Low Inductance Capacitors Introduction The signal integrity characteristics of a Power Delivery Network (PDN) are becoming critical aspects of board level and semiconductor package designs due to higher operating frequencies, larger power demands, and the ever shrinking lower and upper voltage limits around low operating voltages. These power system challenges are coming from mainstream designs with operating frequencies of 300MHz or greater, modest ICs with power demand of 15 watts or more, and operating voltages below 3 volts. The classic PDN topology is comprised of a series of capacitor stages. Figure 1 is an example of this architecture with multiple capacitor stages. An ideal capacitor can transfer all its stored energy to a load instantly. A real capacitor has parasitics that prevent instantaneous transfer of a capacitor’s stored energy. The true nature of a capacitor can be modeled as an RLC equivalent circuit. For most simulation purposes, it is possible to model the characteristics of a real capacitor with one capacitor, one resistor, and one inductor. The RLC values in this model are commonly referred to as equivalent series capacitance (ESC), equivalent series resistance (ESR), and equivalent series inductance (ESL). The ESL of a capacitor determines the speed of energy transfer to a load. The lower the ESL of a capacitor, the faster that energy can be transferred to a load. Historically, there has been a tradeoff between energy storage (capacitance) and inductance (speed of energy delivery). Low ESL devices typically have low capacitance. Likewise, higher capacitance devices typically have higher ESLs. This tradeoff between ESL (speed of energy delivery) and capacitance (energy storage) drives the PDN design topology that places the fastest low ESL capacitors as close to the load as possible. Low Inductance MLCCs are found on semiconductor packages and on boards as close as possible to the load. Slowest Capacitors Fastest Capacitors Semiconductor Product VR Bulk Board-Level Package-Level Die-Level Low Inductance Decoupling Capacitors Figure 1 Classic Power Delivery Network (PDN) Architecture LOW INDUCTANCE CHIP CAPACITORS INTERDIGITATED CAPACITORS The key physical characteristic determining equivalent series inductance (ESL) of a capacitor is the size of the current loop it creates. The smaller the current loop, the lower the ESL. A standard surface mount MLCC is rectangular in shape with electrical terminations on its shorter sides. A Low Inductance Chip Capacitor (LICC) sometimes referred to as Reverse Geometry Capacitor (RGC) has its terminations on the longer side of its rectangular shape. When the distance between terminations is reduced, the size of the current loop is reduced. Since the size of the current loop is the primary driver of inductance, an 0306 with a smaller current loop has significantly lower ESL then an 0603. The reduction in ESL varies by EIA size, however, ESL is typically reduced 60% or more with an LICC versus a standard MLCC. The size of a current loop has the greatest impact on the ESL characteristics of a surface mount capacitor. There is a secondary method for decreasing the ESL of a capacitor. This secondary method uses adjacent opposing current loops to reduce ESL. The InterDigitated Capacitor (IDC) utilizes both primary and secondary methods of reducing inductance. The IDC architecture shrinks the distance between terminations to minimize the current loop size, then further reduces inductance by creating adjacent opposing current loops. An IDC is one single capacitor with an internal structure that has been optimized for low ESL. Similar to standard MLCC versus LICCs, the reduction in ESL varies by EIA case size. Typically, for the same EIA size, an IDC delivers an ESL that is at least 80% lower than an MLCC. 59 Low Inductance Capacitors Introduction LAND GRID ARRAY (LGA) CAPACITORS LOW INDUCTANCE CHIP ARRAYS (LICA®) Land Grid Array (LGA) capacitors are based on the first Low ESL MLCC technology created to specifically address the design needs of current day Power Delivery Networks (PDNs). This is the 3rd low inductance capacitor technology developed by AVX. LGA technology provides engineers with new options. The LGA internal structure and manufacturing technology eliminates the historic need for a device to be physically small to create small current loops to minimize inductance. The first family of LGA products are 2 terminal devices. A 2 terminal 0306 LGA delivers ESL performance that is equal to or better than an 0306 8 terminal IDC. The 2 terminal 0805 LGA delivers ESL performance that approaches the 0508 8 terminal IDC. New designs that would have used 8 terminal IDCs are moving to 2 terminal LGAs because the layout is easier for a 2 terminal device and manufacturing yield is better for a 2 terminal LGA versus an 8 terminal IDC. LGA technology is also used in a 4 terminal family of products that AVX is sampling and will formerly introduce in 2008. Beyond 2008, there are new multi-terminal LGA product families that will provide even more attractive options for PDN designers. The LICA® product family is the result of a joint development effort between AVX and IBM to develop a high performance MLCC family of decoupling capacitors. LICA was introduced in the 1980s and remains the leading choice of designers in high performance semiconductor packages and high reliability board level decoupling applications. LICA® products are used in 99.999% uptime semiconductor package applications on both ceramic and organic substrates. The C4 solder ball termination option is the perfect compliment to flip-chip packaging technology. Mainframe class CPUs, ultimate performance multi-chip modules, and communications systems that must have the reliability of 5 9’s use LICA®. LICA® products with either Sn/Pb or Pb-free solder balls are used for decoupling in high reliability military and aerospace applications. These LICA® devices are used for decoupling of large pin count FPGAs, ASICs, CPUs, and other high power ICs with low operating voltages. When high reliability decoupling applications require the very lowest ESL capacitors, LICA® products are the best option. 470 nF 0306 Impedance Comparison 1 0306 2T-LGA 0306 LICC 0306 8T-IDC Impedance (ohms) 0603 MLCC 0.1 0.01 0.001 1 10 100 1000 Frequency (MHz) Figure 2 MLCC, LICC, IDC, and LGA technologies deliver different levels of equivalent series inductance (ESL). 60 Low Inductance Capacitors LICA® (Low Inductance Decoupling Capacitor Arrays) LICA® arrays utilize up to four separate capacitor sections in one ceramic body (see Configurations and Capacitance Options). These designs exhibit a number of technical advancements: Low Inductance features– Low resistance platinum electrodes in a low aspect ratio pattern Double electrode pickup and perpendicular current paths C4 “flip-chip” technology for minimal interconnect inductance HOW TO ORDER LICA 3 T Style & Size Voltage 5V = 9 10V = Z 25V = 3 102 M F 3 Dielectric Cap/Section Capacitance Height D = X5R (EIA Code) Tolerance Code T = T55T 102 = 1000 pF M = ±20% 6 = 0.500mm S = High K 103 = 10 nF P = GMV 3 = 0.650mm T55T 104 = 100 nF 1 = 0.875mm 5 = 1.100mm 7 = 1.600mm NOTE: Contact factory for availability of Termination and Tolerance Options for Specific Part Numbers. TABLE 1 Typical Parameters T55T/S55S Termination F = C4 Solder Balls- 97Pb/3Sn H = C4 Solder Balls Low ESR G = Lead Free SAC R = Cr-Cu-Au N = Cr-Ni-Au V = Eutectic LeadTin Bump37%Pb/63%Sn X = None Units Co Capacitance, 25°C 1.45 x Co Capacitance, 55°C 0.7 x Co Capacitance, 85°C 15 Dissipation Factor 25° 20 ESR (Nominal) 0.2 DC Resistance 300 IR (Minimum @25°) (Design Dependent) 500 Dielectric Breakdown, Min 8.5 Thermal Coefficient of Expansion 30 Inductance: (Design Dependent) (Nominal) DC to 5 Gigahertz Frequency of Operation -55° to 125°C Ambient Temp Range Nanofarads Nanofarads Nanofarads Percent Milliohms Ohms Megaohms Volts ppm/°C 25-100° Pico-Henries 4 A A # of Inspection Code Reel Packaging Caps/Part Code Face M = 7" Reel 1 = one A = Standard A = Bar R = 13" Reel B = No Bar 6 = 2"x2" Waffle Pack 2 = two B = COTS+ 8 = 2"x2" Black Waffle 4 = four X = MIL-PRF-123 C = Dot, S55S Dielectrics Pack D = Triangle 7 = 2"x2" Waffle Pack w/ termination facing up A = 2"x2" Black Waffle Pack w/ termination facing up C = 4"x4" Waffle Pack w/ clear lid LEAD-FREE COMPATIBLE COMPONENT For RoHS compliant products, please select correct termination style. TERMINATION OPTIONS SOLDER BALLS TERMINATION OPTION F, H, G OR V SOLDER BALL AND PAD DIMENSIONS 0.8 ±.03 (2 pics) 0.6 ±.100mm C } “Centrality”* 0.925 ±0.03mm L = ±.06mm 0.925 ±0.03mm Vertical and Horizontal Pitch=0.4 ±.02mm Code Face to Denote Orientation (Optional) C4 Ball diameter: .164 ±.03mm "Ht" = (Hb +.096 ±.02mm typ) "Hb" ±.06 "W" = ±.06mm Pin A1 is the lower left hand ball. *NOTE: The C4 pattern will be within 0.1mm of the center of the LICA body, in both axes. Code (Body Height) Width (W) Length (L) Height Body (Hb) 1 3 5 6 7 1.600mm 1.600mm 1.600mm 1.600mm 1.600mm 1.850mm 1.850mm 1.850mm 1.850mm 1.850mm 0.875mm 0.650mm 1.100mm 0.500mm 1.600mm TERMINATION OPTION R OR N 79 Low Inductance Capacitors LICA® (Low Inductance Decoupling Capacitor Arrays) TEMPERATURE VS CAPACITANCE CHANGE TYPICAL S21 FOR LICA AT SINGLE VIA Maximum +45% 0 LICA T55T/S55S CERAMIC linear1.sch1.DB[S21] Capacitance Change -14 0% -28 -42 Maximum -30% -56 -70 25°C 50°C 60°C 3 85°C 30 300 3000 Freq (MHz) LICA COMMON PART NUMBER LIST Part Number LICA3T193M3FC4AA LICA3T153P3FC4AA LICA3T134M1FC1AA LICA3T104P1FC1AA LICA3T333M1FC4AA LICA3T263P3FC4AA LICA3T244M5FC1AA LICA3T194P5FC1AA LICA3T394M7FC1AB LICA3T314P7FC1AB Extended Range LICAZT623M3FC4AB LICA3T104M3FC1A LICA3T803P3FC1A LICA3T423M3FC2A LICA3T333P3FC2A LICA3S253M3FC4A LICAZD753M3FC4AD LICAZD504M3FC1AB LICAZD604M7FC1AB LICA3D193M3FC4AB Voltage Thickness (mm) 25 25 25 25 25 25 25 25 25 25 0.650 0.650 0.875 0.875 0.875 0.650 1.100 1.100 1.600 1.600 10 25 25 25 25 25 10 10 10 25 CONFIGURATION Capacitors per Package 4 4 1 1 4 4 1 1 1 1 0.650 0.650 0.650 0.650 0.650 0.650 0.650 0.650 1.600 0.650 4 1 1 2 2 4 4 1 1 4 Schematic D D CAP C B1 A1 B1 D1 C1 B1 A1 D2 C2 B2 A2 CAP 2 A2 C2 D2 CAP 1 Code Face B2 CAP 2 C1 A1 C2 A2 D3 B3 D4 B4 CAP 3 A3 A Code Face Schematic D1 B B2 D2 CAP 1 C1 C A Schematic D1 C3 WAFFLE PACK OPTIONS FOR LICA® Code Face B D1 C1 B1 A1 D2 C2 B2 A2 D3 C3 B3 A3 D4 C4 B4 A4 CAP 4 C4 A4 LICA® PACKAGING SCHEME “M” AND “R” 8mm conductive plastic tape on reel: “M”=7" reel max. qty. 3,000, “R”=13" reel max. qty. 8,000 FLUOROWARE® Code Face to Denote Orientation Code Face to Denote Orientation Wells for LICA® part, C4 side down 76 pieces/foot 1.75mm x 2.01mm x 1.27mm deep on 4mm centers 0.64mm Push Holes H20-080 Option "6" 100 pcs. per 2" x 2" package Note: Standard configuration is Termination side down 72 Option "C" 400 pcs. per 4" x 4" package Code Face to Denote Orientation (Typical) 1.75mm Sprocket Holes: 1.55mm, 4mm pitch