12-Channel Gamma Buffers with VCOM Buffer ADD8701 FEATURES Single-Supply Operation: 7 V to 16 V Dual-Supply Operation: 3.5 V to 8 V Supply Current: 13 mA Max Upper/Lower Buffers Swing to VDD/GND Continuous Output Current: 10 mA VCOM Peak Output Current: 250 mA Offset Voltage: 15 mV Max Slew Rate: 6 V/s Fast Settling Time with Large C-Load GND V12 V11 V10 V9 V8 V7 31 30 26 28 27 26 25 VDD 1 24 GND 2 23 VDD IN12 3 22 V6 IN11 4 21 V5 IN10 5 20 V4 IN9 6 19 V3 9 10 11 12 13 14 15 16 IN3 IN2 IN1 VDD GND 17 V1 IN4 18 V2 8 IN5 7 IN7 IN6 IN8 GENERAL DESCRIPTION The buffers have high slew rate, 10 mA continuous output current, and high capacitive load drive capability. The VCOM buffer has increased drive of 35 mA and can drive large capacitive loads. The ADD8701 offers wide supply range and offset voltages below 15 mV. 32 VCOM IN APPLICATIONS TFT LCD Panels The ADD8701 is a low cost, 12-channel buffer amplifier and VCOM driver that operates from a single supply. The part is designed for high resolution TFT LCD panels, and is built on an advanced, high voltage, CBCMOS process. VCOM OUT FUNCTIONAL BLOCK DIAGRAM The ADD8701 is specified over the –40ºC to +85ºC temperature range and is available in a 32-lead lead frame chip scale package (LFCSP). All inputs and outputs incorporate internal ESD protection circuits. VDD PANEL TIMING CONTROLLER V12 TIMING AND CONTROL GAMMA REFERENCE VOLTAGES SCAN DRIVER CONTROL SOURCE DRIVER NO. 1 SOURCE DRIVER NO. 2 SOURCE DRIVER NO. 8 384 384 384 RESISTOR LADDER ADD8701 R G B SCAN DRIVERS 768 VCOM OUT TFT COLOR PANEL 1024 ⴛ 768 V1 GND VCOM IN VDD Figure 1. Typical SVGA TFT-LCD Application 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. 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 companies. 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. ADD8701–SPECIFICATIONS ELECTRICAL CHARACTERISTICS (7 V ≤ V DD ≤ 16 V, TA = 25°C, unless otherwise specified.) Parameter Symbol Condition INPUT CHARACTERISTICS Offset Voltage Offset Voltage Drift Input Bias Current VOS ∆VOS/∆T IB –40°C ≤ TA ≤ +85°C Input Voltage Range Input Impedance Input Capacitance OUTPUT CHARACTERISTICS Output Voltage High (V11, V12) Min Typ Max Unit 4 5 0.5 15 mV µV/°C µA µA V kΩ pF –40°C ≤ TA ≤ +85°C –0.5 ZIN CIN VOUT 1.1 1.5 VDD + 0.5 400 1 IOUT IPK VDD = 16 V 10 150 V V V V V V V mV mV mV mV mV mA mA VCOM CHARACTERISTICS Continuous Output Current Peak Output Current IOUT IPK VDD = 16 V 35 250 mA mA TRANSFER CHARACTERISTICS Gain AVCL 0.9985 1.005 0.9980 1.005 V/V V/V 0.01 % Output Swing (V3 to V10) Output Swing (V3 to V10) Output Voltage Low (V1, V2) Continuous Output Current Peak Output Current Gain Linearity SUPPLY CHARACTERISTICS Supply Voltage Power Supply Rejection Ratio Supply Current DYNAMIC PERFORMANCE Slew Rate Bandwidth Settling Time to 0.1% (Buffers) Settling Time to 0.1% (VCOM) Phase Margin Channel Separation NOISE PERFORMANCE Voltage Noise Density Current Noise Density VOUT VOUT VOUT NL VDD PSRR ISYS IL = 100 µA VDD = 16 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VDD = 7 V, IL = 5 mA –40°C ≤ TA ≤ +85°C IL = 5 mA, VDD = 16 V IL = 5 mA, VDD = 7 V IL = 100 µA VDD = 16 V, IL = 5 mA –40°C ≤ TA ≤ +85°C VDD = 7 V, IL = 5 mA –40°C ≤ TA ≤ +85°C RL = 2 kΩ –40°C ≤ TA ≤ +85°C RL = 10 kΩ VO = 0.5 to (VDD – 0.5 V) 15.85 15.75 6.75 6.65 15.995 15.9 6.85 14.6 5.6 5 85 140 0.995 0.995 7 VDD = 6 V to 17 V –40°C ≤ TA ≤ +85°C No Load –40°C ≤ TA ≤ +85°C SR BW tS tS fo RL = 10 kΩ, CL = 200 pF –3 dB, RL = 10 kΩ, CL = 200 pF 1 V, RL = 10 kΩ, CL = 200 pF 1 V, RL = 10 kΩ, CL = 200 pF RL = 10 kΩ, CL = 200 pF en en in f = 1 kHz f = 10 kHz f = 10 kHz 70 4 90 10 150 250 300 400 16 V 13 15 dB mA mA 6 4.5 1.1 0.7 55 75 V/µs MHz µs µs Degrees dB 26 25 0.8 nV/√Hz nV/√Hz pA/√Hz Specifications subject to change without notice. –2– REV. 0 ADD8701 ABSOLUTE MAXIMUM RATINGS* PIN CONFIGURATION 32 VCOM OUT 31 GND 30 V12 29 V11 28 V10 27 V9 26 V8 25 V7 Supply Voltage (VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V Input Voltage . . . . . . . . . . . . . . . . . . . . . –0.5 V to VDD + 0.5 V Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C Operating Temperature Range . . . . . . . . . . . . –40°C to +85°C Junction Temperature Range . . . . . . . . . . . . . –65°C to +150°C Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300°C ESD Tolerance (HBM) . . . . . . . . . . . . . . . . . . . . . . . ±1,000 V VDD 1 VCOM IN 2 IN12 3 IN11 4 IN10 5 IN9 6 IN8 7 IN7 8 Package Type JA1 JB2 Unit 32-Lead LFCSP (CP) 35 13 °C/W ORDERING GUIDE Temperature Range ADD8701ACP –40°C to +85°C Package Description TOP VIEW PIN FUNCTION DESCRIPTION NOTES 1 θJA is specified for worst-case conditions, i.e., θJA is specified for device soldered in circuit board for surface-mount packages. 2 ψJB is applied for calculating the junction temperature by reference to the board temperature. Model ADD8701 Package Option 32-Lead LFCSP CP-32 Pin No. Mnemonic Description 1, 15, 23 VDD Power (+) 2 VCOM IN VCOM Buffer Input 3–14 IN12–IN1 Gamma Buffer Inputs 16, 24, 31 GND Power (–) 17–22, 25–30 V1–V12 Gamma Buffer Outputs 32 VCOM OUT VCOM Buffer Output 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 the ADD8701 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 24 GND 23 VDD 22 V6 21 V5 20 V4 19 V3 18 V2 17 V1 IN6 9 IN5 10 IN4 11 IN3 12 IN2 13 IN1 14 VDD 15 GND 16 *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. PIN 1 INDICATOR –3– ADD8701–Typical Performance Characteristics 1,400 600 400 INPUT OFFSET VOLTAGE – mV 800 5,000 4,000 3,000 2,000 200 1,000 0 –5 –3 –1 1 3 5 7 INPUT OFFSET VOLTAGE – mV 9 5 TPC 1. Input Offset Voltage Distribution 10 15 20 25 30 TCVOS – V/C 35 6 OFFSET VOLTAGE – mV 4 2 0 –2 –4 –6 –8 –6 –4 –2 0 2 4 6 COMMON-MODE VOLTAGE – V TPC 4. Offset Voltage vs. Common-Mode Voltage 2 0 –2 –4 –6 –6 –4 –2 0 2 4 6 COMMON-MODE VOLTAGE – V 8 –300 300 –600 –700 VDD = 16V BUFFERS 3 TO 9 100 10 ∆OUTPUT VOLTAGE – V ∆OUTPUT VOLTAGE – V VDD = 16V 85 25 TEMPERATURE – C 100 10 150 VDD = 7V –500 VDD = 16V BUFFERS 1, 2 VDD = 7V VDD = 16V –400 TPC 6. Input Bias Current vs. Temperature 100 200 85 –800 BUFFERS 10 TO 12 250 25 TEMPERATURE – C –200 –900 –40 TPC 5. Offset Voltage vs. Common-Mode Voltage 350 –10 VCOM AND BUFFERS 1 TO 9 4 –10 –8 8 BUFFER 12 –5 –100 –8 –10 –8 0 0 VDD = 8V VCOM, BUFFERS 1 TO 9 INPUT BIAS CURRENT – nA 6 BUFFER 1 TPC 3. Input Offset Voltage vs. Temperature 8 VDD = 8V BUFFERS 10 TO 12 VCOM 5 –20 –40 40 TPC 2. TCVOS Distribution 8 10 –15 0 –7 INPUT BIAS CURRENT – nA 7V < VDD < 16V 15 6,000 1,000 OFFSET VOLTAGE – mV 20 7V < VDD < 16V NUMBER OF AMPLIFIERS NUMBER OF AMPLIFIERS 1,200 7,000 TA = 25C 7V < V DD < 16V SOURCE 1 0.1 SINK 0.01 SOURCE 1 SINK 0.1 0.01 50 0 –40 25 TEMPERATURE – C TPC 7. Input Bias Current vs. Temperature 85 0.001 0.01 0.1 1 10 LOAD CURRENT – mA TPC 8. Output Voltage to Supply Rail vs. Load Current –4– 100 0.001 0.01 0.1 1 10 LOAD CURRENT – mA 100 TPC 9. Output Voltage to Supply Rail vs. Load Current REV. 0 ADD8701 100 100 10 VDD = 16V BUFFERS 11, 12 VDD = 16V BUFFER 10 10 SINK 1 SOURCE 0.1 1 SINK 1 0.1 SOURCE 0.01 0.01 0.001 0.01 0.1 1 10 LOAD CURRENT – mA 0.1 1 10 LOAD CURRENT – mA 4 VDD = 16V VCOM AND BUFFERS 1 TO 9 10 VDD = 7V 8 6 4 8 12 SUPPLY VOLTAGE – V 150 10 10k 2k 1k 560 –10 150 –20 10M 30M TPC 16. Frequency Response vs. Resistive Loading REV. 0 60 40 1M FREQUENCY – Hz 10M 30M TPC 15. Frequency Response vs. Resistive Loading 20 ALL CHANNELS VDD = 8V TA = +25C 10 VDD = 16V VCOM, BUFFERS 1 TO 9 100pF 0 20 0 GAIN – dB VDD = 16V BUFFERS 10 TO 12 POWER SUPPLY REJECTION RATIO – dB 80 20 1M FREQUENCY – Hz –30 100k 85 25 TEMPERATURE – C TPC 14. Supply Current vs. Temperature TPC 13. Supply Current vs. Supply Voltage 0 –10 –20 0 –40 16 10k 2k 1k 560 0 4 2 2 100 20 GAIN – dB SUPPLY CURRENT – mA 6 0.1 1 10 LOAD CURRENT – mA TPC 12. Output Voltage to Supply Rail vs. Load Current VDD = 16V 8 –30 100k SINK 0.01 0.0001 0.01 10 10 SUPPLY CURRENT – mA 100 12 VCM = 1/2 VDD 0 0.1 TPC 11. Output Voltage to Supply Rail vs. Load Current 12 SOURCE 0.001 0.001 0.01 100 TPC 10. Output Voltage to Supply Rail vs. Load Current GAIN – dB ∆OUTPUT VOLTAGE – V ∆OUTPUT VOLTAGE – V ∆OUTPUT VOLTAGE – V 10 0 VDD = 16V VCOM –20 –40 –10 50pF 540pF –20 PSRR –60 1040pF –30 –80 –40 –100 –120 100 1k 10k 100k FREQUENCY – Hz 1M 10M TPC 17. Power Supply Rejection Ratio vs. Frequency –5– –50 100k 1M FREQUENCY – Hz 10M 30M TPC 18. Frequency Response vs. Capacitive Loading ADD8701 VDD = 16V BUFFERS 10 TO 12 160 100pF –10 50pF 540pF –20 –30 1040pF –40 CHANNELS 11 AND 12 140 CHANNELS 3 TO 9 VCOM 120 CHANNELS 1 AND 2 100 80 1M FREQUENCY – Hz 10M 40 30M TPC 19. Frequency Response vs. Capacitive Loading CHANNEL 11 140 VCOM CHANNEL 3 120 CHANNEL 1 100 60 –50 100k VDD = 16V RL = 2k 160 80 60 0 200 400 600 800 1,000 CAPACITIVE LOAD – pF 40 1,200 TPC 20. Input-Output Phase Shift vs. Capacitive Load 0 200 400 600 800 1,000 CAPACITIVE LOAD – pF 1,200 TPC 21. Input-Output Phase Shift vs. Capacitive Load 16 VDD = 16V 14 VDD = 16V RNULL = 33 CL = 100pF SLEW RATE – V/s VOLTAGE – 2V/DIV 12 VOLTAGE – 20mV/DIV GAIN – dB 0 PHASE SHIFT – Degrees 10 180 VDD = 7V RL = 2k PHASE SHIFT – Degrees 180 20 10 VCOM SLEW RATE FALLING 8 VCOM SLEW RATE RISING 6 4 7V < VDD < 16V ROUT SERIES = 33 CLOAD = 0.1F 2 0 –40 TIME – 2s/DIV TPC 22. Large-Signal Transient Response 60 8 –OS +OS 50 40 30 4 VCOM VDD = 8V RL = 5k CL = 100pF RNULL = 33 TA = 25C +tS (0.1%) 0 –4 –tS (0.1%) 20 –8 10 0 10 TPC 24. Small Signal Transient Response VOLTAGE – 3V/DIV 70 TIME – 20s/DIV 12 VDD = 8V VIN = 50mV RL = 2k TA = 25C STEP SIZE – V OVERSHOOT – % 80 85 TPC 23. Slew Rate vs. Temperature 100 90 25 TEMPERATURE – C 100 1k CAPACITIVE LOAD – pF 10k TPC 25. Small-Signal Overshoot vs. Capacitive Load –12 400 600 800 1,000 1,200 SETTLING TIME – ns 1,400 TPC 26. Settling Time vs. Step Size –6– TIME – 40s/DIV TPC 27. No Phase Reversal REV. 0 ADD8701 70 60 50 40 30 20 10 0 –10 0 5 10 15 FREQUENCY – Hz 20 25 TPC 28. Voltage Noise Density vs. Frequency VDD = 16V BUFFERS 10 TO 12 MARKER SET @ 10kHz MARKER READING = 36.6nV/ Hz 60 50 40 30 20 10 0 –10 0 5 10 15 FREQUENCY – Hz 20 25 TPC 29. Voltage Noise Density vs. Frequency APPLICATIONS LCD Gamma Reference Buffers In high resolution TFT-LCD displays, gamma correction must be performed to correct the nonlinearity in the LCD panel’s transmission characteristics. A typical TFT-LCD panel consisting of 256 grayscale levels takes an 8-bit digital word to select an appropriate gamma reference voltage. An 8-bit source driver may use 12 analog voltages that match the characteristic gamma curve for optimum panel picture quality. The ADD8701 is specifically designed to generate analog reference voltages to meet the gamma characteristics of an LCD panel used by the source driver. The gamma reference buffers offer 10 mA drive capability. The ADD8701 is designed to meet the rail-to-rail capability needed by the application and yet offers a low cost-per-channel solution. The design maximizes the die area by offering channels to swing to the positive and negative rails. It is imperative that the channels swinging close to the supply rail be used for the positive gamma references and that the channels swinging close to GND be used for the negative gamma references. See Figure 2 for an example of the application circuit. A12 GMA A11 GMA A10 GMA A9 GMA A8 GMA A7 GMA A6 GMA A5 GMA A4 GMA A3 GMA A2 GMA A1 GMA POSITIVE GAMMA REFERENCES VDD = 16V VCOM AND BUFFERS 1 TO 9 MARKER SET @ 10kHz MARKER READING = 25.7nV/ Hz VOLTAGE NOISE DENSITY – nV/ Hz VOLTAGE NOISE DENSITY – nV/ Hz 70 The output of the VCOM buffer is designed to control the voltage on the back plate of the LCD display. The buffer must be capable of sinking and sourcing capacitive pulse current. The amplifier stability is designed for high load capacitance. A high quality ceramic capacitor is recommended to supply short duration current pulses at the output. The VCOM buffer of the ADD8701 can handle up to 35 mA of continuous output current and can drive up to 1,000 nF of pure capacitive load. Unused Buffers Inputs of any unused buffer should be tied to the ground plane. ADD8701 LCD SOURCE DRIVER Figure 2. Application Circuit REV. 0 –7– NEGATIVE GAMMA REFERENCES LCD VCOM Buffer ADD8701 OUTLINE DIMENSIONS 32-Lead Lead Frame Chip Scale Package [LFCSP] (CP-32) 5.00 BSC SQ 0.60 MAX PIN 1 INDICATOR 12 MAX 32 1 0.50 BSC 4.75 BSC SQ 3.25 3.10 SQ 2.95 BOTTOM VIEW 0.50 0.40 0.30 1.00 0.90 0.80 PIN 1 INDICATOR 0.60 MAX 25 24 TOP VIEW C03599–0–4/03(0) Dimensions shown in millimeters 17 16 9 8 3.50 REF 0.80 MAX 0.65 NOM 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.23 0.18 0.20 REF COPLANARITY 0.08 COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2 –8– REV. 0