TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 features D D D D D D D D Video Camcorder PFB PACKAGE (TOP VIEW) STBY RESET CS SDIN SCLK ADCCLK D D BLKG CLVDO ADDOS AVDD4 AGND4 OBCLP D Single-Chip CCD and Video Signal Processor 10-Bit, 28-MSPS, A/D-Converter Single 3-V Supply Operation Very Low Power: 150 mW Typical, 2-mW Power-Down Mode Differential Nonlinearity Error: < ±0.5 LSB Typical Integral Nonlinearity Error: <±0.9 LSB Typical Programmable Gain Amplifier (PGA) With 0-dB to 36-dB Gain Range (0.045 dB/Step) Automatic or Programmable Optical Black Level and Offset Calibration With Digital Filter and Bad Pixel Limits Additional DACs for External Analog Setting Serial Interface for Register Configuration Internal-Reference Voltages 36 35 34 33 32 31 30 29 28 27 26 25 AGND5 RBD RMD RPD AVDD5 VSS AVDD1 AGND1 SR SV CLCCD CLREF 37 24 38 23 39 22 40 21 20 41 TLV990BPFB 42 18 44 17 45 16 46 15 47 14 13 48 1 48-Pin TQFP Package 19 43 2 3 4 5 6 7 8 OE SCKP DACO2 DACO1 AGND3 AVDD3 DIGND DIVDD D9 D8 D7 D6 9 10 11 12 CCDIN VIDEOIN AVDD2 AGND2 DGND DVDD D0 D1 D2 D3 D4 D5 D application description The TLV990B is a complete CCD and video signal processor/digitizer designed for video camcorder applications. The TLV990B performs all the analog-processing functions necessary to maximize the dynamic range, corrects various errors associated with the CCD sensor, and then digitizes the results with an on-chip high-speed analog-to-digital converter (ADC). The key components of the TLV990B include: an input clamp circuit for CCD and analog video signals, a correlated double sampler (CDS), a programmable-gain amplifier (PGA) with 0 to 36-dB gain range, two internal digital-to-analog converters (DAC) for automatic or programmable optical black level and offset calibration, a 10-bit, 28-MSPS pipeline ADC, a parallel data port for easy microprocessor interface, a serial port for configuring internal control registers, two additional DACs for external system control, and internal reference voltages. Designed in advanced CMOS process, the TLV990B operates from a single 3-V power supply with a normal power consumption of 150 mW at 28 MSPS, and 2 mW in power-down mode. Its very high throughput rate, single 3-V operation, very low-power consumption, and fully-integrated analog processing circuitry make the TLV990B an ideal CCD and video signal-processing solution for electronic video-camcorder applications. This device is available in a 48-pin TQFP package and is specified over a –20°C to 75°C operating-temperature range. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 2001, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 AVAILABLE OPTIONS PACKAGE DEVICE TA TQFP (PFB) – 20°C to 75°C TLV990BPFB functional block diagram AVDD1–5 CLVDO CLCCD CLREF Clamp RMD DVDD DIVDD OE INTERNAL REFERENCE 1.2 V REF CDS/ MUX CCDIN RPD RBD Σ PGA Σ Three State Latch 10-Bit ADC D0 D9 10 VIDEOIN 8-Bit CDAC PGA Regulator Offset Register DACO1 8-Bit DAC DAC REG DACO2 8-Bit DAC DAC REG 8-Bit FDAC Offset Register Digital Averager/ Filter Timing and Control Logic Serial Port VSS DGND AGND1–5 2 Optical Black Pixel Limits POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 DIGND RESET CLK SV SR BLKG OBCLP STBY ADDOS SCKP CS SCLK SDIN TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 Terminal Functions TERMINAL NAME I/O DESCRIPTION NO. ADCCLK 25 I ADC clock input ADDOS 34 I A dc offset is added to video input signal when the ADDOS is pulled low. AGND1 44 Analog ground for internal CDS circuits AGND2 4 Analog ground for internal PGA circuits AGND3 20 Analog ground for internal DAC circuits AGND4 32 Analog ground for internal ADC circuits AGND5 37 Analog ground for internal REF circuits AVDD1 AVDD2 43 Analog supply voltage for internal CDS circuits, 3 V 3 Analog supply voltage for internal PGA circuits, 3 V AVDD3 AVDD4 19 Analog supply voltage for internal DAC circuits, 3 V 33 Analog supply voltage for internal ADC circuits, 3 V AVDD5 BLKG 41 36 I Control input. The CDS operation is disabled when the BLKG is pulled low. CLCCD 47 I CCD signal clamp control input Analog supply voltage for internal ADC circuits, 3 V CCDIN 1 I CCD input CLREF 48 O Clamp reference voltage output CLVDO 35 I Video-signal clamp-control input. Only used in manual clamping mode. Active low. CS 28 I Chip select. A logic low on this input enables the serial port. D0 – D9 7–16 O 10-bit 3-state ADC output data or offset DACs test data DACO1 21 O Digital-to-analog converter output1 DACO2 22 O Digital-to-analog converter output2 DGND 5 Digital ground DIGND 18 Digital interface circuit ground DIVDD DVDD 17 Digital interface circuit supply voltage, 1.8 V– 4.4 V OBCLP 31 I Optical black level and offset calibration control input. Active low. OE 24 I Output data enable. Active low. RBD 38 O Internal bandgap reference for external decoupling RESET 29 I Hardware-reset input, active low. This signal forces a reset of all internal registers RMD 39 O Ref– output for external decoupling RPD 40 O Ref+ output for external decoupling SDIN 27 I Serial data input to configure the internal registers SCKP 23 I Selects the polarity of SCLK. 0 – active low (high when SCLK is not running), 1 – active high (low when SCLK is not running) SCLK 26 I Serial clock input. This clock synchronizes the serial data transfer. SR 45 I CCD reference level sample clock input STBY 30 I Hardware power-down control input, active low SV 46 I CCD signal level sample clock input VIDEOIN 2 I Analog video signal input VSS 42 6 Digital supply voltage, 3 V Silicon substrate, normally connected to analog ground POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Supply voltage, AVDD, DVDD, DIVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 6.5 V Analog input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to AVDD+0.3 V Digital input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to DVDD+0.3 V Operating virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to 150°C Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –20°C to 75°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. recommended operating conditions power supplies MIN NOM MAX 2.7 3 3.3 V Digital supply voltage AVDD DVDD 2.7 3 3.3 V Digital interface supply voltage DIVDD 1.8 4.4 V Analog supply voltage UNIT digital inputs, DIVDD = 3 V, DVDD = 3 V MIN High-level input voltage, VIH NOM MAX 0.8DIVDD Low-level input voltage, VIL V 0.2DIVDD 28 Input ADCCLK frequency UNIT V MHz ADCCLK pulse duration, clock high, tw(MCLKH) 17.8 ns ADCCLK pulse duration, clock low, tw(MCLKL) 17.8 ns Input SCLK frequency 40 MHz SCLK pulse duration, clock high, tw(SCLKH) 12.5 ns SCLK pulse duration, clock low, tw(SCLKL) 12.5 ns 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 electrical characteristics over recommended operating free-air temperature range, TA = 25°C, AVDD=DVDD=3 V, ADCCLK=28 MHz (unless otherwise noted) total device PARAMETER TEST CONDITIONS MIN AVDD operating current DVDD operating current TYP MAX 43 Device power consumption Power consumption in power-down mode UNIT mA 7 mA 150 mW 2 mW INL Full CCD channel integral nonlinearity AVDD=DVDD= 2.7 V – 3.3 V, ADCCLK=18 MSPS, 10 bits Using best fit method DNL Full CCD channel differential nonlinearity AVDD=DVDD= 2.7 V – 3.3 V, ADCCLK=18 MSPS, 10 bits ±0.5 ±0.99 LSB INL Video channel integral nonlinearity AVDD=DVDD= 2.7 V – 3.3 V, ADCCLK=28 MSPS, 9 bits Using best fit method ±0.5 ±2 LSB DNL Video channel differential nonlinearity AVDD=DVDD= 2.7 V – 3.3 V, ADCCLK=28 MSPS, 9 bits ±0.4 ±0.99 LSB No missing code ±0.9 ±2 LSB Assured Full channel output latency CLK cycles 6 analog-to-digital converter (ADC) PARAMETER TEST CONDITIONS ADC resolution in CCD mode MIN ADCCLK=18MSPS TYP MAX 10 Full scale input span Bits 2 Conversion rate UNIT 28 VP-P MHz MAX UNIT 28 MHz 1 V correlated double sample (CDS) and programmable gain amplifier (PGA) PARAMETER TEST CONDITIONS MIN TYP CDS and PGA sample rate CDS full-scale input span Single-ended input Input capacitance of CDS 4 Minimum PGA gain 0 1 dB 36 37 dB Maximum PGA gain 35 PGA gain resolution PGA programming code resolution pF 0.045 dB 10 Bits internal digital-to-analog converters (DAC) for offset correction PARAMETER TEST CONDITIONS DAC resolution MIN TYP MAX UNIT 8 Bits INL Integral nonlinearity ±0.5 LSB DNL Differential nonlinearity ±0.5 LSB Output settling time To 1% accuracy POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 80 ns 5 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 electrical characteristics over recommended operating free-air temperature range, TA = 25°C, AVDD=DVDD=3 V, ADCCLK=28 MHz (unless otherwise noted) user digital-to-analog converters (DAC) PARAMETER TEST CONDITIONS MIN DAC resolution INL Integral nonlinearity DNL Differential nonlinearity Output voltage range Assured by design Output settling time 10 pF external load, settle to 1 mV TYP MAX UNIT 8 Bits ±0.75 LSB ±0.5 LSB 0 VDD V µs 4 reference voltages PARAMETER TEST CONDITIONS Internal bandgap voltage reference MIN TYP MAX UNIT 1.43 1.50 1.58 V Temperature coefficient ADC Ref+ 100 Externally decoupled ADC Ref– ppm/°C 2 V 1 V digital specifications PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Logic inputs IIH IIL High-level input current Ci Input capacitance Low-level input current DIVDD = 3 V –10 10 –10 10 µA 5 pF DIVDD–0.4 0.4 V ±10 µA 5 pF Logic outputs VOH VOL High-level output voltage IOZ Co High-impedance-state output current Low-level output voltage IOH = 50 µA, DIVDD = 3 V IOL = 50 µA, DIVDD = 3 V Output capacitance V key timing requirements PARAMETER TEST CONDITIONS MIN TYP UNIT tSRW tSVW SR pulse width tOD tCSF ADCCLK-to-output data delay CS falling edge to SCLK rising edge 0 ns tCSR SCLK falling edge to CS rising edge 5 ns 6 SV pulse width Measured at 50% of pulse height 10 MAX ns 10 ns 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 ns TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 10 BIT-PGA GAIN CURVE 40 35 Gain – dB 30 25 20 15 10 5 0 0 200 400 600 800 PGA Codes 1000 1200 Figure 1 TYPICAL CHARACTERISTICS Optical Black Interval Dummy Black (Blanking) Interval Signal Interval CCD Output n n+1 SR tSRW SV tSvW BLKG CLCCD OBCLP ADCCLK Latency: 6 ADC Cycles tOD ADC OUT n Figure 2. System Operation Timing Diagram POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 TYPICAL CHARACTERISTICS tCSF tCSR CS 1 2 3 4 5 6 DI15 DI14 DI13 DI12 DI11 DI10 7 16 SCLK SDIN DI9 DI0 SCKP Pin Is Pulled Low tCSF tCSR CS 1 2 3 4 5 6 DI15 DI14 DI13 DI12 DI11 DI10 7 16 SCLK SDIN SCKP Pin Is Pulled High Figure 3. Serial Interface Timing Diagram 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 DI9 DI0 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 TYPICAL CHARACTERISTICS tSRD CCD IN tSVD SR SV tADC_SV ADCCLK MIN TIMING PARAMETER TYP MAX EXPLANATION tSRD Delay between sample reset (SR) rising edge and actual sampling instant (ns) 6 This is the fixed internal delay in the chip. The reset value of the CCD waveform should be stable until the end of this period. tSVD Delay between sample video (SV) rising edge and actual instant of video signal sampling (ns) 6 This is the fixed internal delay in the chip. The video signal value of the CCD waveform should be stable until the end of this period. tADC_SV Time between ADCCLK falling edge and SV falling edge 3 The timing margin required to ensure the ADCCLK positive half cycle is in between two SV pulses Figure 4. Detailed Internal Timing Diagram POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 APPLICATION INFORMATION AVDD 0.1 µF 1 µF AVDD 0.1 µF 0.1 µF 1 µF 1 µF 0.1 µF Inputs 1 µF 0.1 µF 8 9 10 RBD AGND5 RPD RMD SV TLV990BPFB D1 D2 D3 D4 D5 D6 11 12 DGND DVDD D0 35 Inputs Inputs OE 6 7 DVDD 36 34 ADDOS 33 AVDD4 32 AGND4 31 OBCLP 30 STBY 29 RESET 28 CS 27 SDIN 26 SCLK 25 SDCCLK SCKP 5 AGND3 DACO1 DACO2 0.1 µF 0.1 µF CLVDO VIDEOIN AVDD2 AGND2 DIGND AVDD3 AVDD AVDD BLKG D9 DIVDD 3 4 CCDIN D8 1 2 AVDD1 V SS AVDD5 0.1 µF SR AGND1 CLREF 48 47 46 45 44 43 42 41 40 39 38 37 CLCCD Video Signal 1 µF D7 0.1 µF Area CCD 13 14 15 16 17 18 19 20 21 22 23 24 Inputs D (0–9) DIVDD AVDD – 3 V DVDD – 3 V DIVDD – 1.8 V to 4.4 V AVDD 0.1 µF 0.1 µF Analog GND Digital GND NOTE: All analog outputs should be buffered if the load is resistive, or if the load is capacitive and greater than 2-pF. Figure 5. Typical Application Connection 10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 REGISTER DEFINITION serial input data format DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 X X A3 A2 A1 A0 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 A3 A2 A1 A0 0 0 0 0 Control register1 D9–D0 0 0 0 1 PGA gain register 0 0 1 0 User DAC1 register 0 0 1 1 User DAC2 register 0 1 0 0 Coarse offset DAC 0 1 0 1 Fine offset DAC 0 1 1 0 Digital Vb register (sets reference code level at the ADC output during the optical black interval) 0 1 1 1 Optical black setup register (sets the number of black pixels per line for digital averaging) 1 0 0 0 Hot/cold pixel limit register (sets the limit for maximum positive deviation of optical black pixel from Vb value) 1 0 0 1 Reserved 1 0 1 0 Control register2 (sets the weight for digital filtering and video modes) 1 0 1 1 Blanking data register (The data in this register appears at digital output during blanking (BLKG is low)) 1 1 0 0 ADCCLK internal programmable delay register 1 1 0 1 SR and SV internal programmable delay register 1 1 1 0 Test register 10-bit data to be written into the selected register control register1 format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 STBY PDD1 PDD2 ACD AFD OBM X SRSV RTOB RTSY control register1 description BIT NAME D9 STBY Device power-down control: 1 = standby, 0 = active (default) DESCRIPTION D8 PDD1 Power-down user DAC1: 1 = standby, 0 = active (default) D7 PDD2 Power-down user DAC2: 1 = standby, 0 = active (default) D6 ACD Coarse-offset DAC mode control: 0 = autocalibration (default), 1 = bypass autocalibration. Note: When D6 is set to 0, D5 must also be set to 0 (automode). Otherwise, the automode will be disabled on both offset DACs. D5 AFD Fine offset DAC mode control: 0 = autocalibration (default), 1 = bypass autocalibration. Note: D5 can be set to 0 with or without D6 being set to 0. D4 OBM This bit initiates the offset DACs starting sequence. 0 = coarse-offset DAC starts first (default) 1 = fine-offset DAC starts first D3 X Reserved D2 SRSV This bit specifies the polarity of SR and SV input pulses. 0 – SR/SV active low (default) 1 – SR/SV active high D1 RTOB Writing 1 to this bit will reset calculated black-level results in the digital averager. D0 RTSY Writing 1 to this bit will reset entire system to the default settings (edge sensitive). POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 REGISTER DEFINITION PGA register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default PGA gain = 0000000000 or 0 dB user DAC1 and DAC2 registers format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default user DAC register value = XX00000000 coarse offset DAC register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X SIGN Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 coarse offset DAC register description BIT NAME D9 X Reserved D8 SIGN Coarse DAC sign bit, 0 = + sign (default), 1 = – sign D7–D0 DESCRIPTION Coarse DAC control data when the D6 in the control register is set at 1. Default coarse DAC register value = X000000000 fine offset DAC register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X SIGN Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 fine offset DAC register description BIT NAME D9 X Reserved D8 SIGN Fine DAC sign bit, 0 = + sign (default), 1 = – sign D7–D0 DESCRIPTION Fine DAC control data when the D5 in the control register is set at 1. Default fine DAC register value = X000000000 digital Vb (optical black level) register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default Vb register value = 40 Hex 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 REGISTER DEFINITION optical black setup register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OMUX1 OMUX0 HYS X SOFW1 SOFW0 MP PN2 PN1 PN0 optical black setup register description BIT NAME D8, D9 OMUX1, OMUX0 D7 HYS D6 X D5, D4 SOFW1, SOFW0 D3 MP DESCRIPTION These two bits multiplex digital output (data presented at D[9:0] pins): OMUX1 OMUX0 0 0 D[9:0] = ADC output (default) 0 1 D[9:0] = ADC output 1 0 D[9] = fine/coarse (1/0) autocorrection flag D[8] = coarse DAC sign D[7:0] = coarse DAC value 1 1 D[9] = fine/coarse (1/0) autocorrection flag D[8] = fine DAC sign D[7:0] = fine DAC value Sets the hysteresis 0 – Apply hysteresis to FDAC (default) 1 – No hysteresis Reserved These two bits set the digital filter weight when SOF is activated (the SOF bit in control register 2 is set to 1). SOFW1 SOFW0 Weight 0 0 0 (default) 0 1 1 1 0 2 1 1 3 When this bit is 1, the number of optical black pixels to be averaged per line (2N) is multiplied by 3. By setting the MP and PN2–PN0 bits together, the number of optical black pixels can be programmed to have the following numbers: 1, 2, 3 (1X3), 4, 6 (2×3), 8, 12 (4×3), 16, 24 (8×3), 32, 48 (16×3), 64, 96 (32×3), and 192 (64×3). Default: MP = 0, no multiplication D2–D0 PN2–PN0 Number of optical black pixels per line to average = 2N N can be 0, 1, 2, 3, 4, 5, and 6. Or number of pixels per line can be 1, 2, 4, 8 (default), 16, 32, or 64. The maximum number of pixels per line is 64, even if N>6. Default optical black calibration register value = 0000000011 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 REGISTER DEFINITION hot/cold pixel limit register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X X X X HFIT hot/cold pixel limit register description Bit Name D9 – D1 X D0 HFIT Description Reserved Set hot/cold pixel filter 0 – Apply Vb ± .8 hot/cold pixel filtering 1 – No hot/cold pixel filtering (default) Default hot/cold pixel limit register value = 0000000001 control register2 format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 SOF NOS ASOF VGND INM ACL OBOB WT2 WT1 WT0 control register 2 description BIT NAME DESCRIPTION D9 SOF 0 – Normal mode (default) 1 – Start of frame (only used when exposure time is changed) When this bit is set to 1, next positive ADCCLK edge indicates that next pixel line is the beginning of a new frame. The optical black correction will be performed with one line averaging only (digital filtering weight = 1) and without hot/cold pixel limits. D8 NOS Internal test bit, add 255 to optical black pixels when this bit is set to 1; default = 0 D7 ASOF Enable the auto SOF: 1 – Automatically enable SOF at major gain changes (no digital filtering for 1 line) 0 – No auto SOF (default) D6 VGND Short VIDEOIN to GND when this bit is set to 1; default = 0 D5 INM This bit selects the input modes. 0 – CCD mode (default) 1 – Video mode D4 ACL 0 Video mode, autoclamp (default) 1 Video mode, manual clamp WT3–WT0 These three bits set the weight for digital filtering. WT3 WT2 WT1 WT0 Weight (effect of the averaged result of each optical black pixel line on overall optical black averaging) 0 0 0 0 1 0 0 0 1 1/2 0 0 1 0 1/2 0 0 1 1 1/8 0 1 0 0 1/16 0 1 0 1 1/32 0 1 1 0 1/64 0 1 1 1 1/128 (default) 1 0 0 0 1/256 D3–D0 Default control register2 value = X000000000 14 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 REGISTER DEFINITION blanking data register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 0 BDTA 0 0 0 0 0 blanking data register description BIT NAME D5 BDTA DESCRIPTION This register value appears at the digital output when BLKG is low. When this bit is set to 1, digital output during blanking will be VB. Register default value = 0. Default = 0000000000 ADCCLK internal delay register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X ADL3 ADL2 ADL1 ADL0 ADCCLK internal delay register description BIT NAME DESCRIPTION D9–D4 X D3–D0 ADL3–ADL0 Reserved These four bits set the internal ADCCLK delay. ADL3 ADL2 ADL1 ADL0 Typical internal delay 0 0 0 0 0 ns (default) : : 1 1 1 1 10 ns Default register value = XXXXXX0000 SR and SV internal delay register format D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X SVL3 SVL2 SVL1 SVL0 SRL3 SRL2 SRL1 SRL0 SR and SV internal delay register description BIT NAME DESCRIPTION D9–D8 X D7–D4 SVL3–SVL0 Reserved These four bits set the internal SV delay. SVL3 SVL2 SVL1 SVL0 Typical internal delay 0 0 0 0 0 ns (default) : : 1 1 1 1 10 ns D3–D0 SRL3–SRL0 These four bits set the internal SV delay. SRL3 SRL2 SRL1 SRL0 Typical internal delay 0 0 0 0 0 ns (default) : : 1 1 1 1 10 ns Default register value = XX00000000 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 PRINCIPLES OF OPERATION CCD mode operation The output from the CCD sensor is first fed to a correlated double sampler (CDS) through the CCDIN pin. The CCD signal is sampled and held during the reset reference interval and the video signal interval. By subtracting two resulting voltage levels, the CDS removes low frequency noise from the output of the CCD sensor and obtains the voltage difference between the CCD reference level and the video level of each pixel. Two sample/hold control pulses (SR and SV) are required to perform the CDS function. The CCD output is capacitively coupled to the TLV990B. The ac-coupling capacitor is clamped to establish proper dc bias during the dummy pixel interval by the CLCCD input. The bias at the input to the TLV990B is set to 1.2 V. Normally, CLCCD is applied at sensor’s line rate. A capacitor, with a value ten times larger than that of the input ac-coupling capacitor, should be connected between the CLREF pin and the AGND. When operating the TLV990B at its maximum speed, the CCD internal source resistance should be smaller than 50 Ω. Otherwise CCD output buffering is required. The signal is sent to the PGA after the CDS function is complete. The PGA gain can be adjusted from 0 to 36 dB by programming the internal gain register via the serial port. The PGA is digitally controlled with 10-bit resolution on a linear dB scale, resulting in a 0.045-dB gain step. The gain can be expressed by the following equation, Gain = PGA code × 0.045 dB Where PGA code has a range of 0 to 767. Due to different exposure times, there might be a sudden optical black level shift at the start of each frame. Thus, a quick optical black-level correction is desirable. The user can set an internal control bit (the SOF bit in control register2) to automatically disable the hot/cold pixel limits and to set the digital filtering weighting factor to 1 (equivalent to one-line averaging). In this way the optical black correction could be performed very quickly for the first line of each frame. The number pf black pixels in each line is programmable. The number of black pixels per line that can be averaged is 2N, where N can be any integer between 0 and 6. The autocalibration feature can be bypassed if the user prefers to directly program the offset DAC registers. Switching the autocalibration mode to the direct programming mode requires two register writes. First, the control bits for the offset DACs in the control register must be changed, then the desired register-offset value is loaded to the offset DAC registers for proper error correction. If the total offset, including optical black level, is less than ±255 ADC LSBs, only the FDAC needs to be programmed. When switching from direct programming mode to autocalibration mode, the previous DAC register values are used as starting offsets rather than default DAC register values. video mode operation The TLV990B also provides an analog video-processing channel that consists of an input clamp, a PGA, and an ADC. Setting the INM bit to 1 in control register2 enables the video channel. The video signal should be connected to the VIDEOIN pin via a 0.1-µF capacitor, as shown in Figure 5. The video input has its own clamp circuit operated in two modes: autoclamp, and manual clamp. In manual clamp mode, the input is clamped when CLVDO pin is pulled low. During this mode, the dc level of the video sync pulse is forced to the clamp reference voltage (1.2 V). If the dc level of the video sync pulse is less than the clamp voltage (1.2 V), the autoclamp mode can be selected (control register2). No external clamp-control signal is required. The CLVDO pin can be left open. 16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 PRINCIPLES OF OPERATION ADC The ADC employs a pipelined architecture to achieve high throughput and low power consumption. Fullydifferential implementation and digital-error correction ensure 10-bit resolution. The latency of the ADC data output is 6 ADCCLK cycles, as shown in Figure 1. Pulling the OE pin (pin 24) high puts the ADC output in high impedance. user DACs The TLV990B includes two user DACs that can be used for external analog settings. The output voltage of each DAC can be independently set and has a range of 0 V up to the supply voltage, with an 8-bit resolution. When the user DACs are not used in a camera system, they can be put in the standby mode by programming control bits in the control register. internal timing The SR and SV signals are required to operate the CDS, as previously explained. The user needs to synchronize the SR and SV clocks with the CCD signal waveform. The output of the ADC is read out to external circuitry by the ADCCLK signal, which is also used internally to control both ADC and PGA operations. It is required that the positive half cycle of the ADCCLK signal always falls in between two adjacent SV pulses as shown in Fig. 1. The user can then fine tune the ADCCLK timing in relation to the CDS timing to achieve optimal performance. The CLCCD signal is used to activate the input clamping and the OBCLP signal is used to activate auto-optical black and offset correction. input blanking function Large input transients may occur at the TLV990B’s input during some period of operation which can saturate the input circuits and cause long recovery time. To prevent circuit saturation the TLV990B includes an input blanking function that blocks the input signals by disabling the CDS operation whenever the BLKG input is pulled low. The TLV990B digital output will be set by the blanking data register after BLKG is pulled low. NOTE: If the BLKG pulse is located before the OBCLP pulse, there must be at least 4 pixels between the rising edge of the BLKG pulse and the falling edge of the OBCLP pulse. If the BLKG pulse is located after the OBCLP, the minimum number of pixels between the falling edge of the OBCLP and the falling edge of the BLKG pulse should be equal to the number of optical black pixels per line + 4. 3-wire serial interface A simple 3-wire (SCLK, SDIN, and CS) serial interface is provided to allow writing to the TLV990B internal registers. Serial clock SCLK can be run at a maximum frequency of 40 MHz. Serial data SDIN is 16 bits long. The two leading null bits are followed by four address bits for which the internal register is to be updated, and then ten bits of data to be written to the register. The CS pin must be held low to enable the serial port. Data transfer is initiated by the incoming SCLK after CS falls. The SCLK polarity is selectable by pulling the SCKP pin either high or low. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 17 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 PRINCIPLES OF OPERATION device reset When pin RESET (pin 29) is pulled low, all internal registers are set to their default values. The device also resets itself when it is first powered on. In addition, the TLV990B has a software-reset function that resets the device when writing a control bit to the control register. See the register definition section for the register default values. voltage references An internal precision-voltage reference of 1.5 V nominal is provided. This reference voltage is used to generate the ADC Ref– voltage of 1 V and Ref+ of 2 V. It is also used to set the clamp voltage. All internally-generated voltages are fixed values and cannot be adjusted. power-down mode (standby) The TLV990B implements both hardware and software power-down modes. Pulling pin STBY (pin 30) low puts the device in the low-power standby mode. Total supply current drops to about 0.6 mA. Setting a power-down control bit in the control register can also activate the power-down mode. The user can still program all internal registers during the power-down mode. power supply The TLV990B has several power-supply pins. Each major internal analog block has a dedicated AVDD supply pin. All internal digital circuitry is powered by DVDD. Both AVDD and DVDD are 3-V nominal. The DIVDD and DIGND pins supply power to the output digital driver (D9–D0). The DIVDD is independent of the DVDD and can be operated from 1.8 V to 4.4 V. This allows the outputs to interface with digital ASICs requiring different supply voltages. ground and decoupling All ground pins of the TLV990B are not internally connected and must be connected externally to PCB ground. General practices should apply to the PCB design to limit high-frequency transients and noise that are fed back into the supply and reference lines. This requires that the supply and reference pins be sufficiently bypassed. In the case of power supply decoupling, 0.1-µF ceramic chip capacitors are adequate to keep the impedance low over a wide frequency range. Recommended external decoupling for the three voltage-reference pins is shown in Figure 4. Since their effectiveness depends largely on the proximity to the individual supply pin, all decoupling capacitors should be placed as close as possible to the supply pins. To reduce high-frequency and noise coupling, it is highly recommended that digital and analog grounds be shorted immediately outside the package. This can be accomplished by running a low-impedance line between DGND and AGND under the package. 18 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 PRINCIPLES OF OPERATION automatic optical black and offset correction In the TLV990B, the optical black and system channel-offset corrections are performed by an autodigital feedback loop. Two DACs are used to compensate for both channel offset and optical black offset. A coarse correction DAC (CDAC) is located before PGA gain stage, and a fine correction DAC (FDAC) is located after the gain stage. The digital-calibration system is capable of correcting the optical black and channel offset down to one ADC LSB accuracy. The TLV990B automatically starts autocalibration whenever the OBCLP input is pulled low. The OBCLP pulse should be wide enough to cover one positive half cycle of the ADCCLK, as shown in Figure 1. For each line, the optical black pixels plus the channel offset are sampled and converted to digital data by the ADC. A digital circuit averages the data during the optical black pixels. The averaged result is compared digitally with the desired output code stored in the Vb register (default is 40H), then the FDAC is adjusted by control logic to make the ADC output equal to the Vb. If the offset is out of the range of the FDAC (±127 ADC LSBs), the error is corrected by both the CDAC and the FDAC. The CDAC increments or decrements by one CDAC LSB, depending on whether the offset is negative of positive, until the output is within the range of the FDAC. The remaining residue is corrected by the FDAC. The relationship among the FDAC, CDAC, and ADC in terms of number of ADC LSBs is as follows: 1 FDAC LSB = 1 ADC LSB, 1 CDAC LSB = PGA linear gain × n ADC LSB where n is: 2 for 0 ≤ gain code < 64 1.5 for 64 ≤ gain code < 96 1 for 96 ≤ gain code < 128 0.5 for 128 ≤ gain code For example, if PGA gain = 2 (6 dB), then, 1 CDAC LSB = 2 x 4 ADC LSBs = 8 ADC LSBs. After autocalibration is complete, the ADC’s digital output during CCD signal interval can be expressed by the following equation: ADC output [D9–D0] = CCD_input × PGA gain + Vb, where Vb is the desired black level selected by user. The total offset, including optical black offset, is calibrated to be equal to the Vb by adjusting the offset correction DACs during autocalibration. A weighted rolling average of the optical black pixels is taken during averaging. The weighting factor can be programmed in control register2. The weighting factor determines the speed of convergence of the digital filtering implemented within the CCD signal processor. Weighting factors closer to 1 result in faster convergence. As the weighting factor decreases towards its minimum value of 1/128, the speed of convergence of the digital filtering decreases. The algorithm also takes hot pixels and cold pixels into consideration. A hot optical black pixel is a defective pixel that generates too much charge, while a cold pixel is the one that generates very little or no charge. A digital comparator compares the digitized optical black pixels with user-selected hot and cold pixel limits. If the optical black pixel value is out of range, then that hot or cold pixel is replaced with the value of the previous pixel. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 19 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 PRINCIPLES OF OPERATION automatic optical black and offset correction (continued) Due to different exposure times, there might be a sudden optical black level shift at the start of each frame. Thus, a quick optical black level correction is desirable. The user can set an internal control bit (the SOF bit in control register2) to automatically disable the hot/cold pixel limits and to set the digital filtering weighting factor to 1 (equivalent to one-line averaging). In this way the optical black correction could be performed very quickly for the first line of each frame. The number of black pixels in each line is programmable. The number of black pixels per line that can be averaged is 2N, where N can be any integer from 0 to 6. The autocalibration feature can be bypassed if the user prefers to directly program the offset DAC registers. Switching the autocalibration mode to the direct-programming mode requires two register writes. First, the control bits for the offset DACs in the control register must be changed, then the desired offset value for the register is loaded to the offset DAC registers for proper error correction. If the total offset, including optical black level is less than ±255 ADC LSBs, only the FDAC needs to be programmed. When switching from directprogramming mode to autocalibration mode, the previous DAC register values, rather than default DAC register values, are used as starting offsets. 20 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLV990B 3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR SLAS327– FEBRUARY 2001 MECHANICAL DATA PFB (S-PQFP-G48) PLASTIC QUAD FLATPACK 0,27 0,17 0,50 36 0,08 M 25 37 24 48 13 0,13 NOM 1 12 5,50 TYP 7,20 SQ 6,80 9,20 SQ 8,80 Gage Plane 0,25 0,05 MIN 0°– 7° 1,05 0,95 Seating Plane 0,75 0,45 0,08 1,20 MAX 4073176 / B 10/96 NOTES: A. All linear dimensions are in millimeters. B. This drawing is subject to change without notice. C. Falls within JEDEC MS-026 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 21 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. 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