VCA2618 VCA 261 8 SBOS254B – JULY 2002 – REVISED NOVEMBER 2003 Dual, VARIABLE GAIN AMPLIFIER with Input Buffer FEATURES DESCRIPTION z z z z z z The VCA2618 is a highly integrated, dual receive channel, Variable Gain Amplifier (VGA) with analog gain control. GAIN RANGE: up to 43dB 30MHz BANDWIDTH LOW CROSSTALK: 65dB at Max Gain, 5MHz HIGH-SPEED VARIABLE GAIN ADJUST POWER SHUTDOWN MODE HIGH IMPEDANCE INPUT BUFFER The VCA2618’s VGA section consists of two parts: the Voltage Controlled Attenuator (VCA) and the Programmable Gain Amplifier (PGA). The gain and gain range of the PGA can be digitally programmed. The combination of these two programmable elements results in a variable gain ranging from 0dB up to a maximum gain as defined by the user through external connections. The single-ended unity gain input buffer provides predictable high input impedance. The output of the VGA can be used in either a single-ended or differential mode to drive high-performance Analog-to-Digital (A/D) converters. A separate power-down pin reduces power consumption. APPLICATIONS z z z z ULTRASOUND SYSTEMS WIRELESS RECEIVERS TEST EQUIPMENT RADAR The VCA2618 also features low crosstalk and outstanding distortion performance. The combination of low noise and gain range programmability make the VCA2618 a versatile building block in a number of applications where noise performance is critical. The VCA2618 is available in a TQFP-32 package. CP2A CP1A VCA2618 (1 of 2 Channels) NOUTA INA Buffer Voltage Control Attenuator Programmable Gain Amplifier POUTA MGS1 Analog Control VCACNTL Maximum Gain Select MGS2 MGS3 Maximum Gain Select NOUTB INB Buffer Voltage Control Attenuator Programmable Gain Amplifier POUTB CP2B CP1B 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. All trademarks are the property of their respective owners. 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. Copyright © 2002–2003, Texas Instruments Incorporated www.ti.com ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS(1) Power Supply (+VS) ............................................................................. +6V Analog Input ............................................................. –0.3V to (+VS + 0.3V) Logic Input ............................................................... –0.3V to (+VS + 0.3V) Case Temperature ......................................................................... +100°C Junction Temperature .................................................................... +150°C Storage Temperature ...................................................... –40°C to +150°C This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. NOTE: (1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to absolute maximum conditions for extended periods may affect device reliability. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGE/ORDERING INFORMATION SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER TRANSPORT MEDIA, QUANTITY VCA2618YT VCA2618YR Tape and Reel, 250 Tape and Reel, 2000 PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR(1) VCA2618Y TQFP-32 Surface-Mount PBS –40°C to +85°C VCA2618Y " " " " " NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com. ELECTRICAL CHARACTERISTICS At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground differential output (2VPP), MGS = 111, and fIN = 5MHz, unless otherwise noted. VCA2618Y PARAMETER BUFFER Input Resistance Input Capacitance Input Bias Current Maximum Input Voltage Input Voltage Noise Input Current Noise Noise Figure Bandwidth CONDITIONS MIN PGA Gain = 45dB, RS = 50Ω Independent of Gain RF = 550Ω, PGA Gain = 45dB, RS = 75Ω PROGRAMMABLE VARIABLE GAIN AMPLIFIER Peak Input Voltage –3dB Bandwidth Slew Rate Output Signal Range RL > 500Ω Each Side to Ground Output Impedance Output Short-Circuit Current 3rd-Harmonic Distortion VOUT = 2VPP, VCACNTL = 3.0V 2nd-Harmonic Distortion VOUT = 2VPP, VCACNTL = 3.0V VOUT = 2VPP, VCACNTL = 3.0V, MGS = 011 2nd-Harmonic Distortion Overload Performance (2nd-Harmonic Input Signal = 1VPP, VCACNTL = 2V Distortion) Time Delay IMD, 2-Tone VOUT = 2VPP, f = 9.95MHz Crosstalk Group Delay Variation 1MHz < f < 10MHz, Full Gain Range ACCURACY Gain Slope Gain Error(1) –45 –42 VCACNTL = 0.2V to 3.0V VCACNTL = 0.2V to 3.0V VCACNTL = 0.4V to 2.9V Output Offset Voltage GAIN CONTROL INTERFACE Input Voltage (VCACNTL) Range Input Resistance Response Time POWER SUPPLY Specified Operating Range Power Dissipation Power-Down MAX 4.75 UNITS 600 5 1 1 5.4 350 13 100 kΩ pF nA VPP nV/Hz fA/Hz dB MHz 1 30 300 2.5 ±1 1 ±40 –50 –50 –60 –40 to –45 VPP MHz V/µs V Ω mA dBc dBc dBc dB 5 –59 65 13 ns dBc dB ns 16 ±2.0 ±1.3 ±50 dB/V dB dB mV ±2 0.2 to 3.0 1 0.2 45dB Gain Change Operating, Each Channel TYP 5.0 120 9.2 V MΩ µs 5.25 150 V mW mW NOTE: (1) Referenced to best fit dB-linear curve. 2 VCA2618 www.ti.com SBOS254B PIN CONFIGURATION NC DNC CP2A CP1A VDDA GNDA POUTA NOUTA 31 30 29 28 27 26 25 TQFP 32 Top View +INA 1 24 VCACNTL NC 2 23 MGS3 VDDR 3 22 MGS2 VBIAS 4 21 MGS1 VCM 5 20 PD GNDR 6 19 NC NC 7 18 NC +INB 8 17 DNC 16 NOUTB 13 VDDB 15 12 CP1B POUTB 11 CP2B 14 10 DNC GNDB 9 NC VCA2618 PIN DESCRIPTIONS PIN DESIGNATOR 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 +INA NC VDDR VBIAS VCM GNDR NC +INB NC DNC CP2B CP1B VDDB GNDB POUTB NOUTB DESCRIPTION PIN DESIGNATOR Noninverting Input Channel A No Internal Connection Internal Reference Supply Bias Voltage Common-Mode Voltage Internal Reference Ground Not Connected Noninverting Input Channel B No Internal Connection Do Not Connect Coupling Capacitor Channel B Coupling Capacitor Channel B +5V Supply Channel B Ground Channel B Positive Output Channel B Negative Output Channel B 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 DNC NC NC PD MGS1 MGS2 MGS3 VCACNTL NOUTA POUTA GNDA VDDA CP1A CP2A DNC NC VCA2618 SBOS254B www.ti.com DESCRIPTION Do Not Connect No Internal Connection No Internal Connection Power-Down (Active LOW) Maximum Gain Select 1 (MSB) Maximum Gain Select 2 Maximum Gain Select 3 (LSB) VCA Analog Control Negative VCA Output Channel A Positive VCA Output Channel A Ground Channel A +5V Supply Channel A Coupling Capacitor Channel A Coupling Capacitor Channel A Do Not Connect No Internal Connection 3 TYPICAL CHARACTERISTICS At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground, differential output (2VPP) MGS = 111, and fIN = 5MHz, unless otherwise noted. GAIN vs VCA GAIN ERROR vs TEMPERATURE 50 45 +25°C MGS = 101 1.0 MGS = 100 25 20 MGS = 001 15 MGS = 010 10 Gain Error (dB) Gain (dB) 30 +85°C 1.5 MGS = 110 40 35 2.0 MGS = 111 0 –0.5 –40°C –1.0 MGS = 011 5 0.5 –1.5 0 –2.0 –5 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 VCACNTL (V) VCACNTL (V) GAIN ERROR vs VCACNTL 2.5 2.0 2.0 1.5 0.5 0 –0.5 1.5 10MHz 1.0 5MHz 1MHz –1.0 Gain Error (dB) Gain Error (dB) GAIN ERROR vs VCACNTL 2.5 1.0 0.5 0 –0.5 –1.5 –2.0 –2.0 –2.5 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 VCACNTL (V) VCACNTL (V) GAIN MATCH: CHA to CHB, VCACNTL = 3.0V GAIN MATCH: CHA to CHB, VCACNTL = 0.2V 50 45 45 40 40 35 35 30 Units Units 30 25 20 25 20 15 15 4 MGS = 111 –1.0 –1.5 –2.5 MGS = 001 MGS = 011 5 0 0 –0.07 –0.06 –0.05 –0.04 –0.03 –0.02 –0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 10 5 –0.36 –0.30 –0.24 –0.18 –0.12 –0.06 0 0.06 0.12 0.18 0.24 0.30 0.36 0.42 0.48 0.54 0.60 0.66 0.72 0.78 0.84 0.90 10 Delta Gain (dB) Delta Gain (dB) VCA2618 www.ti.com SBOS254B TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground, differential output (2VPP) MGS = 111, and fIN = 5MHz, unless otherwise noted. GAIN vs FREQUENCY (VCACNTL = 3.0V) GAIN vs FREQUENCY 50 50 MGS = 111 VCACNTL = 3.0V 45 40 40 MGS = 011 30 30 Gain (dB) Gain (dB) 35 25 20 20 VCACNTL = 1.6V 10 15 MGS = 001 10 0 5 VCACNTL = 0.2V 0 100k 1M 10M –10 100k 100M 1M Frequency (Hz) RS= 50Ω MGS = 111 350 Noise (nV/√Hz) Noise (nV/√Hz) 400 300 250 200 MGS = 011 150 100M INPUT REFERRED NOISE vs VCACNTL OUTPUT REFERRED NOISE vs VCACNTL 500 450 10M Frequency (Hz) 100 50 0 600 550 500 450 400 350 300 250 200 150 100 50 0 RS= 50Ω MGS = 111 MGS = 011 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 VCACNTL (V) VCACNTL (V) NOISE FIGURE vs RS INPUT REFERRED NOISE vs RS 100 24 22 Noise Figure (dB) Noise (nV√Hz) 20 10 18 16 14 12 10 8 6 4 2 1 1 10 100 10 1k VCA2618 SBOS254B 100 1k RS (Ω) RS (Ω) www.ti.com 5 TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground, differential output (2VPP) MGS = 111, and fIN = 5MHz, unless otherwise noted. 60 55 –30 –35 50 45 40 35 Harmonic Distortion (dBc) Noise Figure (dB) HARMONIC DISTORTION vs FREQUENCY (Differential, 2Vp-p, MGS = 001) NOISE FIGURE vs VCACNTL 30 25 20 15 10 5 0 –50 –55 –60 –70 100k HARMONIC DISTORTION vs FREQUENCY (Differential, 2Vp-p, MGS = 011) HARMONIC DISTORTION vs FREQUENCY (Differential, 2Vp-p, MGS = 111) –30 –35 VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 –40 VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 –45 –50 –55 –60 –65 –70 –75 1M –80 100k 10M 1M 10M Frequency (Hz) Frequency (MHz) HARMONIC DISTORTION vs FREQUENCY (Single-Ended, 1Vp-p, MGS = 001) HARMONIC DISTORTION vs FREQUENCY (Single-Ended, 1Vp-p, MGS = 011) –30 –35 –30 –35 –40 –45 –50 –40 –45 –50 –55 –60 –65 –70 –75 –80 –85 –90 100k 10M Frequency (Hz) Harmonic Distortion (dBc) –30 –35 –40 –45 –50 –55 –60 –65 –70 –75 –80 –85 –90 100k 1M VCACNTL (V) Harmonic Distortion (dBc) Harmonic Distortion (dBc) Harmonic Distortion (dBc) –45 –65 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 1M 10M Frequency (Hz) 6 –40 VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 –55 –60 –65 –70 –75 –80 –85 –90 100k VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 1M 10M Frequency (Hz) VCA2618 www.ti.com SBOS254B TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground, differential output (2VPP) MGS = 111, and fIN = 5MHz, unless otherwise noted. HARMONIC DISTORTION vs FREQUENCY (Single-Ended, 1Vp-p, MGS = 111) HARMONIC DISTORTION vs VCACNTL (Differential, 2Vp-p) –55 –60 –65 –70 –75 –80 –85 VCACNTL = 0.2V, H2 VCACNTL = 0.2V, H3 VCACNTL = 3.0V, H2 VCACNTL = 3.0V, H3 –90 100k Harmonic Distortion (dBc) Harmonic Distortion (dBc) –40 –45 –50 1M 0 –5 –10 –15 –20 –25 –30 –35 –40 –45 –50 –55 –60 –65 –70 –75 –80 MGS = 001, H2 MGS = 011, H2 MGS = 111, H2 MGS = 001, H3 MGS = 011, H3 MGS = 111, H3 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 10M Frequency (Hz) VCACNTL (V) HARMONIC DISTORTION vs VCACNTL (Single-Ended, 1Vp-p) INTERMODULATION DISTORTION (Single-Ended, 1Vp-p, fIN = 10MHz, VCACNTL = 3.0V) 0 0 –5 –10 –15 –20 –25 –30 –35 –40 –45 –50 –55 –60 –65 –70 –75 MGS = 001, H2 MGS = 011, H2 MGS = 111, H2 MGS = 001, H3 MGS = 011, H3 MGS = 111, H3 –10 –20 Amplitude (dB) Harmonic Distortion (dBc) –30 –35 –30 –40 –50 –60 –70 –80 –90 –100 9.5 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 9.6 9.7 9.8 VCACNTL (V) INTERMODULATION DISTORTION (Differential, 2Vp-p, fIN = 10MHz, VCACNTL = 3.0V) 0 CROSS TALK vs FREQUENCY (Differential, 2Vp-p, MGS = 011) 0 –10 –10 –20 VCACNTRL = 0V –20 –30 Cross Talk (dB) Amplitude (dB) 9.9 10.0 10.1 10.2 10.3 10.4 10.5 Frequency (MHz) –40 –50 –60 –70 –30 –40 –60 –80 –70 –90 –80 –100 VCACNTRL = 1.5V –50 VCACNTRL = 3.0V –90 9.5 9.6 9.7 9.8 9.9 10 10.1 10.2 10.3 10.4 10.5 1 Frequency (MHz) 11 16 21 Frequency (MHz) VCA2618 SBOS254B 6 www.ti.com 7 TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VDD = 5V, load resistance = 500Ω on each output to ground, differential output (2Vp-p) MGS = 111, and fIN = 5MHz, unless otherwise noted. OVERLOAD DISTORTION vs FREQUENCY 0.1V 0.25V 0.5V 1V –10 ICC vs TEMPERATURE 59 57 55 –20 ICC (mA) 2nd-Harmonic Distortion (dBc) 0 –30 –40 53 51 49 –50 47 –60 45 1M 10M –40 –25 –10 Frequency (Hz) 5 20 35 50 65 80 95 Temperature (°C) Group Delay (ns) GROUP DELAY (1MHz Aperture) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 VCACNTL = 3.0V VCACNTL = 0.2V 1M 10M 100M Frequency (Hz) 8 VCA2618 www.ti.com SBOS254B OVERVIEW power-on time of the VCA2618 would be increased. If a decrease in the power-on time is needed, the value can be decreased to no less than 100pF. The VCA2618 is a dual-channel, VGA consisting of three primary blocks, an Input Buffer, a VCA, and a PGA. All stages are AC coupled, with the coupling into the PGA stage being made variable by placing an external capacitor between the CP1 and CP2 pins. This will be discussed further in the PGA section. By using the internal coupling into the PGA, the result is a high-pass filter characteristic with cutoff at approximately 75kHz. The output PGA naturally rolls off at around 30MHz, making the usable bandwidth of the VCA2618 between 75kHz and 30MHz. VOLTAGE-CONTROLLED ATTENUATOR The magnitude of the VCA input signal from the input buffer is reduced by a programmable attenuation factor, set by the analog VCA Control Voltage (VCACNTL) at pin 24. The maximum attenuation is programmable by using the three MGS bits (pins 21, 22, and 23). Figure 2 illustrates this dual-adjust characteristic. Channel A Input Buffer VCA Analog Control VCA Control Channel B Input Buffer VCA PGA Channel A Output Maximum Gain Select MGS PGA Channel B Output VCA Attenuation (dB) 0 Minimum Attenuation –25 Maximum Attenuation –43 0 3.0V Control Voltage FIGURE 1. Simplified Block Diagram of the VCA2618. FIGURE 2. Swept Attenuator Characteristic. INPUT BUFFER The MGS bits adjust the overall range of attenuation and maximum gain while the VCACNTL voltage adjusts the actual attenuation factor. At any given maximum gain setting, the analog variable gain characteristic is linear in dB as a function of the control voltage, and is created as a piecewise approximation of an ideal dB-linear transfer function. The VCA control circuitry is common to both channels of the VCA2618. The range for the VCACNTL input spans from 0V to 3V. Although overdriving the VCACNTL input above the recommended 3V maximum will not damage the part, this condition should be avoided. The input buffer is a unity gain amplifier (gain of +1) with a bandwidth of 100MHz with an input resistance of approximately 600kΩ. The input buffer isolates the circuit driving the VCA2618 inputs from the internal VCA block, which would present a varying impedance to the input circuitry. To allow symmetrical operation of the input buffer, the input to the buffer must be AC coupled through an external capacitor. The recommended value of the capacitor is 0.01µF. It should be noted that if the capacitor value were increased, the RS Output Input Q1A Q1B Q2A Q2B Q3A Q3B Q4A Q4B Q5A Q5B VCM A1 A2 A3 A4 A5 B1 B2 FIGURE 3. Programmable Attenuator Section. VCA2618 SBOS254B www.ti.com 9 Attenuator Input A1 to A10 Attenuator Stages RS QS Q1 Q2 Q3 Q4 Q5 Attenuator Output Q6 Q7 Q8 Q9 Q10 VCM A1 A2 A3 C1 A4 C2 V1 A5 C3 V2 V3 A6 C4 V4 C5 A8 C6 V5 Control Input A7 A9 C7 V6 A10 C8 V7 C9 V8 C10 V9 V10 C1 to C10 Clipping Amplifiers 0dB –4.3dB Attenuation Characteristic of Individual FETs VCM – VT 0 V1 V2 V3 V4 V5 V6 V7 V8 V9 V10 Characteristic of Attenuator Control Stage Output OVERALL CONTROL CHARACTERISTICS OF ATTENUATOR 0dB –43dB 0.3V Control Signal 3V FIGURE 4. Piecewise Approximation to Logarithmic Control Characteristics. 10 VCA2618 www.ti.com SBOS254B PGA POST-AMPLIFIER MGS SETTING Figure 5 shows a simplified circuit diagram of the PGA block. As stated before, the input to the PGA is AC coupled by an internal capacitor. Provisions are made so that an external capacitor can be placed in parallel with the internal capacitor, thus lowering the usable low-frequency bandwidth. The lowfrequency bandwidth is set by the following equation: 1 2 • π • 500kΩ • (220pF + CEXTERNAL ) ( ) ATTENUATOR GAIN VCACNTL = 0V to 3V ATTENUATOR + DIFFERENTIAL PGA GAIN 000 Not Valid Not Valid 001 –25dB to 0dB 0dB to 25dB 010 –28dB to 0dB 0dB to 28dB 011 –31dB to 0dB 0dB to 31dB 100 –34dB to 0dB 0dB to 34dB 101 –37dB to 0dB 0dB to 37dB 110 –40dB to 0dB 0dB to 40dB 111 –43dB to 0dB 0dB to 43dB TABLE I. MGS Settings. where CEXTERNAL is the external capacitor value in farads. Care should be taken to avoid using too large a value of capacitor, as this can increase the power-on delay time. input buffer noise dominates; at maximum VCA attenuation (large input signals), the PGA noise dominates. Note that if the PGA output is used single-ended, the apparent gain will be 6dB lower. As described previously, the PGA gain is programmed with the same MGS bits that control the VCA maximum attenuation factor. Specifically, the maximum PGA gain at each MGS setting is the inverse (reciprocal) of the maximum VCA attenuation at that setting. Therefore, the VCA + PGA overall gain will always be 0dB (unity) when the analog VCACNTL input is set to 0V (the maximum attenuation for VCA). For VCACNTL = 3V (no attenuation), the VCA + PGA gain will be controlled by the programmed PGA gain (25dB to 43dB in 3dB steps). For clarity, the gain and attenuation factors are detailed in Table I. LAYOUT CONSIDERATIONS The VCA2618 is an analog amplifier capable of high gain. When working on a PCB layout for the VCA2618, it is recommended to utilize a solid ground plane that is connected to analog ground. This helps to maximize the noise performance of the VCA2618. Adequate power-supply decoupling must be used in order to achieve the best possible performance. Decoupling capacitors on the VCACNTL voltage should also be used to help minimize noise. Recommended values can be obtained from the layout diagram of Figure 6. The PGA architecture converts the single-ended signal from the VCA into a differential signal. Low input noise was also a requirement of the PGA design due to the large amount of signal attenuation that can be asserted before the PGA. At minimum VCA attenuation (used for small input signals), the VDD To Bias Circuitry Q1 RL VCAOUTP Q11 Q12 Q3 VCM Q9 RL VCAOUTN Q8 RS1 VCM Q13 RS2 +In Q4 Q7 Q14 Q2 Q5 –In Q10 Q6 To Bias Circuitry FIGURE 5. Simplified Block Diagram of the PGA Section with the VCA2618. VCA2618 SBOS254B www.ti.com 11 +5V 0.1µF 1µF +5V 0.01µF INA 0.1µF 0.1µF 1µF 1µF 3 28 1 INA 5 VDDA VDDR VCM 0.01µF –OUTA +OUTA 25 26 –OUTA 0.01µF +OUTA VCA2618 –OUTB 0.01µF INB 8 INB +OUTB 16 15 0.01µF –OUTB 0.01µF +OUTB VDDB VBIAS VCNTL 13 4 24 1µF 0.1µF 0.1µF +5V 1µF 0.1µF VCACNTL FIGURE 6. VCA2618 Layout. 12 VCA2618 www.ti.com SBOS254B PACKAGE DRAWING PBS (S-PQFP-G32) PLASTIC QUAD FLATPACK 0,23 0,17 0,50 24 0,08 M 17 25 16 32 9 0,13 NOM 1 8 3,50 TYP Gage Plane 5,05 SQ 4,95 0,25 7,10 SQ 6,90 0,10 MIN 0°– 7° 0,70 0,40 1,05 0,95 Seating Plane 0,08 1,20 MAX 4087735/A 11/95 NOTES: A. All linear dimensions are in millimeters. B. This drawing is subject to change without notice. VCA2618 SBOS254B www.ti.com 13 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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