FEATURES

UNITY-GAIN BANDWIDTH: 250MHz

WIDE BANDWIDTH: 100MHz GBW

HIGH SLEW RATE: 150V/

LOW NOISE: 6.5nV/

RAIL-TO-RAIL I/O

HIGH OUTPUT CURRENT: > 100mA

EXCELLENT VIDEO PERFORMANCE:

Diff Gain: 0.02%, Diff Phase: 0.09

0.1dB Gain Flatness: 40MHz

LOW INPUT BIAS CURRENT: 3pA

QUIESCENT CURRENT: 4.9mA

THERMAL SHUTDOWN

SUPPLY RANGE: 2.5V to 5.5V

MicroSIZE AND PowerPAD

PACKAGES

APPLICATIONS

VIDEO PROCESSING

ULTRASOUND

OPTICAL NETWORKING, TUNABLE LASERS

PHOTODIODE TRANSIMPEDANCE AMPS

ACTIVE FILTERS

HIGH-SPEED INTEGRATORS

ANALOG-TO-DIGITAL (A/D) CONVERTER
INPUT BUFFERS

DIGITAL-TO-ANALOG (D/A) CONVERTER
OUTPUT AMPLIFIERS

BARCODE SCANNERS

COMMUNICATIONS

DESCRIPTION

The OPA354 series of high-speed, voltage-feedback
CMOS operational amplifiers are designed for video and
other applications requiring wide bandwidth. They are
unity-gain stable and can drive large output currents.
Differential gain is 0.02% and differential phase is 0.09

Quiescent current is only 4.9mA per channel.

The OPA354 series op amps are optimized for operation
on single or dual supplies as low as 2.5V (

1.25V) and up

to 5.5V (

2.75V). Common-mode input range extends

beyond the supplies. The output swing is within 100mV of
the rails, supporting wide dynamic range.

For applications requiring the full 100mA continuous
output current, single and dual SO-8 PowerPAD versions
are available.

The single version (OPA354), is available in the tiny
SOT23-5 and SO-8 PowerPAD packages. The dual
version (OPA2354) comes in the miniature MSOP-8 and
SO-8 PowerPAD packages. The quad version (OPA4354)
is offered in TSSOP-14 and SO-14 packages.

Multichannel versions feature completely independent
circuitry for lowest crosstalk and freedom from interaction.
All are specified over the extended -40

C to +125

temperature range.

OPAx357 RELATED PRODUCTS

FEATURES

PRODUCT

Shutdown Version of OPA354 Family

OPAx357

200MHz GBW, Rail-to-Rail Output, CMOS, Shutdown

OPAx355

200MHz GBW, Rail-to-Rail Output, CMOS

OPAx356

38MHz GBW, Rail-to-Rail Input/Output, CMOS

OPAx350/3

75MHz BW G = 2, Rail-to-Rail Output

OPAx631

150MHz BW G = 2, Rail-to-Rail Output

OPAx634

100MHz BW, Differential Input/Output, 3.3V Supply

THS412x

OPA354

OUT

V+

+In

OPA354

OPA2354
OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

250MHz, Rail-to-Rail I/O, CMOS

OPERATIONAL AMPLIFIERS

PRODUCTION DATA information is current as of publication date. Products

conform to specifications per the terms of Texas Instruments standard warranty.

Production processing does not necessarily include testing of all parameters.

www.ti.com

2002-2004, Texas Instruments Incorporated

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

ABSOLUTE MAXIMUM RATINGS

(1)

Supply Voltage, V+ to V-

7.5V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Signal Input Terminals Voltage(2)

(V-) - (0.5V) to (V+) + (0.5V)

. . .

Current(2)

10mA

. . . . . . . . . . . . . . . . . . . . .

Output Short-Circuit(3)

Continuous

. . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Temperature

-55

C to +150

. . . . . . . . . . . . . . . . . . . . . .

Storage Temperature

-65

C to +150

. . . . . . . . . . . . . . . . . . . . . . . .

Junction Temperature

+150

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lead Temperature (soldering, 10s)

+300

. . . . . . . . . . . . . . . . . . . . .

(1) Stresses above these ratings may cause permanent damage.

Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not supported.

(2) Input terminals are diode-clamped to the power-supply rails.

Input signals that can swing more than 0.5V beyond the supply
rails should be current limited to 10mA or less.

(3) Short-circuit to ground, one amplifier per package.

ELECTROSTATIC
DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Texas Instruments
recommends that all integrated circuits be handled with appropriate
precautions. Failure to observe proper handling and installation
procedures can cause damage.

ESD damage can range from subtle performance degradation 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.

PACKAGE/ORDERING INFORMATION

(1)

PRODUCT

PACKAGE-LEAD

PACKAGE

DESIGNATOR(1)

SPECIFIED

TEMPERATURE

RANGE

PACKAGE

MARKING

ORDERING

NUMBER

TRANSPORT

MEDIA, QUANTITY

OPA354

SO-8 PowerPAD

DDA

-40

C to +125

OPA354A

OPA354AIDDA

Rails, 97

OPA354AIDDAR

Tape and Reel, 2500

OPA354

SOT23-5

DBV

-40

C to +125

OABI

OPA354AIDBVT

Tape and Reel, 250

OPA354AIDBVR

Tape and Reel, 3000

OPA2354

SO-8 PowerPAD

DDA

-40

C to +125

OPA2354A

OPA2354AIDDA

Rails, 97

OPA2354AIDDAR

Tape and Reel, 2500

OPA2354

MSOP-8

DGK

-40

C to +125

OACI

OPA2354AIDGKT

Tape and Reel, 250

OPA2354AIDGKR

Tape and Reel, 2500

OPA4354

SO-14

-40

C to +125

OPA4354A

OPA4354AID

Rails, 58

OPA4354AIDR

Tape and Reel, 2500

OPA4354

TSSOP-14

-40

C to +125

OPA4354A

OPA4354AIPWT

Tape and Reel, 250

OPA4354AIPWR

Tape and Reel, 2500

(1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet.

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

ELECTRICAL CHARACTERISTICS: V

= +2.7V to +5.5V Single-Supply

Boldface limits apply over the temperature range, T

= -40

C to +125

All specifications at TA = +25

C, RF = 0

, RL = 1k

connected to VS/2, unless otherwise noted.

OPA354AI

OPA2354AI, OPA4354AI

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

OFFSET VOLTAGE

Input Offset Voltage

VOS

VS = +5V

Specified Temperature Range

vs Temperature

/dT

Specified Temperature Range

vs Power Supply

PSRR

VS = +2.7V to +5.5V, VCM = (VS/2) - 0.15V

200

800

V/V

Specified Temperature Range

900

V/V

INPUT BIAS CURRENT

Input Bias Current

Input Offset Current

IOS

NOISE

Input Voltage Noise Density

f = 1MHz

6.5

nV/

Current Noise Density

f = 1MHz

fA/

INPUT VOLTAGE RANGE

Common-Mode Voltage Range

VCM

(V-) - 0.1

(V+) + 0.1

Common-Mode Rejection Ratio

CMRR

VS = +5.5V, -0.1V < VCM < +3.5V

Specified Temperature Range

VS = +5.5V, -0.1V < VCM < +5.6V

Specified Temperature Range

INPUT IMPEDANCE

Differential

1013 || 2

|| pF

Common-Mode

1013 || 2

|| pF

OPEN-LOOP GAIN

AOL

VS = +5V, +0.3V < VO < +4.7V

110

Specified Temperature Range

VS = +5V, +0.4V < VO < +4.6V

FREQUENCY RESPONSE

Small-Signal Bandwidth

f-3dB

G = +1, VO = 100mVPP, RF = 25

250

MHz

f-3dB

G = +2, VO = 100mVPP

MHz

Gain-Bandwidth Product

GBW

G = +10

100

MHz

Bandwidth for 0.1dB Gain Flatness

f0.1dB

G = +2, VO = 100mVPP

MHz

Slew Rate

VS = +5V, G = +1, 4V Step

150

VS = +5V, G = +1, 2V Step

130

VS = +3V, G = +1, 2V Step

110

Rise-and-Fall Time

G = +1, VO = 200mVPP, 10% to 90%

G = +1, VO = 2VPP, 10% to 90%

Settling Time, 0.1%

VS = +5V, G = +1, 2V Output Step

0.01%

Overload Recovery Time

VIN

Gain = VS

Harmonic Distortion

2nd-Harmonic

G = +1, f = 1MHz, VO = 2VPP, RL = 200

, VCM = 1.5V

-75

dBc

3rd-Harmonic

G = +1, f = 1MHz, VO = 2VPP, RL = 200

, VCM = 1.5V

-83

dBc

Differential Gain Error

NTSC, RL = 150

0.02

Differential Phase Error

NTSC, RL = 150

0.09

degrees

Channel-to-Channel Crosstalk

OPA2354

f = 5MHz

-100

OPA4354

-84

(1) See typical characteristics Output Voltage Swing vs Output Current.
(2) Specified by design.

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

ELECTRICAL CHARACTERISTICS: V

= +2.7V to +5.5V Single-Supply (continued)

Boldface limits apply over the temperature range, T

= -40

C to +125

All specifications at TA = +25

C, RF = 0

, RL = 1k

connected to VS/2, unless otherwise noted.

OPA354AI

OPA2354AI, OPA4354AI

PARAMETER

UNITS

MAX

TYP

MIN

CONDITIONS

OUTPUT

Voltage Output Swing from Rail

VS = +5V, RL = 1k

, AOL > 94dB

0.1

0.3

Specified Temperature Range

VS = +5V, RL = 1k

, AOL > 90dB

0.4

Output Current(1)(2), Single, Dual, Quad

VS = +5V

100

VS = +3V

Closed-Loop Output Impedance

f < 100kHz

0.05

Open-Loop Output Resistance

POWER SUPPLY

Specified Voltage Range

2.7

5.5

Operating Voltage Range

2.5 to 5.5

Quiescent Current (per amplifier)

VS = +5V, Enabled, IO = 0

4.9

Specified Temperature Range

7.5

THERMAL SHUTDOWN

Junction Temperature

Shutdown

+160

Reset from Shutdown

+140

TEMPERATURE RANGE

Specified Range

-40

+125

Operating Range

-55

+150

Storage Range

-65

+150

Thermal Resistance

C/W

SOT23-5, MSOP-8

150

C/W

TSSOP-14

100

C/W

SO-14

100

C/W

SO-8 PowerPAD

C/W

(1) See typical characteristics Output Voltage Swing vs Output Current.
(2) Specified by design.

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

TYPICAL CHARACTERISTICS

At TA = +25

C, VS = 5V, G = +1, RF = 0

, RL = 1k

, and connected to VS/2, unless otherwise noted.

NONINVERTING SMALL-SIGNAL

FREQUENCY RESPONSE

Frequency (Hz)

r
m

l
iz

(
d

10M

100M

100k

= 0.1V

G = +2, R

= 604

G = +1

= 25

G = +5, R

= 604

G = +10, R

= 604

INVERTING SMALL-SIGNAL

FREQUENCY RESPONSE

Frequency (Hz)

r
m

l
iz

(
d

10M

100M

100k

= 0.1V

, R

= 604

G =

NONINVERTING SMALL-SIGNAL STEP RESPONSE

Time (20ns/div)

tpu

l
t
a

(
40mV

/
di

)

NONINVERTING LARGE-SIGNAL STEP RESPONSE

Time (20ns/div)

tput

l
t
ag

(
500mV

/
d

i
v

)

0.1dB GAIN FLATNESS

Frequency (Hz)

l
i
z

i
n

)

10M

100M

100k

0.5

0.4

0.3

0.2

0.1

0.2

0.3

0.4

0.5

= 0.1V

G = +1

= 25

G = +2

= 604

HARMONIC DISTORTION vs OUTPUT VOLTAGE

Output Voltage (V

)

r
m

i
c

t
o

r
ti

(
d

)

100

G =

f = 1MHz

= 200

2nd-Harmonic

3rd-Harmonic

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25

C, VS = 5V, G = +1, RF = 0

, RL = 1k

, and connected to VS/2, unless otherwise noted.

HARMONIC DISTORTION vs NONINVERTING GAIN

Gain (V/V)

r
m

i
c

t
o

r
ti

(
d

)

100

= 2V

f = 1MHz
R

= 200

3rd-Harmonic

2nd-Harmonic

HARMONIC DISTORTION vs INVERTING GAIN

Gain (V/V)

r
m

i
c

t
o

r
ti

(
d

)

100

= 2V

f = 1MHz
R

= 200

3rd-Harmonic

2nd-Harmonic

HARMONIC DISTORTION vs FREQUENCY

Frequency (Hz)

r
m

i
c

t
o

r
ti

(
d

)

10M

100k

100

G = +1
V

= 2V

= 200

= 1.5V

3rd-Harmonic

2nd-Harmonic

HARMONIC DISTORTION vs LOAD RESISTANCE

(

)

r
m

i
c

t
o

r
ti

(
d

)

100

G = +1
V

= 2V

f = 1MHz
V

= 1.5V

3rd-Harmonic

2nd-Harmonic

INPUT VOLTAGE AND CURRENT NOISE

SPECTRAL DENSITY vs FREQUENCY

Frequency (Hz)

l
t
a

i
s

(
n

)
,

r
r
en

(
f
A

)

100M

100

10k

100k

10M

10k

100

Current Noise

Voltage Noise

FREQUENCY RESPONSE FOR VARIOUS R

Frequency (Hz)

l
i
z

i
n

)

10M

100M

100k

= 10k

= 100

= 1k

= 50

G = +1
R

= 0

= 0.1V

= 0pF

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25

C, VS = 5V, G = +1, RF = 0

, RL = 1k

, and connected to VS/2, unless otherwise noted.

FREQUENCY RESPONSE FOR VARIOUS C

Frequency (Hz)

l
i
z

i
n

)

10M

100M

100k

= 100pF

= 47pF

= 5.6pF

G = +1
V

= 0.1V

= 0

RECOMMENDED R

vs CAPACITIVE LOAD

Capacitive Load (pF)

(

)

100

160

140

120

100

OPA354

For 0.1dB

Flatness

FREQUENCY RESPONSE vs CAPACITIVE LOAD

Frequency (Hz)

r
m

l
iz

(
d

100M

10M

100k

OPA354

= 47pF, R

= 140

= 100pF, R

= 120

= 5.6pF, R

= 0

G = +1
V

= 0.1V

COMMON-MODE REJECTION RATIO AND

POWER-SUPPLY REJECTION RATIO vs FREQUENCY

Frequency (Hz)

RR,

(
d

)

10k

100k

10M

100M

100

PSRR

PSRR+

CMRR

OPEN-LOOP GAIN AND PHASE

Frequency (Hz)

pen-

has

(
degr

)

oop

i
n

(
d

)

100

100k

10k

10M

100M

180

160

140

120

100

Phase

Gain

COMPOSITE VIDEO

DIFFERENTIAL GAIN AND PHASE

Number of 150

Loads

/dP

(
%

/
degr

)

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25

C, VS = 5V, G = +1, RF = 0

, RL = 1k

, and connected to VS/2, unless otherwise noted.

INPUT BIAS CURRENT vs TEMPERATURE

Temperature (

Inp

i
a

r
e

(
p

)

105

135

125

10k

100

OUTPUT VOLTAGE SWING vs OUTPUT CURRENT

FOR V

= 3V

Output Current (mA)

tput

l
t
ag

(
V

)

100

120

+125

+25

SUPPLY CURRENT vs TEMPERATURE

Temperature (

l
y

r
e

(
m

)

105

135

125

= 5V

= 2.5V

OUTPUT VOLTAGE SWING vs OUTPUT CURRENT

FOR V

= 5V

Output Current (mA)

tput

l
t
ag

(
V

)

125

100

150

175

200

+25

+125

CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY

Frequency (Hz)

anc

(

)

10M

100M

100k

100

0.1

0.01

OPA354

MAXIMUM OUTPUT VOLTAGE vs FREQUENCY

Frequency (MHz)

l
t
age

(
V

)

100

= 5.5V

= 2.7V

Maximum Output

Voltage without

Slew-Rate

Induced Distortion

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25

C, VS = 5V, G = +1, RF = 0

, RL = 1k

, and connected to VS/2, unless otherwise noted.

OUTPUT SETTLING TIME TO 0.1%

Time (ns)

t
p

r
ro

(
%

)

100

0.5

0.4

0.3

0.2

0.1

0.2

0.3

0.4

0.5

= 2V

OPEN-LOOP GAIN vs TEMPERATURE

Temperature (

Loop

i
n

(
d

)

105

135

125

120

110

100

= 1k

OFFSET VOLTAGE PRODUCTION DISTRIBUTION

Offset Voltage (mV)

pul

ati

0 1

2 3

5 6

7 8

COMMON-MODE REJECTION RATIO AND

POWER-SUPPLY REJECTION RATIO vs TEMPERATURE

Temperature (

RR,

(
d

)

105

135

125

100

Power-Supply Rejection Ratio

Common-Mode Rejection Ratio

CHANNEL-TO-CHANNEL CROSSTALK

Frequency (Hz)

r
os

t
a

l
k

t
-

r
r
e

(
dB

)

10M

100M

100k

100

120

OPA4354

OPA2354

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

APPLICATIONS INFORMATION

The OPA354 is a CMOS, rail-to-rail I/O, high-speed,
voltage-feedback operational amplifier designed for video,
high-speed, and other applications. It is available as a
single, dual, or quad op amp.

The amplifier features a 100MHz gain bandwidth, and
150V/

s slew rate, but it is unity-gain stable and can be

operated as a +1V/V voltage follower.

OPERATING VOLTAGE

The OPA354 is specified over a power-supply range of
+2.7V to +5.5V (

1.35V to

2.75V). However, the supply

voltage may range from +2.5V to +5.5V (

1.25V to

2.75V). Supply voltages higher than 7.5V (absolute

maximum) can permanently damage the amplifier.

Parameters that vary over supply voltage or temperature
are shown in the typical characteristics section of this data
sheet.

RAIL-TO-RAIL INPUT

The specified input common-mode voltage range of the
OPA354 extends 100mV beyond the supply rails. This is
achieved with a complementary input stage

N-channel input differential pair in parallel with a
P-channel differential pair, as shown in Figure 1. The
N-channel pair is active for input voltages close to the
positive rail, typically (V+) - 1.2V to 100mV above the
positive supply, while the P-channel pair is on for inputs
from 100mV below the negative supply to approximately
(V+) - 1.2V. There is a small transition region, typically
(V+) - 1.5V to (V+) - 0.9V, in which both pairs are on. This
600mV transition region can vary

500mV with process

variation. Thus, the transition region (both input stages on)
can range from (V+) - 2.0V to (V+) - 1.5V on the low end,
up to (V+) - 0.9V to (V+) - 0.4V on the high end.

A double-folded cascode adds the signal from the two
input pairs and presents a differential signal to the class AB
output stage.

RAIL-TO-RAIL OUTPUT

A class AB output stage with common-source transistors
is used to achieve rail-to-rail output. For high-impedance
loads (> 200

), the output voltage swing is typically

100mV from the supply rails. With 10

loads, a useful

output swing can be achieved while maintaining high
open-loop gain. See the typical characteristic curve Output
Voltage Swing vs Output Current.

BIAS1

BIAS2

Class AB

Control

Circuitry

(Ground)

V+

Reference
Current

Figure 1. Simplified Schematic

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

OUTPUT DRIVE

The OPA354's output stage can supply a continuous
output current of

100mA and still provide approximately

2.7V of output swing on a 5V supply, as shown in Figure 2.
For maximum reliability, it is not recommended to run a
continuous DC current in excess of

100mA. Refer to the

typical characteristic curve Output Voltage Swing vs
Output Current. For supplying continuous output currents
greater than

100mA, the OPA354 may be operated in

parallel, as shown in Figure 3.

The OPA354 will provide peak currents up to 200mA,
which corresponds to the typical short-circuit current.
Therefore, an on-chip thermal shutdown circuit is provided
to protect the OPA354 from dangerously high junction
temperatures. At 160

C, the protection circuit will shut

down the amplifier. Normal operation will resume when the
junction temperature cools to below 140

SHUNT

Laser Diode

OPA354

50pF

10k

V+

1V In = 100mA
Out, as Shown

Figure 2. Laser Diode Driver

SHUNT

Laser Diode

OPA2354

200pF

100k

10k

2V In = 200mA
Out, as Shown

OPA2354

+5V

Figure 3. Parallel Operation

VIDEO

The OPA354 output stage is capable of driving standard
back-terminated 75

video cables, as shown in Figure 4.

By back-terminating a transmission line, it does not exhibit
a capacitive load to its driver. A properly back-terminated
75

cable does not appear as capacitance; it presents

only a 150

resistive load to the OPA354 output.

Video

Video
Output

+2.5V

+5V

+2.5V

604

OPA354

Figure 4. Single-Supply Video Line Driver

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

The OPA354 can be used as an amplifier for RGB graphic
signals, which have a voltage of zero at the video black
level, by offsetting and AC-coupling the signal. See
Figure 5.

DRIVING ANALOG-TO-DIGITAL
CONVERTERS

The OPA354 series op amps offer 60ns of settling time to
0.01%, making them a good choice for driving high- and
medium-speed sampling A/D converters and reference

circuits. The OPA354 series provide an effective means of
buffering the A/D converter's input capacitance and
resulting charge injection while providing signal gain. For
applications requiring high DC accuracy, the OPA350
series is recommended.

Figure 6 illustrates the OPA354 driving an A/D converter.
With the OPA354 in an inverting configuration, a capacitor
across the feedback resistor can be used to filter
high-frequency noise in the signal.

1/2

OPA2354

604

10nF

604

+3V

V+

Red

Green

Blue

604

Red

(1)

V+

Green

(1)

V+

Blue

(1)

OPA354

10nF

+3V

1/2

OPA2354

604

NOTE: (1) Source video signal offset
300mV above ground to accomodate
op amp swing-to-ground capability.

Figure 5. RGB Cable Driver

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

ADS7816, ADS7861,

or ADS7864

12-Bit A/D Converter

OPA354

+5V

V+

+In

REF

GND

NOTE: A/D Converter Input = 0V to V

REF

+2.5V

330pF

= 0V to

5V for 0V to 5V output.

Figure 6. The OPA354 in Inverting Configuration Driving the ADS7816

CAPACITIVE LOAD AND STABILITY

The OPA354 series op amps can drive a wide range of
capacitive loads. However, all op amps under certain
conditions may become unstable. Op amp configuration,
gain, and load value are just a few of the factors to consider
when determining stability. An op amp in unity-gain
configuration is most susceptible to the effects of
capacitive loading. The capacitive load reacts with the op
amp's output resistance, along with any additional load
resistance, to create a pole in the small-signal response
that degrades the phase margin. Refer to the typical
characteristic curve Frequency Response for Various C

for details.

The OPA354's topology enhances its ability to drive
capacitive loads. In unity gain, these op amps perform well
with large capacitive loads. Refer to the typical
characteristic curve Recommended R

vs Capacitive Load

and Frequency Response vs Capacitive Load for details.

One method of improving capacitive load drive in the
unity-gain configuration is to insert a 10

to 20

resistor

in series with the output, as shown in Figure 7. This
significantly reduces ringing with large capacitive
loads

see the typical characteristic curve Frequency

Response vs Capacitive Load. However, if there is a
resistive load in parallel with the capacitive load, R

creates a voltage divider. This introduces a DC error at the
output and slightly reduces output swing. This error may
be insignificant. For instance, with R

= 10k

and R

, there is only about a 0.2% error at the output.

OPA354

V+

OUT

Figure 7. Series Resistor in Unity-Gain

Configuration Improves Capacitive Load Drive

WIDEBAND TRANSIMPEDANCE AMPLIFIER

Wide bandwidth, low input bias current, and low input
voltage and current noise make the OPA354 an ideal
wideband photodiode transimpedance amplifier for
low-voltage single-supply applications. Low-voltage noise
is important because photodiode capacitance causes the
effective noise gain of the circuit to increase at high
frequency.

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

The key elements to a transimpedance design, as shown
in Figure 8, are the expected diode capacitance (including
the parasitic input common-mode and differential-mode
input capacitance (2 + 2)pF for the OPA354), the desired
transimpedance gain (R

), and the Gain Bandwidth

Product (GBP) for the OPA354 (100MHz). With these 3
variables set, the feedback capacitor value (C

) may be set

to control the frequency response.

OPA354

OUT

10M

< 1pF

(prevents gain peaking)

Figure 8. Transimpedance Amplifier

To achieve a maximally flat 2nd-order Butterworth
frequency response, the feedback pole should be set to:

GBP

Typical surface-mount resistors have a parasitic
capacitance of around 0.2pF that must be deducted from
the calculated feedback capacitance value.

Bandwidth is calculated by:

3dB

GBP

For even higher transimpedance bandwidth, the
high-speed CMOS OPA355 (200MHz GBW) or the
OPA655 (400MHz GBW) may be used.

PCB LAYOUT

Good high-frequency printed circuit board (PCB) layout
techniques should be employed for the OPA354.
Generous use of ground planes, short and direct signal
traces, and a suitable bypass capacitor located at the V+
pin will assure clean, stable operation. Large areas of
copper also provides a means of dissipating heat that is
generated in normal operation.

Sockets are definitely not recommended for use with any
high-speed amplifier.

A 10nF ceramic bypass capacitor is the minimum
recommended value; adding a 1

F or larger tantalum

capacitor in parallel can be beneficial when driving a
low-resistance load. Providing adequate bypass
capacitance is essential to achieving very low harmonic
and intermodulation distortion.

POWER DISSIPATION

Power dissipation depends on power-supply voltage,
signal and load conditions. With DC signals, power
dissipation is equal to the product of output current times
the voltage across the conducting output transistor,
V

- V

. Power dissipation can be minimized by using the

lowest possible power-supply voltage necessary to assure
the required output voltage swing.

For resistive loads, the maximum power dissipation occurs
at a DC output voltage of one-half the power-supply
voltage. Dissipation with AC signals is lower. Application
Bulletin AB-039 (SBOA022), Power Amplifier Stress and
Power Handling Limitations, explains how to calculate or
measure power dissipation with unusual signals and
loads, and can be found at www.ti.com.

Any tendency to activate the thermal protection circuit
indicates excessive power dissipation or an inadequate
heatsink. For reliable operation, junction temperature
should be limited to 150

C, maximum. To estimate the

margin of safety in a complete design, increase the
ambient temperature until the thermal protection is
triggered at 160

C. The thermal protection should trigger

more than 35

C above the maximum expected ambient

condition of your application.

PowerPAD THERMALLY ENHANCED
PACKAGE

Besides the regular SOT23-5 and MSOP-8, the single and
dual versions of the OPA354 also come in SO-8
PowerPAD. The SO-8 PowerPAD is a standard-size SO-8
package where the exposed leadframe on the bottom of
the package can be soldered directly to the PCB to create
an extremely low thermal resistance. This will enhance the
OPA354's power dissipation capability significantly and
eliminates the use of bulky heatsinks and slugs
traditionally used in thermal packages. This package can
be easily mounted using standard PCB assembly
techniques. NOTE: Since the SO-8 PowerPAD is
pin-compatible with standard SO-8 packages, the
OPA354 and OPA2354 can directly replace operational
amplifiers in existing sockets. Soldering the PowerPAD to
the PCB is always required, even with applications that
have low power dissipation. This provides the necessary
thermal and mechanical connection between the
leadframe die pad and the PCB.

(1)

(2)

OPA354

OPA2354

OPA4354

SBOS233C - MARCH 2002- REVISED APRIL 2004

www.ti.com

The PowerPAD package is designed so that the leadframe
die pad (or thermal pad) is exposed on the bottom of the
IC, as shown in Figure 9. This provides an extremely low
thermal resistance (

) path between the die and the

exterior of the package. The thermal pad on the bottom of
the IC can then be soldered directly to the PCB, using the
PCB as a heatsink. In addition, plated-through holes (vias)
provide a low thermal resistance heat flow path to the back
side of the PCB.

Mold Compound (Plastic)

Leadframe Die Pad

Exposed at Base of the Package

(Copper Alloy)

Leadframe (Copper Alloy)

IC (Silicon)

Die Attach (Epoxy)

Figure 9. Section View of a PowerPAD Package

PowerPAD ASSEMBLY PROCESS

1. The PowerPAD must be connected to the device's most
negative supply voltage, which will be ground in
single-supply applications, and V- in split-supply
applications.

2. Prepare the PCB with a top-side etch pattern, as shown
in Figure 10. The exact land design may vary based on the
specific assembly process requirements. There should be
etch for the leads as well as etch for the thermal land.

OPTIONAL:
Additional 4 vias outside
of thermal pad area but
under the package.

REQUIRED:
Thermal pad area 2.286mm x 2.286mm
(90 mils x 90 mils) with 5 vias
(via diameter = 13 mils)

Thermal Land

(Copper)

Minimum Size

4.8mm x 3.8mm

(189 mils x 150 mils)

Figure 10. 8-Pin PowerPAD PCB Etch and Via

Pattern

3. Place the recommended number of plated-through
holes (or thermal vias) in the area of the thermal pad.
These holes should be 13 mils in diameter. They are kept
small so that solder wicking through the holes is not a
problem during reflow. The minimum recommended
number of holes for the SO-8 PowerPAD package is 5, as
shown in Figure 10.

4. It is recommended, but not required, to place a small
number of additional holes under the package and outside
the thermal pad area. These holes provide additional heat
paths between the copper thermal land and the ground
plane. They may be larger because they are not in the area
to be soldered, so wicking is not a problem. This is
illustrated in Figure 10.

5. Connect all holes, including those within the thermal pad
area and outside the pad area, to the internal ground plane
or other internal copper plane for single-supply
applications, and to V- for split-supply applications.

6. When laying out these holes, do not use the typical web
or spoke via connection methodology, as shown in
Figure

11. Web connections have a high thermal

resistance connection that is useful for slowing the heat
transfer during soldering operations. This makes soldering
the vias that have ground plane connections easier.
However, in this application, low thermal resistance is
desired for the most efficient heat transfer. Therefore, the
holes under the PowerPAD package should make their
connection to the internal ground plane with a complete
connection around the entire circumference of the
plated-through hole.

Web or Spoke Via

Solid Via

NOT RECOMMENDED

(due to poor heat conduction)

RECOMMENDED

Figure 11. Via Connection

7. The top-side solder mask should leave the pad
connections and the thermal pad area exposed. The
thermal pad area should leave the 13 mil holes exposed.
The larger holes outside the thermal pad area may be
covered with solder mask.

8. Apply solder paste to the exposed thermal pad area and
all of the package terminals.

9. With these preparatory steps in place, the PowerPAD IC
is simply placed in position and run through the solder
reflow operation as any standard surface-mount
component. This results in a part that is properly installed.

For detailed information on the PowerPAD package
including thermal modeling considerations and repair
procedures, please see Technical Brief SLMA002,
PowerPAD Thermally Enhanced Package, located at
www.ti.com.

PACKAGING INFORMATION

ORDERABLE DEVICE

STATUS(1)

PACKAGE TYPE

PACKAGE DRAWING

PINS

PACKAGE QTY

OPA2354AIDDA

ACTIVE

HSOP

DDA

100

OPA2354AIDDAR

ACTIVE

HSOP

DDA

2500

OPA2354AIDGKR

ACTIVE

VSSOP

DGK

2500

OPA2354AIDGKT

ACTIVE

VSSOP

DGK

250

OPA354AIDBVR

ACTIVE

SOP

DBV

3000

OPA354AIDBVT

ACTIVE

SOP

DBV

250

OPA354AIDDA

ACTIVE

HSOP

DDA

100

OPA354AIDDAR

ACTIVE

HSOP

DDA

2500

OPA4354AID

ACTIVE

SOIC

OPA4354AIDR

ACTIVE

SOIC

2500

OPA4354AIPWR

ACTIVE

TSSOP

2500

OPA4354AIPWT

ACTIVE

TSSOP

250

(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.

PACKAGE OPTION ADDENDUM

www.ti.com

21-May-2004

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Part Number OPA4354