 17.5
10 1k – 23 12

2 150 665 665 55 23

30 787 787 36 18.5
10 931 931 22.5 11.8

30 590 64.9 33 17.5
10 768 84.5 20.7 10.8

R

V

30 768 768 26.5 14
10 866 866 17 9.4

1 150 768 – 44 18.8

30 909 – 28 14.4
10 1k – 16.8 8.3

2 150 649 649 40 18.5

30 787 787 27 14.1
10 931 931 16.5 8.1

30 402 44.2 25 13.3
10 590 64.9 15.3 7.4

R

L

L

F

R

F

R

G

R

G

–3dB BW –0.1dB BW

(MHz) (MHz)

–3dB BW –0.1dB BW

(MHz) (MHz)

IS = 5mA Typical, Peaking ≤ 0.1dB

A

VS = ±5V, RSD = 22.1k

–1 150 604 604 21 10.5

10 150 100 11.1 16.2 5.8

R

V

30 715 715 14.6 7.4
10 681 681 10.5 6.0

1 150 768 – 20 9.6

2 150 634 634 20 9.6

30 866 – 14.1 6.7
10 825 – 9.8 5.1

30 750 750 14.1 7.2
10 732 732 9.6 5.1

30 100 11.1 13.4 7.0
10 100 11.1 9.5 4.7

R

L

F

R

G

–3dB BW –0.1dB BW

(MHz) (MHz)

4

A

VS = ±15V, RSD = 121k

–1 150 619 619 25 12.5

10 150 100 11.1 15.9 4.5

R

V

30 787 787 15.8 8.5
10 825 825 10.5 5.4

1 150 845 – 23 10.6

30 1k – 15.3 7.6
10 1k – 10 5.2

2 150 681 681 23 10.2

30 845 845 15 7.7
10 866 866 10 5.4

30 100 11.1 13.6 6
10 100 11.1 9.6 4.5

R

L

F

R

G

–3dB BW –0.1dB BW

(MHz) (MHz)

WU

TYPICAL PERFOR A CE CHARACTERISTICS

Bandwidth vs Supply VoltageBandwidth vs Supply Voltage

100

90
80
70

60

50
40
30

–3dB BANDWIDTH (MHz)

20
10

0

PEAKING ≤ 0.5dB
PEAKING ≤ 5dB

RF = 470Ω

RF = 560Ω

4

610

8

SUPPLY VOLTAGE (±V)

12

Bandwidth vs Supply Voltage

100

90
80
70
60
50
40
30

–3dB BANDWIDTH (MHz)

20

10

0

PEAKING ≤ 0.5dB
PEAKING ≤ 5dB

RF =390Ω

4

610

8

SUPPLY VOLTAGE (±V)

12

AV = 2

= 100Ω

R

L

RF = 680Ω

RF = 750Ω

RF = 1.5k

14

LT1206 • TPC01

AV = 10

= 100Ω

R

L

RF = 330Ω

RF = 470Ω

RF = 680Ω

RF = 1.5k

14

LT1206 • TPC04

RF = 1k

16

16

18

18

50

40

30

20

–3dB BANDWIDTH (MHz)

10

0

PEAKING ≤ 0.5dB
PEAKING ≤ 5dB

RF = 560Ω

RF = 750Ω

RF = 1k

RF = 2k

4

610

8

SUPPLY VOLTAGE (±V)

12

Bandwidth vs Supply Voltage

50

40

30

20

–3dB BANDWIDTH (MHz)

10

0

PEAKING ≤ 0.5dB
PEAKING ≤ 5dB

4

610

8

SUPPLY VOLTAGE (±V)

12

AV = 2

= 10Ω

R

L

14

LT1206 • TPC02

AV = 10

= 10Ω

R

L

RF = 560Ω

RF = 680Ω

RF = 1k
RF = 1.5k

14

LT1206 • TPC05

16

16

LT1206

Bandwidth and Feedback Resistance
vs Capacitive Load for 0.5dB Peak

10k

BANDWIDTH

1k

FEEDBACK RESISTOR

FEEDBACK RESISTOR (Ω)

A

= 2

V

= ∞

R

L

= ±15V

V

S

= 0.01µF

C

COMP

100

18

1

10 1000

100 10000

CAPACITIVE LOAD (pF)

Bandwidth and Feedback Resistance
vs Capacitive Load for 5dB Peak

10k



BANDWIDTH





1k



FEEDBACK RESISTOR (Ω)

FEEDBACK RESISTOR



0

0

100

18

1

10 100 1k 10k

CAPACITIVE LOAD (pF)

AV = +2

= ∞

R

L

= ±15V

V

S

C

COMP

= 0.01µF

LT1206 • TPC06

100

–3dB BANDWIDTH (MHz)

10

1

LT1206 • TPC03

100

–3dB BANDWIDTH (MHz)

10

1

Differential Phase
vs Supply Voltage

0.50

0.40

0.30
RF = RG = 560Ω

= 2

A

V

N PACKAGE

0.20

DIFFERENTIAL PHASE (DEG)

0.10

0

7

5

9

SUPPLY VOLTAGE (±V)

Differential Gain
vs Supply Voltage

0.10

RL = 15Ω

RL = 30Ω

RL = 50Ω

RL = 150Ω

11

13

LT1206 • TPC07

0.08

0.06

0.04

DIFFERENTIAL GAIN (%)

0.02

15

0

RL = 15Ω

RL = 30Ω

RL = 150Ω

7

5

9

SUPPLY VOLTAGE (±V)

RL = 50Ω

RF = RG = 560Ω

= 2

A

V

N PACKAGE

11

13

LT1206 • TPC08

15

Spot Noise Voltage and Current
vs Frequency

100

–i

n

10

e

n

i

SPOT NOISE (nV/√Hz OR pA/√Hz)

1

10

100 100k

n

1k 10k

FREQUENCY (Hz)

LT1206 • TPC09

5

LT1206

TEMPERATURE (°C)

–50

0

SUPPLY CURRENT (mA)

10

25

0

50

75

LT1206 • TPC12

5

20

15

–25

25

100

125

AV = 1
R

L

= ∞

N PACKAGE

RSD = 0Ω

RSD = 60.4k

R

SD

= 121k

TEMPERATURE (°C)

–50



0.7

0.8

1.0

25 75

LT1206 • TPC15

0.6

0.5

–25 0

50 100 125

0.4

0.3

0.9

OUTPUT SHORT-CIRCUIT CURRENT (A)

SOURCING

SINKING

WU

TYPICAL PERFOR A CE CHARACTERISTICS

24

V

= 0V

S/D

22

20

18

16

14

SUPPLY CURRENT (mA)

12

10

4

610

8

SUPPLY VOLTAGE (±V)

Supply Current
vs Shutdown Pin Current

20

VS = ±15V

18
16
14
12
10

8
6

SUPPLY CURRENT (mA)

4
2

0

100

0

200

SHUTDOWN PIN CURRENT (µA)

TJ = –40˚C

TJ = 25˚C

TJ = 85˚C

TJ = 125˚C

12

300

14

16

LT1206 • TPC10

400

LT1206 • TPC11

Supply Current vs
Ambient Temperature, VS = ±5V

25

20

15

10

SUPPLY CURRENT (mA)

5

0

18

–50

Input Common-Mode Limit
vs Junction Temperature

+

V

– 0.5

–1.0

–1.5

–2.0

2.0

1.5

1.0

COMMON-MODE RANGE (V)

0.5

–

500

V

–50

AV = 1

= ∞

R

50

50

L

N PACKAGE

75

100

LT1206 • TPC11

75

LT1206 • TPC14

RSD = 0Ω

RSD = 10.2k

= 22.1k

R

SD

25

0

–25

TEMPERATURE (°C)

–25 100

0 125

25

TEMPERATURE (°C)

Supply Current vs
Ambient Temperature, VS = ±15VSupply Current vs Supply Voltage

125

Output Short-Circuit Current
vs Junction Temperature

Output Saturation Voltage
vs Junction Temperature

+

V

VS = ±15V

–1

–2

–3

–4

4

3

2

OUTPUT SATURATION VOLTAGE (V)

1

–

V

–25 100

–50

6

0 125

TEMPERATURE (°C)

25

RL = 2k

RL = 50Ω

RL = 50Ω

RL = 2k

50

75

LT1206 • TPC16

Power Supply Rejection Ratio
vs Frequency

70

60

NEGATIVE

50

POSITIVE

40

30

20

POWER SUPPLY REJECTION (dB)

10

0

10k 1M 10M 100M

100k

FREQUENCY (Hz)

RL = 50Ω
V

= ±15V

S

= RG = 1k

R

F

LT1206 • TPC17

Supply Current vs Large Signal
Output Frequency (No Load)

60

AV = 2

= ∞

R

L

= ±15V

V

S

50

= 20V

V

OUT

P-P

40

30

SUPPLY CURRENT (mA)

20

10

10k

100k 1M 10M

FREQUENCY (Hz)

LT1206 • TPC18

WU

TYPICAL PERFOR A CE CHARACTERISTICS

LT1206

Output Impedance vs Frequency

100

VS = ±15V

= 0mA

I

O

10

1

0.1

OUTPUT IMPEDANCE (Ω)

0.01
100k 10M 100M

R

= 121k

S/D

1M

FREQUENCY (Hz)

R

S/D

LT1206 • TPC19

= 0Ω

3rd Order Intercept vs Frequency

60

50

40

30

3rd ORDER INTERCEPT (dBm)

20

Output Impedance in Shutdown
vs Frequency

100k

10k

1k

100

OUTPUT IMPEDANCE (Ω)

10

100k 10M 100M

1M

FREQUENCY (Hz)

AV = 1

= 1k

R

F

= ±15V

V

S

LT1206 • TPC20

Test Circuit for 3rd Order Intercept

VS = ±15V

= 50Ω

R

L

= 590Ω

R

F

= 64.9Ω

R

G

2nd and 3rd Harmonic Distortion
vs Frequency

–30

–40

–50

–60

–70

DISTORTION (dBc)

–80

–90

1

+

LT1206

–

590Ω



65Ω



MEASURE INTERCEPT AT P

V

= ±15V

S

= 2V

V

O

P-P

RL = 10Ω

RL = 30Ω

O

LT1206 • TPC23

2nd

3rd

2nd

3rd

2456789

310

FREQUENCY (MHz)

P

O

50Ω


LT1206 • TPC21

10

0

10 15 20

5

FREQUENCY (MHz)

25 30

LT1206 • TPC22

7

LT1206

WW

SI PLIFIED SCHE ATIC

TO ALL
CURRENT
SOURCES

Q1Q18

+

V

Q5

Q2

Q6

D1

Q10

Q11

Q15

PPLICATI

A

Q17

1.25k

SHUTDOWN

U

O

S

I FOR ATIO

WU

–

V

+

V

Q3

Q4

U

The LT1206 is a current feedback amplifier with high
output current drive capability. The device is stable with
large capacitive loads and can easily supply the high
currents required by capacitive loads. The amplifier will
drive low impedance loads such as cables with excellent
linearity at high frequencies.

Q9

–

V

C

C

R

C

+

V

Q12

Q8

D2

Q7

Q16

50Ω

COMP–IN+IN

OUTPUT

Q14

Q13

–

LT1206 • TC

V

line when the response has 0.5dB to 5dB of peaking. The
curves stop where the response has more than 5dB of
peaking.

For resistive loads, the COMP pin should be left open (see
section on capacitive loads).

Feedback Resistor Selection

The optimum value for the feedback resistors is a function
of the operating conditions of the device, the load imped­ance and the desired flatness of response. The Typical AC
Performance tables give the values which result in the
highest 0.1dB and 0.5dB bandwidths for various resistive
loads and operating conditions. If this level of flatness is
not required, a higher bandwidth can be obtained by use
of a lower feedback resistor. The characteristic curves of
Bandwidth vs Supply Voltage indicate feedback resistors
for peaking up to 5dB. These curves use a solid line when
the response has less than 0.5dB of peaking and a dashed

8

Capacitive Loads

The LT1206 includes an optional compensation network
for driving capacitive loads. This network eliminates most
of the output stage peaking associated with capacitive
loads, allowing the frequency response to be flattened.
Figure 1 shows the effect of the network on a 200pF load.
Without the optional compensation, there is a 5dB peak at
40MHz caused by the effect of the capacitance on the
output stage. Adding a 0.01µ F bypass capacitor between
the output and the COMP pins connects the compensation
and completely eliminates the peaking. A lower value
feedback resistor can now be used, resulting in a response

LT1206

PPLICATI

A

VOLTAGE GAIN (dB)

12

VS = ±15V

10

8
6
4

2

NO COMPENSATION

0
–2
–4
–6

–8

1

U

O

S

I FOR ATIO

RF = 1.2k

COMPENSATION

RF = 2k

= 2k

R

COMPENSATION

FREQUENCY (MHz)

F

10 100

WU

LT1206 • F01

U

Figure 1.

which is flat to 0.35dB to 30MHz. The network has the
greatest effect for CL in the range of 0pF to 1000pF. The
graph of Maximum Capacitive Load vs Feedback Resistor
can be used to select the appropriate value of feedback
resistor. The values shown are for 0.5dB and 5dB peaking
at a gain of 2 with no resistive load. This is a worst case
condition, as the amplifier is more stable at higher gains
and with some resistive load in parallel with the capaci­tance. Also shown is the –3dB bandwidth with the sug­gested feedback resistor vs the load capacitance.

Although the optional compensation works well with
capacitive loads, it simply reduces the bandwidth when it
is connected with resistive loads. For instance, with a 30Ω
load, the bandwidth drops from 55MHz to 35MHz when
the compensation is connected. Hence, the compensation
was made optional. To disconnect the optional compensa­tion, leave the COMP pin open.

a 40pF capacitor and the supply current is typically 100µ A.
The shutdown pin is referenced to the positive supply
through an internal bias circuit (see the simplified sche­matic). An easy way to force shutdown is to use open drain
(collector) logic. The circuit shown in Figure 2 uses a
74C904 buffer to interface between 5V logic and the
LT1206. The switching time between the active and shut­down states is less than 1µs.

A 24k pull-up resistor
speeds up the turn-off time and insures that the LT1206
is completely turned off. Because the pin is referenced to
the positive supply, the logic used should have a break­down voltage of greater than the positive supply voltage.
No other circuitry is necessary as the internal circuit
limits the shutdown pin current to about 500µ A. Figure 3
shows the resulting waveforms.

15V

IN

5V

74C906

+

LT1206

S/D

–

–15V

15V

24k

LT1206 • F02

V

OUT

R

F

R

G

V

ENABLE

Figure 2. Shutdown Interface

Shutdown/Current Set
If the shutdown feature is not used, the SHUTDOWN pin

must be connected to ground or V–.

The shutdown pin can be used to either turn off the biasing
for the amplifier, reducing the quiescent current to less
than 200µ A, or to control the quiescent current in normal
operation.

The total bias current in the LT1206 is controlled by the
current flowing out of the shutdown pin. When the shut­down pin is open or driven to the positive supply, the part
is shut down. In the shutdown mode, the output looks like

OUT

V

ENABLE

AV = 1
R

= 825Ω

F

R

= 50Ω

L

R

= 24k

PU

V

= 1V

IN

P-P

Figure 3. Shutdown Operation

LT1206 • F3

9

LT1206

PPLICATI

A

U

O

S

I FOR ATIO

WU

U

For applications where the full bandwidth of the amplifier
is not required, the quiescent current of the device may be
reduced by connecting a resistor from the shutdown pin to
ground. The quiescent current will be approximately 40
times the current in the shutdown pin. The voltage across
the resistor in this condition is V+ – 3VBE. For example, a
60k resistor will set the quiescent supply current to 10mA
with VS = ±15V.

The photos (Figures 4a and 4b) show the effect of reducing
the quiescent supply current on the large-signal response.
The quiescent current can be reduced to 5mA in the
inverting configuration without much change in response.
In noninverting mode, however, the slew rate is reduced
as the quiescent current is reduced.

Slew Rate

Unlike a traditional op amp, the slew rate of a current
feedback amplifier is not independent of the amplifier gain
configuration. There are slew rate limitations in both the
input stage and the output stage. In the inverting mode,
and for higher gains in the noninverting mode, the signal
amplitude on the input pins is small and the overall slew
rate is that of the output stage. The input stage slew rate
is related to the quiescent current and will be reduced as
the supply current is reduced. The output slew rate is set
by the value of the feedback resistors and the internal
capacitance. Larger feedback resistors will reduce the
slew rate as will lower supply voltages, similar to the way
the bandwidth is reduced. The photos (Figures 5a, 5b and
5c) show the large-signal response of the LT1206 for
various gain configurations. The slew rate varies from
860V/µs for a gain of 1, to 1400V/µs for a gain of –1.

RF = 750Ω

= 50Ω

R

L

Figure 4a. Large-Signal Response vs IQ, AV = –1

RF = 750Ω
R

= 50Ω

L

Figure 4b. Large-Signal Response vs IQ, AV = 2

= 5mA, 10mA, 20mA

I

Q

V

= ±15V

S

= 5mA, 10mA, 20mA

I

Q

= ±15V

V

S

LT1206 • F04a

LT1206 • F04b

RF = 825Ω

= 50Ω

R

L

Figure 5a. Large-Signal Response, AV = 1

RF = RG = 750Ω
R

= 50Ω

L

Figure 5b. Large-Signal Response, AV = –1

V

S

= ±15V

V

= ±15V

S

LT1206 • F05a

LT1206 • F05b

10

LT1206

PPLICATI

A

RF = 750Ω

= 50Ω

R

L

U

O

S

I FOR ATIO

Figure 5c. Large-Signal Response, AV = 2

WU

LT1206 • F04c

U

When the LT1206 is used to drive capacitive loads, the
available output current can limit the overall slew rate. In
the fastest configuration, the LT1206 is capable of a slew
rate of over 1V/ns. The current required to slew a capacitor
at this rate is 1mA per picofarad of capacitance, so
10,000pF would require 10A! The photo (Figure 6) shows
the large signal behavior with CL = 10,000pF. The slew rate
is about 60V/µ s, determined by the current limit of 600mA.

the maximum allowable input voltage. To allow for some
margin, it is recommended that the input signal be less
than ±5V when the device is shut down.

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), but it
does not degrade the stability of the amplifier.

Power Supplies

The LT1206 will operate from single or split supplies from
±5V (10V 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 mis-
match. The inverting bias current can change as much as
5µ A per volt of supply mismatch, though typically the
change is less than 0.5µA per volt.

VS = ±15V
R

= RG = 3k

F

Figure 6. Large-Signal Response, CL = 10,000pF

= ∞

R

L

LT1206 • F06

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
input pins is small, so this clamp has no effect; however,
in the shutdown mode the differential swing can be the
same as the input swing. The clamp voltage will then set

Thermal Considerations

The LT1206 contains a thermal shutdown feature which
protects against excessive internal (junction) tempera­ture. If the junction temperature of the device exceeds the
protection threshold, the device will begin cycling be­tween normal operation and an off state. The cycling is not
harmful to the part. The thermal cycling occurs at a slow
rate, typically 10ms to several seconds, which depends on
the power dissipation and the thermal time constants of
the package and heat sinking. Raising the ambient tem­perature until the device begins thermal shutdown gives a
good indication of how much margin there is in the
thermal design.

For surface mount devices heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Experiments have shown that the
heat spreading copper layer does not need to be electri­cally connected to the tab of the device. The PCB material
can be very effective at transmitting heat between the pad
area attached to the tab of the device, and a ground or

11

LT1206

PPLICATI

A

U

O

S

I FOR ATIO

WU

U

power plane layer either inside or on the opposite side of
the board. Although the actual thermal resistance of the
PCB material is high, the length/area ratio of the thermal
resistance between the layer is small. Copper board stiff­eners and plated through holes can also be used to spread
the heat generated by the device.

Tables 1 and 2 list thermal resistance for each package. For
the TO-220 package, thermal resistance is given for junc­tion-to-case only since this package is usually mounted to
a heat sink. Measured values of thermal resistance for
several different board sizes and copper areas are listed for
each surface mount package. All measurements were
taken in still air on 3/32" FR-4 board with 1oz copper. This
data can be used as a rough guideline in estimating
thermal resistance. The thermal resistance for each appli­cation will be affected by thermal interactions with other
components as well as board size and shape.

Table 1. R Package, 7-Lead DD

COPPER AREA

TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500 sq. mm 2500 sq. mm 2500 sq. mm 25°C/W
1000 sq. mm 2500 sq. mm 2500 sq. mm 27°C/W
125 sq. mm 2500 sq. mm 2500 sq. mm 35°C/W
*Tab of device attached to topside copper

THERMAL RESISTANCE

Calculating Junction Temperature

The junction temperature can be calculated from the
equation:

TJ = (PD × θJA) + T

A

where:

TJ = Junction Temperature
TA = Ambient Temperature
PD = Device Dissipation

θJA = Thermal Resistance (Junction-to Ambient)

As an example, calculate the junction temperature for the
circuit in Figure 7 for the N8, S8, and R packages assuming
a 70°C ambient temperature.

15V

39mA

I

330Ω

+

LT1206

S/D

–

–15V

Figure 7. Thermal Calculation Example

0.01µF

2k 300pF

2k

f = 2MHz

12V

–12V

LT1206 • F07

Table 2. S8 Package, 8-Lead Plastic SOIC

COPPER AREA

TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500 sq. mm 2500 sq. mm 2500 sq. mm 60°C/W
1000 sq. mm 2500 sq. mm 2500 sq. mm 62°C/W
225 sq. mm 2500 sq. mm 2500 sq. mm 65°C/W
100 sq. mm 2500 sq. mm 2500 sq. mm 69°C/W
100 sq. mm 1000 sq. mm 2500 sq. mm 73°C/W
100 sq. mm 225 sq. mm 2500 sq. mm 80°C/W
100 sq. mm 100 sq. mm 2500 sq. mm 83°C/W
*Pins 1 and 8 attached to topside copper

Y Package, 7-Lead TO-220

Thermal Resistance (Junction-to-Case) = 5°C/W

N8 Package, 8-Lead DIP

Thermal Resistance (Junction-to-Ambient) = 100°C/W

THERMAL RESISTANCE

The device dissipation can be found by measuring the
supply currents, calculating the total dissipation, and
then subtracting the dissipation in the load and feedback
network.

PD = (39mA × 30V) – (12V)2/(2k||2k) = 1.03W

Then:

TJ= (1.03W × 100°C/W) + 70°C = 173°C
for the N8 package

TJ= (1.03W × 65°C/W) × + 70°C = 137°C

for the S8 with 225 sq. mm topside heat sinking

TJ= (1.03W × 35°C/W) × + 70°C = 106°C

for the R package with 100 sq. mm topside
heat sinking

Since the Maximum Junction Temperature is 150°C, the
N8 package is clearly unacceptable. Both the S8 and R
packages are usable.

12

U

–

+

LT1206

S/D

0.01µF*

V

OUT

RF**

V

IN

LT1206 • TA07

OPTIONAL, USE WITH CAPACITIVE LOADS
VALUE OF R

F

DEPENDS ON SUPPLY
VOLTAGE AND LOADING. SELECT 
FROM TYPICAL AC PERFORMANCE 
TABLE OR DETERMINE EMPIRICALLY

*

**

COMP

TYPICAL APPLICATIO S

LT1206

V

+

IN

LT1097

–

OUTPUT OFFSET: < 500µV
SLEW RATE: 2V/µs
BANDWIDTH: 4MHz
STABLE WITH C

+

LT1115

–

Precision ×10 Hi Current Amplifier

+

LT1206

COMP

S/D

–

500pF

3k330Ω

10k

1k

< 10nF

L

Low Noise ×10 Buffered Line Driver

15V

1µF

+

15V

1µF

+

+

1µF

+

LT1206

–

S/D

0.01µF

0.01µF

LT1206 • TA03

OUT

OUTPUT

R

CMOS Logic to Shutdown Interface

15V

+

LT1206

S/D

–

10k

–15V

2N3904

5V

24k

LT1206 • TA05

Distribution Amplifier

V

IN

L

75Ω

+

LT1206

–

S/D

75Ω CABLE

75Ω

R

F

75Ω

R

G

75Ω

75Ω

LT1206 • TA06

–15V

68pF

1µF

+

Buffer AV = 1

–15V

560Ω560Ω

909Ω

100Ω

= 32Ω

R

L

= 5V

V
THD + NOISE = 0.0009% AT 1kHz
= 0.004% AT 20kHz
SMALL SIGNAL 0.1dB BANDWIDTH = 600kHz



O

RMS

LT1206 • TA04

13

LT1206

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package

8-Lead Plastic DIP

0.400

(10.160)

MAX

876

5

12

0.300 – 0.320

(7.620 – 8.128)

0.065

(1.651)

0.009 – 0.015

(0.229 – 0.381)

+0.025

0.325

–0.015
+0.635

8.255

()

–0.381

TYP

0.045 ± 0.015

(1.143 ± 0.381)

0.100 ± 0.010

(2.540 ± 0.254)

0.045 – 0.065

(1.143 – 1.651)

R Package

7-Lead Plastic DD

0.060

(1.524)



+0.012

0.331
–0.020

+0.305

8.407

()

–0.508

0.401 ± 0.015

(10.185 ± 0.381)

15° TYP

3

0.175 ± 0.008

(4.445 ± 0.203)

0.059

(1.499)

TYP

0.250 ± 0.010

(6.350 ± 0.254)

4

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)





0.020

(0.508)



MIN

N8 0392

0.050 ± 0.008

(1.270 ± 0.203)

+0.008

0.004
–0.004

+0.203

0.102

()

–0.102

0.105 ± 0.008

(2.667 ± 0.203)

14

+0.012

0.143
–0.020

+0.305

3.632

()

–0.508

0.030 ± 0.008

(0.762 ± 0.203)

0.050 ± 0.010

(1.270 ± 0.254)

0.022 ± 0.005

(0.559 ± 0.127)

0.050 ± 0.012

(1.270 ± 0.305)

DD7 0693

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

S8 Package

8-Lead Plastic SOIC

0.189 – 0.197

(4.801 – 5.004)

7

8

5

6

LT1206

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

0.390 – 0.410

(9.91 – 10.41)

0.010 – 0.020

0.016 – 0.050

0.406 – 1.270

× 45°

0°– 8° TYP

0.228 – 0.244

(5.791 – 6.197)

0.053 – 0.069

(1.346 – 1.752)

Y Package

7-Lead TO-220

0.147 – 0.155
(3.73 – 3.94)

DIA

0.014 – 0.019

(0.355 – 0.483)

0.169 – 0.185
(4.29 – 4.70)

0.150 – 0.157

(3.810 – 3.988)

1

3

2

4

0.050

(1.270)

BSC

0.045 – 0.055
(1.14 – 1.40)

0.004 – 0.010

(0.101 – 0.254)

SO8 0392

0.103 – 0.113
(2.62 – 2.87)

0.026 – 0.036
(0.66 – 0.91)

0.235 – 0.258
(5.97 – 6.55)

0.560 – 0.590

(14.22 – 14.99)

0.152 – 0.202
(3.86 – 5.13)

0.045 – 0.055
(1.14 – 1.40)

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 circuits as described herein will not infringe on existing patent rights.

0.016 – 0.022
(0.41 – 0.56)

0.135 – 0.165
(3.43 – 4.19)

0.620

(15.75)

TYP



(17.78 – 18.49)

0.095 – 0.115 
(2.41 – 2.92)

0.155 – 0.195
(3.94 – 4.95)

0.700 – 0.728



0.260 – 0.320
(6.60 – 8.13)

Y7 0893

15

LT1206

U.S. Area Sales Offices

NORTHEAST REGION
Linear Technology Corporation

One Oxford Valley
2300 E. Lincoln Hwy.,Suite 306
Langhorne, PA 19047
Phone: [phone]
FAX: [phone]

Linear Technology Corporation

266 Lowell St., Suite B-8
Wilmington, MA 01887
Phone: [phone]
FAX: [phone]

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Linear Technology S.A.R.L.

Immeuble "Le Quartz"
58 Chemin de la Justice
92290 Chatenay Malabry
France
Phone: [phone]
FAX: [phone]

GERMANY
Linear Techonolgy GMBH

Untere Hauptstr. 9
D-85386 Eching
Germany
Phone: [phone]
FAX: [phone]

SOUTHEAST REGION
Linear Technology Corporation

17060 Dallas Parkway
Suite 208
Dallas, TX 75248
Phone: [phone]
FAX: [phone]

CENTRAL REGION
Linear Technology Corporation

Chesapeake Square
229 Mitchell Court, Suite A-25
Addison, IL 60101
Phone: [phone]
FAX: [phone]

International Sales Offices

KOREA
Linear Technology Korea Branch

Namsong Building, #505
Itaewon-Dong 260-199
Yongsan-Ku, Seoul
Korea
Phone: [phone]
FAX: [phone]

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Linear Technology Pte. Ltd.

101 Boon Keng Road
#02-15 Kallang Ind. Estates
Singapore 1233
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FAX: [phone]

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Woodland Hills, CA 91364
Phone: [phone]
FAX: [phone]

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Linear Technology Corporation

782 Sycamore Dr.
Milpitas, CA 95035
Phone: [phone]
FAX: [phone]

TAIWAN
Linear Technology Corporation

Rm. 801, No. 46, Sec. 2
Chung Shan N. Rd.
Taipei, Taiwan, R.O.C.
Phone: [phone]
FAX: [phone]

UNITED KINGDOM
Linear Technology (UK) Ltd.

The Coliseum, Riverside Way
Camberley, Surrey GU15 3YL
United Kingdom
Phone: [phone]
FAX: [phone]

JAPAN
Linear Technology KK

5F YZ Bldg.
4-4-12 Iidabashi, Chiyoda-Ku
Tokyo, 102 Japan
Phone: [phone]
FAX: [phone]

Linear Technology Corporation

16

1630 McCarthy Blvd., Milpitas, CA 95035-7487

[phone]

●

FAX

: [phone]

●

TELEX

World Headquarters

Linear Technology Corporation

1630 McCarthy Blvd.
Milpitas, CA 95035-7487
Phone: [phone]
FAX: [phone]

: 499-3977

06/24/93

LT/GP 0993 10K REV 0 • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1993