AD ADD8701 12-channel gamma buffers with vcom buffer Datasheet

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