ADA4850-2YCPZ-R2 [ADI]
High Speed, Rail-to-Rail Output, Op Amp with Ultralow Power-Down; 高速，轨到轨输出运算放大器，具有超低省电
| 型号： | ADA4850-2YCPZ-R2 |
| 厂家： | 
ADI |
| 描述： | High Speed, Rail-to-Rail Output, Op Amp with Ultralow Power-Down |
| 文件： | 总16页 (文件大小：567K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
High Speed, Rail-to-Rail Output,
Op Amp with Ultralow Power-Down
ADA4850-1/ADA4850-2
FEATURES
PIN CONFIGURATIONS
Ultralow power-down current: 150 nA/amp max
Low quiescent current: 2.4 mA/amp
High speed
175 MHz −3 dB bandwidth
220 V/µs slew rate
ADA4850-1
8
7
6
5
+V
S
POWER DOWN
1
2
3
4
OUTPUT
NC
NC
–IN
+IN
–V
S
85 ns settling time to 0.1%
Excellent video specifications
0.1 dB flatness: 14 MHz
NC = NO CONNECT
Figure 1. 8-Lead, 3 mm × 3 mm LFCSP
Differential gain: 0.12%
Differential phase: 0.09°
Single-supply operation: 2.7 V to 6 V
Rail-to-rail output
Output swings to within 80 mV of either rail
Low voltage offset: 0.6 mV
ADA4850-2
V
1
1
2
3
4
12 +V
OUT
S
–IN1
+IN1
11
V
2
OUT
APPLICATIONS
Portable multimedia players
Video cameras
10 –IN2
+IN2
–V
S
9
Digital still cameras
Consumer video
NC = NO CONNECT
Figure 2. 16-Lead, 3 mm × 3 mm LFCSPP
GENERAL DESCRIPTION
The ADA4850-1, ADA4850-21 are low price, high speed,
voltage feedback rail-to-rail output op amps with ultralow
power-down. Despite their low price, the ADA4850-1/
ADA4850-2 provide excellent overall performance and
versatility. The 175 MHz −3 dB bandwidth and 220 V/µs
slew rate make these amplifiers well-suited for many general-
purpose, high speed applications.
The ADA4850-1/ADA4850-2 are designed to work in the
extended temperature range of −40°C to +125°C.
2
1
0
–1
–2
–3
The ADA4850-1/ADA4850-2 are designed to operate at supply
voltages as low as 2.7 V and up to 6 V at 2.4 mA of supply
current per amplifier. In power-down mode, the supply current
is less than 150 nA, ideal for battery-powered applications.
–4
G = +1
The ADA4850 family provides users with a true single-supply
capability, allowing input signals to extend 200 mV below the
negative rail and to within 2.2 V of the positive rail. The output
of the amplifier can swing within 80 mV of either supply rail.
V
= 5V
S
–5
–6
R
= 1kΩ
L
V
= 0.1V p-p
OUT
1
10
100
1000
FREQUENCY (MHz)
With its combination of low price, excellent differential gain
(0.12%), differential phase (0.09º), and 0.1 dB flatness out to
14 MHz, these amplifiers are ideal for video applications.
Figure 3. Small Signal Frequency Response
1 Patent pending.
Rev. A
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2005 Analog Devices, Inc. All rights reserved.
ADA4850-1/ADA4850-2
TABLE OF CONTENTS
Specifications with +3 V Supply..................................................... 3
Headroom and Overdrive Recovery Considerations............ 12
Specifications with +5 V Supply..................................................... 4
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Typical Performance Characteristics ............................................. 6
Circuit Description......................................................................... 12
Operating the ADA4850-1/ADA4850-2 on
Bipolar Supplies.......................................................................... 13
Power-Down Pins....................................................................... 13
Outline Dimensions....................................................................... 14
Ordering Guide .......................................................................... 14
REVISION HISTORY
4/05—Rev. 0 to Rev. A
AddedADA4850-1..............................................................Universal
Added 8-Lead LFCSP.........................................................Universal
Changes to Features.......................................................................... 1
Changes to General Description .................................................... 1
Changes to Figure 3.......................................................................... 1
Changes to Table 1............................................................................ 3
Changes to Table 2............................................................................ 4
Changes to Power-Down Pins Section and Table 5 ................... 13
Updated Outline Dimensions....................................................... 14
Changes to Ordering Guide .......................................................... 14
2/05—Revision 0: Initial Version
Rev. A | Page 2 of 16
ADA4850-1/ADA4850-2
SPECIFICATIONS WITH +3 V SUPPLY
TA = 25°C, RF = 0 Ω for G = +1, RF = 1 kΩ for G > +1, RL = 1 kΩ, unless otherwise noted.
Table 1.
Parameter
Conditions
Min
Typ
Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth
G = +1, VO = 0.1 V p-p
160
45
14
110
80
MHz
MHz
MHz
V/µs
ns
G = +2, VO = 0.5 V p-p, RL = 150 Ω
G = +2, VO = 0.5 V p-p, RL = 150 Ω
G = +2, VO = 1 V Step
Bandwidth for 0.1 dB Flatness
Slew Rate
Settling Time to 0.1%
G = +2, VO = 1 V Step, RL = 150 Ω
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion (dBc) HD2/HD3
Input Voltage Noise
fC = 1 MHz, VO = 2 V p-p, G = +3, RL = 150 Ω
f = 100 kHz
−72/−77
10
dBc
nV/√Hz
Input Current Noise
f = 100 kHz
2.5
pA/√Hz
%
Degrees
Differential Gain
Differential Phase
G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p
G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p
0.2
0.2
DC PERFORMANCE
Input Offset Voltage
Input Offset Voltage Drift
Input Bias Current
Input Bias Current Drift
Input Bias Offset Current
Open-Loop Gain
0.6
4
4.1
4.4
mV
µV/°C
µA
2.4
4
nA/°C
nA
dB
30
100
VO = 0.25 V to 0.75 V
78
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
Input Common-Mode Voltage Range
Input Overdrive Recovery Time (Rise/Fall)
Common-Mode Rejection Ratio
POWER-DOWN
Differential/common-mode
0.5/5.0
1.2
−0.2 to +0.8
60/50
MΩ
pF
V
ns
dB
VIN = +3.5 V to −0.5 V, G = +1
VCM = 0.5 V
−76
−108
Power-Down Input Voltage
Power-down ADA4850-1/ADA4850-2
Enabled ADA4850-1/ADA4850-2
<0.7/<0.6
>0.8/>1.7
0.7
V
V
µs
ns
Turn-Off Time
Turn-On Time
60
Power-Down Bias Current/ Power Down Pin
Enabled
Power-Down
Power-down = 3 V
Power-down = 0 V
37
0.01
55
0.2
µA
µA
OUTPUT CHARACTERISTICS
Output Overdrive Recovery Time (Rise/Fall)
Output Voltage Swing
VIN = +0.7 V to −0.1 V, G = +5
Sinking/sourcing
70/100
0.06 to 2.83 0.03 to 2.92
105/74
ns
V
mA
Short-Circuit Current
POWER SUPPLY
Operating Range1
2.7
2.4
15
6
2.8
150
V
Quiescent Current/Amplifier
Quiescent Current (Power-Down)/Amplifier
Positive Power Supply Rejection
Negative Power Supply Rejection
mA
nA
dB
dB
+VS = +3 V to +4 V, −VS = 0 V
+VS = +3 V, −VS = 0 V to –1 V
−83
−83
−100
−102
1 For operation on bipolar supplies, see the Operating the ADA4850-1/ADA4850-2 on Bipolar Supplies section.
Rev. A | Page 3 of 16
ADA4850-1/ADA4850-2
SPECIFICATIONS WITH +5 V SUPPLY
TA = 25°C, RF = 0 Ω for G = +1, RF = 1 kΩ for G > +1, RL = 1 kΩ, unless otherwise noted.
Table 2.
Parameter
Conditions
Min
Typ
Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth
G = +1, VO = 0.1 V p-p
G = +1, VO = 0.5 V p-p
G = +2, VO = 1.4 V p-p, RL = 150 Ω
G = +2, VO = 4 V Step
G = +2, VO = 2 V Step
175
110
9
220
160
85
MHz
MHz
MHz
V/µs
V/µs
ns
Bandwidth for 0.1 dB Flatness
Slew Rate
Settling Time to 0.1%
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion (dBc) HD2/HD3
Input Voltage Noise
G = +2, VO = 1 V Step, RL = 150 Ω
fC = 1 MHz, VO = 2 V p-p, G = +2, RL = 150 Ω
f = 100 kHz
−81/−86
10
dBc
nV/√Hz
Input Current Noise
f = 100 kHz
2.5
pA/√Hz
%
Degrees
dB
Differential Gain
Differential Phase
Crosstalk(RTI)-ADA4850-2
DC PERFORMANCE
G = +3, NTSC, RL = 150 Ω
G = +3, NTSC, RL = 150 Ω
f = 4.5 MHz, RL = 150 Ω, VO = 2 V p-p
0.12
0.09
60
Input Offset Voltage
Input Offset Voltage Drift
Input Bias Current
Input Bias Current Drift
Input Bias Offset Current
Open-Loop Gain
0.6
4
4.2
4.2
mV
µV/°C
µA
2.3
4
nA/°C
nA
dB
30
105
VO = 2.25 V to 2.75 V
83
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
Input Common-Mode Voltage Range
Input Overdrive Recovery Time (Rise/Fall)
Common-Mode Rejection Ratio
POWER-DOWN
Differential/common-mode
0.5/5.0
1.2
−0.2 to +2.8
50/40
MΩ
pF
V
ns
dB
VIN = +5.5 V to −0.5 V, G = +1
VCM = 2.0 V
−85
−110
Power-Down Input Voltage
Power-down ADA4850-1/ADA4850-2
Enabled ADA4850-1/ADA4850-2
<0.7/<0.6
>0.8/>1.7
0.7
V
V
µs
ns
Turn-Off Time
Turn-On Time
50
Power-Down Bias Current/ Power Down Pin
Enabled
Power-Down
Power-down = 5 V
Power-down = 0 V
0.05
0.02
0.13 mA
0.2
µA
OUTPUT CHARACTERISTICS
Output Overdrive Recovery Time (Rise/Fall)
Output Voltage Swing
VIN = +1.1 V to −0.1 V, G = +5
Sinking/sourcing
60/70
ns
V
mA
0.14 to 4.83 0.07 to 4.92
118/94
Short-Circuit Current
POWER SUPPLY
Operating Range1
2.7
2.5
15
6
2.9
150
V
Quiescent Current/Amplifier
Quiescent Current (Power-Down)/Amplifier
Positive Power Supply Rejection
Negative Power Supply Rejection
mA
nA
dB
dB
+VS = +5 V to +6 V, −VS = 0 V
+VS = +5 V, −VS = −0 V to −1 V
−84
−84
−100
−102
1 For operation on bipolar supplies, see the Operating the ADA4850-1/ADA4850-2 on Bipolar Supplies section.
Rev. A | Page 4 of 16
ADA4850-1/ADA4850-2
ABSOLUTE MAXIMUM RATINGS
The power dissipated in the package (PD) is the sum of the
quiescent power dissipation and the power dissipated in the die
due to the ADA4850-1/ADA4850-2 drive at the output. The
quiescent power is the voltage between the supply pins (VS)
times the quiescent current (IS).
Table 3.
Parameter
Rating
Supply Voltage
12.6 V
Power Dissipation
See Figure 4
(−VS + 6) V
(−VS − 0.5 ) V to (+VS + 0.5) V
+VS to −VS
−65°C to +125°C
−40°C to +125°C
300°C
Power Down Pin Voltage
Common-Mode Input Voltage
Differential Input Voltage
Storage Temperature
Operating Temperature Range
PD = Quiescent Power + (Total Drive Power − Load Power)
2
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
VS VOUT
VOUT
RL
PD =
(
VS × IS
)
+
×
–
2
RL
Lead Temperature Range
(Soldering 10 sec)
RMS output voltages should be considered. If RL is referenced
to −VS, as in single-supply operation, the total drive power is
VS × IOUT. If the rms signal levels are indeterminate, consider
the worst case, when VOUT = VS/4 for RL to midsupply.
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.
2
VS/4
RL
)
PD =
(
VS × IS +
)
In single-supply operation with RL referenced to −VS, the worst
case is VOUT = VS/2.
THERMAL RESISTANCE
Airflow increases heat dissipation, effectively reducing θJA.
Also, more metal directly in contact with the package leads and
exposed paddle from metal traces, through holes, ground, and
power planes reduce θJA.
θJA is specified for the worst-case conditions, that is, θJA is
specified for the device soldered in the circuit board for surface-
mount packages.
Table 4. Thermal Resistance
Figure 4 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the LFCSP (91°C/W)
package on a JEDEC standard 4-layer board. θJA values are
approximations.
Package Type
16-Lead LFCSP
8-Lead LFCSP
θJA
91
80
Unit
°C/W
°C/W
2.5
Maximum Power Dissipation
The maximum safe power dissipation for the ADA4850-1/
ADA4850-2 is limited by the associated rise in junction
temperature (TJ) on the die. At 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
ADA4850-1/ADA4850-2. Exceeding a junction temperature of
150°C for an extended period of time can result in changes in
silicon devices, potentially causing degradation or loss of
functionality.
2.0
LFCSP-8
LFCSP-16
1.5
1.0
0.5
0
–55 –45 –35 –25 –15 –5
5
15 25 35 45 55 65 75 85 95 105 115 125
AMBIENT TEMPERATURE (°C)
Figure 4. Maximum Power Dissipation vs. Temperature for a 4-Layer Board
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate
on the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. A | Page 5 of 16
ADA4850-1/ADA4850-2
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, RF = 0 Ω for G = +1, RF = 1 kΩ for G > +1, RL = 1 kΩ, unless otherwise noted.
1
4
6pF
G = +1
= 5V
V
R
V
= 5V
= 150Ω
S
V
3
S
L
0
R
V
= 1kΩ
= 0.1V p-p
L
OUT
= 0.1V p-p
2
OUT
G = –1
–1
–2
–3
–4
–5
–6
1
0
G = +2
1pF
0pF
–1
–2
–3
–4
–5
–6
G = +10
1
10
FREQUENCY (MHz)
100
300
1
10
FREQUENCY (MHz)
100
Figure 5. Small Signal Frequency Response for Various Gains
Figure 8. Small Signal Frequency Response for Various Capacitor Loads
6.2
2
1
V
= 5V
S
G = +2
= 150Ω
6.1
6.0
5.9
5.8
5.7
5.6
5.5
5.4
R
= 150Ω
L
R
L
0
–1
–2
–3
–4
V
= 5V, V
= 2V p-p
= 1.4V p-p
= 3V, V = 0.5V p-p
OUT
S
OUT
R
= 1kΩ
L
V
= 5V, V
OUT
S
V
S
V
= 5V, V
= 0.1V p-p
OUT
S
V
= 5V
S
G = +1
= 0.1V p-p
–5
–6
V
OUT
100k
1M
10M
FREQUENCY (Hz)
100M
1
10
100
1000
FREQUENCY (MHz)
Figure 6. Small Signal Frequency Response for Various Loads
Figure 9. 0.1 dB Flatness Response
3
2
1
0
V
= 5V
S
G = +1
V
= 0.5V p-p
OUT
V
= 3V
S
1
–1
–2
–3
–4
–5
R
= 150Ω
L
0
–1
–2
–3
–4
–5
–6
R
= 1kΩ
L
V
= 5V
S
G = +1
–6
–7
R
= 150Ω
L
V
= 0.1V p-p
OUT
1
10
100
1000
1
10
100
1000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 10. Large Frequency Response for Various Loads
Figure 7. Small Signal Frequency Response for Various Supplies
Rev. A | Page 6 of 16
ADA4850-1/ADA4850-2
3
2
300
250
200
150
100
50
G = +2
= 5V
V
= 3V
S
+125°C
+85°C
V
G = +1
R
V
S
R
= 1kΩ
= 1kΩ
L
NEGATIVE SLEW RATE
L
= 0.1V p-p
OUT
1
0
POSITIVE SLEW RATE
+25°C
–40°C
–1
–2
–3
–4
–5
0
1
10
100
1000
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
FREQUENCY (MHz)
OUTPUT VOLTAGE STEP (V)
Figure 11. Small Signal Frequency Response for Various Temperatures
Figure 14. Slew Rate vs. Output Voltage
3
10k
1k
V
= 5V
S
G = +1
R
V
2
1
= 1kΩ
L
+125°C
+85°C
= 0.1V p-p
OUT
V
= 3V, 5V, ADA4850-2
S
0
100
10
–1
–2
–3
–4
–5
+25°C
–40°C
V
= 3V, 5V, ADA4850-1 ENABLE
S
V
= 3V, 5V, ADA4850-1 POWER DOWN
S
1
0.1
1
10
100
1000
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
FREQUENCY (MHz)
POWER-DOWN VOLTAGE (V)
Figure 12. Small Signal Frequency Response for Various Temperatures
Figure 15. Supply Current vs. Power-Down Voltage
140
120
100
80
0
–40
–50
–60
–70
–80
–90
–100
G = +2
V
= 5V
S
V
= 5V
S
–30
R
= 150Ω
L
V
= 2V p-p
OUT
–60
PHASE
–90
V
2 TO V
OUT
1
OUT
60
–120
–150
–180
–210
–240
40
GAIN
V
1 TO V 2
OUT
OUT
20
0
–20
10
100
1k
10k
100k
1M
10M
100M
1G
100k
1M
10M
FREQUENCY (Hz)
100M
FREQUENCY (Hz)
Figure 13. Open-Loop Gain and Phase vs. Frequency
Figure 16. Crosstalk vs. Frequency
Rev. A | Page 7 of 16
ADA4850-1/ADA4850-2
–40
2.575
2.550
2.525
2.500
2.475
2.450
2.425
10pF
0pF
G = +1
G = +1
V
V
= 5V
V
= 5V
S
S
–50
–60
= 500mV p-p
R
= 150Ω
OUT
L
R
= 1kΩ HD2
L
–70
R
= 150Ω HD2
L
–80
R
= 1kΩ HD3
L
–90
R
= 150Ω HD3
–100
–110
L
0.1
1
10
100
0
20
40
60
80
100 120 140 160 180 200
TIME (ns)
FREQUENCY (MHz)
Figure 17. Harmonic Distortion vs. Frequency for Various Loads
Figure 20. Small Signal Transient Response for Capacitive Load
–50
3.25
G = +2
G = +2
V
= 5V
R
V
= 1kΩ
S
L
= 5V
R
= 1kΩ
S
L
–60
–70
V
= 500mV p-p
HD2
OUT
3.00
2.75
2.50
2.25
2.00
1.75
V
= 200mV p-p
HD2
OUT
–80
–90
V
= 200mV p-p
OUT
HD3
–100
–110
–120
V
= 500mV p-p
OUT
HD3
0.1
1
10
100
0
50
100
150
200
FREQUENCY (MHz)
TIME (ns)
Figure 18. Harmonic Distortion vs. Frequency for Various VOUT
Figure 21. Large Signal Transient Response
0.65
2.875
2.750
2.625
2.500
2.375
2.250
2.125
0.875
G = +2
G = +1
= 1kΩ
R
= 1kΩ
L
S
R
L
V
= 5V
0.60
0.55
0.50
0.45
0.40
0.35
0.750
0.625
0.500
0.375
0.250
0.125
V
= 5V
S
V
= 3V
S
0
50
100
150
200
0
50
100
150
200
TIME (ns)
TIME (ns)
Figure 19. Small Signal Transient Response for Various Supplies
Figure 22. Large Signal Transient Response for Various Supplies
Rev. A | Page 8 of 16
ADA4850-1/ADA4850-2
6
5
1000
100
10
G = +2
V
= 5V
S
f
= 400kHz
IN
V
4
DISABLE
3
2
1
0
V
OUT
–1
1
10
100
1k
10k
100k
1M
10M
100M
0
15
30
45
TIME (µs)
FREQUENCY (Hz)
Figure 23. Enable/Disable Time
Figure 26. Voltage Noise vs. Frequency
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
100
10
1
G = +1
V
= 5V
S
INPUT
R
= 150Ω
L
f = 1MHz
OUTPUT
–0.5
0
100 200 300 400 500 600 700 800 900 1000
TIME (ns)
10
100
1k
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 24. Input Overdrive Recovery
Figure 27. Current Noise vs. Frequency
3.5
3.0
350
300
250
200
150
100
50
G = +5
V
= 5V
S
V
= 3V
S
N = 1720
x = 450µV
σ = 750µV
R
= 150Ω
L
OUTPUT
f = 1MHz
2.5
2.0
1.5
1.0
0.5
0
5 × INPUT
–0.5
0
–4
0
100 200 300 400 500 600 700 800 900 1000
TIME (ns)
–3
–2
–1
0
1
2
3
4
V
(mV)
OFFSET
Figure 25. Output Overdrive Recovery
Figure 28. Input Offset Voltage Distribution
Rev. A | Page 9 of 16
ADA4850-1/ADA4850-2
400
380
–1.2
–1.4
–1.6
–1.8
–2.0
–2.2
–2.4
+I
B
V
= 5V
S
360
340
320
300
280
260
240
220
200
V
= 5V
S
–I
B
V
= 3V
S
–1.0 –0.5
0
0.5
1.0
V
1.5
(V)
2.0
2.5
3.0
3.5
–40 –25 –10
5
20
35
50
65
80
95 110 125
TEMPERATURE (°C)
CM
Figure 29. Input Offset Voltage vs. Common-Mode Voltage
Figure 32. Input Bias Current vs. Temperature for Various Supplies
0.6
0.5
0.4
0.3
0.2
0.1
0
95
V
R
= 5V
= 1kΩ
S
L
V
= 3V
S
90
85
80
75
70
65
+V
SAT
+V – V
OUT
S
–V
SAT
–V – V
S
OUT
V
= 5V
S
0
5
10
15
20
25
30
35
40
45
50
–40 –25 –10
5
20
35
50
65
80
95 110 125
LOAD CURRENT (mA)
TEMPERATURE (°C)
Figure 30. Output Saturation Voltage vs. Load Current
(Voltage Differential from Rails)
Figure 33. Output Saturation Voltage vs. Temperature
(Voltage Differential from Rails)
–30
–32
–34
–36
–38
–40
–42
–44
–46
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
V
= 3V
S
V
= 5V
S
V
= 3V
S
V
= 5V
S
–40 –25 –10
5
20
35
50
65
C)
80
95 110 125
–40 –25 –10
5
20
35
50
65
80
95 110 125
TEMPERATURE (
°
TEMPERATURE (°C)
Figure 31. Power-Down Bias Current vs. Temperature for Various Supplies
Figure 34. Current vs. Temperature for Various Supplies
Rev. A | Page 10 of 16
ADA4850-1/ADA4850-2
–20
–30
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
V
= 5V
V
= 5V
S
S
–40
–50
+PSR
CHANNEL 1
–60
–70
CHANNEL 2
–PSR
–80
–90
–100
–110
–120
100
1k
10k
100k
1M
10M
100M
1k
10k
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 37. Common-Mode Rejection Ratio (CMRR) vs. Frequency
Figure 35. Power Supply Rejection (PSR) vs. Frequency
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
V
= 5V
S
V
= 3V
S
–0.1
–40 –25 –10
5
20
35
50
65
80
95 110 125
TEMPERATURE (°C)
Figure 36. Input Offset Voltage vs. Temperature for Various Supplies
Rev. A | Page 11 of 16
ADA4850-1/ADA4850-2
CIRCUIT DESCRIPTION
The ADA4850-1/ADA4850-2 feature a high slew rate input
stage that is a true single-supply topology, capable of sensing
signals at or below the negative supply rail. The rail-to-rail
output stage can swing to within 80 mV of either supply rail
when driving light loads and within 0.17 V when driving 150 Ω.
High speed performance is maintained at supply voltages as low
as 2.7 V.
Higher frequency signals require more headroom than the
lower frequencies to maintain distortion performance. Figure 39
illustrates how the rising edge settling time for the amplifier
configured as a unity-gain follower stretches out as the top of a
1 V step input approaches and exceeds the specified input
common-mode voltage limit.
3.6
V
= 5V
S
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
1.8
G = +1
R
HEADROOM AND OVERDRIVE RECOVERY
CONSIDERATIONS
Input
= 1kΩ
L
The ADA4850-1/ADA4850-2 are designed for use in low
voltage systems. To obtain optimum performance, it is useful to
understand the behavior of the amplifier as input and output
signals approach the amplifier’s headroom limits. The input
common-mode voltage range extends 200 mV below the
negative supply voltage or ground for single-supply operation to
within 2.2 V of the positive supply voltage. Therefore, in a gain
of +3, the ADA4850-1/ADA4850-2 can provide full rail-to-rail
output swing for supply voltage as low as 3.3 V, assuming the
input signal swing is from −VS (or ground) to 1.1 V.
V
= 2V TO 3V
STEP
V
= 2.1V TO 3.1V
STEP
V
= 2.2V TO 3.2V
= 2.3V TO 3.3V
STEP
V
STEP
V
= 2.4V TO 3.4V
STEP
0
10
20
30
40
50
60
70
80
90
100
TIME (ns)
Figure 39. Pulse Response, Input Headroom Limits
Exceeding the headroom limit is not a concern for any inverting
gain on any supply voltage, as long as the reference voltage at
the amplifier’s positive input lies within the amplifier’s input
common-mode range.
The recovery time from input voltages 2.2 V or closer to the
positive supply is approximately 50 ns, which is limited by the
settling artifacts caused by transistors in the input stage coming
out of saturation.
The input stage sets the headroom limit for signals when the
amplifier is used in a gain of +1 for signals approaching the
positive rail. For high speed signals, however, there are other
considerations. Figure 38 shows −3 dB bandwidth vs. dc input
voltage for a unity-gain follower. As the common-mode voltage
approaches the positive supply, the bandwidth begins to drop
when within 2 V of +VS. This can manifest itself in increased
distortion or settling time.
The ADA4850-1/ADA4850-2 do not exhibit phase reversal, even
for input voltages beyond the voltage supply rails. Going more than
0.6 V beyond the power supplies turns on protection diodes at the
input stage, which greatly increase the current draw of the devices.
Output
For signals approaching the negative supply and inverting gain,
and high positive gain configurations, the headroom limit is the
output stage. The ADA4850-1/ADA4850-2 amplifiers use a
common-emitter output stage. This output stage maximizes the
available output range, limited by the saturation voltage of the
output transistors. The saturation voltage increases with drive
current, due to the output transistor collector resistance.
2
V
V
V
V
= 3V
CM
CM
CM
CM
1
0
= 3.1V
= 3.2V
= 3.3V
–1
–2
–3
–4
–5
–6
As the saturation point of the output stage is approached, the
output signal shows increasing amounts of compression and
clipping. As in the input headroom case, higher frequency signals
require a bit more headroom than the lower frequency signals.
V
= 5V
S
G = +1
= 1kΩ
R
L
Output overload recovery is typically within 40 ns after the
amplifier’s input is brought to a nonoverloading value.
V
= 0.1V p-p
OUT
0.1
1
10
100
1000
Figure 40 shows the output recovery transients for the amplifier
recovering from a saturated output from the top and bottom
supplies to a point at midsupply.
FREQUENCY (MHz)
Figure 38. Unity-Gain Follower Bandwidth vs.
Frequency for Various Input Common-Mode
Rev. A | Page 12 of 16
ADA4850-1/ADA4850-2
6.5
5.5
OPERATING THE ADA4850-1/ADA4850-2 ON
BIPOLAR SUPPLIES
V
= 5V
S
V
= +2.5V TO 0V
G = –1
R
OUT
= 1kΩ
L
The ADA4850-1/ADA4850-2 can operate on bipolar supplies
up to 5 V. The only restriction is that the voltage between −VS
and the power-down pin must not exceed 6 V. Voltage
differences greater than 6 V can cause permanent damage to the
amplifier. For example, when operating on 5 V supplies, the
power-down pin must not exceed +1 V.
4.5
3.5
INPUT
VOLTAGE
EDGES
2.5
1.5
0.5
POWER-DOWN PINS
V
= –2.5V TO 0V
OUT
–0.5
–1.5
The ADA4850-1/ADA4850-2 feature an ultralow power-down
mode that lowers the supply current to less than 150 nA. When
a power-down pin is brought to within 0.6 V of the negative
supply, the amplifier is powered down. Table 5 outlines the
power-down pin functionality. To ensure proper operation, the
power-down pins (PD) should not be left floating.
0
10
20
30
40
50
TIME (ns)
60
70
80
90
100
Figure 40. Overload Recovery
Table 5. Power-Down Pins Functionality
3 V and 5 V
Supply Voltage
Powered Down
Enabled
ADA4850-1
0 V to 0.7 V
0.8 to +VS
ADA4850-2
0 V to 0.6 V
1.7 V to +VS
Rev. A | Page 13 of 16
ADA4850-1/ADA4850-2
OUTLINE DIMENSIONS
0.50
0.40
0.30
3.00
BSC SQ
0.60 MAX
8
PIN 1
INDICATOR
0.45
1
PIN 1
INDICATOR
1.89
1.74
1.59
2.75
BSC SQ
1.50
REF
TOP
VIEW
EXPOSED
PAD
0.50
BSC
(BOTTOM VIEW)
4
5
0.25
MIN
1.60
1.45
1.30
0.80 MAX
0.65TYP
0.90
0.85
0.80
12° MAX
0.05 MAX
0.02 NOM
SEATING
PLANE
0.30
0.23
0.18
0.20 REF
Figure 41. 8-Lead Lead Frame Chip Scale Package [LFCSP_VD]
3 mm × 3 mm Body, Very Thin, Dual Lead
(CP-8-2)
Dimensions shown in millimeters
0.50
0.40
0.30
3.00
BSC SQ
0.60 MAX
PIN 1
INDICATOR
*
1.65
13
12
16
1
0.45
1.50 SQ
1.35
PIN 1
INDICATOR
2.75
BSC SQ
TOP
VIEW
EXPOSED
PAD
(BOTTOM VIEW)
4
9
8
5
0.50
BSC
0.25 MIN
1.50 REF
0.80 MAX
12° MAX
0.65 TYP
0.90
0.85
0.80
0.05 MAX
0.02 NOM
SEATING
PLANE
0.30
0.23
0.18
0.20 REF
*
COMPLIANT TO JEDEC STANDARDS MO-220-VEED-2
EXCEPT FOR EXPOSED PAD DIMENSION.
Figure 42. 16-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
3 mm × 3 mm Body, Very Thin Quad
(CP-16-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Package Description
Package Outline
CP-8-2
CP-8-2
Branding
HWB
HWB
HWB
HTB
ADA4850-1YCPZ-R21
ADA4850-1YCPZ-RL1
ADA4850-1YCPZ-RL71
ADA4850-2YCPZ-R21
ADA4850-2YCPZ-RL1
ADA4850-2YCPZ-RL71
8-Lead Lead Frame Chip Scale Package (LFCSP_VD)
8-Lead Lead Frame Chip Scale Package (LFCSP_VD)
8-Lead Lead Frame Chip Scale Package (LFCSP_VD)
CP-8-2
16-Lead Lead Frame Chip Scale Package (LFCSP_VQ) CP-16-3
16-Lead Lead Frame Chip Scale Package (LFCSP_VQ) CP-16-3
16-Lead Lead Frame Chip Scale Package (LFCSP_VQ) CP-16-3
HTB
HTB
1 Z = Pb-free part.
Rev. A | Page 14 of 16
ADA4850-1/ADA4850-2
NOTES
Rev. A | Page 15 of 16
ADA4850-1/ADA4850-2
NOTES
©2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05320–0−4/05(A)
Rev. A | Page 16 of 16
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