TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 features D D D D D D D D D PW OR NS PACKAGE (TOP VIEW) 8-Bit Resolution Differential Linearity Error – ± 0.3 LSB Typ, ± 1 LSB Max (25°C) – ± 1 LSB Max Integral Linearity Error – ± 0.6 LSB, ± 0.75 LSB Max (25°C) – ± 1 LSB Max Maximum Conversion Rate of 40 Megasamples Per Second (MSPS) Max Internal Sample and Hold Function 5-V Single Supply Operation Low Power Consumption . . . 85 mW Typ Analog Input Bandwidth . . . ≥ 75 MHz Typ Internal Reference Voltage Generators OE DGND D1(LSB) D2 D3 D4 D5 D6 D7 D8(MSB) VDDD CLK 1 24 2 23 3 22 4 21 5 20 6 19 7 18 8 17 9 16 10 15 11 14 12 13 DGND REFB REFBS AGND AGND ANALOG IN VDDA REFT REFTS VDDA VDDA VDDD AVAILABLE OPTIONS applications D D D D D D D PACKAGE Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK) Demodulators Digital Television Charge-Coupled Device (CCD) Scanners Video Conferencing Digital Set-Top Box Digital Down Converters High-Speed Digital Signal Processor Front End TA TSSOP (PW) SOP (NS) – 0°C to 70°C TLC5540CPW TLC5540CNSLE – 40°C to 85°C TLC5540IPW TLC5540INSLE description The TLC5540 is a high-speed, 8-bit analog-to-digital converter (ADC) that converts at sampling rates up to 40 megasamples per second (MSPS). Using a semiflash architecture and CMOS process, the TLC5540 is able to convert at high speeds while still maintaining low power consumption and cost. The analog input bandwidth of 75 MHz (typ) makes this device an excellent choice for undersampling applications. Internal resistors are provided to generate 2-V full-scale reference voltages from a 5-V supply, thereby reducing external components. The digital outputs can be placed in a high impedance mode. The TLC5540 requires only a single 5-V supply for operation. 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 1999, 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 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 functional block diagram Resistor Reference Divider OE REFB 270 Ω NOM Lower Sampling Comparators (4 Bit) REFT REFBS Lower Encoder (4 Bit) D1(LSB) D2 Lower Data Latch 80 Ω NOM D3 AGND D4 Lower Sampling Comparators (4 Bit) AGND Lower Encoder (4 Bit) VDDA D5 320 Ω NOM REFTS ANALOG IN CLK D6 Upper Data Latch Upper Sampling Comparators (4 Bit) D7 Upper Encoder (4 Bit) D8(MSB) Clock Generator schematics of inputs and outputs EQUIVALENT OF ANALOG INPUT EQUIVALENT OF EACH DIGITAL INPUT VDDA AGND VDDD D1 – D8 OE, CLK ANALOG IN 2 VDDD EQUIVALENT OF EACH DIGITAL OUTPUT DGND POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 DGND TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 Terminal Functions TERMINAL NAME AGND NO. I/O 20, 21 DESCRIPTION Analog ground ANALOG IN 19 I Analog input CLK 12 I Clock input DGND 2, 24 D1 – D8 3 – 10 O Digital data out. D1:LSB, D8:MSB 1 I Output enable. When OE = L, data is enabled. When OE = H, D1–D8 is high impedance. OE VDDA VDDD 14, 15, 18 REFB 23 REFBS 22 REFT 17 REFTS 16 Digital ground Analog VDD 11, 13 Digital VDD I ADC reference voltage in (bottom) Reference voltage (bottom). When using the internal voltage divider to generate a nominal 2-V reference, the REFBS terminal is shorted to the REFB terminal and the REFTS terminal is shorted to the REFT terminal (see Figure 13 and Figure 14). I Reference voltage in (top) Reference voltage (top). When using the internal voltage divider to generate a nominal 2-V reference, the REFTS terminal is shorted to the REFT terminal and the REFBS terminal is shorted to the REFB terminal (see Figure 13 and Figure 14). absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VDDA, VDDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Reference voltage input range, VI(REFT), VI(REFB), VI(REFBS), VI(REFTS) . . . . . . . . . . . . . . . AGND to VDDA Analog input voltage range, VI(ANLG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AGND to VDDA Digital input voltage range, VI(DGTL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DGND to VDDD Digital output voltage range, VO(DGTL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DGND to VDDD Operating free-air temperature range, TA: TLC5540C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C TLC5540I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 40°C to 85°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 150°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. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 recommended operating conditions Supply voltage MIN NOM MAX VDDA – AGND VDDD – AGND 4.75 5 5.25 4.75 5 5.25 AGND – DGND – 100 0 100 Reference input voltage (top), VI(REFT) VI(REFB)+1.8 0 Reference input voltage (bottom), VI(REFB) Analog input voltage range, VI(ANLG) (see Note 1) Full scale voltage, VI(REFT) – VI(REFB) VI(REFB) 1.8 High-level input voltage, VIH VI(REFB)+2 0.6 VDDA VI(REFT)–1.8 VI(REFT) 5 4 Low-level input voltage, VIL UNIT V mV V V V V V 1 V Pulse duration, clock high, tw(H) 12.5 ns Pulse duration, clock low, tw(L) 12.5 ns TLC5540C Operating free-air free air temperature, temperature TA TLC5540I NOTE 1: 1.8 V ≤ VI(REFT) – VI(REFB) < VDD 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 0 70 °C – 40 85 °C TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 electrical characteristics at VDD = 5 V, VI(REFT) = 2.6 V, VI(REFB) = 0.6 V, fs = 40 MSPS, TA = 25°C (unless otherwise noted) TEST CONDITIONS† PARAMETER EL ED Linearity error error, integral Linearity error error, differential fs = 40 MSPS,, VI = 0.6 V to 2.6 V Self bias (1), VRB Short REFB to REFBS Self bias (1), VRT Short REFT to REFTS Self bias (2), VRB Short REFB to AGND TYP MAX TA = 25°C TA = MIN to MAX MIN ± 0.6 ±1 TA = 25°C TA = MIN to MAX ± 0.3 ± 0.75 See Figure 13 See Figure 14 Self bias (2), VRT Short REFT to REFTS Reference-voltage current Reference-voltage resistor VI(REFT) – VI(REFB) = 2 V Between REFT and REFB terminals Ci Analog input capacitance VI(ANLG) = 1.5 V + 0.07 Vrms EZS EFS Zero-scale error 0.57 0.61 0.65 2.47 2.63 2.80 IIH IIL High-level input current Low-level input current VDD = 5.25 V, VDD = 5.25 V, VIH = VDD VIL = 0 IOH IOL High-level output current OE = GND, Low-level output current OE = GND, VDD = 4.75 V, VDD = 4.75 V, VOH = VDD – 0.5 V VOL = 0.4 V IOZH(lkg) High-level high-impedance-state output leakage current OE = VDD, VDD = 5.25, VOH = VDD IOZL(lkg) Low-level high-impedance-state output leakage current OE = VDD, VDD = 4.75, IDD Supply current fs = 40 MSPS, CL 25 pF, NTSC‡ ramp wave input, See Note 2 V 2.18 2.29 5.2 7.5 2.4 12 mA 165 270 350 Ω – 18 – 43 – 68 – 25 0 25 4 VI(REFT) – VI(REFB) = 2 V LSB ±1 AGND Iref Rref Full-scale error ±1 UNIT pF 5 5 – 1.5 mV µA mA 2.5 16 µA VOL = 0 16 17 27 mA † Conditions marked MIN or MAX are as stated in recommended operating conditions. ‡ National Television System Committee NOTE 2: Supply current specification does not include Iref. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 operating characteristics at VDD = 5 V, VRT = 2.6 V, VRB = 0.6 V, fs = 40 MSPS, TA = 25°C (unless otherwise noted) TEST CONDITIONS† PARAMETER fs fs Maximum conversion rate Minimum conversion rate TA = MIN to MAX TA = MIN to MAX BW Analog input full-power bandwidth At – 3 dB, tpd tPHZ Delay time, digital output VI(ANLG) = 2 Vpp CL ≤ 10 pF (see Note 3) Disable time, output high to Hi-Z CL ≤ 15 pF, tPLZ tPZH Disable time, output low to Hi-Z CL ≤ 15 pF, Enable time, Hi-Z to output high CL ≤ 15 pF, tPZL Enable time, Hi-Z to output low CL ≤ 15 pF, Differential gain NTSC 40 IRE‡ modulation wave, fs = 14.3 MSPS Differential phase tAJ td(s) fs = 40 MSPS ENOB Effective number of bits fs = 40 MSPS fs = 20 MSPS THD Total harmonic distortion fs = 40 MSPS Spurious free dynamic range fs = 20 MSPS fs = 40 MSPS POST OFFICE BOX 655303 MSPS 9 MHz 15 ns IOH = – 4.5 mA IOL = 5 mA 20 ns 20 ns IOH = – 4.5 mA IOL = 5 mA 15 ns 15 ns fI = 1 MHz fI = 3 MHz 1% fI = 3 MHz fI = 6 MHz 0.7 degrees 30 ps 4 ns 47 44 fI = 6 MHz fI = 10 MHz 47 46 45 44 42 7.64 7.61 fI = 10 MHz fI = 3 MHz 7.16 fI = 6 MHz fI = 1 MHz 6.8 fI = 3 MHz fI = 6 MHz 7.47 43 35 42 41 38 dBc 40 fI = 6 MHz • DALLAS, TEXAS 75265 Bits 7 fI = 10 MHz fI = 3 MHz fI = 3 MHz dB 45.2 42 fI = 3 MHz fI = 6 MHz † Conditions marked MIN or MAX are as stated in recommended operating conditions. ‡ Institute of Radio Engineers NOTE 3: CL includes probe and jig capacitance. 6 UNIT MSPS 5 fI = 10 MHz fI = 1 MHz fs = 20 MSPS MAX 75 Sampling delay time Signal-to-noise ratio TYP 40 Aperture jitter time fs = 20 MSPS SNR MIN 38 41 46 42 dBc TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 PARAMETER MEASUREMENT INFORMATION tw(H) tw(L) CLK (Clock) ANALOG IN (Input Signal) D1 – D8 (Output Data) N+2 N+1 N N+4 N+3 N–3 N–2 N–1 N N+1 tpd Figure 1. I/O Timing Diagram Reference Level (2.5 V) OE Data Output Active Hi-Z 2.4 V Active 0.4 V tPHZ tPLZ tPZH tPZL Figure 2. I/O Timing Diagram POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 TYPICAL CHARACTERISTICS POWER DISSIPATION vs SAMPLING FREQUENCY ANALOG INPUT BANDWIDTH 0.5 200 VDD = 5 V TA = 25°C 0 –1 – 1.5 Gain – dB Power Dissipation – mW – 0.5 150 100 –2 – 2.5 –3 – 3.5 50 VCC = 5 V, VRT = 2.6 V, VRB = 0.6 V CLK = 40 MHz ANALOG IN = 100 k – 100 MHz Sine Wave VI = 2 V(PP) –4 – 4.5 –5 0.1 0 0 5 25 35 10 20 30 15 fs – Sampling Frequency – MHz 40 1 Figure 3 SIGNAL-TO-NOISE RATIO vs INPUT FREQUENCY 50 8 fs = 20 MHz fs = 20 MHz 45 7 SNR – Signal-to-Noise Ratio – dB ENOB – Effective Number of Bits – BITS 100 Figure 4 EFFECTIVE NUMBER OF BITS vs INPUT FREQUENCY fs = 40 MHz 6 5 4 3 2 VDD = 5 V, VI = 1 V(PP) VRB = 2.6 V, VRT = 0.6 V 1 0 fs = 40 MHz 40 35 30 25 20 15 10 VDD = 5 V, VI = 1 V(PP) VRB = 2.6 V, VRT = 0.6 V 5 0 0 5 10 15 0 fI – Input Frequency – MHz 5 10 fI – Input Frequency – MHz Figure 5 8 10 fI – Input Frequency – MHz Figure 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 TYPICAL CHARACTERISTICS EFFECTIVE NUMBER OF BITS vs AMBIENT TEMPERATURE DIFFERENTIAL NONLINEARITY 8 1 Differential Nonlinearity – LSB 0.8 0.6 ENOB – Effective Number of Bits – BITS VI = Vramp = 0.6 V – 2.6 V, 500 Hz VRT = 2.6 V, VRB = 0.6 V, VDD = 5 V fs = 40 MHz TA = 25°C 0.4 0.2 0 – 0.2 – 0.4 – 0.6 – 0.8 40 80 120 160 200 7.5 7 6.5 6 – 40 –1 0 VDD = 5 V, VI = 1 V(PP), 3 MHz Sine Wave VRT = 2.6 V, VRB = 0.6 V, fs = 20 MHz 240 – 20 0 20 Figure 7 INTEGRAL NONLINEARITY FFT SPECTRUM VI = Vramp = 0.6 V – 2.6 V, 500 Hz VRT = 2.6 V, VRB = 0.6 V, VDD = 5 V fs = 40 MHz, TA = 25°C VI = 2 V(PP), 1 MHz Sine Wave VRT = 2.6 V, VRB = 0.6 V fs = 20 MHz, TA = 25°C – 10 – 20 Magnitude – dB Integral Nonlinearity – LSB 0 0.4 0.2 0 – 0.2 – 30 – 40 – 50 – 60 – 0.4 – 70 – 0.6 – 80 – 0.8 – 90 –1 0 100 Figure 8 1 0.6 80 60 TA – Ambient Temperature – °C Digital Output Code 0.8 40 – 100 40 80 120 160 Digital Output Code 200 240 0 1 2 3 4 5 6 7 8 9 10 f – Frequency – MHz Figure 9 Figure 10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 APPLICATION INFORMATION grounding and power supply considerations A signal ground is a low-impedance path for current to return to the source. Inside the TLC5540 A/D converter, the analog ground and digital ground are connected to each other through the substrate, which has a very small resistance (~30 Ω) to prevent internal latch-up. For this reason, it is strongly recommended that a printed circuit board (PCB) of at least 4 layers be used with the TLC5540 and the converter DGND and AGND pins be connected directly to the analog ground plane to avoid a ground loop. Figure 11 shows the recommended decoupling and grounding scheme for laying out a multilayer PC board with the TLC5540. This scheme ensures that the impedance connection between AGND and DGND is minimized so that their potential difference is negligible and noise source caused by digital switching current is eliminated. TLC5540 VDDD 11 0.1 µF 13 0.1 µF GND 24 2 14 0.1 µF VDDA 15 0.1 µF 18 AGND 20 21 0.1 µF Signal Plane Analog Ground Plane Digital Supply Plane Analog Supply Plane Signal Plane Figure 11. AVDD, DVDD, AGND, and DGND Connections printed circuit board (PCB) layout considerations When designing a circuit that includes high-speed digital and precision analog signals such as a high speed ADC, PCB layout is a key component to achieving the desired performance. The following recommendations should be considered during the prototyping and PCB design phase: D D D D D 10 Separate analog and digital circuitry physically to help eliminate capacitive coupling and crosstalk. When separate analog and digital ground planes are used, the digital ground and power planes should be several layers from the analog signals and power plane to avoid capacitive coupling. Full ground planes should be used. Do not use individual etches to return analog and digital currents or partial ground planes. For prototyping, breadboards should be constructed with copper clad boards to maximize ground plane. The conversion clock, CLK, should be terminated properly to reduce overshoot and ringing. Any jitter on the conversion clock degrades ADC performance. A high-speed CMOS buffer such as a 74ACT04 or 74AC04 positioned close to the CLK terminal can improve performance. Minimize all etch runs as much as possible by placing components very close together. It also proves beneficial to place the ADC in a corner of the PCB nearest to the I/O connector analog terminals. It is recommended to place the digital output data latch (if used) as close to the TLC5540 as possible to minimize capacitive loading. If D0 through D7 must drive large capacitive loads, internal ADC noise may be experienced. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 PRINCIPLES OF OPERATION functional description The TLC5540 uses a modified semiflash architecture as shown in the functional block diagram. The four most significant bits (MSBs) of every output conversion result are produced by the upper comparator block CB1. The four least significant bits (LSBs) of each alternate output conversion result are produced by the lower comparator blocks CB-A and CB-B in turn (see Figure 12). The reference voltage that is applied to the lower comparator resistor string is one sixteenth of the amplitude of the refence applied to the upper comparator resistor string. The sampling comparators of the lower comparator block require more time to sample the lower voltages of the reference and residual input voltage. By applying the residual input voltage to alternate lower comparator blocks, each comparator block has twice as much time to sample and convert as would be the case if only one lower comparator block were used. VI(1) VI(2) VI(3) VI(4) ANALOG IN (Sampling Points) CLK1 CLK2 CLK3 CLK4 CLK (Clock) Upper Comparators Block (CB1) S(1) C(1) S(2) C(2) S(3) C(3) S(4) C(4) Upper Data UD(0) UD(1) UD(2) UD(3) Lower Reference Voltage RV(0) RV(1) RV(2) RV(3) S(1) Lower Comparators Block (CB-A) Lower Data (B) C(1) S(3) H(3) H(0) C(0) S(2) LD(– 2) C(3) LD(1) LD(– 1) Lower Data (A) Lower Comparators Block (CB-B) H(1) H(2) C(2) LD(0) S(4) H(4) LD(2) tpd D1 – D8 (Data Output) OUT(– 2) OUT(–1) OUT(0) OUT(1) Figure 12. Internal Functional Timing Diagram This conversion scheme, which reduces the required sampling comparators by 30 percent compared to standard semiflash architectures, achieves significantly higher sample rates than the conventional semiflash conversion method. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 PRINCIPLES OF OPERATION functional description (continued) The MSB comparator block converts on the falling edge of each applied clock cycle. The LSB comparator blocks CB-A and CB-B convert on the falling edges of the first and second following clock cycles, respectively. The timing diagram of the conversion algorithm is shown in Figure 12. analog input operation The analog input stage to the TLC5540 is a chopper-stabilized comparator and is equivalently shown below: φ2 S2 φ1 To Encoder Logic VDDA Cs φ2 S3 φ1 φ1 ANALOG IN S1 Vref(N) To Encoder Logic φ2 Cs φ2 S(N) φ1 To Encoder Logic Cs Figure 13. External Connections for Using the Internal Reference Resistor Divider Figure 13 depicts the analog input for the TLC5540. The switches shown are controlled by two internal clocks, φ1 and φ2. These are nonoverlapping clocks that are generated from the CLK input. During the sampling period, φ1, S1 is closed and the input signal is applied to one side of the sampling capacitor, Cs. Also during the sampling period, S2 through S(N) are closed. This sets the comparator input to approximately 2.5 V. The delta voltage is developed across Cs. During the comparison phase, φ2, S1 is switched to the appropriate reference voltage for the bit value N. S2 is opened and Vref(N) – VCs toggles the comparator output to the appropriate digital 1 or 0. The small resistance values for the switch, S1, and small value of the sampling capacitor combine to produce the wide analog input bandwidth of the TLC5540. The source impedance driving the analog input of the TLC5540 should be less than 100 Ω across the range of input frequency spectrum. reference inputs – REFB, REFT, REFBS, REFTS The range of analog inputs that can be converted are determined by REFB and REFT, REFT being the maximum reference voltage and REFB being the minimum reference voltage. The TLC5540 is tested with REFT = 2.6 V and REFB = 0.6 V producing a 2-V full-scale range. The TLC5540 can operate with REFT – REFB = 5 V, but the power dissipation in the reference resistor increases significantly (93 mW nominally). It is recommended that a 0.1 µF capacitor be attached to REFB and REFT whether using externally or internally generated voltages. 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 PRINCIPLES OF OPERATION internal reference voltage conversion Three internal resistors allow the device to generate an internal reference voltage. These resistors are brought out on terminals VDDA, REFTS, REFT, REFB, REFBS, and AGND. Two different bias voltages are possible without the use of external resistors. Internal resistors are provided to develop REFT = 2.6 V and REFB = 0.6 V (bias option one) with only two external connections. This is developed with a 3-resistor network connected to VDDA. When using this feature, connect REFT to REFTS and connect REFB to REFBS. For applications where the variance associated with VDDA is acceptable, this internal voltage reference saves space and cost (see Figure 14). A second internal bias option (bias two option) is shown in Figure 15. Using this scheme REFB = AGND and REFT = 2.28 V nominal. These bias voltage options can be used to provide the values listed in the following table. Table 1. Bias Voltage Options BIAS VOLTAGE BIAS OPTION 1 VRB 0.61 VRT 2.63 VRT – VRB 2.02 2 AGND 2.28 2.28 To use the internally-generated reference voltage, terminal connections should be made as shown in Figure 14 or Figure 15. The connections in Figure 14 provide the standard video 2-V reference. TLC5540 VDDA 5 V (Analog) REFTS 18 R1 320 Ω NOM 16 17 0.1 µF REFT REFB 2.63 V dc Rref 270 Ω NOM 23 0.61 V dc 22 0.1 µF REFBS AGND R2 80 Ω NOM 21 Figure 14. External Connections Using the Internal Bias One Option POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 PRINCIPLES OF OPERATION TLC5540 18 VDDA 5 V (Analog) R1 320 Ω NOM REFTS 16 17 0.1 µF 2.28 V dc REFT Rref 270 Ω NOM REFB 23 0 V dc 22 REFBS R2 80 Ω NOM AGND 21 Figure 15. External Connections Using the Internal Bias Two Option functional operation Table 2 shows the TLC5540 functions. Table 2. Functional Operation 14 DIGITAL OUTPUT CODE INPUT SIGNAL VOLTAGE STEP Vref(T) 255 1 1 1 1 1 1 1 1 • • • • • • • • • • • • • • • • • • • • • 128 1 0 0 0 0 0 0 0 • 127 0 1 1 1 1 1 1 1 • • • • • • • • • • MSB LSB • • • • • • • • • • Vref(B) 0 0 0 0 0 0 0 0 0 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 MECHANICAL DATA PW (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PINS SHOWN 0,30 0,19 0,65 14 0,10 M 8 0,15 NOM 4,50 4,30 6,60 6,20 Gage Plane 0,25 1 7 0°– 8° A 0,75 0,50 Seating Plane 0,15 0,05 1,20 MAX PINS ** 0,10 8 14 16 20 24 28 A MAX 3,10 5,10 5,10 6,60 7,90 9,80 A MIN 2,90 4,90 4,90 6,40 7,70 9,60 DIM 4040064/F 01/97 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion not to exceed 0,15. Falls within JEDEC MO-153 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 TLC5540 8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTER SLAS105C – JANUARY 1995 – REVISED MAY 1999 MECHANICAL DATA NS (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PIN SHOWN PINS ** 14 16 20 24 A MAX 10,50 10,50 12,90 15,30 A MIN 9,90 9,90 12,30 14,70 DIM 0,51 0,35 1,27 14 0,25 M 8 0,15 NOM 5,60 5,00 8,20 7,40 Gage Plane 1 7 0,25 0°– 10° A 1,05 0,55 Seating Plane 2,00 MAX 0,05 MIN 0,10 4040062 / B 10/94 NOTES: A. All linear dimensions are in millimeters. B. This drawing is subject to change without notice. C. Body dimensions do not include mold flash or protrusion, not to exceed 0,15. 16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 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 acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor 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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TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 1999, Texas Instruments Incorporated