16 V 5 + 1-Channel Operational Amplifier ADD8706 PIN CONFIGURATION Single-supply operation: 4.5 V to 16.5 V Upper/lower buffers swing to VS/GND Continuous output current: 35 mA VCOM peak output current: 250 mA Offset voltage: 15 mV Slew rate: 6 V/µs Unity gain stable with large capacitive loads Supply current: 750 µA per amplifier +IN A 1 16 OUT A +IN B 2 15 OUT B +IN C 3 14 OUT C +IN D 4 +IN E 5 V+ 6 +IN F 7 –IN F 8 APPLICATIONS ADD8706 13 OUT D 12 OUT E 11 V– 10 NC 9 OUT F NC = NO CONNECT TFT LCD monitor panels TFT LCD notebook panels Communications equipment Portable instrumentation Electronic games ADC/DAC buffer 04352-0-001 FEATURES Figure 1. 16-Lead TSSOP GENERAL DESCRIPTION The ADD8706 is a single-supply, 5-channel buffer with a separate VCOM amplifier that has been optimized for today’s low cost TFT LCD notebook and monitor panels. The top and bottom channels swing to the top/bottom rails, respectively, and can be used as end-point gamma references. The middle channels are ideal for midpoint gamma references. The VCOM amplifier provides very high continuous and peak currents. All channels have excellent transient response as well as high slew rate and capacitive load drive capability. The ADD8706 is specified over the –40°C to +85°C temperature range. The ADD8706 is available in a 16-lead TSSOP package. Table 1. Input Output Characteristics Channel A B C D E F VIH VS VS – 1.7 V VS – 1.7 V VS – 1.7 V VS – 1.7 V VS – 1.7 V VIL GND + 1.7 V GND GND GND GND GND IO (mA) 15 15 15 15 15 35 ISC (mA) 150 150 150 150 150 250 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 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: 781.326.8703 © 2003 Analog Devices, Inc. All rights reserved. ADD8706 TABLE OF CONTENTS Electrical Characteristics ................................................................. 3 Theory.............................................................................................9 Absolute Maximum Ratings............................................................ 5 Input/Output Characteristics ......................................................9 ESD Caution.................................................................................. 5 Important Note..............................................................................9 Typical Performance Characteristics ............................................. 6 Outline Dimensions ....................................................................... 11 Application Information.................................................................. 9 Ordering Guide .......................................................................... 11 REVISION HISTORY Revision 0: Initial Version Rev. 0 | Page 2 of 12 ADD8706 ELECTRICAL CHARACTERISTICS Table 2. VS = 16 V, VCM = VS/2, TA @ 25 °C, unless otherwise noted Parameter SUPPLY CHARACTERISTICS Supply Voltage Power Supply Rejection Ratio Total Supply Current Symbol VS PSRR ISY INPUT CHARACTERISTICS Offset Voltage Offset Voltage Drift Input Bias Current VOS ∆VOS/∆T IB Condition VS = 4 V to 17 V, –40°C ≤ TA ≤ +85°C VO = VS/2, No Load –40°C ≤ TA ≤ +85°C Min 4.5 70 Typ 90 4.5 2 10 400 –40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C Input Offset Current Amplifier F Common-Mode Rejection Ratio Amplifier F Input Impedance Input Capacitance OUTPUT CHARACTERISTICS Output Voltage High (A) Optimized for High Swing IOS CMRR 10 –40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C VCM = 0 to (VS – 1.7 V) 54 ZIN CIN VOH Output Voltage High (B to D) Optimized for Midrange VOH Output Voltage High (E) Optimized for Low Swing VOH Output Voltage High (F) Optimized for VCOM VOH Output Voltage Low (A) Optimized for High Swing VOL Output Voltage Low (B–D) Optimized for Midrange VOL Output Voltage Low (E) Optimized for Low Swing VOL Output Voltage Low (F) Optimized for VCOM VOL Continuous Output Current (A to E) Continuous Output Current (F) Peak Output Current (A to E) Peak Output Current (F) IOUT IOUT IPK IPK VIN = 16 V, IL = 100 µA VIN = 16 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 14 V, IL = 100 µA VIN = 14 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 14 V, IL = 100 µA VIN = 14 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 16 V, IL = 100 µA VIN = 16 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 1.7 V, IL = 100 µA VIN = 1.7 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 0 V, IL = 100 µA VIN = 0 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 0 V, IL = 100 µA VIN = 0 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VIN = 0 V, IL = 100 µA VIN = 0 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VS = 16 V VS = 16 V VS = 16 V VS = 16 V Rev. 0 | Page 3 of 12 15.75 15.65 13.90 13.85 13.9 13.85 15.8 15.75 Max Unit 16 V dB mA mA 5.4 6 15 1100 1500 100 250 mV µV/°C nA nA nA nA 95 400 1 dB kΩ pF 15.99 15.85 V V V V V V V V V V V V V V V mV mV mV mV mV mV mV mV mV mA mA mA mA 14 13.985 14 13.99 15.995 15.9 1.70 1.71 5 200 5 80 5 50 15 35 50 200 1.730 1.725 300 350 200 300 150 250 ADD8706 Parameter TRANSFER CHARACTERISTICS Amplifier Gain Buffer Gain Buffer Gain Linearity DYNAMIC PERFORMANCE Slew Rate Bandwidth Phase Margin Channel Separation NOISE PERFORMANCE Voltage Noise Density Current Noise Density Symbol Condition Min Typ Max Unit AVO AVCL 1 0.995 0.995 10 0.9985 0.9980 0.01 1.005 1.005 NL RL = 2 kΩ, VO = 0.5 to (VS – 2 V) RL = 2 kΩ –40°C ≤ TA ≤ +85°C RL = 2kΩ, VO = 0.5 to (VS – 0.5 V) V/mV V/V V/V % SR BW Øo RL = 2 kΩ, CL = 200 pF –3 dB, RL = 2 kΩ, CL = 40 pF RL = 2 kΩ, CL = 40 pF 4 6 6 55 75 V/µs MHz Degrees dB en f = 1 kHz f = 10 kHz f = 10 kHz 26 25 0.8 nV/√Hz nV/√Hz pA/√Hz in Rev. 0 | Page 4 of 12 ADD8706 ABSOLUTE MAXIMUM RATINGS Table 3. ADD8706 Stress Ratings* Table 4. Package Characteristics Parameter Supply Voltage (VS) Input Voltage Differential Input Voltage Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature Range ESD Tolerance (HBM) Package Type 16-Lead TSSOP (RU) Rating 18 V −0.5 V to VS + 0.5 V VS –65°C to +150°C –40°C to +85°C –65°C to +150°C 300°C ±1500 V 1 θJA1 180 θJC 35 Unit °C/W θJA is specified for worst-case conditions, i.e., θJA is specified for devices soldered onto a circuit board for surface-mount packages. *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 sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. 0 | Page 5 of 12 ADD8706 TYPICAL PERFORMANCE CHARACTERISTICS 70 18 VS = 16V INPUT OFFSET CURRENT (nA) 60 50 40 30 20 10 14 12 10 8 6 4 0 –10 –8 –6 –4 –2 0 2 4 INPUT OFFSET VOLTAGE (mV) 6 8 10 04532-0-025 2 0 –60 Figure 2. Input Offset Voltage, VS = 16 V 35 –40 –20 0 20 40 TEMPERATURE (°C) 60 80 100 04352-0-028 QUANTITY OF AMPLIFIERS VS = 16V 16 Figure 5. Input Offset Current vs. Temperature 10k VS = 16V VS = 4.5V SINK 30 A ∆OUTPUT VOLTAGE (mV) QUANTITY OF AMPLIFIERS 1k 25 20 15 10 B, C, D F 100 E 10 1 0 14 28 42 56 TCVOS (µV/°C) 70 84 98 0.1 0.001 0.1 1 LOAD CURRENT (mA) 10 100 Figure 6. Output Sink Voltage vs. Load Current, All Channels Figure 3. Input Offset Voltage Drift, VS = 16 V 10k 400 VS = 16V VS = 4.5V SOURCE A B, C, D, E 200 ∆OUTPUT VOLTAGE (mV) 1k 0 –200 –400 E B 100 A 10 F 1 –600 –800 –60 D C –40 –20 0 20 40 TEMPERATURE (°C) 60 80 100 0.1 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 Figure 7. Output Source Voltage vs. Load Current, All Channels Figure 4. Input Bias Current vs. Temperature Rev. 0 | Page 6 of 12 04352-0-015 F 04352-0-027 INPUT BIAS CURRENT (nA) 0.01 04352-0-013 0 04352-0-026 5 ADD8706 0.76 A 1k SUPPLY CURRENT/AMPLIFIER (mA) F 100 B, C, D 10 E 0.1 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 04352-0-014 1 0.75 0.74 0.73 0.72 0.71 0.70 0.69 –60 Figure 8. Output Sink Voltage vs. Load Current, All Channels –40 –20 80 100 100 A 10 F 0.1 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 04352-0-016 1 VS = 16V 100 80 –PSRR 60 +PSRR 40 20 0 100 1k 10k 100k 1M 10M 04352-0-018 POWER SUPPLY REJECTION RATIO (dB) B, C, D, E 1k 1M 10M FREQUENCY (Hz) Figure 9. Output Source Voltage vs. Load Current, All Channels Figure 12. PSRR vs. Frequency 0.9 140 VS = 16V COMMON-MODE REJECTION (dB) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 2 4 6 8 10 12 SUPPLY VOLTAGE (V) 14 16 18 04352-0-022 SUPPLY CURRENT PER AMPLIFIER (mA) 60 120 VS = 16V SOURCE 0 0 20 40 TEMPERATURE (°C) Figure 11. Supply Current vs. Temperature 10k ∆OUTPUT VOLTAGE (mV) VS = 16V 04352-0-010 ∆OUTPUT VOLTAGE (mV) VS = 16V SINK 04352-0-029 10k 120 100 80 60 40 20 0 100 Figure 10. Supply Current vs. Supply Voltage 1k 100k 10k FREQUENCY (Hz) Figure 13. CMRR vs. Frequency Rev. 0 | Page 7 of 12 ADD8706 0 100 80 45 OVERSHOOT (%) 135 20 80 PHASE SHIFT (Degrees) 90 40 70 60 –OS 50 +OS 40 30 180 0 VS = ±16V VIN = 100mV AV = 1 RL = 10kΩ 90 60 GAIN (dB) 100 VS = 16V RL = 10kΩ CL = 40pF 20 100k 1M FREQUENCY (Hz) 225 100M 10M 0 Figure 14. Frequency vs. Gain and Shift 10 100 CAPACITIVE LOAD (pF) 1k 04352-0-020 10k 04352-0-012 10 –20 1k Figure 17. Overshoot vs. Capacitive Load 100 80 VS = 16V RL = 2kΩ CL = 100pF VS = 16V RL = 10kΩ VOLTAGE (50mV/DIV) 60 40 GAIN (dB) 100pF 20 0 50pF –20 540pF –40 1040pF –60 1M 10M FREQUENCY (Hz) 100M TIME (1µs/DIV) 04352-0-021 –100 100k 04352-0-008 –80 Figure 18. Small-Signal Transient Response Figure 15. Gain vs. Capacitive Load 500 450 AV = 1 VS == 16V RL = 2kΩ CL = 100pF 400 VOLTAGE (2V/DIV) CH. A–E 300 250 200 150 CH. F 100 0 100 1k 100k 10k FREQUENCY (Hz) 1M 10M TIME (1µs/DIV) Figure 16. Impedance vs. Frequency Figure 19. Large Signal Transient Response Rev. 0 | Page 8 of 12 04352-0-013 50 04352-0-005 IMPEDANCE (Ω) 350 ADD8706 APPLICATION INFORMATION THEORY The ADD8706 is designed for use in LCD gamma correction circuits. This is an ideal on-chip solution for low-end panels. It provides five gamma voltages and a VCOM output. These gamma voltages provide the reference voltages for the column driver RDACs. Due to the capacitive nature of LCD panels, it is necessary for these drivers to provide high capacitive load drive. The VCOM output is the center voltage common to all the LCD pixels. The VCOM circuit is common to all the pixels in the panel. This requires the VCOM driver to supply continuous currents up to 35 mA. INPUT/OUTPUT CHARACTERISTICS The ADD8706 has five buffers specifically designed for the needs of an LCD panel. Figure 20 shows a typical gamma correction curve for a normally white twisted nematic LCD panel. The symmetric curve comes from the need to reverse the polarity on the LC pixels to avoid “burning” in the image. Therefore, the application requires gamma voltages that come close to both supply rails. To accommodate this transfer function, the five ADD8706 buffers have been designed with three different buffer designs in one package. VDD VG1 Buffer A has an NPN emitter-follower input stage, which provides an input range that includes the top rail, but is limited to 1.7 V away from the bottom rail. It is designed to source 15 mA of continuous current, making this buffer ideal for providing the top voltage on the RDAC string. Buffers B, C, and D use a single-supply PNP input stage with an intermediate common-mode voltage range. The output was designed to sink or source up to 15 mA of continuous current. The limited input range and equivalent sink and source current make these buffers suitable for the middle voltage ranges on the RDAC string. Buffer E also uses a single-supply PNP input stage, but the output is designed to sink only up to 15 mA of continuous current. This buffer is designed for the RDAC’s lower range. Amplifier F is designed with an input range limited to midscale applications. It is capable of delivering 35 mA of continuous current. These qualities make Amplifier F suitable for VCOM applications. IMPORTANT NOTE VG2 GAMMA VOLTAGE The outputs of the buffers and amplifier have been designed to match the performance needs of the gamma correction and VCOM circuits. All have rail-to-rail outputs, but the current drive capabilities differ. The difference in current drive and input voltage range determine the buffer and amplifier use. Because of the asymmetric nature of Buffers A and E, care must be taken to connect an input that forces the amplifiers to operate in their most productive output states. Buffer A has very limited sink capabilities, while Buffer E does not source well. Set the Buffer A input to enable the amplifier output to source current and set the Buffer E input to force a sinking output current. This means making sure the input is above the midpoint of the common-mode input range for Buffer A and below the midpoint for Buffer E. Mathematically speaking, make sure VIN > VS/2 for Buffer A and VIN < VS/2 for Buffer E. VG3 VG4 VG5 VG6 VG7 VG8 VG9 VSS 0 16 32 GRAY SCALE BITS 48 64 04352-0-003 VG10 Figure 20. LCD Gamma Correction Curve The nature of LCD panels introduces a large amount of parasitic capacitance from the column drivers as well as the capacitance associated with the liquid crystals via the common plane. This makes capacitive drive capability an important factor when designing the gamma correction circuit. Figure 21 shows an application using the ADD8706 to generate 10 gamma outputs. Note that the five outputs are routed through another resistor network to generate the extra five output voltages, which feed into the column driver. Rev. 0 | Page 9 of 12 ADD8706 VDD ADD8706 COLUMN DRIVER GAMMA 1 A GAMMA 2 B GAMMA 3 GAMMA 4 C GAMMA 5 GAMMA 6 D GAMMA 7 GAMMA 8 E GAMMA 9 GAMMA 10 VDD VCOM VCOM 00000-x-000 F Figure 21. ADD8706 Application Circuit Rev. 0 | Page 10 of 12 ADD8706 OUTLINE DIMENSIONS 5.10 5.00 4.90 16 9 4.50 4.40 4.30 6.40 BSC 1 8 PIN 1 1.20 MAX 0.15 0.05 0.30 0.19 0.65 BSC COPLANARITY 0.10 0.20 0.09 8° 0° SEATING PLANE 0.75 0.60 0.45 COMPLIANT TO JEDEC STANDARDS MO-153AB Figure 22. 16-Lead Thin Shrink Small Outline Package [TSSOP] (RU) Dimensions shown in millimeters ORDERING GUIDE Model1 ADD8706ARUZ ADD8706ARUZ-REEL 1 Temperature Range −40°C to +85°C −40°C to +85°C Package Description 16-Lead TSSOP 16-Lead TSSOP Z = Pb-free part. Rev. 0 | Page 11 of 12 Package Option RU-16 RU-16 ADD8706 NOTES © 2003 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C04352–0–10/03(0) Rev. 0 | Page 12 of 12