LMH6555EVAL/NOPB

User's Guide SNOA489A – June 2007 – Revised April 2013 AN-1615 LMH6555 Evaluation Board 1 Evaluation Board Texas Instruments suggests the following evaluation board as a guide for high frequency layout and as an aid in device testing and characterization: Device Package Evaluation Board Ordering ID LMH6555 16-Pin WQFN LMH6555EVAL The evaluation board can be ordered when a device sample request is placed with Texas Instruments. RFN (NOTE 1) NOTE 1: RFN and RFP NOT USED WITH LMH6555 NOTE 2: TRANSFORMER PART NUMBER: MINI-CIRCUITS TC1_1_13M (OPTIONAL). OPEN RFP (NOTE 1) REMOVE R9 and R10 TO USE TX1. OPEN 0: 16 IN+ 12 R9 (NOTE 2) U1 0: VCC RGP VCC VCC 9 J1 11 VCC + VIN VOUT 0: 13 RGN J3 0: 5 VIN IN- - + VOUT 8 (NOTE 2) 6 1 R8 0: 3 4 J2 - VOUT R6 J7 VOUT + TX1 10 R10 (NOTE 2) 0: C3 1 2 3 4 6 7 14 15 LMH6555 0: 0: GND GND GND GND GND GND GND GND VCM_REF R7 R5 - J4 C8 0.01 PF VCM 0.1 PF R1 OPEN VCC GND J5 C1 C2 C5 C6 0.01 PF 0.01 PF 0.1 PF 10 PF VCC + J6 Figure 1. Evaluation Board Schematic All trademarks are the property of their respective owners. SNOA489A – June 2007 – Revised April 2013 Submit Documentation Feedback AN-1615 LMH6555 Evaluation Board Copyright © 2007–2013, Texas Instruments Incorporated 1 Description 2 Description 2.1 Input Conditions www.ti.com The LMH6555 evaluation board is intended for use in the following applications: • Single ended to differential output • Differential input to differential output For single ended input applications, either “IN+” (J1) or “IN−” (J3) SMA inputs can be used. As implied, J1 will have positive gain and J3 negative. You can set the value of “RGP” and “RGN” resistors (0 Ω is installed on the evaluation board). For most single-ended input applications, the driven input (either RGP or RGN) would be set to 0 Ω while being driven from a 50 Ω source and the undriven input resistor (either RGN or RGP) would be set to 50 Ω (with the SMA connector side of the resistor shorted to ground) to provide impedance matching (50 Ω) between the two inputs. Alternatively, with 0 Ω resistors installed for RGP and RGN on the board, the undriven input (either J1 or J3) can be terminated with a 50 Ω SMA termination to achieve the same effect. For differential input applications, use both J1 and J3. Again, “RGP” and “RGN” resistors are used to ensure that, in a typical application, each LMH6555 input sees 50 Ω to ground. Otherwise, there will be an insertion gain imbalance due to unequal input impedances. A differential source with 100 Ω built-in resistance can be directly plugged into J1 and J3 (RGP = RGN = 0 Ω). 2.2 Output Conditions The LMH6555 evaluation board differential output appears across J7 (VOUT+) and J2 (VOUT−) SMA connectors. The optional Balun Transformer (TX1, not included) combines the two LMH6555 outputs and allows one to observe the combined output at either J7 or J2 down to the frequency of operation of the Balun transformer used (4.5 MHz in the case of the transformer specified in Table 1). To do so both J7 and J2 are each to be terminated with 50 Ω to ground. Most laboratory equipment has 50 Ω input impedance built-in. Thus, the observed output will be properly terminated by the measurement equipment. The unused output needs to be terminated with 50 Ω as well. Alternatively, both J7 and J2 outputs can be used with a 100 Ω differential load as would be the case when the LMH6555 evaluation board is used to drive the 100 Ω differential input of a high speed ADC such as the ADC081000/ADC081500. The evaluation board is configured for such an application with R9 and R10 (0 Ω for both) passing the LMH6555 output signals directly to J7 and J2 and TX1 not installed. 2.3 VCM_REF Input The LMH6555 output common mode is set by the “VCM_REF” input pin voltage. The evaluation board terminal labeled “VCM” should be tied to the appropriate DC source to drive this pin voltage. The range of voltages for this pin is from 0.95 V to 1.50 V and there are decoupling capacitors (C3, C8) on the board. The “VCM” input cannot be left floating as this could cause the output to rail in the absence of a common mode control voltage. When used in conjunction with the ADC081000 A/D converter (or equivalent), the “VCMO” output pin of that A/D converter can be used to drive the “VCM” pin on the LMH6555 evaluation board. In some cases, a general-purpose buffer may be needed to supply the current needed for the “VCM_REF” input pin of the LMH6555. To find out if a buffer is necessary, Consult the A/D converter data sheet. NOTE: ADC081000 “VCMO” is limited to ±1 µA and, therefore, an external buffer is necessary in this case. 2 AN-1615 LMH6555 Evaluation Board SNOA489A – June 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Bill of Materials (BOM) www.ti.com 3 Bill of Materials (BOM) Table 1. Bill of Materials Ref. Designator Description Quantity 1 TX1 Mini-circuits P/N TC1-1-13M (optional) 1 (optional) 2 R9, R10 O Ω Resistors 2 3 U1 LMH6555SQ 1 4 RGP, RGN, R5, R6, R7, R8 O Ω Resistors 6 5 C6 10 µF Tantalum size A (3216) 1 6 C5, C8 0.1 µF ceramic SMT (0603) 2 7 C1, C2, C3 0.01 µF Ceramic SMT (0402) 3 8 J4, J5, J6 Test Point 3 9 J1, J2, J3, J7 SMA Connector (Digikey J502–ND) 4 Figure 2. LMH6555 Evaluation Board Top View With Components SNOA489A – June 2007 – Revised April 2013 Submit Documentation Feedback AN-1615 LMH6555 Evaluation Board Copyright © 2007–2013, Texas Instruments Incorporated 3 Bill of Materials (BOM) www.ti.com Figure 3. LMH6555 Evaluation Board Bottom View With Circuit 4 AN-1615 LMH6555 Evaluation Board SNOA489A – June 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily performed. TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide adequate design and operating safeguards. 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 relating to any combination, machine, or process in which TI components or services are used. Information published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use of any TI components in safety-critical applications. In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and requirements. Nonetheless, such components are subject to these terms. No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties have executed a special agreement specifically governing such use. Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of non-designated products, TI will not be responsible for any failure to meet ISO/TS16949. Products Applications Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps DSP dsp.ti.com Energy and Lighting www.ti.com/energy Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial Interface interface.ti.com Medical www.ti.com/medical Logic logic.ti.com Security www.ti.com/security Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video RFID www.ti-rfid.com OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com Wireless Connectivity www.ti.com/wirelessconnectivity Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2013, Texas Instruments Incorporated