ADA4800ACPZ-R2

Low Power, High Speed CCD Buffer Amplifier ADA4800 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 FUNCTIONAL BLOCK DIAGRAM ADA4800 IN 1 IISF IAL VEE 2 IBUFF ICC +1 5 6 ISF VCC IIDRV OUT 3 4 IDRV Figure 1. 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 chargecoupled 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. 7.5V 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. VISF 3V RISF 10kΩ ISF 6 5 0.1µF + 10µF RIDRV 249kΩ IDRV 4 09162-001 15V VCC IIDRV IISF IBUFF +1 ADA4800 1 IAL IN 49.9Ω 2 3 VEE 10Ω 22pF 7.5V OUT 1kΩ Figure 2. Typical Test Circuit 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 www.analog.com Fax: 781.461.3113 ©2010 Analog Devices, Inc. All rights reserved. 09162-102 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 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. Parameter GAIN Voltage Gain INPUT/OUTPUT CHARACTERISTICS I/O Offset Voltage IDRV Current Input/Output Voltage Range Input Bias Current (IBUFF) DYNAMIC PERFORMANCE −3 dB Bandwidth Condition VIN = 6.5 V to 8.5 V, RISF = 0 Ω Min 0.995 Typ 0.998 30 52 VEE + 1.4 1 RIDRV = 300 kΩ (ICC = 1.1 mA), VOUT = 0.1 V p-p RIDRV = 150 kΩ (ICC = 2.1 mA), VOUT = 0.1 V p-p RIDRV = 50 kΩ (ICC = 4.7 mA), VOUT = 0.1 V p-p VOUT = 2 V step VIN = 7.5 V to 8.5 V, 10% to 90% VIN = 8.5 V to 7.5 V, 10% to 90% VIN = 9.5 V to 7.5 V (falling edge) VIN = 7.5 V to 9.5 V (rising edge) VIN = 8.5 V to 7.5 V (falling edge) VIN = 7.5 V to 8.5 V (rising edge) VIN = 8.5 V to 7.5 V (falling edge) VIN = 7.5 V to 8.5 V (rising edge) @ 20 MHz 4 −40 182 288 400 415 2.2 1.8 5 4.5 4.5 4 0.4 0.35 1.5 15 1.4 17 1.8 +85 Max 1.005 41 59 VCC − 1.4 Unit V/V mV μA V μA MHz MHz MHz V/μs ns ns ns ns ns ns ns ns nV/√Hz V mA °C RIDRV = 249 kΩ, VIDRV = 15 V Slew Rate Rise Time Fall Time 1% Settling Time I/O Delay Time Output Voltage Noise POWER SUPPLY Supply Voltage Range Supply Current (ICC) OPERATING TEMPERATURE RANGE 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 INPUT/OUTPUT CHARACTERISTICS Active Load Current (IAL) Condition VISF = 0 V VISF = 3 V VISF = 7.5 V RISF = 10 kΩ VEE + 1.7 −40 Min Typ 1 3 12.7 111 Max Unit μA mA mA μA V °C ISF Current (IISF) Input Voltage Range OPERATING TEMPERATURE RANGE 120 VCC +85 Rev. A | Page 3 of 16 ADA4800 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 2. Parameter Supply Voltage Input Voltage ISF Pin IDRV Pin Storage Temperature Range Operating Temperature Range Junction Temperature Range Rating 18 V VEE to VCC VEE to VCC VEE to VCC −65°C to +150°C −40°C to +85°C −65°C to +150°C THERMAL RESISTANCE θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 3. Thermal Resistance Package Type 6-Lead LFCSP θJA 160 Unit °C/W ESD CAUTION 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 ADA4800 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS ADA4800 IN 1 6 ISF VEE 2 EPAD 5 VCC OUT 3 4 IDRV NOTES 1. EXPOSED PAD IS NOT INTERNALLY CONNECTED TO DIE. CONNECT TO ANY LOW IMPEDANCE NODE OR LEAVE FLOATING. Figure 3. Pin Configuration Table 4. Pin Function Descriptions Pin No. 1 2 3 4 5 6 Mnemonic IN VEE OUT IDRV VCC ISF Description Input. Connect this pin to the CCD sensor output. Negative Power Supply Voltage. Output. Connect this pin to the AFE input. 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. Positive Power Supply Voltage. 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. Exposed Pad. Not internally connected to die. Connect to any low impedance node or leave floating. EPAD EPAD Rev. A | Page 5 of 16 09162-002 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. 1 0 –1 –2 RIDRV = 150kΩ GAIN (dB) GAIN (dB) RIDRV = 50kΩ 3 0 –3 –6 –9 –12 –15 –18 RIDRV = 150kΩ RIDRV = 50kΩ –3 –4 –5 –6 RIDRV = 300kΩ –7 –8 VOUT = 100mV p-p 09162-003 RIDRV = 200kΩ RIDRV = 200kΩ –21 –24 –27 VOUT = 2V p-p –30 1M RIDRV = 300kΩ 10M 100M 1G 10M 100M 1G FREQUENCY (Hz) FREQUENCY (Hz) Figure 4. Small Signal Frequency Response with Various IDRV Resistances Figure 7. Large Signal Frequency Response with Various IDRV Resistances 3 TA = –40°C 0 % SETTLING ERROR 1.5 2.4 1.0 2.0 –3 GAIN (dB) TA = +25°C TA = +85°C 0.5 1.6 VOUT (V) VOUT (V) 09162-008 09162-007 –6 0 VOUT –0.5 VIN – VOUT 1.2 –9 0.8 –12 VOUT = 100mV p-p 10M 100M 1G 09162-004 –1.0 0.4 –15 1M –1.5 0 1 2 3 4 5 TIME (ns) 6 7 8 9 0 10 FREQUENCY (Hz) Figure 5. Small Signal Frequency Response at Various Temperatures Figure 8. Settling Time, 2 V to 0 V Output Transition 2.0 1.5 1.0 % SETTLING ERROR 1.4 1.2 1.0 % SETTLING ERROR 2.0 1.5 1.0 0.5 0 –0.5 VIN – VOUT –1.0 –1.5 –2.0 0 1 2 3 4 5 6 7 8 9 TIME (ns) VOUT 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 –0.2 0.5 0 –0.5 –1.0 VOUT –1.5 –2.0 0 1 2 3 4 5 6 7 8 9 TIME (ns) VIN – VOUT 0.8 0.6 0.4 0.2 0 –0.2 VOUT (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 09162-006 –9 1M ADA4800 800 1.2 1.0 0.8 0.6 INPUT 0.4 0.2 0 –0.2 0 1 2 3 4 5 TIME (ns) 6 7 8 9 10 OUTPUT INPUT TO OUTPUT DELAY TIME (ps) 700 PULSE RESPONSE (V) 09162-009 600 1V TO 0V PULSE 500 0.5V TO 0V PULSE 400 0V TO 0.5V PULSE 300 0V TO 1V PULSE 200 11 12 13 14 15 16 SUPPLY VOLTAGE (V) Figure 10. Input to Output Delay Time vs. Supply Voltage Figure 13. Negative Pulse Response, 1 V to 0 V 1.2 1.0 INPUT PULSE RESPONSE (V) PULSE RESPONSE (V) 2.5 2.0 0.8 0.6 OUTPUT 0.4 0.2 0 –0.2 0 1 2 3 4 5 TIME (ns) 6 7 8 9 10 1.5 INPUT 1.0 OUTPUT 0.5 0 09162-010 15 17 19 21 23 25 27 TIME (ns) Figure 11. Positive Pulse Response, 0 V to 1 V Figure 14. Negative Pulse Response, 2 V to 0 V 2.5 30 RISF = 10kΩ 1.5 INPUT 1.0 OUTPUT 0.5 ACTIVE LOAD CURRENT, IAL (mA) 2.0 PULSE RESPONSE (V) 25 20 15 10 0 5 –5.5 –3.5 –1.5 0.5 VISF (V) 2.5 4.5 6.5 TIME (ns) 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 09162-018 0 2 4 6 8 10 12 14 09162-011 –0.5 0 –7.5 09162-014 –0.5 13 09162-013 ADA4800 0.14 1.6 0.12 0.10 CURRENT (mA) IISF 1.4 1.2 1.0 ICC (mA) 0.08 0.06 IIDRV 0.04 0.8 0.6 0.4 0.02 0.2 09162-019 TEMPERATURE (°C) –5.5 –3.5 –1.5 0.5 2.5 4.5 6.5 VIDRV (V) Figure 16. ISF and IDRV Currents vs. Temperature Figure 18. ICC vs. Voltage on IDRV Pin (VIDRV) 0 –5 –10 –15 VOS (mV) VOS (mV) 700 600 500 400 300 200 100 0 –100 –200 –300 –400 –500 –600 09162-020 –20 –25 –30 –35 –40 –40 –15 10 35 60 85 0 2 4 6 8 VIN (V) 10 12 14 TEMPERATURE (°C) Figure 17. VOS vs. Temperature Figure 19. Output Offset Voltage vs. Input Voltage Rev. A | Page 8 of 16 09162-022 –700 09162-021 0 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 0 –7.5 ADA4800 TEST CIRCUIT VISF 0.11mA 1.41mA 3V 10µF RIDRV 249kΩ 4 0.05mA RISF0.1µF 10kΩ ISF 6 + 15V VCC 5 IDRV IDRV ISF IBUFF +1 ADA4800 1 IAL IN 2 3 VEE 4.68mA OUT 10Ω 22pF 7.5V 1kΩ 09162-026 2.96mA 49.9Ω 7.5V Figure 20. Typical Current Flow Rev. A | Page 9 of 16 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. I ISF = VISF − 1.55 V R ISF + 3 kΩ SETTING BANDWIDTH WITH PIN 4 (IDRV) (1) The IDRV pin establishes the buffer’s ICC quiescent current. As ICC is increased, power dissipation and bandwidth both increase. Set the current using Equation 3. where: VISF is referenced to Pin 2. VISF can be an external voltage source, VCC, or a GPO output as explained in the following paragraphs. RISF is the external resistor between the ISF pin and VISF. The 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. I IDRV = VIDRV − 0.8 V R IDRV + 28 kΩ (3) 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) Rev. A | Page 10 of 16 ADA4800 APPLICATIONS 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. VISF 15V RISF 120kΩ ISF 0.1µF 6 5 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 generalpurpose 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. VISF 0V TO 3V GPO PIN RISF 10kΩ ISF 6 0.1µF + 47µF RIDRV 249kΩ IDRV 4 15V 0.1µF VCC 5 0.1µF + 47µF RIDRV 249kΩ IDRV 4 0.1µF 15V IISF IBUFF +1 IIDRV 0.1µF VCC IIDRV ADA4800 IISF IBUFF +1 ADA4800 1 IAL IN 2 3 VEE OUT AFE 09162-028 CCD 1 IAL IN 2 3 VEE OUT AFE 09162-027 Figure 22. Using GPO to Drive ISF Voltage CCD Figure 23 shows an example of the ADA4800 power save feature. GPO1 20kΩ 20kΩ ISF Figure 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. AFE GPO2 MAIN BOARD FPC Figure 23. Example Block Diagram for Sink Current Selection POWER 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 Sleep Active GPO1 High-Z 0 High-Z 1 1 GPO2 High-Z 0 1 High-Z 1 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. Resistance (kΩ) High-Z N/A 20 20 10 Active Load Current, IAL (mA) 0 1.90 3.36 Rev. A | Page 11 of 16 09162-029 ADA4800 ADA4800 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 dissipation. 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 immediately 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. VCC EXTERNAL PIN ADA4800 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 09162-030 ADA4800 OUTLINE DIMENSIONS 1.65 1.60 SQ 1.55 4 1.15 1.05 0.95 0.50 BSC 6 PIN 1 INDEX AREA 0.375 0.300 0.225 3 TOP VIEW EXPOSED PAD 0.60 0.50 0.40 1 BOTTOM VIEW PIN 1 INDICATOR (R 0.15) 0.60 0.55 0.50 SEATING PLANE 0.30 0.25 0.20 0.05 MAX 0.02 NOM FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 101409-A 0.152 REF 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 Model 1 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 ADA4800 NOTES Rev. A | Page 14 of 16 ADA4800 NOTES Rev. A | Page 15 of 16 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