41 dB Range, 1 dB Step Size, Programmable Dual VGA AD8372 Dual independent digitally controlled VGA Differential input and output 150 Ω differential input Open-collector differential output 7.8 dB noise figure to 100 MHz @ maximum gain HD2/HD3 better than 77 dBc for 1 V p-p differential output −3 dB bandwidth of 150 MHz 41 dB gain range 1 dB step size ± 0.2 dB Serial 8-bit bidirectional SPI control interface Wide input dynamic range Pin-programmable output stage Power-down feature Single 5 V supply: 106 mA per channel 32-lead LFCSP, 5 mm × 5 mm package FUNCTIONAL BLOCK DIAGRAM ENB1 AD8372 REF2 IPC1 OPC1 INC1 RXT2 ONC1 CHANNEL 1 POSTAMP CLK2 CLK1 SDO1 SDI1 RXT2 REGISTERS AND GAIN DECODER SDO2 SDI2 LCH1 LCH2 IPC2 OPC2 INC2 REF1 ONC2 CHANNEL 2 POSTAMP ENB2 07051-001 FEATURES Figure 1. APPLICATIONS Differential ADC drivers CMTS upstream direct sampling receivers CATV modem signal scaling Generic RF/IF gain stages Single-ended-to-differential conversion GENERAL DESCRIPTION The AD8372 is a dual, digitally controlled, variable gain amplifier that provides precise gain control, high IP3, and low noise figure. The excellent distortion performance and moderate signal bandwidth make the AD8372 a suitable gain control device for a variety of multichannel receiver applications. For wide input dynamic range applications, the AD8372 provides a broad 41 dB gain range. The gain is programmed through a bidirectional 4-pin serial interface. The serial interface consists of a clock, latch, data input, and data output lines for each channel. The AD8372 provides the ability to set the transconductance of the output stage using a single external resistor. The RXT1 and RXT2 pins provide a band gap derived stable reference voltage of 1.56 V. Typically 2.0 kΩ shunt resistors to ground are used to set the maximum gain to a nominal value of 31 dB. The current setting resistors can be adjusted to manipulate the gain and distortion performance of each channel. This is a flexible feature in applications where it is desirable to trade off distortion performance for lower power consumption. The AD8372 is powered on by applying the appropriate logic level to the ENB1, ENB2 pins. When powered down, the AD8372 consumes less than 2.6 mA and offers excellent input-to-output isolation. The gain setting is preserved when powered down. Fabricated on an Analog Devices high frequency BiCMOS process, the AD8372 provides precise gain adjustment capabilities with good distortion performance. The quiescent current of the AD8372 is typically 106 mA per channel. The AD8372 amplifier comes in a compact, thermally enhanced 5 mm × 5 mm 32-lead LFCSP package and operates over the temperature range of −40°C to +85°C. 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. Specifications subject to change without notice. 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 owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2007 Analog Devices, Inc. All rights reserved. AD8372 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................8 Applications....................................................................................... 1 Theory of Operation ...................................................................... 10 Functional Block Diagram .............................................................. 1 Single-Ended and Differential Signals..................................... 10 General Description ......................................................................... 1 Passive Filter Techniques........................................................... 10 Revision History ............................................................................... 2 Digital Gain Control .................................................................. 10 Specifications..................................................................................... 3 Driving Analog-to-Digital Converters.................................... 10 Serial Control Interface Timing ................................................. 5 Evaluation Board Schematic ......................................................... 12 Absolute Maximum Ratings............................................................ 6 Outline Dimensions ....................................................................... 13 ESD Caution.................................................................................. 6 Ordering Guide .......................................................................... 13 Pin Configuration and Function Descriptions............................. 7 REVISION HISTORY 11/07—Revision 0: Initial Version Rev. 0 | Page 2 of 16 AD8372 SPECIFICATIONS VS = 5 V, T = 25°C, ZS = 150 Ω, ZL = 250 Ω at 35 MHz, 1 V p-p differential output, RXT1 = RXT2 = 2.0 kΩ, unless otherwise noted. Table 1. Parameter DYNAMIC PERFORMANCE −3 dB Bandwidth INPUT STAGE Maximum Input Swing at Each Input Pin Input Resistance Common-Mode Input Voltage CMRR GAIN Maximum Voltage Gain Minimum Voltage Gain Gain Step Size Gain Step Accuracy Gain Flatness Gain Temperature Sensitivity Step Response OUTPUT STAGE Output Voltage Swing Output Resistance Channel Isolation NOISE/HARMONIC PERFORMANCE 5 MHz Noise Figure Second Harmonic Third Harmonic Output IP3 Output 1 dB Compression Point 35 MHz Noise Figure Second Harmonic Third Harmonic Output IP3 Output 1 dB Compression Point 65 MHz Noise Figure Second Harmonic Third Harmonic Output IP3 Output 1 dB Compression Point 85 MHz Noise Figure Second Harmonic Third Harmonic Output IP3 Output 1 dB Compression Point Conditions Min VOUT < 1 V p-p, CLOAD < 3pF Pin IPCI, Pin INC1, Pin IPC2, and Pin INC2 Differential Gain code = 1x101010 (max gain) Gain code = 1x101010 Gain code = 1x000001 From gain code 1x000001 to 1x101010 From gain code 1x000001 to 1x101010 Gain code = 1x101010, from 5 MHz to 65MHz Gain code = 1x101010 For 6 dB gain step, 10% settling Pin OPCI, Pin ONC1, Pin OPC2, and Pin ONC2 At P1dB, gain code = 1x101010 Differential Measured at differential output for differential input applied to alternate channel Typ Max Unit 130 MHz 5 150 2.4 55 V p-p Ω V dB 32 −9 1.0 ±0.3 0.7 7.5 20 dB dB dB dB dB mdB/°C ns 9 3.5 55 V p-p kΩ dB 7.8 79 91 32 18.2 dB dBc dBc dBm dBm 7.8 79 87 35 18.1 dB dBc dBc dBm dBm 7.9 78 85 35 17.9 dB dBc dBc dBm dBm 8.1 77 85 35 17.7 dB dBc dBc dBm dBm Gain code = 1x101010 (max gain) Gain code = 1x101010 (max gain) Gain code = 1x101010 (max gain) Gain code = 1x101010 Rev. 0 | Page 3 of 16 AD8372 Parameter POWER INTERFACE Supply Voltage Quiescent Current per Channel Conditions Typ 4.5 vs. Temperature Power-Down Current, Both Channels vs. Temperature ENABLE INTERFACE Enable Threshold ENB1, ENB2 Input Bias Current GAIN CONTROL INTERFACE VIH Input Bias Current Serial Port Output Feedthrough Min Thermal connection made to exposed paddle under device −40°C ≤ TA ≤ +85°C ENB1 and ENB2 low −40°C ≤ TA ≤ +85°C Pin ENB1 and Pin ENB2 Minimum voltage to enable the device ENB1, ENB2 = 0 V Pin CLK1, Pin CLK2, Pin SDI1, Pin SDI2, Pin SDO1, Pin SDO2, Pin LCH1, and Pin LCH2 Minimum voltage for a logic high Worse-case feedthrough from CLK1, CLK2, SDI1, SDI2, SDO1, SDO2, LCH1, LCH2 to OPC1 and ONC2, or OPC2 and ONC2 Max Unit 5.5 V mA 135 mA mA mA 106 1.2 1.3 400 0.8 V nA 400 −60 V nA dB 2.4 Table 2. Gain Code vs. Voltage Gain Look-Up Table 8-Bit Binary Gain Code 1 RW DC 000000 RW DC 000001 RW DC 000010 RW DC 000011 RW DC 000100 RW DC 000101 RW DC 000110 RW DC 000111 RW DC 001000 RW DC 001001 RW DC 001010 RW DC 001011 RW DC 001100 RW DC 001101 RW DC 001110 RW DC 001111 RW DC 010000 RW DC 010001 RW DC 010010 RW DC 010011 RW DC 010100 RW DC 010101 1 8-Bit Binary Gain Code 1 RW DC 010110 RW DC 010111 RW DC 011000 RW DC 011001 RW DC 011010 RW DC 011011 RW DC 011100 RW DC 011101 RW DC 011110 RW DC 011111 RW DC 100000 RW DC 100001 RW DC 100010 RW DC 100011 RW DC 100100 RW DC 100101 RW DC 100110 RW DC 100111 RW DC 101000 RW DC 101001 RW DC 101010 RW DC 101011 Voltage Gain (dB) < −60 −9 −8 −7 −6 −5 −4 −3 −2 −1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 RW is the Read/Write bit, RW = 0 for read mode, RW = 1 for write mode. DC is the Don’t Care bit. Rev. 0 | Page 4 of 16 Voltage Gain (dB) +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 +30 +31 +32 < −60 AD8372 SERIAL CONTROL INTERFACE TIMING tCLK tPW CLK1 OR CLK2 tLH tLS LCH1 OR LCH2 tDS SDI1 OR SDI2 tDH WRITE BIT DON'T CARE LSB LSB + 1 LSB + 2 MSB – 2 MSB – 1 MSB 07051-003 NOTES 1. THE FIRST SDI BIT DETERMINES WHETHER THE PART IS WRITING TO OR READING FROM THE INTERNAL GAIN WORD REGISTER. FOR A WRITE OPERATION, THE FIRST BIT SHOULD BE A HIGH LOGIC LEVEL, FOR A READ OPERATION THE FIRST BIT SHOULD BE A LOGIC 1. THE GAIN WORD BIT IS THEN REGISTERED INTO THE SDI PIN ON THE NEXT RISING CLOCK. Figure 2. Write Mode Timing Diagram tLH tPW tCLK tD CLK1 OR CLK2 tLS LCH1 OR LCH2 SDI1 OR SDI2 tDH READ BIT SDO1 OR SDO2 DC LSB DC DC DC DC LSB + 1 LSB + 2 MSB – 2 MSB – 1 DC DC MSB 07051-004 tDS NOTES 1. THE GAIN WORD BIT IS UPDATED AT THE SDO PIN ON THE FALLING CLOCK EDGE. Figure 3. Read Mode Timing Diagram Table 3. Serial Programming Timing Parameters Parameter Clock Pulse Width (tPW) Clock Period (tCK) Write Mode Setup Time Data vs. Clock (tDS) Hold Time Data vs. Clock (tDH) Setup Time Latch vs. Clock (tLS) Hold Time Latch vs. Clock (tLH) Read Mode Clock to Data Out (tD) Rev. 0 | Page 5 of 16 Min 10 20 Unit ns ns 0.0 1.6 −1.8 2.0 ns ns ns ns 4.5 ns AD8372 ABSOLUTE MAXIMUM RATINGS 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 section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 4. Parameter Supply Voltage, VS ENB1, ENB2, SDI1, SDI2, SDO1, SDO2, CLK1, CLK2, LCH1, LCH2 Differential Input Voltage, VIPC1 − VINC1, VIPC2 − VINC2 Internal Power Dissipation θJA (Exposed Paddle Soldered Down) θJC (At Exposed Paddle) Maximum Junction Temperature Operating Temperature Range Storage Temperature Range 1 2 Rating 5.5 V VS + 500 mV V p-p 1.4 W 34.6°C/W1, 2 3.6°C/W2 150°C −40°C to +85°C −65°C to +150°C ESD CAUTION Still air. All values are modeled using a standard 4-layer JEDEC test board with the pad soldered to the board and thermal vias in the board. Rev. 0 | Page 6 of 16 AD8372 32 31 30 29 28 27 26 25 DGD1 INC1 IPC1 REF1 RXT1 AGD1 ENB1 AVS1 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 1 2 3 4 5 6 7 8 PIN 1 INDICATOR AD8372 TOP VIEW (Not to Scale) 24 23 22 21 20 19 18 17 OPC1 ONC1 AGD1 SDO1 SDO2 AGD2 ONC2 OPC2 Figure 4. Pin Configuration Table 3. Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Mnemonic DVS1 LCH1 SDI1 CLK1 CLK2 SDI2 LCH2 DVS2 DGD2 INC2 IPC2 REF2 RXT2 AGD2 ENB2 AVS2 OPC2 ONC2 AGD2 SDO2 SDO1 AGD1 ONC1 OPC1 AVS1 ENB1 AGD1 RXT1 REF1 IPC1 INC1 DGD1 Description Digital Supply Pin for Channel 1 Latch Input for Channel 1 Serial Data Input for Channel 1 Clock Input for Channel 1 Clock Input for Channel 2 Serial Data Input for Channel 2 Serial Data Input for Channel 2 Latch Input for Channel 2 Digital Supply Pin for Channel 2 Digital Ground for Channel 2 Negative Input for Channel 2 Positive Input for Channel 2 Reference Voltage for Channel 2 External Bias Setting Resistor Connection for Channel 2 Analog Ground for Channel 2 Chip Enable Pin for Channel 2 Analog Supply Pin for Channel 2 Positive Output for Channel 2 Negative Output for Channel 2 Analog Ground for Channel 2 Serial Data Output for Channel 2 Serial Data Output for Channel 1 Analog Ground for Channel 1 Negative Output for Channel 1 Positive Output for Channel 1 Analog Supply Pin for Channel 1 Chip Enable Pin for Channel 1 Analog Ground for Channel 1 External Bias Setting Resistor Connection for Channel 1 Reference Voltage for Channel 1 Positive Input for Channel 1 Negative Input for Channel 1 Digital Ground for Channel 1 Rev. 0 | Page 7 of 16 07051-002 DGD2 INC2 IPC2 REF2 RXT2 AGD2 ENB2 AVS2 9 10 11 12 13 14 15 16 DVS1 LCH1 SDI1 CLK1 CLK2 SDI2 LCH2 DVS2 AD8372 TYPICAL PERFORMANCE CHARACTERISTICS VS = 5 V, TA = 25°C, ZS = 150 Ω, ZL = 250 Ω, 1 V p-p differential output, both channels enabled, unless otherwise noted. 20 40 OUTPUT REFERRED P1dB (dBm) VOLTAGE GAIN (dB) 30 20 10 0 –10 19 +25°C 18 +85°C –40°C 17 16 1G FREQUENCY (Hz) 15 0 10 40 50 60 70 80 90 Figure 8. P1dB, Maximum Gain –60 180 9 –65 160 8 140 7 120 6 100 5 80 4 60 3 40 2 20 1 –70 RESISTANCE (Ω) –75 HD2 –80 HD3 –85 –90 –95 0 10 20 30 40 50 60 70 80 90 FREQUENCY (MHz) 0 07051-006 –100 0 50000000 150000000 200000000 250000000 0 300000000 FREQUENCY (MHz) Figure 6. 2nd and 3rd Harmonic Distortion Figure 9. Input Equivalent Parallel Impedance 70 100 90 60 80 OIP2 – AV = 32 70 50 CMRR (dB) OIP2 – AV = 10 60 OIP2 – AV = –9 50 40 OIP3 – AV = 10 OIP3 – AV = 32 30 40 30 20 OIP3 – AV = –9 20 10 10 0 10 20 30 40 50 60 FREQUENCY (MHz) 70 80 90 0 07051-007 0 100000000 0 10 20 30 40 50 60 70 FREQUENCY (MHz) Figure 7. OIP2 and OIP3 Figure 10. CMRR vs. Frequency Rev. 0 | Page 8 of 16 80 90 100 07051-010 HARMONIC DISTORTION (dBc) 30 FREQUENCY (MHz) Figure 5. Gain vs. Frequency by Gain Code (All Codes), Differential In, Differential Out OIP2/OIP3 (dBm) 20 CAPACITANCE (pF) 100M 07051-009 10M 07051-005 –30 1M 07051-008 –20 AD8372 50 45 AV = 0dB NOISE FIGURE (dB) 40 35 AV = 10dB 30 25 AV = 20dB 20 15 AV = 32dB 07051-011 10 5 0 20 40 60 80 100 120 140 160 180 200 FREQUENCY (MHz) 20ns/DIV 07051-012 0 Figure 11. Noise Figure vs. Frequency Figure 13. AD8372 Response to 6 dB Step Change in Gain (Gain Register Setting 36 to Setting 42); Falling Edge Shown is Serial Clock Input Edge 0 –10 –20 (dB) –30 –40 –50 –60 –70 –90 1M 10M 100M 1G FREQUENCY (Hz) 07051-013 –80 Figure 12. Isolation, Input to Opposite Output at Maximum Gain (To calculate output to output gain, subtract 29 dB from this plot) Rev. 0 | Page 9 of 16 AD8372 THEORY OF OPERATION The AD8372 is a dual differential variable gain amplifier. Each amplifier consists of a 150 Ω digitally controlled 6 dB attenuator followed by a 1 dB vernier and a fixed gain transconductance amplifier. The differential output on each amplifier consists of a pair of open-collector transistors. It is recommended that each opencollector output be biased to +5 V with a high value inductor. A 33 μH inductor, such as the Coilcraft® 1812LS-333XJL, is an excellent choice for this component. A 250 Ω resistor should be placed across the differential outputs to provide a current-tovoltage conversion and as a source impedance for passive filtering, post AD8372. The gain for each side is based on a 250 Ω differential load and varies as the RLOAD changes per the following equations: Gain = 20log(RLOAD/250), for voltage gain Gain = 10log(RLOAD/250), for power gain The dependency of the gain on the load is due to the opencollector output stage that is biased using external chokes. The inductance of the chokes and the resistance of the load determine the low frequency pole of the amplifier. The high frequency pole is set by the parasitic capacitance of the chokes and outputs in parallel with the output resistance. The total supply current of 106 mA per side consists of 70 mA for the combined outputs and about 36 mA through the power supply pins. Each side has an external resistor (REXT) to ground to set the transconductance of the output stage. For optimum distortion, 106 mA total current per side is recommended, making the REXT value about 2.0 kΩ. Each side has a 2.4 V reference pin and that same common-mode voltage appears on the inputs. This reference should be decoupled using a 0.1 μF capacitor. The part can be powered down to less than 2.6 mA by setting the ENB pin low for the appropriate side. The noise figure of the AD8372 is 7.8 dB at maximum gain and increases as the gain is reduced. The increase in noise figure is equal to the reduction in gain. The linearity of the part measured at the output is first-order independent of the gain setting. Layout considerations should include minimizing capacitance on the outputs by avoiding ground planes under the chokes, and equalizing the output line lengths for phase balance. SINGLE-ENDED AND DIFFERENTIAL SIGNALS The AD8372 was designed to be used by applying differential signals to the inputs and using the differential output drive of the device to drive the next device in the signal chain. The excellent distortion performance of the AD8372 is due primarily to the use of differential signaling techniques to cancel various distortion components in the device. In addition, all ac characterization was done using differential signal paths. Using this device with either the input or the output in a singleended circuit significantly degrades the overall performance of the AD8372. PASSIVE FILTER TECHNIQUES The AD8372 has a 100 Ω differential input impedance. For optimal performance, the differential output load should be 250 Ω. When designing passive filters around the AD8372, these impedances must be taken into account. DIGITAL GAIN CONTROL The digital gain control interface consists of four pins: SDI, SDO, CLK, and LATCH. The interface is active when the LATCH pin is shifted low. Gain words are written into the AD8372 via the SDI pin, and read back from the SDO pin. The first bit clocked into the data input pin determines whether the interface is in write or read mode. The second bit is a don’t care bit, while the remaining six bits program the gain. In read mode, the SDO pin clocks out the 6-bit gain word, LSB to MSB. The gain can be programmed between −9 dB and 32 dB in 1 dB steps. Timing details are given in Figure 2 and Figure 3. The gain code table is given in Table 3. DRIVING ANALOG-TO-DIGITAL CONVERTERS The AD8372 was designed with the intention of driving high speed, high dynamic range ADCs. The circuit in Figure 14 represents a simplified front end of one-half of the AD8372 dual VGA driving an AD9445 14-bit, 125 MHz analog-to-digital converter. The input of the AD8372 is driven differentially using a 1:3 impedance ratio transformer, which also matches the 150 Ω input resistance to a 50 Ω source. The open-collector outputs are biased through the 33 μH inductors and are accoupled from the 142 Ω load resistors that, in parallel with the 2 kΩ input resistance of the ADC, provide a 250 Ω load for gain accuracy. The ADC is ac-coupled from the 142 Ω resistors to negate a dc affect on the input common-mode voltage of the AD9445. Including the series 33 Ω resistors improves the isolation of the AD8372 from the switching currents caused by the ADC input sample and hold. The AD9445 represents a 2 kΩ differential load and requires a 2 V p-p signal when VREF = 1 V for a full-scale output. This circuit provides variable gain, isolation, and source matching for the AD9445. Using this circuit with the AD8372 in a gain of 32 dB (maximum gain), an SFDR performance of 74.5 dBc is achieved at 85 MHz. See Figure 15. Rev. 0 | Page 10 of 16 AD8372 5V 5V 1:3 0.1µF 33µH 142Ω 0.1µF 0.1µF 33Ω ½ VIN+ VGA VIN– AD8372 50Ω 0.1µF AC 0.1µF 14 142Ω 5V 07051-018 CKL1 SD01 ENA1 33µH 0.1µF 33Ω AD9445 14-BIT ADC Figure 14. AD8372 Driving an AD9445 ADC 0 FUND: –1.053dBFS –10 2ND: –74.55dBc –20 3RD: –86.45dBc 4TH: –91.35dBc –30 5TH: –89.57dBc 6TH: –91.15dBc –40 1 SNR: 58.12dBc SNRFS: 59.18dBc THD: –73.99dBc SINAD: 58.01dBc SFDR: 74.73dBc WO SPUR: –85.5dBc NOISE FLOOR: –101.3dB –50 (dBc) –60 2 –70 –80 5 –90 6 4 3 –100 –110 –120 ENCODE: 105MHz SAMPLES: 32768 ANALOG: 19.8766MHz –140 –150 0 FUND LEAK: 100 HARM LEAK: 3 DC LEAK: 6 5.25 10.50 15.75 21.00 26.25 31.50 36.75 42.00 47.25 52.50 FREQUENCY (MHz) 07051-019 –130 Figure 15. 74.5 dB SFDR Performance of the AD8372 Driving the AD9445 ADC Rev. 0 | Page 11 of 16 Figure 16. AD8372 Evaluation Board Schematic A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 H1-10 H1-11 H1-12 H1-7 H1-8 P2 P2 P2 P2 R0603 R0603 R0603 A20 A19 A18 A17 A16 A15 A14 A13 A12 A11 R0603 R0603 R0603 R0603 H1-9 H1-1 DGND C0603 0 C20 0.1UF R4 0 R5 0 R6 0 R7 0 R8 0 R10 0 R9 DGND C0603 TBD C1 DGND C0603 TBD C2 DGND C0603 TBD C3 DGND C0603 TBD C4 DGND C0603 TBD C5 DGND C0603 TBD C7 DGND C0603 TBD C6 DGND C0603 TBD C8 P2 P2 P2 P2 H1-15 H1-16 P2 H1-3 P2 H1-5 P2 P2 H1-4 P2 H1-6 P2 H1-14 H1-13 DGND DGND DGND DGND DGND DGND B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 75 OHMS H1-8 H1-7 H1-12 H1-11 H1-10 H1-9 H1-6 H1-12 H1-1 AGND C0603 AGND R0603 R34 TBD R0603 TBD R41 R0603 A GND B11 B12 B13 B14 B15 B16 B17 B18 B19 B20 P2 P2 P2 P2 P2 P2 P2 P2 P2 P2 AGND R0603 TBD R19 AGND 75 OHMS T2 AGND AGND H1-16 H1-15 H1-3 H1-4 H1-5 H1-6 H1-14 H1-13 R0603 TBD R20 50 OHMS T1 75 OHMS C0603 C23 0.1UF TBD C0603 AGND R0603 R33 TBD R0603 TBD DGND AGND AGND AGND 0.1UF C32 C0603 R0603 2.74K R2 32 31 30 29 28 27 26 25 Z1 AD8372 C0603 C19 0.1UF H1-6 H1-12 P1 13 H1-9 H1-10 H1-11 H1-12 H1-6 H1-5 H1-4 P1 12 P1 11 AGND R0603 H1-3 R1 2.74K AGND AGND W2 R0603 TBD R48 R0603 P1 25 P1 24 P1 23 P1 22 P1 21 P1 20 10K C10 AGND AGND C0603 R0603 R0603 0.1UF C13 1NF C12 C0603 R0603 C0603 0 C9 AGND TBD C0603 C16 1NF C0603 AGND P1 19 P1 18 P1 17 P1 16 P1 15 P1 14 A GND 0 R13 0 R14 H1-15 181 2 R0603 0 R22 H1-15 H1-7 SDO2 SDO1 100 OHMS 100 OHMS 100 OHMS R16 0 0.1UF C17 C0603 R0603 H1-15 TBD R3 AGND SDO2 SDO1 AGND R18 10K H1-15 H1-12 H1-6 R0603 R0603 TBD R47 H1-7 R17 17 18 19 20 21 22 23 24 H1-13 OCP2 ONC2 AGD2 SDO2 SDO1 AGD1 ONC1 OPC1 AGND W1 9 10 11 12 13 14 15 16 P1 10 P1 9 P1 8 P1 7 P1 6 P1 5 P1 4 P1 3 P1 2 P1 1 AGND DGND 7 LCH2 8 DVS2 5 CLK2 6 SDI2 3 SDI1 4 CLK1 1 DVS1 2 LCH1 C24 0.1UF R42 R0603 R32 TBD 75 OHMS 0.1UF C26 C0603 AGND 75 OHMS R0603 TBD R40 50 OHMS 0.1UF C27 C0603 75 OHMS 75 OHMS 0.1UF C25 C0603 C22 0.1UF R0603 TBD R39 75 OHMS R0603 R31 TBD 50 OHMS 50 OHMS AGND IPC2 P2 H1-1 H1-9 H1-10 H1-11 H1-5 H1-4 H1-3 DGND C0603 6 C21 0.1UF W3 W4 PR I SE C R12 DGD1 DGD2 R0603 INC1 INC2 TBD RXT1 RXT2 R15 AGD1 ADG2 A GND ENB1 ENB2 R0603 IPC1 IPC2 W5 W6 W7 W8 REF1 REF2 L1 0 4 AGND AVS1 AVS2 33UH 4 3 2 1 L2 R11 181 2 R24 0 R0603 R0603 AGND 0 R49 H1-15 AGND H1-15 C1206 TBD L5 R25 0 R0603 DGND DGND H1-13 TBD R38 0.1UF C29 C0603 R0603 R0603 R0603 AGND AGND R0603 0 R0603 0 R26 R0603 0 R46 R43 AGND AGND 3528 R45 0 R0603 3 2 1 SEC T4 10UF C33 3 2 1 SEC 6 4 6 A GND RED TES TLOOP R0603 C1206 TBD L6 A GND H1-15 TBD R27 TBD AGND TE STLOOP AGND 3528 10UF C34 50 OHMS DGND ONC1 OPC1 ONC2 ORANGE R0603 AGND 50 OHMS 50 OHMS R29 VSS R28 TBD 0.1UF C15 C0603 R0603 50 OHMS R0603 TBD R30 0.1UF C14 C0603 AGND VDD PRI PRI 4 H1-1 T3 100 OHMS AGND 100 OHMS R0603 0 R21 100 OHMS R0603 0 R44 100 OHMS R0603 0.1UF C28 R37 TBD R36 TBD R35 TBD C0603 0.1UF C18 C0603 100 OHMS 0.1UF C11 C0603 100 OHMS 100 OHMS R0603 0 R23 181 2 33UH L3 3 2 1 SE C PR I Rev. 0 | Page 12 of 16 6 33UH H1-1 181 2 INC1 L4 IPC1 33UH AD8372 CHAR BD OPC2 AD8372 EVALUATION BOARD SCHEMATIC INC2 07051-014 AD8372 OUTLINE DIMENSIONS 0.60 MAX 5.00 BSC SQ 0.60 MAX PIN 1 INDICATOR TOP VIEW 0.50 BSC 4.75 BSC SQ 0.50 0.40 0.30 32 1 3.25 3.10 SQ 2.95 EXPOSED PAD (BOTTOM VIEW) 17 16 9 8 0.25 MIN 3.50 REF 0.80 MAX 0.65 TYP 12° MAX 1.00 0.85 0.80 PIN 1 INDICATOR 25 24 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 Figure 17. 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 5 mm × 5 mm Body, Very Thin Quad (CP-32-2) Dimensions shown in millimeters ORDERING GUIDE Model AD8372ACPZ-WP 1 AD8372ACPZ-R71 AD8372-EVALZ1 1 Temperature Range −40°C to +85°C −40°C to +85°C Package Description 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ], Waffle Pack 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ], 7” Reel Evaluation Board Z = RoHS Compliant Part. Rev. 0 | Page 13 of 16 Package Option CP-32-2 CP-32-2 Ordering Quantity 1,500 AD8372 NOTES Rev. 0 | Page 14 of 16 AD8372 NOTES Rev. 0 | Page 15 of 16 AD8372 NOTES ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D07051-0-11/07(0) Rev. 0 | Page 16 of 16