ADA4800ACPZ-RL,ADA4800ACPZ-R7,ADA4800ACPZ-R7,ADA4800ACPZ-R7, 规格书,Datasheet 资料

FEATURES

Integrated active load and gain of 1 buffer Very low buffer power consumption As low as 20 mW on chip

Power save feature to reduce active load current by GPO control

High buffer speed

400 MHz, −3 dB bandwidth 415 V/μs slew rate

Fast settling time to 1%, 2 V step: 5 ns Adjustable buffer bandwidth Push-pull output stage

Adjustable active load current

Small package: 1.6 mm × 1.6 mm × 0.55 mm

APPLICATIONS

CCD image sensor output buffer Digital still cameras Camcorders

GENERAL DESCRIPTION

The ADA4800 is voltage buffer integrated with an active load. The buffer is a low power, high speed, low noise, high slew rate, fast settling, fixed gain of 1 monolithic amplifier for charge-coupled device (CCD) applications. For CCD applications, the active load current source (IAL) can load the open source CCD sensor outputs and the buffer can drive the AFE load. The active current load can also be switched off, to use the ADA4800 as just a unity gain buffer. The buffer consumes only 20 mW of static power. In applications where power savings is critical, the ADA4800 features a power save mode (see the Power Save Mode section), which further reduces the total current

consumption. The bandwidth of the ADA4800 buffer is also fully adjustable through the IDRV pin.

The buffer of the ADA4800 employs a push-pull output stage architecture, providing drive current and maximum slew capability for both rising and falling signal transitions. At a 5 mA quiescent current setting, it provides 400 MHz, −3 dB bandwidth, which makes this buffer well suited for CCD

sensors from machine vision to digital still camera applications. The ADA4800 is ideal for driving the input of the Analog Devices, Inc., 12-bit and 14-bit high resolution analog front ends (AFE) such as the AD9928, AD9990, AD9920A, AD9923A, and AD997x family.

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.

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Low Power, High SpeedCCD Buffer Amplifier

ADA4800

FUNCTIONAL BLOCK DIAGRAM

ADA4800IN16ISFIISFIALIBUFFICCVEE2+15VCCIIDRVOUT34IDRV100-26190

Figure 1.

The versatility of the ADA4800 allows for seamless interfacing with many CCD sensors from various manufacturers. The ADA4800 is designed to operate at supply voltages as low as 4 V and up to 17 V. It is available in a 1.6 mm × 1.6 mm × 0.55 mm, 6-lead LFCSP package and is rated to operate over the industrial temperature range of −40oC to +85oC.

VISF3VR10kISFΩ0.1µF+10µFR249kIDRVΩ15VISFVCCIDRV654IIIDRVISFIBUFFADA4800+1I1AL23INVEEOUT49.9Ω10Ω1kΩ22pF7.5V7.5V201-26190

Figure 2. Typical Test Circuit

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 ©2010 Analog Devices, Inc. All rights reserved.

ADA4800

TABLE OF CONTENTS

Features .............................................................................................. 1 Applications ....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Buffer Electrical Characteristics ................................................. 3 Active Current Load Electrical Characteristics ........................ 3 Absolute Maximum Ratings ............................................................ 4 Thermal Resistance ...................................................................... 4 ESD Caution .................................................................................. 4 Pin Configuration and Function Descriptions ............................. 5

Typical Performance Characteristics ..............................................6 Test Circuit .........................................................................................9 Theory of Operation ...................................................................... 10 Setting Active Load Current with Pin 6 (ISF) ........................ 10 Setting Bandwidth with Pin 4 (IDRV)..................................... 10 Applications Information .............................................................. 11 Open Source CCD Output Buffer ............................................ 11 Power Save Mode ....................................................................... 11 Power Supply Bypassing ............................................................ 12 Power Sequencing ...................................................................... 12 Outline Dimensions ....................................................................... 13 Ordering Guide .......................................................................... 13

REVISION HISTORY

7/10—Rev. 0 to Rev. A

Deleted Figure 15 .............................................................................. 7 Changes to Setting Active Load Current with Pin 6 ISF Section and Setting Bandwidth with Pin 4 (IDRV) Section ................... 10 6/10—Revision 0: Initial Version

Rev. A | Page 2 of 16

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ADA4800

SPECIFICATIONS

BUFFER ELECTRICAL CHARACTERISTICS

TA = 25°C, VCC = 15 V, VEE = 0 V, RIDRV = 249 kΩ connected to VIDRV, RLOAD = 1 kΩ in parallel with 22 pF in series with 10 Ω, VIN = 7.5 V, unless otherwise noted (see Figure 2 for a test circuit). Table 1.

MM

Parameter Condition in Typ ax Unit

GAIN Voltage Gain VIN = 6.5 V to 8.5 V, RISF = 0 Ω 0.995 0.998 1.005 V/V INPUT/OUTPUT CHARACTERISTICS I/O Offset Voltage 30 41 mV IDRV Current RIDRV = 249 kΩ, VIDRV = 15 V 52 59 μA Input/Output Voltage Range VEE + 1.4 VCC − 1.4 V Input Bias Current (IBUFF) 1 μA DYNAMIC PERFORMANCE −3 dB Bandwidth RIDRV = 300 kΩ (ICC = 1.1 mA), VOUT = 0.1 V p-p 182 MHz RIDRV = 150 kΩ (ICC = 2.1 mA), VOUT = 0.1 V p-p 288 MHz RIDRV = 50 kΩ (ICC = 4.7 mA), VOUT = 0.1 V p-p 400 MHz Slew Rate VOUT = 2 V step 415 V/μs Rise Time VIN = 7.5 V to 8.5 V, 10% to 90% 2.2 ns Fall Time VIN = 8.5 V to 7.5 V, 10% to 90% 1.8 ns 1% Settling Time VIN = 9.5 V to 7.5 V (falling edge) 5 ns VIN = 7.5 V to 9.5 V (rising edge) 4.5 ns VIN = 8.5 V to 7.5 V (falling edge) 4.5 ns VIN = 7.5 V to 8.5 V (rising edge) 4 ns I/O Delay Time VIN = 8.5 V to 7.5 V (falling edge) 0.4 ns

MM VIN = 7.5 V to 8.5 V (rising edge) 0.35 ns Output Voltage Noise @ 20 MHz 1.5 nV/√Hz POWER SUPPLY Supply Voltage Range 4 15 17 V Supply Current (ICC) 1.4 1.8 mA OPERATING TEMPERATURE RANGE −40 +85 °C

ACTIVE CURRENT LOAD ELECTRICAL CHARACTERISTICS

TA = 25°C, VEE = 0 V, VISF = 3 V, RISF = 10 kΩ connected to VISF, VIN = 7.5 V, unless otherwise noted (see Figure 2 for a test circuit). Table 2.

Parameter Condition in Typ ax Unit INPUT/OUTPUT CHARACTERISTICS Active Load Current (IAL) VISF = 0 V 1 μA

VISF = 3 V 3 mA

VISF = 7.5 V 12.7 mA ISF Current (IISF) RISF = 10 kΩ 111 120 μA Input Voltage Range VEE + 1.7 VCC V OPERATING TEMPERATURE RANGE −40 +85 °C

Rev. A | Page 3 of 16

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ADA4800

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted. Table 2.

THERMAL RESISTANCE

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

θJA Unit 160 °C/W

Parameter Rating Table 3. Thermal Resistance Supply Voltage 18 V

Package Type Input Voltage VEE to VCC

ISF Pin VEE to VCC 6-Lead LFCSP IDRV Pin VEE to VCC

Storage Temperature Range −65°C to +150°C

ESD CAUTION Operating Temperature Range −40°C to +85°C

Junction Temperature Range −65°C to +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.

Rev. A | Page 4 of 16

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ADA4800

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

ADA4800IN16ISFVEE2EPAD5VCCOUT34IDRVNOTES1.EXPOSED PAD IS NOT INTERNALLYCONNECTED TO DIE. CONNECT TO ANY LOWIMPEDANCE NODE OR LEAVE FLOATING.09162-002

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description 1 IN Input. Connect this pin to the CCD sensor output. 2 VEE Negative Power Supply Voltage. 3 OUT Output. Connect this pin to the AFE input. 4 IDRV Bandwidth Adjustment Pin. Connect this pin to VCC or an external voltage with an external resistor. This pin

allows bandwidth to be controlled by adjusting ICC. This pin can also be used to power down the buffer.

5 VCC Positive Power Supply Voltage. 6 ISF Active Load Current Adjustment Pin. Connect to VCC or an external voltage with an external resistor. This pin can

also be connected to the microcontroller logic output through an external resistor for power save mode. This pin can also be used to power down the active current load.

EPAD EPAD Exposed Pad. Not internally connected to die. Connect to any low impedance node or leave floating.

Rev. A | Page 5 of 16

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ADA4800

TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25°C, VCC = 7.5 V, VEE = −7.5 V, RIDRV = 249 kΩ connected to VIDRV, VISF = −4.5 V, RISF = 10 kΩ connected to VISF, VIN shunt terminated with 49.9 Ω to 0 V, RLOAD = 1 kΩ in parallel with 22 pF in series with 10 Ω to 0 V.

10–1–2GAIN (dB)GAIN (dB)RIDRV = 50kΩ30–3–6RIDRV = 50kΩ–3–4–5–6–7–8RIDRV = 150kΩ–9–12–15–18RIDRV = 150kΩRIDRV = 200kΩRIDRV = 200kΩRIDRV = 300kΩ–21–24RIDRV = 300kΩ09162-00310M100M1G10M100M1GFREQUENCY (Hz)FREQUENCY (Hz)Figure 4. Small Signal Frequency Response with Various IDRV Resistances Figure 7. Large Signal Frequency Response with Various IDRV Resistances

3TA = –40°C0% SETTLING ERROR1.52.41.02.0–3GAIN (dB)TA = +25°CTA = +85°C0.51.6VOUT (V)VOUT (V)09162-00809162-007–60VOUTVIN – VOUT1.2–9–0.50.8–12VOUT = 100mV p-p10M100M1G09162-004–1.00.4–151M–1.5012345TIME (ns)6789010FREQUENCY (Hz)Figure 5. Small Signal Frequency Response at Various Temperatures Figure 8. Settling Time, 2 V to 0 V Output Transition

2.01.51.0% SETTLING ERROR1.41.21.0% SETTLING ERROR2.01.51.00.50–0.5VIN – VOUT–1.0–1.5–2.00123456789VOUT1.41.21.00.80.60.40.20–0.2TIME (ns)0.50–0.5–1.0VOUT–1.5–2.00123456789TIME (ns)VIN – VOUT0.80.60.40.20–0.2VOUT (V)09162-005

Figure 6. Settling Time, 1 V to 0 V Output Transition

Figure 9. Settling Time, 0 V to 1 V Output Transition

Rev. A | Page 6 of 16

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09162-006–91MVOUT = 100mV p-p–27VOUT = 2V p-p–301M

8001.21.00.80.6INPUT0.40.20–0.2012345TIME (ns)678OUTPUTINPUT TO OUTPUT DELAY TIME (ps)ADA4800

700PULSE RESPONSE (V)09162-0096001V TO 0V PULSE5000.5V TO 0V PULSE4000V TO 0.5V PULSE3000V TO 1V PULSE1213141516910SUPPLY VOLTAGE (V)Figure 10. Input to Output Delay Time vs. Supply Voltage Figure 13. Negative Pulse Response, 1 V to 0 V

1.21.0INPUTPULSE RESPONSE (V)PULSE RESPONSE (V)2.52.00.80.6OUTPUT0.40.20–0.2012345TIME (ns)6789101.5INPUT1.0OUTPUT0.5009162-01015171921232527TIME (ns)Figure 11. Positive Pulse Response, 0 V to 1 V

2.5Figure 14. Negative Pulse Response, 2 V to 0 V

30RISF = 10kΩ1.5INPUT1.0OUTPUT0.5ACTIVE LOAD CURRENT, IAL (mA)2.0PULSE RESPONSE (V)2520151005TIME (ns)–5.5–3.5–1.50.5VISF (V)2.54.56.5

Figure 12. Positive Pulse Response, 0 V to 2 V Figure 15. Input Current vs. Voltage on ISF Pin (VISF)

Rev. A | Page 7 of 16

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09162-0180246810121409162-011–0.50–7.509162-014–0.51309162-01320011ADA4800

0.140.120.10CURRENT (mA)1.6IISF1.41.21.0ICC (mA)0.080.060.040.02IIDRV0.80.60.40.209162-019TEMPERATURE (°C)

–5.5–3.5–1.50.52.54.56.5VIDRV (V)Figure 16. ISF and IDRV Currents vs. Temperature Figure 18. ICC vs. Voltage on IDRV Pin (VIDRV)

0–5–10–15VOS (mV)700600500400300200VOS (mV)1000–100–200–300–400–500–600–70002468VIN (V)101214–20–25–30–35–40–4009162-020–1510356085TEMPERATURE (°C)

09162-02209162-0210–40–30–20–10010203040506070800–7.5

Figure 17. VOS vs. Temperature Figure 19. Output Offset Voltage vs. Input Voltage

Rev. A | Page 8 of 16

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ADA4800

TEST CIRCUIT

VISF0.11mA1.41mA3V0.05mARISF0.1µF10kΩISF6+10µFRIDRV249kΩ415VVCC5IDRVIDRVISFIBUFFADA4800+1I1AL23INVEEOUTAAmm10Ω1kΩ68949.9Ω622pF2.4.7.5V7.5VFigure 20. Typical Current Flow

Rev. A | Page 9 of 16

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620-26190

ADA4800

THEORY OF OPERATION

The ADA4800 is a buffer integrated with an active load. Each element (the active load and the buffer) operates independently, as described in the following sections.

Figure 22 illustrates an ADA4800 application configuration for using this power save feature.

An external resistor connected between the ISF and the microcontroller GPO pin determines the amount of current that flows into the input pin. This current can be calculated by using Equation 1 and Equation 2.

SETTING ACTIVE LOAD CURRENT WITH PIN 6 (ISF)

The ISF pin is used to establish the value of the active current load (IAL). Set the ISF current using Equation 1.

IISF=

VISF−1.55VRISF+3kΩ

(1)

The IDRV pin establishes the buffer’s ICC quiescent current. As ICC is increased, power dissipation and bandwidth both

where: increase. Set the current using Equation 3. VISF is referenced to Pin 2. VISF can be an external voltage source,

V−0.8VVCC, or a GPO output as explained in the following paragraphs. IIDRV=IDRV (3) R+28kΩRISF is the external resistor between the ISF pin and VISF. IDRVThe active load current (into the IN pin) is directly proportional

to IISF and can be calculated by Equation 2.

IAL = IISF × 27

(2)

The ADA4800 allows for additional power savings by reducing the active load current. The active load current can be logically controlled by connecting the ISF pin to any general-purpose output (GPO) pin of a system microcontroller through an external resistor. A GPO logic high enables the flow of the active load current. Appling –VS or connecting a high-Z to the ISF pin places the ADA4800 into power save mode by shutting down the active load current.

where:

VIDRV is referenced to Pin 2. VIDRV can be an external voltage source or VCC.

RIDRV is the external resistor between the IDRV pin and VIDRV. The ICC current is directly proportional to IIDRV and can be calculated by Equation 4.

ICC = IIDRV × 26

Applying –VS to the IDRV pin shuts down the buffer.

(4)

SETTING BANDWIDTH WITH PIN 4 (IDRV)

Rev. A | Page 10 of 16

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ADA4800

ADA4800 as an open source CCD buffer configured for using this power save feature. Power save mode allows IAL current to be logically controlled by connecting the ISF pin to any general-purpose output (GPO) pin of the system microcontroller through an external resistor. A GPO logic high enables the flow of input sink current, while a logic low disables the input sink current and asserts the power save mode.

VISF0V TO 3VGPO PINRISF10kΩISFRISF120kΩISF0.1µF65APPLICATIONS INFORMATION

OPEN SOURCE CCD OUTPUT BUFFER

With low power, high slew rate, and fast settling time, the ADA4800 is the ideal solution for an output buffer for CCD sensors with an open source output configuration. Figure 21 shows a typical application circuit for the ADA4800 as a CCD sensor output buffer.

The output of the CCD is connected directly to the IN pin of the ADA4800, whose OUT pin is then ac-coupled into the input of the analog front end.

VISF15V0.1µF+47µFRIDRV249kΩIDRV40.1µF+47µFRIDRV249kΩIDRV415V0.1µFVCC515V0.1µF6IISFIBUFF+1IIDRV0.1µFVCCIIDRVADA4800IISFIBUFF+1ADA48001IALIN23VEEOUTAFE09162-028CCD1IALIN23

VEEOUTAFE09162-027Figure 22. Using GPO to Drive ISF Voltage

CCDFigure 23 shows an example of the ADA4800 power save feature.

GPO120kΩ20kΩISFFigure 21. Typical Application Block Diagram

To help reduce the effects of power supply noise coupling into the ISF and IDRV pins, use 0.1 μF ceramic bypass decoupling capacitors. For best performance, place these capacitors as close to each of these pins as is physically possible.

AFEGPO2

Figure 23. Example Block Diagram for Sink Current Selection

MAIN BOARDFPCPOWER SAVE MODE

The buffer of the ADA4800 consumes only 20 mW of static power. To achieve even more power savings, the ADA4800 active load current can be switched off during standby mode or reduced during monitoring mode. Figure 22 illustrates the Table 5. Input Sink Current Selection

Mode Standby

Three combinations of IAL are provided with Figure 23.

Selection of the IAL is controlled by the logic signals applied to the GPO1 and GPO2 pins. Table 5 summarizes the IAL selections.

GPO1 GPO2 Resistance (kΩ) High-Z High-Z High-Z

0 0 N/A Sleep High-Z 1 20

1 High-Z 20

Active 1 1 10

Active Load Current, IAL (mA) 0 1.90

3.36

Rev. A | Page 11 of 16

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09162-029ADA4800ADA4800

POWER SUPPLY BYPASSING

Attention must be paid to bypassing the power supply pin of the ADA4800. Use high quality capacitors with low equivalent series resistance (ESR), such as multilayer ceramic capacitors (MLCCs), to minimize supply voltage ripple and power dissipa-tion. A large, usually tantalum, 2.2 μF to 47 μF capacitor located in close proximity to the ADA4800 is required to provide good decoupling for lower frequency signals. The actual value is

determined by the circuit transient and frequency requirements. In addition, 0.1 μF MLCC decoupling capacitors should be located as close to the power supply pin as is physically possible, no more than ⅛ inch away. The ground returns should terminate imme-diately into the ground plane. Locating the bypass capacitor return close to the load return minimizes ground loops and improves performance.

POWER SEQUENCING

All I/O pins are ESD protected with internal back-to-back diodes connected to VCC and GND as shown in Figure 24. With the ADA4800 supply turned off (VCC = 0 V), a voltage on an I/O pin can turn on the protection diodes and cause permanent damage or destroy the IC. To prevent this condition during power-on, no voltages should be applied to any I/O pins until VCC is fully on and settled. During power-off, I/O pin voltages should be removed or reduced to 0 V before VCC is turned off.

VCCEXTERNALPINADA4800

Figure 24. Simplified Input/Output Circuitry

In the presence of a voltage on an I/O pin with VCC = 0 V, the current should be limited to 5 mA or less by the source or by adding a series resistor.

Rev. A | Page 12 of 16

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09162-030

ADA4800

OUTLINE DIMENSIONS

1.651.60SQ1.5541.151.050.950.50BSC6PIN1INDEXAREA0.3750.3000.2253TOPVIEWEXPOSEDPAD0.600.500.401BOTTOMVIEWPIN1INDICATOR(R0.15)0.600.550.50SEATINGPLANE0.300.250.200.05MAX0.02NOMFORPROPERCONNECTIONOFTHEEXPOSEDPAD,REFERTOTHEPINCONFIGURATIONANDFUNCTIONDESCRIPTIONSSECTIONOFTHISDATASHEET.101409-A0.152REF

Figure 25. 6-Lead Lead Frame Chip Scale Package [LFCSP_UD]

1.60 mm × 1.60 mm Body, Ultra Thin, Dual Lead

(CP-6-4)

Dimensions shown in millimeters

ORDERING GUIDE

Model1

ADA4800ACPZ-R2 ADA4800ACPZ-R7 ADA4800ACPZ-RL

1

Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C Package Description

6-Lead Lead Frame Chip Scale Package [LFCSP_UD] 6-Lead Lead Frame Chip Scale Package [LFCSP_UD] 6-Lead Lead Frame Chip Scale Package [LFCSP_UD] Package Option CP-6-4 CP-6-4 CP-6-4 Branding H2E H2E H2E

Z = RoHS Compliant Part.

Rev. A | Page 13 of 16

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ADA4800

NOTES

Rev. A | Page 14 of 16

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ADA4800

Rev. A | Page 15 of 16

NOTES

ADA4800

NOTES

©2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09162-0-7/10(A)

Rev. A | Page 16 of 16

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