Datasheet ADA4850-2 Datasheet (Analog Devices)

V

High Speed, Rail-to-Rail Output,

FEATURES

Ultralow power-down current: 0.3 µA/amp max Low quiescent current: 2.4 mA/amp 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

APPLICATIONS

Portable multimedia players Video cameras Digital still cameras Consumer video

Op Amp with Ultralow Power Down

ADA4850-2

PIN CONFIGURATION

2 C N

6

1

ADA4850-2

1

OUT

2–IN1

3+IN1

4–V

S

5 C

N

NC = NO CONNECT

Figure 1. 16-Lead, 3 mm × 3 mm LFCSP

1 C N

5

1

6 C

N

D

P

4

3

1

12 +V

S

11 V

2

OUT

10 –IN2

9 +IN2

8

7

C

N

05320-043

GENERAL DESCRIPTION

The ADA4850-21 (dual) is a low price, high speed, voltage feedback rail-to-rail output op amp with ultralow power-down. Despite its low price, the ADA4850-2 provides excellent overall performance and versatility. The 175 MHz −3 dB bandwidth and 220 V/µs slew rate make this amplifier well-suited for many general-purpose, high speed applications.

The ADA4850-2 is designed to operate at supply voltages as low as 2.7 V and up to 6 V using only 2.4 mA of supply current per amplifier. To further reduce power consumption, the amplifier is equipped with a power-down mode, which lowers the supply current to less than 0.1 µA, making it ideal in 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. On the output, the amplifier can swing within 80 mV of either supply rail.

With its combination of low price, excellent differential gain (0.12%), differential phase (0.09º), and 0.1 dB flatness out to 14 MHz, this amplifier is ideal for video applications.

Rev. 0

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 Anal og Devices. Trademarks and registered trademarks are the property of their respective owners.

The ADA4850-2 is available in a 16-lead, 3 mm × 3 mm LFCSP and is designed to work in the extended temperature range (−40°C to +125°C).

4

G = +1 V

= 5V

3

S

= 1kΩ

R

L

= 5pF

C

2

L

1

0

–1

–2

–3

CLOSED-LOOP GAIN (dB)

–4

–5

–6

1 10010 1k

FREQUENCY (MHz)

1

Patent pending.

Figure 2. Small Signal Frequency Respon se

www.analog.com

05320-054

ADA4850-2

REVISION HISTORY

2/05—Revision 0: Initial Version

Headroom and Overdrive Recovery Considerations ............ 12

Operating the ADA4850-2 on Bipolar Supplies..................... 13

Power-Down Pin ........................................................................ 13

Outline Dimensions....................................................................... 14

Ordering Guide .......................................................................... 14

Rev. 0 | Page 2 of 16

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 MHz G = +2, VO = 0.5 V p-p, RL = 150 Ω 45 MHz Bandwidth for 0.1 dB Flatness G = +2, VO = 0.5 V p-p, RL = 150 Ω 14 MHz Slew Rate G = +2, VO = 1 V Step 110 V/µs

NOISE/DISTORTION PERFORMANCE

Input Voltage Noise f = 100 kHz 10 Input Current Noise f = 100 kHz 2.5 Differential Gain G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p 0.2 % Differential Phase G = +3, NTSC, RL = 150 Ω, VO = 2 V p-p 0.2 Degrees

DC PERFORMANCE

Input Offset Voltage 0.6 4.1 mV Input Offset Voltage Drift 4

Input Bias Current 2.4 4.4 µA Input Bias Current Drift 4

Input Bias Offset Current 30 nA Open-Loop Gain VO = 0.25 V to 0.75 V 78 102 dB

INPUT CHARACTERISTICS

Input Resistance Differential/common-mode 0.5/5.0 MΩ Input Capacitance 1.2 pF Input Common-Mode Voltage Range −0.2 to +0.8 V Input Overdrive Recovery Time (Rise/Fall) VIN = +3.5 V to −0.5 V, G = +1 60/50 ns Common-Mode Rejection Ratio VCM = 0.5 V −76 −108 dB

POWER-DOWN

Power-Down Input Voltage Power-down <0.6 V Enabled >1.7 V Turn-Off Time 0.7 µs Turn-On Time 60 ns Power-Down Bias Current

Enabled Power-down = 3 V 37 47 µA Power-Down Power-down = 0 V 0.01 0.16 µA

OUTPUT CHARACTERISTICS

Output Overdrive Recovery Time (Rise/Fall) VIN = +0.7 V to −0.1 V, G = +5 70/100 ns Output Voltage Swing 0.06 to 2.83 0.03 to 2.92 V Short-Circuit Current Sinking/sourcing 105/74 mA

POWER SUPPLY

Operating Range

1

2.7 6 V Quiescent Current Both amplifiers enabled 4.7 5.4 mA Quiescent Current (Power-Down) Power-down = low <0.1 0.3 µA Positive Power Supply Rejection +VS = +3 V to +4 V, −VS = 0 V −83 −100 dB Negative Power Supply Rejection +VS = +3 V, −VS = 0 V to –1 V −83 −102 dB

1

For operation on bipolar supplies, see the section. Operating the ADA4850-2 on Bipolar Supplies

nV/√Hz pA/√Hz

µV/°C

nA/°C

Rev. 0 | Page 3 of 16

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 175 MHz G = +1, VO = 0.5 V p-p 110 MHz Bandwidth for 0.1 dB Flatness G = +2, VO = 1.4 V p-p, RL = 150 Ω 9 MHz Slew Rate G = +2, VO = 4 V Step 220 V/µs G = +2, VO = 2 V Step 160 V/µs Settling Time to 0.1% G = +2, VO = 1 V Step, RL = 150 Ω 85 ns

NOISE/DISTORTION PERFORMANCE

Input Voltage Noise f = 100 kHz 10 Input Current Noise f = 100 kHz 2.5 Differential Gain G = +3, NTSC, RL = 150 Ω 0.12 % Differential Phase G = +3, NTSC, RL = 150 Ω 0.09 Degrees

DC PERFORMANCE

Input Offset Voltage 0.6 4.2 mV Input Offset Voltage Drift 4

Input Bias Current 2.3 4.2 µA Input Bias Current Drift 4

Input Bias Offset Current 30 nA Open-Loop Gain VO = 2.25 V to 2.75 V 83 108 dB

INPUT CHARACTERISTICS

Input Resistance Differential/common-mode 0.5/5.0 MΩ Input Capacitance 1.2 pF Input Common-Mode Voltage Range −0.2 to +2.8 V Input Overdrive Recovery Time (Rise/Fall) VIN = +5.5 V to −0.5 V, G = +1 50/40 ns Common-Mode Rejection Ratio VCM = 2.0 V −85 −110 dB

POWER-DOWN

Power-Down Input Voltage Power-down <0.6 V Enabled >1.7 V Turn-Off Time 0.7 µs Turn-On Time 50 ns Power-Down Bias Current

Enabled Power-down = 5 V 52 71 µA Power-Down Power-down = 0 V 0.02 0.17 µA

OUTPUT CHARACTERISTICS

Output Overdrive Recovery Time (Rise/Fall) VIN = +1.1 V to −0.1 V, G = +5 60/70 ns Output Voltage Swing 0.14 to 4.83 0.07 to 4.92 V Short-Circuit Current Sinking/sourcing 118/94 mA

POWER SUPPLY

Operating Range

1

2.7 6 V Quiescent Current Both amplifiers enabled 4.9 5.6 mA Quiescent Current (Power-Down) Power-down = low <0.1 0.3 µA Positive Power Supply Rejection +VS = +5 V to +6 V, −VS = 0 V −84 −98 dB Negative Power Supply Rejection +VS = +5 V, −VS = −0 V to −1 V −84 −102 dB

1

For operation on bipolar supplies, see the section. Operating the ADA4850-2 on Bipolar Supplies

nV/√Hz pA/√Hz

µV/°C

nA/°C

Rev. 0 | Page 4 of 16

ADA4850-2

(

)

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 12.6 V Power Dissipation See Figure 3 Power Down Pin Voltage (−VS + 6) V Common-Mode Input Voltage (−VS − 0.5 ) V to (+VS + 0.5) V Differential Input Voltage +VS to −V

S

Storage Temperature −65°C to +125°C Operating Temperature Range −40°C to +125°C Lead Temperature Range

300°C

(Soldering 10 sec)

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.

The power dissipated in the package (P quiescent power dissipation and the power dissipated in the die due to the ADA4850-2 drive at the output. The quiescent power is the voltage between the supply pins (V current (I

).

S

= Quiescent Power + (Tot a l Dr i ve Po w e r − Load Power)

P

D

VV

⎛

S

()

D

IVP

SS

⎜ ⎝

OUT

×+×=

R

2

L

RMS output voltages should be considered. If RL is referenced

, as in single-supply operation, the total drive power is

to −V

S

× I

V

the worst case, when V

. If the rms signal levels are indeterminate, consider

S

OUT

= VS/4 for RL to midsupply.

OUT

2

4/

V

()

D

S

+×=

IVP

SS

R

L

In single-supply operation with R case is V

= VS/2.

OUT

) is the sum of the

D

) times the quiescent

S

2

V

⎞

OUT

–

⎟ ⎠

referenced to −VS, the worst

L

R

L

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, θJA is specified for the device soldered in the circuit board for surfacemount packages.

Table 4. Thermal Resistance

Package Type θ

JA

LFCSP 91 °C/W

Maximum Power Dissipation

Unit

Airflow increases heat dissipation, effectively reducing θ Also, 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 LFCSP (91°C/W) package on a JEDEC standard 4-layer board. θ approximations.

2.5

The maximum safe power dissipation for the ADA4850-2 is limited by the associated rise in junction temperature (T

) on

J

2.0

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 ADA4850-2. Exceeding a

1.5 LFCSP

1.0

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.

0.5

MAXIMUM POWER DISSIPATION (W)

0

–40

–30 –20 –10 0 10 20 40 8030 50 60 70 10090 120110

AMBIENT TEMPERATURE (°C)

Figure 3. 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.

values are

JA

.

JA

05320-055

Rev. 0 | Page 5 of 16

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

0

–1

–2

–3

–4

–5

NORMALIZED CLOSED-LOOP GAIN (dB)

–6

1 10 100

G = +10

FREQUENCY (MHz)

G = +2

VS = 5V R

= 150Ω

L

V

OUT

Figure 4. Small Signal Frequency Response for Various Gains

2

1

0

RL = 150Ω

= 0.1V p-p

G = –1

05320-044

4

G = +1 V

= 5V

3

S

= 1kΩ

R

L

V

2

OUT

1

0

–1

–2

–3

CLOSED-LOOP GAIN (dB)

–4

–5

–6

1 10010 300

Figure 7. Small Signal Frequency Response for Various Capacitor Loads

6.2

6.1

6.0

= 0.1V p-p

FREQUENCY (MHz)

0pF

1pF

6pF

VS = 5V G = +2 R

= 150Ω

L

05320-007

–1

–2

–3

CLOSED-LOOP GAIN (dB)

–4

VS = 5V G = +1

–5

V

= 0.1V p-p

OUT

–6

1 10010 1k

RL = 1kΩ

FREQUENCY (MHz)

Figure 5. Small Signal Frequency Response for Various Loads

3

2

1

0

–1

–2

–3

CLOSED-LOOP GAIN (dB)

–4

G = +1 R

= 150Ω

–5

L

V

= 0.1V p-p

OUT

–6

1 10010 1k

FREQUENCY (MHz)

VS = 5V

= 3V

V

S

Figure 6. Small Signal Frequency Response for Various Supplies

05320-045

05320-046

5.9

5.8

GAIN (dB)

5.7

5.6

5.5

5.4

VS = 5V, V

100k 100M

= 5V, V

V

S

OUT

VS = 3V, V

= 2V p-p

= 1.4V p-p

OUT

= 0.5V p-p

OUT

VS = 5V, V

1M 10M

= 0.1V p-p

OUT

FREQUENCY (Hz)

Figure 8. 0.1 dB Flatness Response

1

0

–1

–2

–3

–4

CLOSED-LOOP GAIN (dB)

–5

–6

–7

1 10010 1k

= 150Ω

R

L

R

= 1kΩ

L

FREQUENCY (MHz)

VS = 5V G = +1 V

OUT

= 0.5V p-p

Figure 9. Large Frequency Response for Various Loads

05320-047

05320-048

Rev. 0 | Page 6 of 16

ADA4850-2

3

VS = 3V G = +1

2

= 1kΩ

R

L

= 0.1V p-p

V

OUT

1

0

–1

–2

CLOSED-LOOP GAIN (dB)

–3

–4

+125°C

+85°C

+25°C

–40°C

300

G = +2 V

= 5V

S

= 1kΩ

R

L

250

200

150

100

SLEW RATE (V/µs)

50

NEGATIVE SLEW RATE

POSITIVE SLEW RATE

–5

1 1000

10 100

FREQUENCY (MHz)

Figure 10. Small Signal Frequency Response for Various Temperatures

3

VS = 5V G = +1

2

R

= 1kΩ

L

V

= 0.1V p-p

OUT

1

0

–1

–2

CLOSED-LOOP GAIN (dB)

–3

–4

–5

1 1000

+25°C

–40°C

10 100

FREQUENCY (MHz)

+125°C

+85°C

Figure 11. Small Signal Frequency Response for Various Temperatures

140

120

100

80

60

40

OPEN-LOOP GAIN (dB)

20

0

PHASE

GAIN

VS = 5V

0

–30

–60

–90

–120

–150

–180

–210

05320-057

05320-098

OPEN-LOOP PHASE (Degrees)

0

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

OUTPUT VOLTAGE STEP (V)

Figure 13. Slew Rate vs. Output Voltage

10k

1k

VS = 3V, ENABLING

100

10

SUPPLY CURRENT (µA)

1

0.1 0 0.5 1.0 1.5 2.0 2.5 3.0

A AND B

POWER-DOWN VOLTAGE (V)

Figure 14. Supply Current vs. Power-Down Voltage

–40

G = +2

= 5V

V

S

= 150Ω

R

L

–50

V

= 2V p-p

OUT

–60

V

2 TO V

OUT

1

V

1 TO V

OUT

2

OUT

–70

–80

CROSSTALK (dB)

–90

OUT

VS = 5V, ENABLING

A AND B

3.5 4.0

4.5 5.0

5.0

05320-024

05320-036

–20

100k10k100 1k10 1M 10M 100M 1G

FREQUENCY (Hz)

Figure 12. Open-Loop Gain and Phase vs. Frequency

–240

05320-012

Rev. 0 | Page 7 of 16

–100

1M100k 10M 100M

FREQUENCY (Hz)

Figure 15. Cross talk vs. Frequency

05320-037

ADA4850-2

–

40

G = +1 V

= 5V

S

–50

V

= 500mV p-p

OUT

2.575

2.550

G = +1

= 5V

V

S

= 150Ω

R

L

10pF

0pF

–60

R

= 1kΩ HD2

–70

–80

–90

HARMONIC DISTORTION (dBc)

–100

–110

0.1 100

L

RL = 150Ω HD2

= 1kΩ HD3

R

L

= 150Ω HD3

R

L

110

FREQUENCY (MHz)

Figure 16. Harmonic Distortion vs. Frequency for Various Loads

50

G = +2 V

= 5V

S

= 1kΩ

R

L

–60

–70

V

OUT

–80

–90

–100

HARMONIC DISTORTION (dBc)

–110

–120

0.1 100

V

= 200mV p-p

HD2

= 500mV p-p

OUT

HD2

V

= 200mV p-p

OUT

HD3

V

= 500mV p-p

OUT

HD3

110

FREQUENCY (MHz)

Figure 17. Harmonic Distortion vs. Frequency for Various V

0.65 G = +2

= 1kΩ

R

L

= 5V

V

S

0.60

OUT

05320-102

05320-103

2.525

2.500

2.475

OUTPUT VOLTAGE (V)

2.450

2.425 0 20 40 60 80 100 120 140 160 180 200

TIME (ns)

Figure 19. Small Signal Transient Response for Capacitive Load

3.25 G = +2 R

= 1kΩ

L

= 5V

V

S

3.00

2.75

2.50

2.25

2.00

OUTPUT VOLTAGE FOR 5V SUPPLY (V)

1.75

500 100 150 200

TIME (ns)

Figure 20. Large Signal Transient Response

2.875 G = +1

= 1kΩ

R

L

2.750

0.875

0.750

05320-020

05320-050

0.55

0.50

0.45

OUTPUT VOLTAGE (V)

0.40

0.35 500 100 150 200

TIME (ns)

Figure 18. Small Signal Transient Response for Various Supplies

05320-019

2.625

2.500

OUTPUT VOLTAGE FOR 5V SUPPLY (V)

2.375

2.250

2.125

V

= 3V

S

500 100 150 200

TIME (ns)

VS = 5V

Figure 21. Large Signal Transient Response for Various Supplies

0.625

0.500

0.375

0.250

0.125

OUTPUT VOLTAGE FOR 3V SUPPLY (V)

05320-049

Rev. 0 | Page 8 of 16

ADA4850-2

6

5

V

4

DISABLE

3

2

VOLTAGE (V)

1

0

–1

03015 45

V

OUT

TIME (µs)

Figure 22. Enable/Disable Time

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

INPUT AND OUTPUT VOLTAGE (V)

0.5 0

–0.5

0 1000

OUTPUT

100 200 300 400 500 600 700 800 900

INPUT

TIME (ns)

Figure 23. Input Overdrive Recovery

3.5

3.0

2.5

2.0

1.5

1.0

0.5

INPUT AND OUTPUT VOLTAGE (V)

0

5 × INPUT

OUTPUT

G = +2 VS = 5V f

= 400kHz

IN

G = +1

= 5V

V

S

= 150Ω

R

L

f = 1MHz

G = +5

= 3V

V

S

= 150Ω

R

L

f = 1MHz

05320-025

05320-058

1000

100

10

VOLTAGE NOISE (nV/ Hz)

100

10

CURRENT NOISE (pA/ Hz)

350

300

250

200

COUNT

150

100

50

1

100k10k100 1k10 1M 10M 100M

FREQUENCY (Hz)

Figure 25. Voltage Noise vs. Frequency

100k10k100 1k10 1M 10M 100M 1G

FREQUENCY (Hz)

Figure 26. Current Noise vs. Frequency

VS = 5V N = 1720 x = 450µV σ = 750µV

05320-059

05320-095

–0.5

0 1000

100 200 300 400 500 600 700 800 900

TIME (ns)

Figure 24. Output Overdrive Recovery

05320-060

Rev. 0 | Page 9 of 16

0

–4 4

–3 –2 –1 0 1 2 3

V

(mV)

OFFSET

Figure 27. Input Offset Voltage Distribution

05320-065

ADA4850-2

400

380

360

340

320

V)

µ

(

300

OS

V

280

260

240

220

200

–1.0 3.5

Figure 28. Input Offset Voltage vs. Common-Mode Voltage

0.6

0.5

0.4

VS = 5V

–0.5 0 0.5 1.0 1.5 2.0 2.5 3.0

VCM (V)

+V

SAT

VS = 3V

05320-063

–1.2

+I

B

–1.4

–1.6

VS = 5V

–1.8

–2.0

INPUT BIAS CURRENT (µA)

–2.2

–2.4

–40 125

–25–105 203550658095110

TEMPERATURE (°C)

VS = 3V

–I

B

Figure 31. Input Bias Current vs. Temperature for Various Supplies

95

VS = 5V R

= 1kΩ

L

90

+VS– V

85

OUT

05320-092

0.3

0.2

0.1

OUTPUT SATURATION VOLTAGE (V)

0

050

5 1015202530354045

LOAD CURRENT (mA)

VS = 5V

–V

SAT

05320-064

Figure 29. Output Saturation Voltage vs. Load Current

(Voltage Differential from Rails)

–30

–32

–34

–36

–38

–40

–42

–44

POWER-DOWN PIN BIAS CURRENT (µA)

–46

–40 125

–25–105 203550658095110

VS = 3V

VS = 5V

TEMPERATURE (°C)

05320-091

Figure 30. Power-Down Bias Current vs. Temperature for Various Supplies

80

75

70

OUTPUT SATURATION VOLTAGE (mV)

65

–25–105 203550658095110

–40 125

Figure 32. Output Saturation Voltage vs. Temperature

4.9

4.8

4.7

4.6

4.5

4.4

SUPPLY CURRENT (mA)

4.3

4.2 –40 125

–25–105 203550658095110

Figure 33. Current vs. Temperature for Various Supplies

–VS– V

OUT

TEMPERATURE (°C)

(Voltage Differential from Rails)

VS = 5V

VS = 3V

TEMPERATURE (°C)

05320-062

05320-090

Rev. 0 | Page 10 of 16

ADA4850-2

0

VS = 5V

–10 –20 –30 –40 –50 –60 –70 –80 –90

POWER SUPPLY REJECTION (dB)

–100

–110

100

+PSR

1M100k1k 10k 10M 100M

FREQUENCY (Hz)

Figure 34. Power Supply Rejection (PSR) vs. Frequency

0.7

0.6

–PSR

05320-094

–20

VS = 5V

–30

–40

–50

–60

–70

–80

–90

–100

COMMON-MODE REJECTION (dB)

–110

–120

1k

10k 100k 1M 10M 100M

CHANNEL 1

CHANNEL 2

FREQUENCY (Hz)

Figure 36. Common-Mode Rejection Ratio (CMRR) vs. Frequency

05320-034

0.5

0.4

0.3

0.2

0.1

INPUT OFFSET VOLTAGE (mV)

0

–0.1

–25–105 203550658095110

–40 125

VS = 5V

VS = 3V

TEMPERATURE (°C)

Figure 35. Input Offset Voltage vs. Temperature for Various Supplies

05320-093

Rev. 0 | Page 11 of 16

ADA4850-2

CIRCUIT DESCRIPTION

The ADA4850-2 features 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.

HEADROOM AND OVERDRIVE RECOVERY CONSIDERATIONS

Input

The ADA4850-2 is 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 ADA4850-2 can provide full rail-to-rail output swing for supply voltage as low as 3.3 V, assuming the input signal swing is from

(or ground) to 1.1 V.

−V

S

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 37 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 +V distortion or settling time.

2

1

0

–1

–2

GAIN (dB)

–3

–4

VS = 5V G = +1

= 1kΩ

R

L

–5

–6

= 0.1V p-p

V

OUT

0.1 1000

Figure 37. Unity-Gain Follower Bandwidth vs.

Frequency for Various Input Common-Mode

. This can manifest itself in increased

S

VCM = 3V

= 3.1V

V

CM

V

= 3.2V

CM

= 3.3V

V

CM

1 10 100

FREQUENCY (MHz)

05320-096

Higher frequency signals require more headroom than the lower frequencies to maintain distortion performance. Figure 38 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 VS = 5V

3.4

G = +1

= 1kΩ

R

L

3.2

3.0

2.8

2.6

2.4

OUTPUT VOLTAGE (V)

2.2

2.0

1.8

0 100

10 20 30 40 50 60 70 80 90

V

STEP

= 2.1V TO 3.1V

V

STEP

V

STEP

V

STEP

TIME (ns)

= 2V TO 3V

= 2.2V TO 3.2V

= 2.3V TO 3.3V V

= 2.4V TO 3.4V

STEP

05320-061

Figure 38. 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 ADA4850-2 does 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 ADA4850-2 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.

Output overload recovery is typically within 40 ns after the amplifier’s input is brought to a nonoverloading value.

Figure 39 shows the output recovery transients for the amplifier recovering from a saturated output from the top and bottom supplies to a point at midsupply.

Rev. 0 | Page 12 of 16

ADA4850-2

6.5

V

= +2.5V TO 0V

5.5

4.5

3.5 INPUT

2.5

VOLTAGE EDGES

1.5

0.5

INPUT AND OUTPUT VOLTAGE (V)

–0.5

–1.5

0 100

10 20 30 40 50 60 70 80 90

OUT

V

OUT

TIME (ns)

= –2.5V TO 0V

Figure 39. Overload Recovery

VS = 5V G = –1 R

= 1kΩ

L

05320-042

OPERATING THE ADA4850-2 ON BIPOLAR SUPPLIES

The ADA4850-2 can operate on bipolar supplies up to ±5 V. The only restriction is that the voltage between −V

and the power-

S

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.

POWER-DOWN PIN

The ADA4850-2 features an ultralow power-down mode that lowers the supply current to less than 0.1 µA. When a powerdown pin (Pin 13 or Pin 14) is brought to within 1 V of the negative supply, the amplifier is powered down. Table 5 outlines the power-down pin functionality. The power-down pins (PD) should not be left floating.

Table 5. Power-Down Pin Functionality

Supply Voltage 3 V 5 V

Powered Down 0 V to 0.6 V 0 V to 0.6 V Enabled 1.7 V to 3 V 1.7 V to 5 V

Rev. 0 | Page 13 of 16

ADA4850-2

R

OUTLINE DIMENSIONS

INDICATO

SEATING

PIN 1

0.90

0.85

0.80

PLANE

12° MAX

3.00

BSC SQ

TOP

VIEW

0.30

0.23

0.18 *

COMPLIANT EXCEPT FOR EXPOSED PAD DIMENSION.

2.75

BSC SQ

0.80 MAX

0.65 TYP

0.05 MAX

0.02 NOM

0.20 REF

TO

JEDEC STANDARDS MO-220-VEED-2

0.45

0.50

BSC

1.50 REF

0.60 MAX

12

9

Figure 40. 16-Lead Lead Frame Chip Scale Package [LFCSP]

(CP-16-3)

Dimensions shown in millimeters

13

EXPOSED

PAD

(BOTTOM VIEW)

8

0.50

0.40

0.30

16

1

4

5

N

P

I

D

N

I

*

1.65

1.50 SQ

1.35

0.25 MIN

1

O

A

C

T

I

ORDERING GUIDE

Model Temperature Range Package Description Package Outline Branding

ADA4850-2YCPZ-R2 ADA4850-2YCPZ-RL1 −40°C to +125°C 16-Lead Lead Frame Chip Scale Package (LFCSP) CP-16-3 HTB ADA4850-2YCPZ-RL71 −40°C to +125°C 16-Lead Lead Frame Chip Scale Package (LFCSP) CP-16-3 HTB

1

Z = Pb-free part.

1

−40°C to +125°C 16-Lead Lead Frame Chip Scale Package (LFCSP) CP-16-3 HTB

Rev. 0 | Page 14 of 16

ADA4850-2

NOTES

Rev. 0 | Page 15 of 16

ADA4850-2

NOTES

D05320–0−2/05(0)

Rev. 0 | Page 16 of 16

Datasheet ADA4850-2 Datasheet (Analog Devices)

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

PIN CONFIGURATION

GENERAL DESCRIPTION

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS WITH +3 V SUPPLY

SPECIFICATIONS WITH +5 V SUPPLY

ABSOLUTE MAXIMUM RATINGS

THERMAL RESISTANCE

Maximum Power Dissipation

ESD CAUTION

TYPICAL PERFORMANCE CHARACTERISTICS

CIRCUIT DESCRIPTION

HEADROOM AND OVERDRIVE RECOVERY CONSIDERATIONS

Input

Output

OPERATING THE ADA4850-2 ON BIPOLAR SUPPLIES

POWER-DOWN PIN

OUTLINE DIMENSIONS

ORDERING GUIDE