1650 MHz (G = +1)
730 MHz (G = +2, VO = 2 V p-p)
4300 V/μs (G = +2, 4 V step)
Settling time 12 ns to 0.1%, 2 V step
Excellent for QXGA resolution video
Gain flatness 0.1 dB to 190 MHz
0.05% differential gain error, R
0.01° differential phase error, R
Low voltage offset: 0.7 mV (typical)
Low input bias current: 7 μA (typical)
Low noise: 1.8 nV/√Hz
Low distortion over wide bandwidth: SFDR −73 dBc @ 20 MHz
High output drive: 100 mA output load drive
Supply operation: +5 V to ±5 V voltage supply
Supply current: 9.5 mA/amplifier
APPLICATIONS
High resolution video graphics
Professional video
Consumer video
High speed instrumentation
Muxing
GENERAL DESCRIPTION
The AD8003 is a triple ultrahigh speed current feedback amplifier.
Using ADI’s proprietary eXtra Fast Complementary Bipolar
(XFCB) process, the AD8003 achieves a bandwidth of 1.5 GHz
and a slew rate of 4300 V/μs. Additionally, the amplifier provides
excellent dc precision with an input bias current of 50 μA
maximum and a dc input voltage of 0.7 mV.
The AD8003 has excellent video specifications with a frequency
response that remains flat out to 190 MHz and 0.1% settling within
12 ns to ensure that even the most demanding video systems
maintain excellent fidelity. For applications that use NTSC video,
as well as high speed video, the amplifier provides a differential
gain of 0.05% and a differential gain of 0.01°.
The AD8003 has very low spurious-free dynamic range (SFDR)
(−73 dBc @ 20 MHz) and noise (1.8 nV/√Hz). With a supply
range between 5 V and 11 V and ability to source 100 mA of
output current, the AD8003 is ideal for a variety of applications.
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
= 150 Ω
L
= 150 Ω
L
AD8003
CONNECTION DIAGRAM
S2
FEEDBACK 2
+V
19
G=+5
+V
18
FEEDBACK 3
17
–IN 3
16
+IN 3
15
POWER DOWN 3
14
–V
13
G=+1
+V
FEEDBACK 1
–IN 1
+IN 1
POWER DOWN 1
–V
–VS2POWER DOWN 2
24 23 22 21 20
1
S1
2
3
4
5
6
S1
78910 11 12
NC
+IN 2
–IN 2
OUT 1NCOUT 2NCOUT 3
Figure 1. 24-Lead, 4 mm × 4 mm LFCSP_VQ (CP-24)
The AD8003 operates on only 9.5 mA of supply current per
amplifier. The independent power-down function of the AD8003
reduces the quiescent current even further to 1.6 mA.
The AD8003 amplifier is available in a compact 4 mm × 4 mm,
24-lead LFCSP_VQ. The AD8003 is rated to work over the
industrial temperature range of −40°C to +85°C.
3
VS=±5V
G=+1,R
2
G=+2,+5,R
R
1
V
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-L OOP GAIN (dB)
–6
–7
11001000
Figure 2. Large Signal Frequency Response for Various Gains
Changes to Figure 34 ...................................................................... 11
10/05—Revision 0: Initial Version
Rev. B | Page 2 of 16
AD8003
SPECIFICATIONS WITH ±5 V SUPPLY
TA = 25°C, VS = ±5 V, RL = 150 Ω, Gain = +2, RF = 464 Ω, unless otherwise noted.
Table 1.
Parameter Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
–3 dB Bandwidth G = +1, Vo = 0.2 V p-p, RF = 432 Ω 1650 MHz
G = +2, Vo = 2 V p-p 730 MHz
G = +10, Vo = 0.2 V p-p 290 MHz
G = +5, Vo = 2 V p-p 330 MHz
Bandwidth for 0.1 dB Flatness Vo = 2 V p-p 190 MHz
Slew Rate G = +2, Vo = 2 V step, RL = 150 Ω 3800 V/μs
Settling Time to 0.1% G = +2, Vo = 2 V step 12 ns
Overload Recovery Input/Output 30/40 ns
NOISE/HARMONIC PERFORMANCE
Second/Third Harmonic @ 5 MHz G = +1, Vo = 2 V p-p 76/97 dBc
Second/Third Harmonic @ 20 MHz G = +1, Vo = 2 V p-p 79/73 dBc
Input Voltage Noise f = 1 MHz 1.8 nV/√Hz
Input Current Noise (I−/I+) f = 1 MHz 36/3 pA/√Hz
Differential Gain Error NTSC, G = +2, RL= 150 Ω 0.05 %
Differential Phase Error NTSC, G = +2, RL= 150 Ω 0.01 Degree
DC PERFORMANCE
Input Offset Voltage −9.3 +0.7 +9.3 mV
T
Input Offset Voltage Drift 7.4 μV/°C
Input Bias Current +IB/−IB −19/−40 −7/−7 +4/+50 μA
T
Input Offset Current ±14.2 μA
Transimpedance Vo = ±2.5 V 400 600 1100 kΩ
INPUT CHARACTERISTICS
Noninverting Input Impedance 1.6/3 MΩ/pF
Input Common-Mode Voltage Range ±3.6 V
Common-Mode Rejection Ratio VCM = ±2.5 V −51 −48 −46 dB
OUTPUT CHARACTERISTICS
Output Voltage Swing RL = 150 Ω ±3.85 ±3.9 ±3.92 V
Linear Output Current VO = 2 V p-p, second harmonic < −50 dBc 100 mA
Capacitive Load Drive 40% over shoot 27 pF
POWER DOWN PINS
Power-Down Input Voltage Power down <VS − 2.5 V
Enable >VS − 2.5 V
Turn-Off Time
Turn-On Time
Input Current
Enabled 0.1 μA
Power-Down −365 −235 −85 μA
POWER SUPPLY
Operating Range 4.5 10 V
Quiescent Current per Amplifier Enabled 8.1 9.5 10.2 mA
Quiescent Current per Amplifier Power down 1.2 1.4 1.6 mA
Power Supply Rejection Ratio (+PSRR/−PSRR) −59/−57 −57/−53 −55/−50 dB
− T
MIN
MIN
1.08 mV
MAX
− T
(+IB/−IB) −3.8/+29.5 μA
MAX
50% of power-down voltage to
10% of V
final, VIN = 0.5 V p-p
OUT
50% of power-down voltage to
90% of V
final, VIN = 0.5 V p-p
OUT
40 ns
130 ns
Rev. B | Page 3 of 16
AD8003
SPECIFICATIONS WITH +5 V SUPPLY
TA = 25°C, VS = 5 V, RL = 150 Ω, Gain = +2, RF = 464 Ω, unless otherwise noted.
Table 2.
Parameter Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
–3 dB Bandwidth G = +1, Vo = 0.2 V p-p, RF = 432 Ω 1050 MHz
G = +2, Vo = 2 V p-p 590 MHz
G = +10, Vo = 0.2 V p-p 290 MHz
G = +5, Vo = 2 V p-p 310 MHz
Bandwidth for 0.1 dB Flatness Vo = 2 V p-p 83 MHz
Slew Rate G = +2, Vo = 2 V step, RL = 150 Ω 2860 V/μs
Settling Time to 0.1% G = +2, Vo = 2 V step 12 ns
Overload Recovery Input/Output 40/60 ns
NOISE/HARMONIC PERFORMANCE
Second/Third Harmonic @ 5 MHz G = +1, Vo = 2 V p-p 75/78 dBc
Second/Third Harmonic @ 20 MHz G = +1, Vo = 2 V p-p 66/61 dBc
Input Voltage Noise f = 1 MHz 1.8 nV/√Hz
Input Current Noise (I−/I+) f = 1 MHz 36/3 pA/√Hz
Differential Gain Error NTSC, G = +2, RL= 150 Ω 0.04 %
Differential Phase Error NTSC, G = +2, RL= 150 Ω 0.01 Degree
DC PERFORMANCE
Input Offset Voltage −6.5 +2.7 +11 mV
T
Input Offset Voltage Drift 14.2 μV/°C
Input Bias Current (+IB/−IB) −21/−50 −7.7/−2.3 +5/+48 μA
T
Input Offset Current ±5.4 μA
Transimpedance 300 530 1500 kΩ
INPUT CHARACTERISTICS
Noninverting Input Impedance 1.6/3 MΩ/pF
Input Common-Mode Voltage Range 1.3 to 3.7 V
Common-Mode Rejection Ratio −50 −48 −45 dB
OUTPUT CHARACTERISTICS
Output Voltage Swing RL = 150 Ω ±1.52 ±1.57 ±1.62 V
Linear Output Current VO = 2 V p-p, second harmonic < −50 dBc 70 mA
Capacitive Load Drive 45% over shoot 27 pF
POWER DOWN PINS
Power-Down Input Voltage Power down <VS − 2.5 V
Enable >VS − 2.5 V
Turn-Off Time
Turn-On Time
Input Current
Enabled 0.1 μA
Power-Down −160 −43 +80 μA
POWER SUPPLY
Operating Range 4.5 10 V
Quiescent Current per Amplifier Enabled 6.3 7.9 9.4 mA
Quiescent Current per Amplifier Power down 0.8 0.9 1.1 mA
Power Supply Rejection Ratio (+PSRR/−PSRR) −59/−56 −57/−53 −55/−50 dB
− T
MIN
MIN
2.06 mV
MAX
− T
(+IB/−IB) −4/−27.8 μA
MAX
50% of power-down voltage to
10% of V
final, VIN = 0.5 V p-p
OUT
50% of power-down voltage to
90% of V
final, VIN = 0.5 V p-p
OUT
125 ns
80 ns
Rev. B | Page 4 of 16
AD8003
(
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 11 V
Power Dissipation See Figure 3
Common-Mode Input Voltage −VS − 0.7 V to +VS + 0.7 V
Differential Input Voltage
±V
S
Exposed Paddle Voltage −VS
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +85°C
Lead Temperature (Soldering 10 sec) 300°C
Junction Temperature 150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, θJA is specified
for device soldered in circuit board for surface-mount packages.
Table 4. Thermal Resistance
Package Type θJA Unit
24-Lead LFCSP_VQ 70 °C/W
Maximum Power Dissipation
The maximum safe power dissipation for the AD8003 is limited
by the associated rise in junction temperature (T
approximately 150°C, which is the glass transition temperature,
the plastic changes its properties. Even temporarily exceeding
this temperature limit may change the stresses that the package
exerts on the die, permanently shifting the parametric performance
of the AD8003. Exceeding a junction temperature of 175°C for
an extended period can result in changes in silicon devices,
potentially causing degradation or loss of functionality.
) on the die. At
J
RMS output voltages should be considered. If R
, as in single-supply operation, the total drive power is VS ×
−V
S
I
. If the rms signal levels are indeterminate, consider the
In addition, more metal directly in contact with the package
leads and exposed paddle from metal traces, through holes,
ground, and power planes reduce θ
.
JA
Figure 3 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the exposed paddle,
4 mm × 4 mm LFCSP_VQ (70°C/W) package on a JEDEC
standard 4-layer board. θ
3.0
2.5
2.0
1.5
1.0
0.5
MAXIMUM POW ER DISSIPATION (W )
0
–35 –15525456585105
–55125
Figure 3. Maximum Power Dissipation vs. Temperature for a 4-Layer Board
values are approximations.
JA
AMBIENT TEMPERATURE (°C)
05721-037
ESD CAUTION
The power dissipated in the package (P
) is the sum of the
D
quiescent power dissipation and the power dissipated in the die
due to the AD8003 drive at the output. The quiescent power is
the voltage between the supply pins (V
current (I
).
S
= Quiescent Power + (Total Drive Power – Load Power)
P
D
⎛
V
V
()
D
⎜
IVP
SS
⎜
⎝
OUTS
×+×=
R
2
L
) times the quiescent
S
⎞
⎟
⎟
⎠
2
V
OUT
–
R
L
Rev. B | Page 5 of 16
AD8003
TYPICAL PERFORMANCE CHARACTERISTICS
3
VS = ±5V
R
= 464Ω
F
2
R
= 150Ω
L
V
= 200mV p-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
–7
1101001000
FREQUENCY (MHz)
G = –1
G = –2
Figure 4. Small Signal Frequency Response for Various Gains
05721-002
3
VS=±5V
G=+1,R
2
G=+2,+10,R
R
1
V
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
–7
11001000
= 150Ω
L
= 200mV p -p
OUT
=432Ω
F
= 464Ω
F
10
FREQUENCY (MHz)
G=+2
G=+1
G=+10
Figure 7. Small Signal Frequency Response for Various Gains
05721-003
3
G = +2
R
= 150Ω
L
2
V
= 200mV p-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
–7
11001000
10
FREQUENCY (MHz)
VS = ±5V
VS = +5V
Figure 5. Small Signal Frequency Response for Various Supplies
3
G = +2
V
= ±5V
S
2
R
= 150Ω
L
V
= 200mV p-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
–7
11001000
10
FREQUENCY (MHz)
Figure 6. Small Signal Feedback Resistor (R
RF = 392Ω
RF = 432Ω
RF = 464Ω
RF = 357Ω
) Optimization
F
3
G = +2
V
= ±5V
S
2
R
= 150Ω
L
V
= 200mV p-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
05721-004
–7
11001000
10
FREQUENCY (MHz)
T = +105°C
T = +25°C
T = –40°C
05721-005
Figure 8. Small Signal Frequency Response for Various Temperatures
3
G = +2
V
= ±5V
S
2
R
= 150Ω
L
V
= 2V p-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-LOOP GAIN (dB)
–6
05721-007
–7
11001000
10
FREQUENCY (MHz)
RF = 392Ω
RF = 432Ω
RF = 357Ω
RF = 464Ω
05721-008
Figure 9. Large Signal Feedback Resistor (RF) Optimization
Rev. B | Page 6 of 16
AD8003
–
–
6
G = +1
V
=±5V
S
R
= 150Ω
L
V
= 200mV p-p
3
OUT
0
–3
–6
–9
NORMALIZED CL OSED-LOO P GAIN ( dB)
–12
110100100010000
FREQUENCY (MHz)
Figure 10. G = +1 Series Resistor (R
3
VS=±5V
G=+1,R
2
G=+2,+5,R
R
1
V
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-L OOP GAIN (dB)
–6
–7
11001000
=150Ω
L
OUT
=432Ω
F
=2Vp-p
= 464Ω
F
10
FREQUENCY (MHz)
G=+2
RS = 50Ω
) Optimization
S
G=+5
R
0
=
S
RS = 25Ω
G=+1
Ω
Figure 11. Large Signal Frequency Response for Various Gains
30
G=+1
R
= 100Ω
L
–40
–50
–60
–70
–80
–90
DISTORTION (dBc)
–100
–110
–120
=2Vp-p
V
OUT
SECOND
THIRD
0.1110100
FREQUENCY (MHz)
VS=±5V
V
=+5V
S
Figure 12. Harmonic Distortion vs. Frequency for Various Supplies
05721-006
05721-009
05721-017
0.3
G = +2
R
= 150Ω
0.2
L
V
= 2V p-p
OUT
0.1
0
–0.1
–0.2
–0.3
–0.4
–0.5
–0.6
–0.7
NORMALIZED CL OSED-LOO P GAIN ( dB)
–0.8
–0.9
1101001000
FREQUENCY (MHz )
VS =±5V
VS =+5V
Figure 13. 0.1 dB Flatness Response
3
VS=±5V
G=+2
2
R
= 150Ω
L
V
=2Vp-p
OUT
1
0
–1
–2
–3
–4
–5
NORMALIZED CLOSED-L OOP GAIN (dB)
–6
–7
11001000
10
FREQUENCY (MHz)
T = + 105°C
T = –40° C
T = +25°C
05721-010
Figure 14. Large Signal Frequency Response for Various Temperatures
30
G=+2
R
=150Ω
L
–40
V
=2Vp-p
OUT
–50
–60
–70
–80
–90
DISTORTION (dBc)
–100
–110
–120
0.1110100
SECOND
THIRD
FREQUENCY ( MHz)
VS=±5V
V
=+5V
S
05721-018
Figure 15. Harmonic Distortion vs. Frequency for Various Supplies
05721-016
Rev. B | Page 7 of 16
AD8003
–
–20
–30
–40
10
G = +2
V
OUT
f
= 5MHz
C
= 2V p-p
SECOND
VS =±5V
V
=+5V
S
0.20
0.15
0.10
0.05
V
VS=
G=+2
R
= 150Ω
L
V
= 200mV p -p
+
5
V
=
S
±
5
V
OUT
2.70
2.65
2.60
2.55
–50
–60
DISTORTION (dBc)
–70
–80
–90
1012141618202224262830
THIRD
R
(Ω)
L
Figure 16. Harmonic Distortion vs. R
L
05721-019
0
–0.05
OUTPUT VO LTAGE (V )
–0.10
–0.15
–0.20
01
1234567891011121314
Figure 19. Small Signal Pulse Response for Various Supplies
2.0
G = +2
= 150Ω
R
L
= 2V p-p
V
1.5
OUT
1.0
0.5
0
–0.5
OUTPUT VO LTAGE (V )
–1.0
–1.5
–2.0
015
=
VS
+
5
V
V
±
5
V
=
S
1 2 3 4 5 6 7 8 9 10 11 12 13 14
TIME (ns)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
OUTPUT VOLTAGE ( V)
05721-012
Figure 17. Large Signal Pulse Response for Various Supplies
0.3
0.2
0.1
0
–0.1
OUTPUT VOLTAGE (V)
G=+2
–0.2
= 150Ω
R
L
V
=±5V
S
= 200mV p -p
V
OUT
–0.3
05101520253035
Figure 20. Small Signal Pulse Response for Various Capacitive Loads
TIME (ns)
CL=0pF
C
L
TIME (ns)
= 15pF
C
L
= 27pF
2.50
2.45
OUTPUT VO LTAGE (V )
2.40
2.35
2.30
5
5721-011
05721-020
2.8
2.7
2.6
=15pF
C
2.5
CL=0pF
2.4
OUTPUT VOLTAGE (V)
G=+2
2.3
= 150Ω
R
L
=5V
V
S
= 200mV p -p
V
OUT
2.2
0510152025303 5
L
C
TIME (ns)
= 27pF
L
Figure 18. Small Signal Pulse Response for Various Capacitive Loads
05721-022
Rev. B | Page 8 of 16
AMPLITUDE (V)
–0.5
–1.0
–1.5
1.5
G=+2
V
=±5V
S
R
= 150Ω
L
1.0
0.5
0
–5
010515202530354045
V
V
SETTLE
TIME (ns)
OUT
V
IN
Figure 21. Short-Term 0.1% Settling Time
0.3
0.2
0.1
0
–0.1
–0.2
–0.3
SETTLING (%)
05721-021
AD8003
(
6000
G=+2
R
= 150Ω
L
5000
4000
3000
2000
SLEW RATE (V/µs)
1000
0
123456
07
VS=
V
+
5
V
V
OUT p-p
±
5
V
=
S
(V)
RISE
FALL
05721-013
Figure 22. Slew Rate vs. Output Voltage
5
4
3
2
1
0
–1
AMPLITUDE (V)
–2
–3
–4
–5
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT
INPUT × 2
TIME (µs)
G = +2
V
= ±5V
S
= 150Ω
R
L
05721-024
Figure 23. Output Overdrive Recovery
0
G=0
V
=±5V
S
R
= 150Ω
L
–10
–20
–30
–40
COMMON-MO DE REJECTIO N (dB)
–50
5
4
3
2
1
0
–1
AMPLITUDE (V)
–2
–3
–4
–5
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT
INPUT
TIME (µs)
G = +1
V
R
Figure 25. Input Overdrive Recovery
1000
G=+1/+2
V
=±5V
S
100
Ω)
10
IMPEDANCE
1
0.1
0.11101001000
FREQUENCY (MHz)
Figure 26. Output Impedance vs. Frequency
0
G=+2
V
=±5V
S
R
= 150Ω
L
–10
–20
–30
–40
–50
POWER SUPPLY REJECTI ON (dB)
–60
PSR–
PSR+
= ±5V
S
= 150Ω
L
05721-023
05721-027
–60
0.1110100
FREQUENCY ( MHz)
Figure 24. Common-Mode Rejection vs. Frequency
05721-026
Rev. B | Page 9 of 16
–70
0.11101001000
FREQUENCY ( MHz)
Figure 27. Power Supply Rejection vs. Frequency
05721-025
AD8003
(
80
20
60
VS=±5V
40
VS=+5V
20
(mV)
OS
0
V
–20
–40
–60
–5–4–3–2–101234
(V)
V
CM
Figure 28. Offset Voltage vs. Input Common-Mode Range
10
8
VS = +5V
6
4
VS = ±5V
2
0
(μA)
B
I
–2
–4
–6
–8
–10
–5–4–3–2–101234
V
(V)
OUT
Figure 29. Inverting Input Bias Current Linearity
15
VS=±5V
10
VS=+5V
5
µA)
0
B
I
–5
–10
–15
05721-031
5
–20
–5–4–3–2–101234
V
(V)
CM
05721-032
5
Figure 31. Noninverting Input Bias Current vs. Common-Mode Range
6
V
D
±
5
V
V
=
S
(
S
I
)
5
4
V
V
(
S
D
I
+
5
V
=
S
3
AMPLITUDE (V)
2
V
V
U
(
T
O
V
O
U
)
+
=
S
5
V
)
±
5
V
=
S
(
T
V
)
1
V
U
(
T
O
±
5
V
V
=
)
05721-033
5
0
01
0.1 0.2 0.3 0.4 0.5 0.6 0. 7 0.8 0.9
S
TIME (µs)
V
O
G=+2
R
=150Ω
L
V
=0.5Vdc
IN
V
U
(
T
+
=
S
5
V
)
05721-014
.0
Figure 32. Disable Switching Time for Various Supplies
10
G=+2
R
=150Ω
L
9
V
=±5V
S
8
7
6
I
S
D
I
5
4
3
2
POSITIVE SUPPLY CURRENT (mA)
I
1
0
–4–3–2–101234
–55
POWERDOWNPINVOLTAGE(V
DIS
(V))
Figure 30. POWER DOWN Pin Current and Supply Current vs.
POWER DOWN Pin Voltage
200
150
100
50
0
–50
–100
–150
C
C
–200
POWER DOW N PIN CURRENT (µA)
–250
–300
05721-028
10
G=+2
R
=150Ω
L
9
V
=5V
S
8
7
6
I
C
C
5
4
3
2
POSITIVE SUPPLY CURRENT (mA)
1
0
05
0.51.01.52.02.53.03.54.04.5
POWERDOWNPINVOLTAGE(V
DIS
(V))
40
30
20
10
I
S
D
I
0
–10
–20
–30
–40
POWER DOW N PIN CURRENT (µA)
–50
–60
.0
05721-029
Figure 33. POWER DOWN Pin Current and Supply Current vs.
POWER DOWN Pin Voltage
Rev. B | Page 10 of 16
AD8003
√
1000
VS =±5V
R
= 1kΩ
F
100
10
INPUT VOLTAGE NOISE (nV/√Hz)
1
101001k10k100k1M10M
FREQUENCY (Hz)
Figure 34. Input Voltage Noise vs. Frequency
0
G=+2
R
= 150Ω
L
–10
DRIVING: CH1 AND CH3
RECEIVING: CH2
–20
–30
–40
–50
–60
–70
–80
NORMALIZE D CLOSED-LOOP GAIN (dB)
–90
–100
0.11101001000
FREQUENCY ( MHz)
VS=
Figure 35. Worst-Case Crosstalk
VS=
05721-034
±
5
V
+
5
V
05721-015
10000
VS=±5V
Hz)
1000
100
10
INPUT CURRENT NOI SE (pA/
1
101001k10k100k1M10M
FREQUENCY (Hz)
Figure 36. Input Current Noise vs. Frequency
1M
100k
10k
MAGNITUDE (Ω)
1k
100
1k10k100k1M10M100M1G
FREQUENCY (Hz)
Figure 37. Transimpedance
I–
I+
05721-035
200
180
160
140
120
100
80
PHASE (Degrees )
60
40
20
0
05721-030
Rev. B | Page 11 of 16
AD8003
T
APPLICATIONS INFORMATION
GAIN CONFIGURATIONS
Unlike conventional voltage feedback amplifiers, the feedback
resistor has a direct impact on the closed-loop bandwidth and
stability of the current feedback op amp circuit. Reducing the
resistance below the recommended value can make the amplifier
response peak and can even become unstable. Increasing the
size of the feedback resistor reduces the closed-loop bandwidth.
Table 5 provides a convenient reference for quickly determining
the feedback and gain set resistor values, and the small and
large signal bandwidths for common gain configurations. The
feedback resistors in Tab le 5 have been optimized for 0.1 dB
flatness frequency response.
Table 5. Recommended Values and Frequency Response1
Figure 38 and Figure 39 show the typical noninverting and inverting
configurations and recommended bypass capacitor values.
R
G
R
V
IN
V
IN
S
Figure 38. Noninverting Gain
R
G
R
F
–
AD8003
+
–V
R
F
–
AD8003
+
FB
–V
S
FB
–V
−3 dB
SS BW
(MHz)
+V
S
+V
0.1µF
10µF
+V
S
+V
0.1µF
10µF
0.1µF
10µF
0.1µF
Large
Signal
−3 dB
BW
V
O
V
O
Large
Signal
0.1 dB
BW
V
O
R
L
05721-038
V
O
R
L
RGB VIDEO DRIVER
Figure 40 shows a typical RGB driver application using bipolar
75Ω
75Ω
75Ω
= RG =
F
R
OUT
G
OU
B
OUT
supplies. The gain of the amplifier is set at +2, where R
464 Ω. The amplifier inputs are terminated with shunt 75 Ω
resistors, and the outputs have series 75 Ω resistors for proper
video matching. In Figure 40, the POWER DOWN pins are not
shown connected to any signal source for simplicity. If the powerdown function is not used, it is recommended that the POWER
DOWN pins be tied to the positive supply and not be left floating
(not connected).
In applications that require a fixed gain of +2, as previously
mentioned, the designer may consider the ADA4862-3.
The ADA4862-3 is another high performance triple current
feedback amplifier. The ADA4862-3 has integrated feedback
and gain set resistors that reduce board area and simplify designs.
PD3
PD2
PD1
+V
14
23
5
1
R
IN
75Ω
G
IN
75Ω
B
IN
75Ω
R
464Ω
R
464Ω
R
464Ω
R
464Ω
R
464Ω
R
464Ω
4
G
3
F
2
AD8003
22
G
21
F
20
15
G
16
F
17
6
19
24
18
13
Figure 40. RGB Video Driver
10µF
0.1µF
10µF
0.1µF
10µF
0.1µF
10µF
0.1µF
10µF
0.1µF
10µF
0.1µF
S
–V
S
+V
S
–V
S
+V
S
–V
S
05721-036
10µF
–V
S
Figure 39. Inverting Gain
05721-039
Rev. B | Page 12 of 16
AD8003
PRINTED CIRCUIT BOARD LAYOUT
Printed circuit board (PCB) layout is usually one of the last
steps in the design process and often proves to be one of the
most critical. A high performance design can be rendered
mediocre due to poor or sloppy layout. Because the AD8003
can operate into the RF frequency spectrum, high frequency
board layout considerations must be taken into account. The
PCB layout, signal routing, power supply bypassing, and
grounding must all be addressed to ensure optimal performance.
LOW DISTORTION PINOUT
The AD8003 LFCSP features ADI’s low distortion pinout. The
pinout lowers the second harmonic distortion and simplifies the
circuit layout. The close proximity of the noninverting input
and the negative supply pin creates a source of second harmonic
distortion. Physical separation of the noninverting input pin
and the negative power supply pin reduces this distortion.
By providing an additional output pin, the feedback resistor
can be connected directly between the feedback pin and the
inverting input. This greatly simplifies the routing of the
feedback resistor and allows a more compact circuit layout,
which reduces its size and helps to minimize parasitics and
increase stability.
SIGNAL ROUTING
To minimize parasitic inductances, ground planes should be
used under high frequency signal traces. However, the ground
plane should be removed from under the input and output pins
to minimize the formation of parasitic capacitors, which degrades
phase margin. Signals that are susceptible to noise pickup should be
run on the internal layers of the PCB, which can provide
maximum shielding.
POWER SUPPLY BYPASSING
Power supply bypassing is a critical aspect of the PCB design
process. For best performance, the AD8003 power supply pins
need to be properly bypassed.
Each amplifier has its own supply pins brought out for the utmost
flexibility. Supply pins can be commoned together or routed to a
dedicated power plane. Commoned supply connections can also
reduce the need for bypass capacitors on each supply line. The
exact number and values of the bypass capacitors are dictated
by the design specifications of the actual circuit.
A parallel combination of different value capacitors from each
of the power supply pins to ground tends to work the best.
Paralleling different values and sizes of capacitors helps to ensure
that the power supply pins see a low ac impedance across a wide
band of frequencies. This is important for minimizing the coupling
of noise into the amplifier. Starting directly at the power supply
pins, the smallest value and physical-sized component should
be placed on the same side of the board as the amplifier, and as
close as possible to the amplifier, and connected to the ground
plane. This process should be repeated for the next largest capacitor
value. It is recommended that a 0.1 μF ceramic 0508 case be used
for the AD8003. The 0508 offers low series inductance and
excellent high frequency performance. The 0.1 μF case provides
low impedance at high frequencies. A 10 μF electrolytic capacitor
should be placed in parallel with the 0.1 μF. The 10 μF capacitor
provides low ac impedance at low frequencies. Smaller values
of electrolytic capacitors can be used depending on the circuit
requirements. Additional smaller value capacitors help provide a
low impedance path for unwanted noise out to higher
frequencies but are not always necessary.
EXPOSED PADDLE
The AD8003 features an exposed paddle, which lowers the
thermal resistance by approximately 40% compared to a
standard SOIC plastic package. The paddle can be soldered
directly to the ground plane of the board. Thermal vias or heat
pipes can also be incorporated into the design of the mounting
pad for the exposed paddle. These additional vias improve the
thermal transfer from the package to the PCB. Using a heavier
weight copper also reduces the overall thermal resistance path
to ground.
Rev. B | Page 13 of 16
Placement of the capacitor returns (grounds), where the capacitors
enter into the ground plane, is also important. Returning the
capacitor grounds close to the amplifier load is critical for
distortion performance. Keeping the capacitors distance short,
but equal from the load, is optimal for performance.
In some cases, bypassing between the two supplies can help
improve PSRR and maintain distortion performance in
crowded or difficult layouts. Designers should note this as
another option for improving performance.
AD8003
Minimizing the trace length and widening the trace from the
capacitors to the amplifier reduces the trace inductance. A
series inductance with the parallel capacitance can form a tank
circuit, which can introduce high frequency ringing at the output.
This additional inductance can also contribute to increased
distortion due to high frequency compression at the output.
The use of vias should be minimized in the direct path to the
amplifier power supply pins because vias can introduce parasitic
inductance, which can lead to instability. When required, use
multiple large diameter vias because this lowers the equivalent
parasitic inductance.
GROUNDING
The use of ground and power planes is encouraged as a method
of proving low impedance returns for power supply and signal
currents. Ground and power planes can also help to reduce stray
trace inductance and provide a low thermal path for the amplifier.
Ground and power planes should not be used under any of the
pins of the AD8003. The mounting pads and the ground or power
planes can form a parasitic capacitance at the amplifiers input.
Stray capacitance on the inverting input and the feedback
resistor form a pole, which degrades the phase margin, leading
to instability. Excessive stray capacitance on the output also forms a
pole, which degrades phase margin.
Rev. B | Page 14 of 16
AD8003
OUTLINE DIMENSIONS
0.60 MAX
19
18
EXPOSED
(BOTTOM VIEW)
13
12
PAD
24
6
7
1
2.50 REF
PIN 1
INDICATOR
2.25
2.10 SQ
1.95
0.25 MIN
PIN 1
INDICATOR
1.00
0.85
0.80
12° MAX
SEATING
PLANE
4.00
BSC SQ
TOP
VIEW
0.80 MAX
0.65 TYP
COMPLIANT TOJEDEC STANDARDS MO-220-VGGD-2
0.30
0.23
0.18
3.75
BSC SQ
0.20 REF
0.05 MAX
0.02 NOM
0.60 MAX
0.50
BSC
0.50
0.40
0.30
COPLANARITY
0.08
Figure 41. 24-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
4 mm × 4 mm Body, Very Thin Quad
(CP-24-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature Range Package Description Package Option Ordering Quantity