BUF600AU中文资料_数据手册_规格书

®

BUF600

BUF601

BUF600

BUF601

HIGH-SPEED BUFFER AMPLIFIER

FEATURES

APPLICATIONS

● OPEN-LOOP BUFFER

● VIDEO BUFFER/LINE DRIVER

● HIGH-SLEW RATE: 3600V/µs, 5.0Vp-p

● INPUT/OUTPUT AMPLIFIER FOR

MEASUREMENT EQUIPMENT

● BANDWIDTH: 320MHz, 5.0Vp-p

900MHz, 0.2Vp-p

● PORTABLE SYSTEMS

● LOW INPUT BIAS CURRENT: 0.7µA/1.5µA

● LOW QUIESCENT CURRENT: 3mA/6mA

● GAIN FLATNESS: 0.1dB, 0 to 300MHz

● TRANSMISSION SYSTEMS

● TELECOMMUNICATIONS

● HIGH-SPEED ANALOG SIGNAL

PROCESSING

● ULTRASOUND

The BUF601, with 6mA quiescent current and there-

fore lower output impedance, can easily drive 50Ω

inputs or 75Ω systems and cables.

DESCRIPTION

The BUF600 and BUF601 are monolithic open-loop

unity-gain buffer amplifiers with a high symmetrical

slew rate of up to 3600V/µs and a very wide band-

width of 320MHz at 5Vp-p output swing. They use a

complementary bipolar IC process, which incorpo-

rates pn-junction isolated high-frequency NPN and

PNP transistors to achieve high-frequency performance

previously unattainable with conventional integrated

circuit technology.

The broad range of analog and digital applications

extends from decoupling of signal processing stages,

impedance transformation, and input amplifiers for

RF equipment and ATE systems to video systems,

distribution fields, IF/communications systems, and

output drivers for graphic cards.

V+ = +5V

(1)

Their unique design offers a high-performance alter-

native to expensive discrete or hybrid solutions.

The BUF600 and BUF601 feature low quiescent

current, low input bias current, small signal delay time

and phase shift, and low differential gain and phase

errors.

V_IN

(4)

V_OUT

(8)

The BUF600 with 3mA quiescent current is well-

suited for operation between high-frequency

processing stages. It demonstrates outstanding perfor-

mance even in feedback loops of wide-band amplifiers

or phase-locked loop systems.

Bias

Circuitry

BUFFER

V– = –5V

(5)

Simplified Circuit Diagram

International Airport Industrial Park

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Mailing Address: PO Box 11400, Tucson, AZ 85734

FAXLine: (800) 548-6133 (US/Canada Only)

•

Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706

•

Tel: (520) 746-1111 • Twx: 910-952-1111

Internet: http://www.burr-brown.com/

•

Cable: BBRCORP

•

Telex: 066-6491

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FAX: (520) 889-1510

•

Immediate Product Info: (800) 548-6132

®

PDS-1128F

Printed in U.S.A. March, 1998

1

BUF600, 601

SPECIFICATIONS

DC SPECIFICATION

At V_CC= ±5V, R_LOAD= 10kΩ, R_SOURCE= 50Ω, and T_AMB= +25°C, unless otherwise noted.

BUF600AP, AU

TYP

BUF601AU

TYP

PARAMETER

CONDITIONS

MIN

MAX

MIN

MAX

UNITS

INPUT OFFSET VOLTAGE

Initial

vs Temperature

vs Supply (tracking)

vs Supply (non-tracking)

±15

9

–72

–55

–54

±30

±15

25

–77

–55

–54

±30

mV

µV/°C

dB

V_CC= ±4.5V to ±5.5V

V_CC= +4.5V to +5.5V

V_CC= –4.5V to –5.5V

–54

INPUT BIAS CURRENT

Initial

vs Temperature

vs Supply (tracking)

vs Supply (non-tracking)

+3.5

0.4

0.15

0.5

–2.5/+5

+3.5

0.7

0.3

0.5

20

–5/+10

µA

nA/°C

µA/V

nA/V

V_CC= ±4.5V to ±5.5V

V

_CC= +4.5V to +5.5V

V_CC= –4.5V to –5.5V

20

INPUT IMPEDANCE

4.8 || 1

2.5 || 1

MΩ || pF

INPUT NOISE

Voltage Noise Density

Signal-to-Noise Ratio

f = 100kHz to 100MHz

S/N = 20 Log (0.7/(Vn • √5MHz))

5.2

95

4.8

96

nV/√Hz

dB

TRANSFER CHARACTERISTICS

Voltage Gain; V_IN= ±2.5V

R_LOAD= 100Ω

R_LOAD= 200Ω

R_LOAD= 10kΩ

0.95

0.99

V/V

0.96

0.99

RATED OUTPUT

Voltage Output

V_IN= ±2.7V

R_LOAD= 100Ω

±2.5

±20

±2.6

V

mA

Ω

R_LOAD= 200Ω

DC, R_LOAD= 100Ω

±2.5

±20

±2.6

DC Current Output

Output Impedance

6.2

3.6

POWER SUPPLY

Rated Voltage

Derated Performance

Quiescent Current

±5

±3

±5

±6

V

mA

±4.5

±2.6

±5.5

±3.4

±4.5

±5.4

±5.5

±6.6

TEMPERATURE RANGE

Specification

Storage

–40

85

125

–40

85

125

°C

AC SPECIFICATION

At V_CC= ±5V, R_LOAD= 200Ω (BUF600) and 100Ω (BUF601), R_SOURCE= 50Ω, and T_AMB= +25°C, unless otherwise noted.

BUF600AP, AU

BUF601AU

TYP

PARAMETER

CONDITIONS

MIN

TYP

MAX

MIN

MAX

UNITS

FREQUENCY DOMAIN

LARGE SIGNAL BANDWIDTH

(–3dB)

V

_O= 5Vp-p, C_OUT= 1pF

320

400

700

320

400

700

MHz

V_O= 2.8Vp-p, C_OUT= 1pF

V_O= 1.4Vp-p, C_OUT= 1pF

SMALL SIGNAL BANDWIDTH

GROUP DELAY TIME

V_O= 0.2Vp-p, C_OUT= 1pF

650

250

900

200

MHz

ps

DIFFERENTIAL GAIN

V_IN= 0.3Vp-p, f = 4.43MHz

V = 0 to 0.7V

BUF600 R_LOAD= 200Ω

0.5

0.075

%

R

_LOAD= 1kΩ

BUF601 R_LOAD= 100Ω

_LOAD= 500Ω

0.4

0.05

R

DIFFERENTIAL PHASE

V_IN= 0.3Vp-p, f = 4.43MHz

V = 0 to 0.7V

BUF600 R_LOAD= 200Ω

0.02

0.04

Degrees

R

_LOAD= 1kΩ

BUF601 R_LOAD= 100Ω

_LOAD= 500Ω

0.025

0.03

R

®

2

BUF600, 601

AC-SPECIFICATIONS (CONT)

At V_CC= ±5V, R_LOAD= 200Ω (BUF600) and 100Ω (BUF601), R_SOURCE= 50Ω, and T_AMB= +25°C, unless otherwise noted.

BUF600AP, AU

BUF601AU

TYP

PARAMETER

CONDITIONS

MIN

TYP

MAX

MIN

MAX

UNITS

HARMONIC DISTORTION

Second Harmonic

Third Harmonic

Second Harmonic

Third Harmonic

f = 10MHz, V_O= 1.4Vp-p

f = 30MHz, V_O= 1.4Vp-p

f = 50MHz, V_O= 1.4Vp-p

–65

–64

–51

–56

–43

–48

–65

–67

–59

–62

–53

–54

dBc

Second Harmonic

Third Harmonic

GAIN FLATNESS PEAKING

V_O= 0.4Vp-p, DC to 30MHz

V_O= 0.4Vp-p, 30MHz to 300MHz

0.01

0.3

0.005

0.1

dB

LINEAR PHASE DEVIATION

V_O= 0.4Vp-p, DC to 30MHz

V_O= 0.4Vp-p, 30 to 300MHz

5.5

55

3.8

45

Degrees

TIME DOMAIN

RISE TIME

10% to 90%, 700ps

1.4Vp-p Step

0.82

0.97

1.18

0.87

0.95

1.13

ns

2.8Vp-p Step

5.0Vp-p Step

SLEW RATE

V_O= 1.4Vp-p

V_O= 2.8Vp-p

V_O= 5.0Vp-p

1500

2400

3400

1500

2400

3600

V/µs

FUNCTIONAL DESCRIPTION

PIN CONFIGURATION

FUNCTION

DESCRIPTION

Top View

DIP/SO-8

In

Analog Input

Out

+V_CC

–V_CC

Analog Output

Positive Supply Voltage; typical +5VDC

Negative Supply Voltage; typical –5VDC

8

+V_CC

NC

In

1

2

3

4

Out

7

NC

6

ELECTROSTATIC

DISCHARGE SENSITIVITY

NC

5

–V_CC

This integrated circuit can be damaged by ESD. Burr-Brown

recommends that all integrated circuits be handled with

appropriate precautions. Failure to observe proper handling

and installation procedures can cause damage.

BUF600, BUF601

ABSOLUTE MAXIMUM RATINGS

ESD damage can range from subtle performance degrada-

tion to complete device failure. Precision integrated circuits

may be more susceptible to damage because very small

parametric changes could cause the device not to meet its

published specifications.

Power Supply Voltage.......................................................................... ±6V

Input Voltage⁽¹⁾......................................................................... ±V_CC±0.7V

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

Storage Temperature ...................................................... –40°C to +125°C

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

Lead Temperature (soldering, 10s)................................................ +300°C

NOTE: (1) Inputs are internally diode-clamped to ±V_CC.

PACKAGE/ORDERING INFORMATION

PACKAGE

DRAWING

NUMBER⁽¹⁾

TEMPERATURE

RANGE

PRODUCT

PACKAGE

BUF600AP

BUF600AU

BUF601AU

Plastic 8-Pin DIP

SO-8 Surface Mount

006

182

–40°C to +85°C

NOTE: (1) For detailed drawing and dimension table, please see end of data

sheet, or Appendix C of Burr-Brown IC Data Book.

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes

no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change

without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant

any BURR-BROWN product for use in life support devices and/or systems.

®

3

BUF600, 601

INPUT PROTECTION

All input pins on the BUF600 and BUF601 are internally

protected from ESD by means of a pair of back-to-back

reverse-biased diodes to the power supplies as shown. These

diodes will begin to conduct when the input voltage exceeds

either power supply by about 0.7V. This situation can occur

with loss of the amplifier’s power supplies while a signal

source is still present. The diodes can typically withstand a

continuous current of 30mA without destruction. To insure

long term reliability, however, the diode current should be

externally limited to 10mA or so whenever possible.

Static damage has been well recognized for MOSFET de-

vices, but any semiconductor device deserves protection

from this potentially damaging source. The BUF600 and

BUF601 incorporate on-chip ESD protection diodes as shown

in Figure 1. This eliminates the need for the user to add

external protection diodes, which can add capacitance and

degrade AC performance.

ESD Protection Diodes

internally connected to

all pins.

The internal protection diodes are designed to withstand

2.5kV (using the Human Body Model) and will provide

adequate ESD protection for most normal handling proce-

dures. However, static damage can cause subtle changes in

amplifier input characteristics without necessarily destroy-

ing the device. In precision amplifiers, this may cause a

noticeable degradation of offset and drift. Therefore, static

protection is strongly recommended when handling the

BUF600 and BUF601.

+V_CC

External

Internal

Circuitry

–V_CC

FIGURE 1. Internal ESD Protection.

TYPICAL PERFORMANCE CURVES

At V_CC= ±5V, R_LOAD= 10kΩ, and T_A= 25°C, unless otherwise noted.

OFFSET VOLTAGE vs TEMPERATURE

5

INPUT BIAS CURRENT vs TEMPERATURE

2

4

3

2

1.8

BUF601

1.6

1.4

1.2

1

BUF600

0

–1

0.8

0.6

0.4

0.2

0

BUF600

BUF601

–2

–3

–4

–5

–40

–20

0

20

40

60

80

100

–40

–20

0

20

40

60

80

100

Temperature (°C)

INPUT IMPEDANCE vs FREQUENCY BUF600

INPUT IMPEDANCE vs FREQUENCY BUF601

10M

1M

10M

1M

100k

10k

1k

100k

10k

1k

100

1k

10k

100k

1M

10M

100M

100

1k

10k

100k

1M

10M

100M

Frequency (Hz)

®

4

BUF600, 601

TYPICAL PERFORMANCE CURVES (CONT)

At V_CC= ±5V, R_LOAD= 10kΩ, and T_A= 25°C, unless otherwise noted.

INPUT VOLTAGE NOISE

SPECTRAL DENSITY BUF600/601

QUIESCENT CURRENT vs TEMPERATURE

100

10

1

12

10

8

BUF601

6

BUFF600

BUFF601

BUF600

4

2

0

100

1000

Frequency (Hz)

10k

100k

–40

–20

0

20

40

60

80

100

Temperature (°C)

BUF600 TRANSFER FUNCTION

BUF600 GAIN ERROR vs INPUT VOLTAGE

(Full Temperature Range, R_LOAD= 200Ω)

–40°C

5

4

14

12

10

8

BUF600

R_LOAD= 200Ω

3

2

+25°C

85°C

1

0

6

–1

–2

–3

–4

–5

4

2

0

–5

–4

–3

–2

–1

0

1

2

3

4

5

–5 –4

–3

–2

–1

0

1

2

3

4

5

Input Voltage (V)

BUF601 GAIN ERROR vs INPUT VOLTAGE

BUF601 TRANSFER FUNCTION

14

12

10

8

5

4

(Full Temperature Range, R_LOAD= 100Ω)

BUF601

R_LOAD= 100Ω

–40°C

+25°C

3

2

+85°C

1

0

6

–1

–2

–3

–4

–5

4

2

0

–5 –4

–3

–2

–1

0

1

2

3

4

5

–5

–4

–3

–2

–1

0

1

2

3

4

5

Input Voltage (V)

®

5

BUF600, 601

TYPICAL PERFORMANCE CURVES (CONT)

At V_CC= ±5V, R_LOAD= 100Ω (BUF601), R_LOAD= 200Ω (BUF600), and T_A= 25°C, unless otherwise noted.

GROUP DELAY TIME vs FREQUENCY

2

BUF600/601 GAIN FLATNESS

1.5

1

2

1

0

0.5

0

BUF601

BUF600

–0.5

–1.0

–1.5

–2

R_LOAD= 100Ω

V_O= 0.2Vp-p BUF600 R_LOAD= 200Ω

BUF601 R_LOAD= 100Ω

–2.5

–3

300k

1M

10M

100M

1G

3G

300k

1M

10M

100M

1G

Frequency (Hz)

BUF600 SMALL SIGNAL PULSE RESPONSE

V_I= 0.2Vp-p

BUF600 LARGE SIGNAL PULSE RESPONSE

160

120

80

4

3

V_I= 5Vp-p

t_RISE= t_FALL= 1.5ns

(Generator)

t_RISE= t_FALL= 1.5ns

(Generator)

2

V_I

40

1

V_O

0

–40

–80

–120

–160

–1

–2

–3

–4

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

Time (ns)

BUF600 SMALL SIGNAL PULSE RESPONSE

V_I= 0.2Vp-p

BUF600 LARGE SIGNAL PULSE RESPONSE

V_I= 5Vp-p

160

120

80

4

3

t_RISE= t_FALL= 3ns

(Generator)

t_RISE= t_FALL= 3ns

(Generator)

2

40

1

V_I

0

V_O

–40

–80

–120

–160

–1

–2

–3

–4

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

Time (ns)

®

6

BUF600, 601

TYPICAL PERFORMANCE CURVES (CONT)

At V_CC= ±5V, R_LOAD= 100Ω (BUF601), R_LOAD= 200Ω (BUF600), and T_A= 25°C, unless otherwise noted.

BUF601 SMALL SIGNAL PULSE RESPONSE

BUF601 LARGE SIGNAL PULSE RESPONSE

V_I= 5Vp-p

160

120

80

4

3

V_I= 0.2Vp-p

t_RISE= t_FALL= 1.5ns

(Generator)

t_RISE= t_FALL= 1.5ns

(Generator)

2

V_O

V_I

40

1

V_I

V_O

0

–40

–80

–120

–160

–1

–2

–3

–4

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

Time (ns)

BUF601 SMALL SIGNAL PULSE RESPONSE

V_I= 0.2Vp-p

BUF601 LARGE SIGNAL PULSE RESPONSE

V_I= 5Vp-p

160

120

80

4

3

t_RISE= t_FALL= 3ns

(Generator)

t_RISE= t_FALL= 3ns

(Generator)

2

40

1

V_I

0

V_O

–40

–80

–120

–160

–1

–2

–3

–4

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

Time (ns)

BUF601 BANDWIDTH vs C_OUTwith RECOMMENDED R_S

BUF600 BANDWIDTH vs C_OUTwith RECOMMENDED R_S

20

15

20

15

+5V

1

+5V

1

R_S

180Ω

R_S

V_O

C_OUT

180Ω

V_I

V_O

V_I

8

601

600

4

10

C_OUT

R_IN

R_L

5

R_L

5

–5V

5

–5V

5

0

–5

R_SC_OUT

f_–3dB

–5

R_SC_OUT

f_–3dB

1

2

3

1

2

3

4

0Ω 1pF 980MHz

30Ω 12pF 435MHz

15Ω 33pF 260MHz

12Ω 47pF 215MHz

4

1

0Ω 1pF 820MHz

30Ω 12pF 425MHz

15Ω 33pF 270MHz

12Ω 47pF 215MHz

–10

–15

–20

–25

–30

4

–10

–15

–20

–25

–30

2

3

4

V_I= 0.4Vp-p

1M

300k

1M

10M

100M

1G

3G

300k

10M

100M

1G

3G

Frequency (Hz)

®

7

BUF600, 601

TYPICAL PERFORMANCE CURVES (CONT)

At V_CC= ±5V, R_LOAD= 100Ω (BUF601), R_LOAD= 200Ω (BUF600), and T_A= 25°C, unless otherwise noted.

BUF600 BANDWIDTH vs R_LOAD

BUF601 BANDWIDTH vs R_LOAD

V_I= 0.2Vp-p

20

15

20

15

V₁= 0.2Vp-p

10

5

50Ω

150Ω

0

–5

100Ω

150Ω

500Ω

1kΩ

–10

–15

–20

–25

–30

–10

–15

–20

–25

–30

300k

1M

10M

100M

1G

3G

300k

1M

10M

100M

1G

3G

Frequency (Hz)

BUF600 BANDWIDTH vs OUTPUT VOLTAGE

BUF601 BANDWIDTH vs OUTPUT VOLTAGE

20

15

20

15

5Vp-p

2.8Vp-p

10

5

1.4Vp-p

0.6Vp-p

1.4Vp-p

0.6Vp-p

0

–5

–10

–15

–20

–25

dB

–10

–15

–20

–25

dB

0.2Vp-p

300k

1M

10M

100M

1G

3G

300k

1M

10M

100M

1G

3G

Frequency (Hz)

HARMONIC DISTORTION vs FREQUENCY

0

–10

–20

–30

–40

–50

–60

–70

–80

0

–10

–20

–30

–40

–50

–60

–70

–80

BUF601 R_LOAD= 100Ω

BUF600 R_LOAD= 200Ω

2f

3f

2f

3f

0.1M

1M

10M

Frequency (Hz)

100M

0.1M

1M

10M

Frequency (Hz)

100M

®

8

BUF600, 601

TYPICAL PERFORMANCE CURVES (CONT)

At V_CC= ±5V, R_LOAD= 100Ω (BUF601), R_LOAD= 200Ω (BUF600), and T_A= 25°C, unless otherwise noted.

I_Qvs TIME (Warmup)

BUF600, BUF601 GAIN ERROR vs INPUT VOLTAGE

100

99

98

97

96

95

94

5

4

3

2

1

0

(Full Temperature Range, R_LOAD= 10kΩ)

BUF600

BUF601

BUF600

BUF601

0

1

2

3

4

5

6

7

8

–5 –4

–3

–2

–1

0

1

2

3

4

5

Input Voltage (V)

Time (s)

DISCUSSION OF

PERFORMANCE

The BUF600 and BUF601 are fabricated using a high-

performance complementary bipolar process, which

provides high-frequency NPN and PNP transistors with

variations in source impedances. A resistor between 100Ω

and 250Ω in series with the buffer input lead will usually

eliminate oscillation problems from inductive sources such

as unterminated cables without sacrificing speed.

gigahertz transition frequencies (f ). Power supplies are

Τ

rated at ±6V maximum, with the data sheet parameters

specified at ±5V supplies. The BUF600 and BUF601 are

3-stage open-loop buffer amplifiers consisting of comple-

mentary emitter followers with a symmetrical class AB

Darlington output stage. The complementary structure pro-

vides both sink and source current capability independent of

the output voltage, while maintaining constant output and

input impedances. The amplifiers use no feedback, so their

low-frequency gain is slightly less than unity and somewhat

dependent on loading. The optimized input stage is respon-

sible for the high slew rate of up to 3600V/µs, wide large

signal bandwidth of 320MHz, and quiescent current reduc-

tion to ±3mA (BUF600) and ±6mA (BUF601). These

features yield an excellent large signal bandwidth/quiescent

current ratio of 320MHz, 5Vp-p at 3mA/6mA quiescent

current. The complementary emitter followers of the input

stage work with current sources as loads. The internal PTAT

power supply controls their quiescent current and with

its temperature characteristics keeps the transconductance

of the buffer amplifiers constant. The Typical Performance

Curves show the quiescent current variation versus

temperature.

Another excellent feature is the output-to-input isolation

over a wide frequency range. This characteristic is very

important when the buffer drives different equipment over

cables. Often the cable is not perfect or the termination is

incorrect and reflections arise that act like a signal source at

the output of the buffer.

Open-loop devices often sacrifice linearity and introduce

frequency distortion when driving low load impedance. The

BUF600 and BUF601, however, do not. Their design yields

low distortion products. The harmonic distortion character-

istics into loads greater than 100Ω (BUF601) and greater

than 200Ω (BUF600) are shown in the Typical Performance

Curves. The distortion can be improved even more by

increasing the load resistance.

Differential gain (DG) and differential phase (DP) are among

the important specifications for video applications. DG is

defined as the percent change in gain over a specified change

in output voltage level (0V to 0.7V.) DP is defined as the

phase change in degrees over the same output voltage

change. Both DG and DP are specified at the PAL subcarrier

frequency of 4.43MHz. The errors for differential gain are

lower than 0.5%, while those for differential phase are lower

than 0.04°.

The cross current in the input stage is kept very low,

resulting in a low input bias current of 0.7µA/1.5µA and

high input impedance of 4.8MΩ || 1pF/2.5MΩ || 1pF. The

second stage drives the output transistors and reduces the

output impedance and the feedthrough from output to input

when driving RLC loads.

With its minimum 20mA long-term DC output current

capability, 50mA pulse current, low output impedance over

frequency, and stability to drive capacitive loads, the BUF601

can drive 50Ω and 75Ω systems or lines. The BUF600 with

lower quiescent current and therefore higher output imped-

ance is well-suited primarily to interstage buffering. This

type of open-loop amplifier is a new and easy-to-use step to

prevent an interaction between two points in complex high-

speed analog circuitry.

The input of the BUF600 and BUF601 looks like a high

resistance in parallel with a 1pF capacitance. The input

characteristics change very little with output loading and

input voltage swing. The BUF600 and BUF601 have excel-

lent input-to-output isolation and feature high tolerance to

®

9

BUF600, 601

The buffer outputs are not current-limited or protected. If the

output is shorted to ground, high currents could arise when

the input voltage is ±3.6V. Momentary shorts to ground (a

few seconds) should be avoided but are unlikely to cause

permanent damage.

+5V Pos

C₄

2.2µF

C₂

470nF

BUF600AP

1

R_IN

R_OUT

51Ω

Out

In

CIRCUIT LAYOUT

8

4

+1

The high-frequency performance of the BUF600 and BUF601

can be greatly affected by the physical layout of the printed

circuit board. The following tips are offered as suggestions,

not as absolute musts. Oscillations, ringing, poor bandwidth

and settling, and peaking are all typical problems that plague

high-speed components when they are used incorrectly.

160Ω

5

GND

C₃

2.2µF

C₁

470nF

–5V Neg

•

Bypass power supplies very close to the device pins. Use

tantalum chip capacitors (approximately 2.2µF); a paral-

lel 470nF ceramic chip capacitor may be added if desired.

Surface-mount types are recommended due to their low

lead inductance.

FIGURE 2. Test Circuit.

IMPEDANCE MATCHING

The BUF600 and BUF601 provide power gain and isolation

between source and load when used as an active tap or

impedance matching device as illustrated in Figure 3. In this

example, there is no output matching path between the

buffer and the 75Ω line. Such matching is not needed when

the distant end of the cable is properly terminated, since

there is no reflected signal when the buffer isolates the

source. This technique allows the full output voltage of the

buffer to be applied to the load.

•

PC board traces for power lines should be wide to reduce

impedance or inductance.

Make short and low inductance traces. The entire physi-

cal circuit should be as small as possible.

Use a low-impedance ground plane on the component

side to ensure that low-impedance ground is available

throughout the layout.

•

Do not extend the ground plane under high-impedance

nodes sensitive to stray capacitances, such as the buffer’s

input terminals.

+5V

Sockets are not recommended, because they add signifi-

cant inductance and parasitic capacitance. If sockets must

be used, consider using zero-profile solderless sockets.

2.2µF

470nF

Use low-inductance and surface-mounted components.

Using all surface-mount components will offer the best

AC performance.

1

75Ω

V_I

V_O

8

4

BUF

160Ω

300Ω

5

•

A resistor (100Ω to 250Ω) in series with the input of the

buffers may help to reduce peaking.

75Ω

2.2µF

Plug-in prototype boards and wire-wrap boards will not

function well. A clean layout using RF techniques is

essential—there are no shortcuts.

470nF

–5V

FIGURE 3. Impedance Converter.

®

10

BUF600, 601

DRIVING CABLES

Direct Drive

The most obvious way is to connect the cable directly to the

output of the buffer. This results in a gain determined by the

buffer output resistance and the characteristic impedance of

the cable, assuming it is properly terminated.

+5V

Z_O

A_V

=

Z_O+ R_O

1

BUF

5

Z_O

8

4

Double termination of a cable is the cleanest way to drive it,

since reflections are absorbed on both ends of the cable. The

cable source resistor is equal to the characteristic impedance

less the output resistance of the buffer amplifiers. The gain

is –6dB excluding of the cable attenuation.

V_I

V_O

150Ω

Z_O

–5V

+5V

VIDEO DISTRIBUTION AMPLIFIER

In this broadcast quality circuit, the OPA623 provides a very

high input impedance so that it may be used with a wide

variety of signal sources including video DACs, CCD cam-

eras, video switches or 75Ω cables. The OPA623 provides a

voltage gain of 2.5V/V, while the potentiometer of 200Ω

allows the overall gain to be adjusted to drive the standard

signal levels into the back-terminated 75Ω cables. Back

matching prevents multiple reflections in the event that the

remote end of the cable is not properly terminated.

R_OUT= Z_O– R_O

1

BUF

5

Z_O

8

4

V_I

V_O

150Ω

R_OUT

Z_O

–5V

A_V= – 6dB

Double Matched

FIGURE 4. Driving Cables.

+5V

2.2µF

470nF

1

68Ω

120Ω

8

4

BUF601

V_O

5

–5V

2.2µF

470nF

+5V

2.2µF

470nF

1

BUF601

5

68Ω

8

+5V

–5V

2.2µF

470nF

+5V

7

OPA658

4

3

2.2µF

470nF

V_I

6

150Ω

2

200Ω

75Ω

1

BUF601

5

68Ω

8

–5V

250Ω

100Ω

470nF

2.2µF

–5V

FIGURE 5. Video Distribution Amplifier.

®

11

BUF600, 601

+5V

2.2µF

470nF

8

1

BUF601

5

100Ω

8

4

V_O

120Ω

3

V_I

DT

2

+5V

470nF

OPA660

2.2µF

100Ω

R

150Ω

1

7

–5V

6

5

+

DB

4

1

R₂

150Ω

–5V

R_Q

250Ω

R₂

G = +2 = 1 +

R₁

–5V

FIGURE 6. Inside a Feedback Loop of a Voltage Feedback Amplifier (BUF601 and OPA660).

+5V

2.2µF

470nF

8

1

BUF601

5

V_O

150Ω

75Ω

4

V_O

100Ω

8

R₂

240Ω

DT

3

2

2.2µF

+5V

470nF

2.2µF

OPA660

10nF

–5V

470pF

R₁

42Ω

7

100Ω

6

5

DB

V_I

4

1

75Ω

470pF

250Ω

R₂

2 (R₁+ R_OUT

V_O

V_I

10nF

G ≈ –

= –2.031 =

)

2.2µF

–5V

FIGURE 7. Output Buffer for an Inverting RF-Amplifier (Direct Feedback).

®

12

BUF600, 601

+5V

68nF

150Ω

1

BUF600/1

5

8

4

V_I

V_O

75Ω

47kΩ

–5V

+5V

1kΩ

CA 3080

–5V

10kΩ

Clamp

Pulse

0.1µF

47kΩ

2N3904

1N

4148

4Vp-p

560kΩ

–5V

FIGURE 8. Input Amplifier with Baseband Video DC Restoration.

+5V

R_IN

160Ω

R_OUT

51Ω

Generator

Network

Analyzer

1

DUT

5

50Ω

In

Out

8

4

R_IN

50Ω

=

R_IN

50Ω

–5V

Test Fixture

FIGURE 9. Test Circuit Frequency Response.

+5V

R_IN

160Ω

R_OUT

51Ω

Pulse

Generator

Digitizing

Scope

1

DUT

5

50Ω

In

Out

8

4

R_IN

50Ω

=

R_IN

50Ω

=

50Ω

–5V

Test Fixture

FIGURE 10. Test Circuit Pulse Response.

®

13

BUF600, 601

+5V

7

R_IN

160Ω

R_OUT

75Ω

Generator

1

DUT

5

120Ω

75Ω

Video

Analyzer

In

Out

8

3

2

4

75Ω

6

OPA681

R_{IN =}

75Ω

4

75Ω

–5V

Test Fixture

–5V

4.43MHz

400Ω

VDC

400Ω

FIGURE 11. Test Circuit Differential Gain and Phase.

®

14

BUF600, 601

是否Rohs认证：	不符合	生命周期：	Transferred
包装说明：	SOP,	Reach Compliance Code：	unknown
风险等级：	5.77	Is Samacsys：	N
放大器类型：	BUFFER	JESD-30 代码：	R-PDSO-G8
JESD-609代码：	e0	功能数量：	1
端子数量：	8	封装主体材料：	PLASTIC/EPOXY
封装代码：	SOP	封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE	认证状态：	Not Qualified
子类别：	Buffer Amplifier	表面贴装：	YES
技术：	BIPOLAR	温度等级：	INDUSTRIAL
端子面层：	Tin/Lead (Sn/Pb)	端子形式：	GULL WING
端子位置：	DUAL	Base Number Matches：	1

型号	制造商	描述	价格	文档
BUF600AU-TR	BB	Video Amplifier, 1 Func, Bipolar, PDSO8,	获取价格
BUF601	BB	HIGH-SPEED BUFFER AMPLIFIER	获取价格
BUF601AP	BB	Video Amplifier, 1 Func, Bipolar, PDIP8,	获取价格
BUF601AU	BB	HIGH-SPEED BUFFER AMPLIFIER	获取价格
BUF601AU-TR	BB	Video Amplifier, 1 Func, Bipolar, PDSO8,	获取价格
BUF601AU/2K5	TI	High-Speed Buffer Amplifier 8-SOIC	获取价格
BUF602	TI	High-Speed, Closed-Loop Buffer	获取价格
BUF602ID	TI	High-Speed, Closed-Loop Buffer	获取价格
BUF602IDBVR	TI	High-Speed, Closed-Loop Buffer	获取价格
BUF602IDBVRG4	TI	High-Speed, Closed-Loop Buffer	获取价格

BUF600AU

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