High Speed, Rail-to-Rail Output Op Amps with Ultralow Power-Down ADA4850-1/ADA4850-2
FEATURES
Ultralow power-down current: 150 nA/amplifier maximum Low quiescent current: 2.4 mA/amplifier High speed 175 MHz, −3 dB bandwidth 220 V/μs slew rate 85 ns settling time to 0.1% Excellent video specifications 0.1 dB flatness: 14 MHz 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
PIN CONFIGURATIONS
POWER DOWN 1 NC 2 –IN 3 +IN 4
ADA4850-1
8 +VS 7 OUTPUT 6 NC 5 –VS
05320-106
NC = NO CONNECT
Figure 1. 8-Lead, 3 mm × 3 mm LFCSP
16 NC 15 NC 14 PD1 13 PD2
ADA4850-2
VOUT1 1 –IN1 2 +IN1 3 –VS 4 12 +VS 11 VOUT2 10 –IN2 9 +IN2
APPLICATIONS
Portable multimedia players Video cameras Digital still cameras Consumer video Clock buffers
NC 5
NC 7
NC 6
NC 8
NC = NO CONNECT
Figure 2. 16-Lead, 3 mm × 3 mm LFCSP
GENERAL DESCRIPTION
The ADA4850-1/ADA4850-21 are low price, high speed, voltage feedbacks rail-to-rail output op amps with ultralow powerdown. 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 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. 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. With its combination of low price, excellent differential gain (0.12%), differential phase (0.09°), and 0.1 dB flatness out to 14 MHz, these amplifiers are ideal for video applications. The ADA4850-1/ADA4850-2 are designed to work in the extended temperature range of −40°C to +125°C.
1
2 1
CLOSED-LOOP GAIN (dB)
0 –1 –2 –3 –4 –5 –6 1 10 100 1000 FREQUENCY (MHz) G = +1 VS = 5V RL = 1kΩ VOUT = 0.1V p-p
05320-054
Figure 3. Small Signal Frequency Response
Patents pending.
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2005–2007 Analog Devices, Inc. All rights reserved.
05320-043
ADA4850-1/ADA4850-2 TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 Pin Configurations ........................................................................... 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Specifications with +3 V Supply................................................. 3 Specifications with +5 V Supply................................................. 4 Absolute Maximum Ratings............................................................ 5 Thermal Resistance ...................................................................... 5 ESD Caution...................................................................................5 Typical Performance Characteristics ..............................................6 Circuit Description......................................................................... 12 Headroom and Overdrive Recovery Considerations ............ 12 Operating the ADA4850-1/ADA4850-2 on Bipolar Supplies........................................................................................ 13 Power-Down Pins....................................................................... 13 Outline Dimensions ....................................................................... 14 Ordering Guide .......................................................................... 14
REVISION HISTORY
12/07—Rev. A to Rev. B Changes to Applications .................................................................. 1 Updated Outline Dimensions ....................................................... 14 Changes to Ordering Guide .......................................................... 14 4/05—Rev. 0 to Rev. A Added ADA4850-1.............................................................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. B | Page 2 of 16
ADA4850-1/ADA4850-2 SPECIFICATIONS
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 DYNAMIC PERFORMANCE −3 dB Bandwidth Bandwidth for 0.1 dB Flatness Slew Rate Settling Time to 0.1% NOISE/DISTORTION PERFORMANCE Harmonic Distortion (dBc) HD2/HD3 Input Voltage Noise Input Current Noise Differential Gain Differential Phase DC PERFORMANCE Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Bias Current Drift Input Bias Offset Current Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range Input Overdrive Recovery Time (Rise/Fall) Common-Mode Rejection Ratio POWER-DOWN Power-Down Input Voltage Turn-Off Time Turn-On Time Power-Down Bias Current/ Power Down Pin Enabled Power-Down OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range 1 Quiescent Current/Amplifier Quiescent Current (Power-Down)/Amplifier Positive Power Supply Rejection Negative Power Supply Rejection
1
Conditions G = +1, VO = 0.1 V p-p 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 G = +2, VO = 1 V step, RL = 150 Ω fC = 1 MHz, VO = 2 V p-p, G = +3, RL = 150 Ω f = 100 kHz f = 100 kHz G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p
Min
Typ 160 45 14 110 80 −72/−77 10 2.5 0.2 0.2 0.6 4 2.4 4 30 100 0.5/5.0 1.2 −0.2 to +0.8 60/50 −108 1.7 0.7 60 37 0.01 70/100 0.03 to 2.92 105/74
Max
Unit MHz MHz MHz V/μs ns dBc nV/√Hz pA/√Hz % Degrees
4.1 4.4
VO = 0.25 V to 0.75 V Differential/common-mode
78
mV μV/°C μA nA/°C nA dB MΩ pF V ns dB V V μs ns
VIN = +3.5 V to −0.5 V, G = +1 VCM = 0.5 V Power-down ADA4850-1/ADA4850-2 Enabled ADA4850-1/ADA4850-2
−76
Power-down = 3 V Power-down = 0 V VIN = +0.7 V to −0.1 V, G = +5 0.06 to 2.83 Sinking/sourcing 2.7
55 0.2
μA μA ns V mA
+VS = +3 V to +4 V, −VS = 0 V +VS = +3 V, −VS = 0 V to –1 V
−83 −83
2.4 15 −100 −102
6 2.8 150
V mA nA dB dB
For operation on bipolar supplies, see the Operating the ADA4850-1/ADA4850-2 on Bipolar Supplies section.
Rev. B | 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 DYNAMIC PERFORMANCE −3 dB Bandwidth Bandwidth for 0.1 dB Flatness Slew Rate Settling Time to 0.1% NOISE/DISTORTION PERFORMANCE Harmonic Distortion (dBc) HD2/HD3 Input Voltage Noise Input Current Noise Differential Gain Differential Phase Crosstalk (RTI)–ADA4850-2 DC PERFORMANCE Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Bias Current Drift Input Bias Offset Current Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range Input Overdrive Recovery Time (Rise/Fall) Common-Mode Rejection Ratio POWER-DOWN Power-Down Input Voltage Turn-Off Time Turn-On Time Power-Down Bias Current/Power Down Pin Enabled Power-Down OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range 1 Quiescent Current/Amplifier Quiescent Current (Power-Down)/Amplifier Positive Power Supply Rejection Negative Power Supply Rejection
1
Conditions 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 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 f = 100 kHz G = +3, NTSC, RL = 150 Ω G = +3, NTSC, RL = 150 Ω f = 4.5 MHz, RL = 150 Ω, VO = 2 V p-p
Min
Typ 175 110 9 220 160 85 −81/−86 10 2.5 0.12 0.09 60 0.6 4 2.3 4 30 105 0.5/5.0 1.2 −0.2 to +2.8 50/40 −110 1.7 0.7 50 0.05 0.02 60/70 0.07 to 4.92 118/94
Max
Unit MHz MHz MHz V/μs V/μs ns dBc nV/√Hz pA/√Hz % Degrees dB
4.2 4.2
VO = 2.25 V to 2.75 V Differential/common-mode
83
mV μV/°C μA nA/°C nA dB MΩ pF V ns dB V V μs ns
VIN = +5.5 V to −0.5 V, G = +1 VCM = 2.0 V Power-down ADA4850-1/ADA4850-2 Enabled ADA4850-1/ADA4850-2
−85
Power-down = 5 V Power-down = 0 V VIN = +1.1 V to −0.1 V, G = +5 0.14 to 4.83 Sinking/sourcing 2.7
0.13 0.2
mA μA ns V mA
+VS = +5 V to +6 V, −VS = 0 V +VS = +5 V, −VS = −0 V to −1 V
−84 −84
2.5 15 −100 −102
6 2.9 150
V mA nA dB dB
For operation on bipolar supplies, see the Operating the ADA4850-1/ADA4850-2 on Bipolar Supplies section.
Rev. B | Page 4 of 16
ADA4850-1/ADA4850-2 ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Supply Voltage Power Dissipation Power Down Pin Voltage Common-Mode Input Voltage Differential Input Voltage Storage Temperature Operating Temperature Range Lead Temperature Range (Soldering 10 sec) Junction Temperature Rating 12.6 V 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 150°C
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). PD = Quiescent Power + (Total Drive Power − Load Power)
⎛V V PD = (VS × I S ) + ⎜ S × OUT ⎜2 RL ⎝
⎞ VOUT 2 ⎟− ⎟ RL ⎠
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.
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.
PD = (VS × I S ) +
(VS /4)2
RL
In single-supply operation with RL referenced to −VS, the worst case is VOUT = VS/2. 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. 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.
2.5
THERMAL RESISTANCE
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.
Package Type 16-Lead LFCSP 8-Lead LFCSP θJA 91 80 Unit °C/W °C/W
MAXIMUM POWER DISSIPATION (W)
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
–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
Rev. B | Page 5 of 16
05320-055
0
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
NORMALIZED CLOSED-LOOP GAIN (dB)
4
VS = 5V RL = 150Ω VOUT = 0.1V p-p
CLOSED-LOOP GAIN (dB)
3 2 1 0 –1 –2 –3 –4
0
G = +1 VS = 5V RL = 1kΩ VOUT = 0.1V p-p
6pF
–1 –2 G = +2
G = –1
1pF 0pF
–3 G = +10 –4 –5
–5
05320-007
–6
1 10 FREQUENCY (MHz) 100
05320-044
–6
1
10 FREQUENCY (MHz)
100
300
Figure 5. Small Signal Frequency Response for Various Gains
2 1
CLOSED-LOOP GAIN (dB)
Figure 8. Small Signal Frequency Response for Various Capacitor Loads
6.2
RL = 150Ω
6.1 6.0 5.9
GAIN (dB)
VS = 5V G = +2 RL = 150Ω
0 –1 –2 –3 –4 –5 –6 1 10 100 1000 FREQUENCY (MHz) VS = 5V G = +1 VOUT = 0.1V p-p
05320-045
RL = 1kΩ
5.8 5.7 5.6 5.5 5.4 100k
VS = 5V, VOUT = 2V p-p VS = 5V, VOUT = 1.4V p-p VS = 3V, VOUT = 0.5V p-p VS = 5V, VOUT = 0.1V p-p
1M
10M FREQUENCY (Hz)
100M
Figure 6. Small Signal Frequency Response for Various Loads
3 2 VS = 3V
CLOSED-LOOP GAIN (dB) CLOSED-LOOP GAIN (dB)
1 0 –1 –2 –3 –4 –5 –6 –7
05320-046
Figure 9. 0.1 dB Flatness Response
VS = 5V G = +1 VOUT = 0.5V p-p RL = 150Ω
1 0 –1 VS = 5V –2 –3 –4 –5 –6 1 10 100 1000 FREQUENCY (MHz) G = +1 RL = 150Ω VOUT = 0.1V p-p
RL = 1kΩ
1
10
100
1000
FREQUENCY (MHz)
Figure 7. Small Signal Frequency Response for Various Supplies
Figure 10. Large Frequency Response for Various Loads
Rev. B | Page 6 of 16
05320-048
05320-047
ADA4850-1/ADA4850-2
3 2
CLOSED-LOOP GAIN (dB)
300 VS = 3V G = +1 RL = 1kΩ VOUT = 0.1V p-p +125°C +85°C 250
G = +2 VS = 5V RL = 1kΩ
NEGATIVE SLEW RATE
1
SLEW RATE (V/μs)
0 –1 –2 –3 –4 –5 1 10 100 1000 FREQUENCY (MHz) +25°C –40°C
200 POSITIVE SLEW RATE 150
100
50
05320-057
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
OUTPUT VOLTAGE STEP (V)
Figure 11. Small Signal Frequency Response for Various Temperatures
Figure 14. Slew Rate vs. Output Voltage
3 2
CLOSED-LOOP GAIN (dB)
10k
VS = 5V G = +1 RL = 1kΩ VOUT = 0.1V p-p
+125°C +85°C
1k
SUPPLY CURRENT (μA)
1 0 –1 +25°C –2 –3 –40°C
VS = 3V, 5V, ADA4850-2 100
10
VS = 3V, 5V, ADA4850-1 ENABLE
VS = 3V, 5V, ADA4850-1 POWER DOWN 1
–4 –5 1 10 100 1000 FREQUENCY (MHz)
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
POWER-DOWN VOLTAGE (V)
Figure 12. Small Signal Frequency Response for Various Temperatures
140 VS = 5V 120 100 80 60 40 GAIN 20 0 –20 10 –180 –210 –240 1G PHASE –30 0
Figure 15. Supply Current vs. Power-Down Voltage
–40 G = +2 VS = 5V RL = 150Ω VOUT = 2V p-p
–50
OPEN-LOOP GAIN (dB)
–60 –90 –120 –150
OPEN-LOOP PHASE (Degrees)
CROSSTALK (dB)
–60 VOUT2 TO VOUT1 –70
–80 VOUT1 TO VOUT2 –90
100
1k
10k
100k
1M
10M
100M
05320-012
1M
10M FREQUENCY (Hz)
100M
FREQUENCY (Hz)
Figure 13. Open-Loop Gain and Phase vs. Frequency
Figure 16. Crosstalk vs. Frequency
Rev. B | Page 7 of 16
05320-037
–100 100k
05320-036
05320-098
0.1
05320-024
0
ADA4850-1/ADA4850-2
–40 –50
HARMONIC DISTORTION (dBc)
2.575
G = +1 VS = 5V VOUT = 500mV p-p
OUTPUT VOLTAGE (V)
2.550
G = +1 VS = 5V RL = 150Ω
10pF 0pF
–60 RL = 1kΩ HD2 RL = 150Ω HD2 RL = 1kΩ HD3 RL = 150Ω HD3
2.525
–70
2.500
–80
2.475
–90 –100 –110 0.1
2.450
05320-102
1
10 FREQUENCY (MHz)
100
0
20
40
60
80
100
120
140
160
180
200
TIME (ns)
Figure 17. Harmonic Distortion vs. Frequency for Various Loads
–50
Figure 20. Small Signal Transient Response for Capacitive Load
3.25
HARMONIC DISTORTION (dBc)
VOUT = 500mV p-p HD2
OUTPUT VOLTAGE FOR 5V SUPPLY (V)
G = +2 VS = 5V –60 RL = 1kΩ
3.00
G = +2 RL = 1kΩ VS = 5V
–70 VOUT = 200mV p-p HD2 VOUT = 200mV p-p HD3
2.75
–80
2.50
–90
2.25
–100 –110 –120 0.1 VOUT = 500mV p-p HD3
2.00
05320-103
1
10 FREQUENCY (MHz)
100
0
50
100 TIME (ns)
150
200
Figure 18. Harmonic Distortion vs. Frequency for Various VOUT
0.65
OUTPUT VOLTAGE FOR 5V SUPPLY (V)
Figure 21. Large Signal Transient Response
2.875 G = +1 RL = 1kΩ 2.750 0.750 0.875
0.60
0.55
2.625
0.625
0.50
2.500
0.500
0.45
2.375
VS = 5V
0.375
0.40
2.250 VS = 3V
0.250
05320-019
0
50
100 TIME (ns)
150
200
0
50
100 TIME (ns)
150
Figure 19. Small Signal Transient Response for Various Supplies
Figure 22. Large Signal Transient Response for Various Supplies
Rev. B | Page 8 of 16
05320-049
0.35
2.125
0.125 200
OUTPUT VOLTAGE FOR 3V SUPPLY (V)
G = +2 RL = 1kΩ VS = 5V
OUTPUT VOLTAGE (V)
05320-050
1.75
05320-020
2.425
ADA4850-1/ADA4850-2
6 5 4
VOLTAGE (V)
G = +2 VS = 5V fIN = 400kHz
VOLTAGE NOISE (nV/ Hz)
1000
VDISABLE
100
3 2
10
1 0 VOUT
05320-025
0
15 TIME (μs)
30
45
100
1k
10k
100k
1M
10M
100M
FREQUENCY (Hz)
Figure 23. Enable/Disable Time
5.5 5.0
INPUT AND OUTPUT VOLTAGE (V)
Figure 26. Voltage Noise vs. Frequency
100
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 OUTPUT
INPUT
G = +1 VS = 5V RL = 150Ω f = 1MHz
CURRENT NOISE (pA/ Hz)
10
05320-058
0
100
200
300
400
500
600
700
800
900
1000
100
1k
10k
100k
1M
10M
100M
1G
TIME (ns)
FREQUENCY (Hz)
Figure 24. Input Overdrive Recovery
3.5 3.0
INPUT AND OUTPUT VOLTAGE (V)
Figure 27. Current Noise vs. Frequency
350
OUTPUT 2.5 2.0 5 × INPUT 1.5 1.0
G = +5 VS = 3V RL = 150Ω f = 1MHz
300 250
VS = 5V N = 1720 x = 450μV σ = 750μV
COUNT
200
150
100
0.5
50
0
0
100
200
300
400
500
600
700
800
900
1000
05320-060
–3
–2
–1
0
1
2
3
4
TIME (ns)
VOFFSET (mV)
Figure 25. Output Overdrive Recovery
Figure 28. Input Offset Voltage Distribution
Rev. B | Page 9 of 16
05320-065
–0.5
0 –4
05320-095
–0.5
1 10
05320-059
–1
1 10
ADA4850-1/ADA4850-2
400 380 VS = 5V 360 340
VOS (μV)
–1.2 +IB –1.4
INPUT BIAS CURRENT (μA)
–1.6 VS = 5V –1.8 –IB VS = 3V –2.0
320 300 280 260 240 220 –0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
05320-063
–2.2
05320-092
200 –1.0
–2.4 –40
–25
–10
5
20
35
50
65
80
95
110
125
VCM (V)
TEMPERATURE (°C)
Figure 29. Input Offset Voltage vs. Common-Mode Voltage
0.6
Figure 32. Input Bias Current vs. Temperature for Various Supplies
95
0.5
VS = 3V +VSAT
OUTPUT SATURATION VOLTAGE (mV)
VS = 5V RL = 1kΩ 90
OUTPUT SATURATION VOLTAGE (V)
0.4
85
+VS – VOUT
0.3 –VSAT 0.2 VS = 5V
80 –VS – VOUT 75
0.1
70
05320-064
0
5
10
15
20
25
30
35
40
45
50
–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)
–30
Figure 33. Output Saturation Voltage vs. Temperature (Voltage Differential from Rails)
4.9
POWER-DOWN PIN BIAS CURRENT (μA)
–32 –34 –36 –38 –40 –42
VS = 3V
4.8 VS = 5V
SUPPLY CURRENT (mA)
4.7 4.6 VS = 3V 4.5 4.4 4.3 4.2 –40
VS = 5V
05320-091
–46 –40
–25
–10
5
20
35
50
65
80
95
110
125
–25
–10
5
20
35
50
65
80
95
110
125
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 31. Power-Down Bias Current vs. Temperature for Various Supplies
Figure 34. Current vs. Temperature for Various Supplies
Rev. B | Page 10 of 16
05320-090
–44
05320-062
0
65 –40
ADA4850-1/ADA4850-2
0 –10 VS = 5V –30 –20 VS = 5V
POWER SUPPLY REJECTION (dB)
–20 –30 +PSR –40 –50 –60 –70 –80 –90 –100 1k 10k 100k 1M 10M 100M
05320-094
COMMON-MODE REJECTION (dB)
–40 –50 –60 –70 –80 –90 –100 –110 10k 100k 1M 10M 100M
05320-034
CHANNEL 1
CHANNEL 2
–PSR
–110 100
–120 1k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 35. Power Supply Rejection (PSR) vs. Frequency
0.7 0.6
Figure 37. Common-Mode Rejection (CMR) vs. Frequency
INPUT OFFSET VOLTAGE (mV)
0.5 VS = 5V 0.4 0.3 VS = 3V 0.2 0.1
05320-093
0 –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. B | 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 3.4 3.2 VS = 5V G = +1 RL = 1kΩ
HEADROOM AND OVERDRIVE RECOVERY CONSIDERATIONS
OUTPUT VOLTAGE (V)
Input
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 railto-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. 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 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.
2 VCM = 3V 1 0 –1 VCM = 3.1V VCM = 3.2V VCM = 3.3V
3.0 2.8 2.6 2.4 2.2 2.0
05320-061
VSTEP = 2V TO 3V VSTEP = 2.1V TO 3.1V VSTEP = 2.2V TO 3.2V VSTEP = 2.3V TO 3.3V VSTEP = 2.4V TO 3.4V
1.8 0 10 20 30 40 50 TIME (ns) 60 70 80 90 100
Figure 39. Pulse Response, Input Headroom Limits
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 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. 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.
GAIN (dB)
–2 –3 –4 –5 –6 0.1 VS = 5V G = +1 RL = 1kΩ VOUT = 0.1V p-p 1 10 FREQUENCY (MHz) 100 1000
05320-096
Output overload recovery is typically within 40 ns after the amplifier’s input is brought to a nonoverloading value.
Figure 38. Unity-Gain Follower Bandwidth vs. Frequency for Various Input Common-Mode
Rev. B | Page 12 of 16
ADA4850-1/ADA4850-2
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.
6.5 5.5 VOUT = +2.5V TO 0V VS = 5V G = –1 RL = 1kΩ
OPERATING THE ADA4850-1/ADA4850-2 ON BIPOLAR SUPPLIES
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.
INPUT AND OUTPUT VOLTAGE (V)
4.5 3.5 INPUT 2.5 VOLTAGE EDGES 1.5 0.5 –0.5 –1.5 0 10 20 30 40 50 TIME (ns) 60 70 80 90 100 VOUT = –2.5V TO 0V
POWER-DOWN PINS
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 pins functionality. To ensure proper operation, the power-down pins (PD1, PD2) should not be left floating. Table 5. Power-Down Pins Functionality
Supply Voltage Power Down Enabled 3 V and 5 V 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
Figure 40. Overload Recovery
Rev. B | Page 13 of 16
05320-042
ADA4850-1/ADA4850-2 OUTLINE DIMENSIONS
3.25 3.00 SQ 2.75 0.60 MAX 0.60 MAX
5 8
0.50 BSC
PIN 1 INDICATOR
TOP VIEW
2.95 2.75 SQ 2.55
EXPOSED PAD
(BOT TOM VIEW)
1.60 1.45 1.30 PIN 1 INDICATOR
4
1
12° MAX 0.90 MAX 0.85 NOM SEATING PLANE
0.70 MAX 0.65 TYP
0.50 0.40 0.30 0.05 MAX 0.01 NOM
1.89 1.74 1.59
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 0.45 PIN 1 INDICATOR TOP VIEW 2.75 BSC SQ 0.50 BSC 12° MAX 0.90 0.85 0.80 SEATING PLANE 0.30 0.23 0.18 0.80 MAX 0.65 TYP 0.05 MAX 0.02 NOM 0.20 REF
0.60 MAX
PIN 1 INDICATOR
*1.65 1.50 SQ 1.35
13 12
16
1
EXPOSED PAD
9 (BOTTOM VIEW) 4 8 5
0.25 MIN
1.50 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 ADA4850-1YCPZ-R2 1 ADA4850-1YCPZ-RL1 ADA4850-1YCPZ-RL71 ADA4850-2YCPZ-R21 ADA4850-2YCPZ-RL1 ADA4850-2YCPZ-RL71
1
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 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) 16-Lead Lead Frame Chip Scale Package (LFCSP_VQ) 16-Lead Lead Frame Chip Scale Package (LFCSP_VQ) 16-Lead Lead Frame Chip Scale Package (LFCSP_VQ)
Package Option CP-8-2 CP-8-2 CP-8-2 CP-16-3 CP-16-3 CP-16-3
061507-B
0.30 0.23 0.18
0.20 REF
Branding HWB HWB HWB HTB HTB HTB
Z = RoHS Compliant Part.
Rev. B | Page 14 of 16
ADA4850-1/ADA4850-2 NOTES
Rev. B | Page 15 of 16
ADA4850-1/ADA4850-2 NOTES
©2005–2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05320-0-12/07(B)
Rev. B | Page 16 of 16
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