Radiation Hardened High Speed, Monolithic Digital-to-Analog Converter HS-565BRH, HS-565BEH Features The HS-565BRH, HS-565BEH are fast, radiation hardened 12-bit current output, digital-to-analog converters. This part replaces the HS-565ARH, which is no longer available. The monolithic chips include a precision voltage reference, thin-film R-2R ladder, reference control amplifier and twelve high-speed bipolar current switches. • Electrically Screened to SMD # 5962-96755 The Intersil Dielectric Isolation process provides latch-up free operation while minimizing stray capacitance and leakage currents, to produce an excellent combination of speed and accuracy. Also, ground currents are minimized to produce a low and constant current through the ground terminal, which reduces error due to code-dependent ground currents. • Very High Speed: Settles to 0.50 LSB in 500ns Max HS-565BRH, HS-565BEH die are laser trimmed for a maximum integral nonlinearity error of ±0.25 LSB at +25°C. In addition, the low noise buried zener reference is trimmed both for absolute value and minimum temperature coefficient. • ±0.75 LSB Accuracy Guaranteed Over Temperature (±0.125 LSB Typical at +25°C) Specifications for Rad Hard QML devices are controlled by the Defense Supply Center in Columbus (DSCC). The SMD numbers listed here must be used when ordering. • High Speed A/D Converters • QML Qualified per MIL-PRF-38535 Requirements • Total Dose . . . . . . . . . . . . . . . . . . . . . . . . . . 100 krad (Si) (Max) • DAC and Reference on a Single Chip • Pin Compatible with AD-565A and HI-565A • Monotonicity Guaranteed Over Temperature • 0.50 LSB Max Nonlinearity Guaranteed Over Temperature • Low Gain Drift (Max., DAC Plus Reference) . . . . . . . . . . . . . . . . . . 50ppm/°C Applications • Precision Instrumentation • Signal Reconstruction Detailed Electrical Specifications for these devices are contained in SMD 5962-96755. A “hot-link” is provided on our website for downloading. BIP. OFF. 8 REF OUT VCC 4 3 + - REF IN REF GND 6 5 11 5k 10V DAC 0.5mA 19.95k 3.5k 10 9.95k IREF 5k 9 IO + - (4X IREF X CODE) 20V SPAN 10V SPAN OUT 2.5k 3k 7 -VEE 12 PWR GND 24 . . . 13 MSB LSB FIGURE 1. FUNCTIONAL DIAGRAM May 7, 2012 FN4607.4 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2003, 2012. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. HS-565BRH, HS-565BEH Pin Configurations HS9-565BRH, HS9-565BEH MIL-STD-1835 CDFP4-F24 (CERAMIC FLATPACK) TOP VIEW HS1-565BRH, HS1-565BEH MIL-STD-1835 CDIP2-T24 (SBDIP) TOP VIEW NC 1 24 2 23 3 22 4 21 21 BIT 4 IN NC VCC REF OUT REF GND 5 REF GND 5 20 BIT 5 IN REF IN 6 20 19 REF IN 6 19 BIT 6 IN 18 BIT 7 IN BIPOLAR RIN 8 17 BIT 8 IN -VEE BIPOLAR RIN IDAC OUT 7 -VEE 7 IDAC OUT 9 NC 1 24 BIT 1 IN (MSB) NC 2 23 BIT 2 IN VCC 3 22 BIT 3 IN REF OUT 4 8 18 17 9 16 10 15 16 BIT 9 IN 10V SPAN 20V SPAN 11 10V SPAN 10 15 BIT 10 IN PWR GND 12 14 13 20V SPAN 11 14 BIT 11 IN PWR GND 12 13 BIT 12 IN (LSB) BIT 1 IN (MSB) BIT 2 IN BIT 3 IN BIT 4 IN BIT 5 IN BIT 6 IN BIT 7 IN BIT 8 IN BIT 9 IN BIT 10 IN BIT 11 IN BIT 12 IN (LSB) Ordering Information ORDERING NUMBER PART NUMBER PART MARKING TEMP. RANGE (°C) PACKAGE (Pb-Free) PKG. DWG. # 5962R9675502V9A HS0-565BRH-Q +25 5962R9675502VJC HS1-565BRH-Q Q 5962R96 75502VJC -55 to +125 24 Ld SBDIP D24.6 5962R9675502VXC HS9-565BRH-Q Q 5962R96 75502VXC -55 to +125 24 Ld Flatpack K24.A HS9-565BRH/PROTO HS9-565BRH/PROTO HS9- 565BRH /PROTO -55 to +125 5962R9675503V9A HS0-565BEH-Q 5962R9675503VJC HS1-565BEH-Q Q 5962R96 75503VJC -55 to +125 24 Ld SBDIP D24.6 5962R9675503VXC HS9-565BEH-Q Q 5962R96 75503VXC -55 to +125 24 Ld Flatpack K24.A +25 NOTE: These Intersil Pb-free Hermetic packaged products employ 100% Au plate - e4 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. 2 FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Burn-In Bias Circuit +15V D1 C1 -15V D2 C2 +10V D3 C3 Definitions of Specifications 1 NC BIT 1 24 F0 2 NC BIT 2 23 F1 3 VCC BIT 3 22 F2 4 REF OUT BIT 4 21 F3 5 REF GND BIT 5 20 F4 6 REF IN BIT 6 19 F5 7 -VEE BIT 7 18 F6 8 BIP OFF BIT 8 17 F7 9 OUT BIT 9 16 F8 10 10V SPAN BIT 10 15 F9 11 20V SPAN BIT 11 14 F10 12 PWR GND BIT 12 13 F11 D1 = D2 = D3 = IN4002 or Equivalent F0 to F11: VIH = 5.0V ±0.5V VIL = 0.0V ±0.5V F0 = 100kHz ±10% (50% Duty Cycle) F1 = F0/2 F7 = F0/128 F2 = F0/4 F8 = F0/256 F3 = F0/8 F9 = F0/512 F4 = F0/16 F10 = F0/1024 F5 = F0/32 F11 = F0/2048 F6 = F0/64 +10V DIGITAL INPUT ANALOG OUTPUT STRAIGHT BINARY OFFSET BINARY TWO’S COMPLEMENT (Note) 000.... 000 Zero -FS (Full Scale) Zero 100.... 000 0.50 FS Zero -FS 111.... 111 +FS - 1LSB +FS - 1LSB Zero - 1LSB 011.... 111 0.50 FS - 1LSB Zero - 1LSB +FS - 1LSB MSB...LSB Accuracy Nonlinearity - Nonlinearity of a D/A converter is an important measure of its accuracy. It describes the deviation from an ideal straight line transfer curve drawn between zero (all bits OFF) and full scale (all bits ON). Differential Nonlinearity - For a D/A converter, it is the difference between the actual output voltage change and the ideal (1 LSB) voltage change for a one bit change in code. A Differential Nonlinearity of ±1 LSB or less guarantees monotonicity; i.e., the output always increases and never decreases for an increasing input. Radiation Bias Circuit -15V The HS-565BRH, HS-565BEH accepts digital input codes in binary format and may be user connected for any one of three binary codes. Straight binary, Two’s Complement (see note below), or Offset Binary. NOTE: Invert MSB with external inverter to obtain Two’s Complement Coding NOTES: +15V Digital Inputs 1 NC BIT 1 24 2 NC BIT 2 23 Settling Time 3 VCC BIT 3 22 4 REF OUT BIT 4 21 5 REF GND BIT 5 20 6 REF IN BIT 6 19 Settling time is the time required for the output to settle to within the specified error band for any input code transition. It is usually specified for a full scale or major carry transition, settling to within 0.50 LSB of final value. 7 -VEE BIT 7 18 Drift 8 BIP OFF BIT 8 17 9 OUT BIT 9 16 Gain Drift - The change in full scale analog output over the specified temperature range expressed in parts per million of full scale range per °C (ppm of FSR/°C). Gain error is measured with respect to +25°C at high (TH) and low (TL) temperatures. Gain drift is calculated for both high (TH - +25°C) and low ranges (+25°C - TL) by dividing the gain error by the respective change in temperature. The specification is the larger of the two representing worst case drift. 10 10V SPAN BIT 10 15 11 20V SPAN BIT 11 14 12 PWR GND BIT 12 13 NOTE: Power Supply Levels are ±0.5V 3 +5V Offset Drift - The change in analog output with all bits OFF over the specified temperature range expressed in parts per million of full scale range per °C (ppm of FSR/°C). Offset error is measured with respect to +25°C at high (TH) and low (TL) temperatures. Offset drift is calculated for both high (TH - +25°C) and low (+25°C - TL) ranges by dividing the offset error by the respective change in temperature. The specification given is the larger of the two, representing worst case drift. FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Power Supply Sensitivity No Trim Operation Power Supply Sensitivity is a measure of the change in gain and offset of the D/A converter resulting from a change in -15V or +15V supplies. It is specified under DC conditions and expressed as parts per million of full scale range per percent of change in power supply (ppm of FSR/%). The HS-565BRH, HS-565BEH will perform as specified without calibration adjustments. To operate without calibration, substitute 50Ω resistors for the 100Ω trimming potentiometers: In Figure 2 replace R2 with 50Ω; also remove the network on pin 8 and connect 50Ω to ground. For bipolar operation in Figure 3, replace R3 and R4 with 50Ω resistors. Typical unipolar zero will be ±0.50 LSB plus the op amp offset. Compliance Compliance Voltage is the maximum output voltage range that can be tolerated and still maintain its specified accuracy. Compliance Limit implies functional operation only and makes no claims to accuracy. The feedback capacitor C must be selected to minimize settling time. R4 100Ω Glitch REF OUT A glitch on the output of a D/A converter is a transient spike resulting from unequal internal ON-OFF switching times. Worst case glitches usually occur at half scale or the major carry code transition from 011 . . . 1 to 100 . . . 0 or vice versa. For example, if turn ON is greater than turn OFF for 011 . . . 1 to 100 . . . 0, an intermediate state of 000 . . . 0 exists, such that, the output momentarily glitches toward zero output. Matched switching times and fast switching will reduce glitches considerably. Applying the HS-565BRH and HS-565BEH 3 + IREF 0.5mA 6 19.95k REF IN 5 REF GND ( t )2 + ( t )2 D A where tD, tA are settling times for the DAC and amplifier. +15V 100kΩ VCC BIP. OFF. 3 11 REF IN 5 REF GND 5k 10V - IREF 19.95k 3.5k 10 9.95k DAC 0.5mA 5k (4 x IREF x CODE) - 20V SPAN 9 2.5k 3k VO 10V SPAN DAC OUT IO + -15V 8 HS-565BRH 6 R1 50kΩ 100Ω + 5k 10V - 3.5k 10 9.95k DAC 5k (4 x IREF x CODE) - 9 2.5k 3k VO 10V SPAN DAC OUT IO + 20V SPAN - C + R (SEE TABLE 1) CODE INPUT The HS-565BRH, HS-565BEH current output may be converted to voltage using the standard connections shown in Figures 2 and 3. The choice of operational amplifier should be reviewed for each application, since a significant trade-off may be made between speed and accuracy. Remember settling time for the DAC-amplifier combination is: 4 8 11 7 -VEE R2 100Ω BIP. OFF. HS-565BRH OP AMP Selection REF OUT R3 100Ω VCC 4 - C + R (SEE TABLE 1) PWR GND 24 . . . . . 13 MSB LSB FIGURE 3. BIPOLAR VOLTAGE OUTPUT Calibration Calibration provides the maximum accuracy from a converter by adjusting its gain and offset errors to zero. For the HS-565BRH, HS-565BEH, these adjustments are similar whether the current output is used, or whether an external op amp is added to convert this current to a voltage. Refer to Table 1 for the voltage output case, along with Figure 2 or 3. Calibration is a two step process for each of the five output ranges shown in Table 1. First adjust the negative full scale (zero for unipolar ranges). This is an offset adjust which translates the output characteristic, i.e., affects each code by the same amount. Next adjust positive FS. This is a gain error adjustment, which rotates the output characteristic about the negative FS value. For the bipolar ranges, this approach leaves an error at the zero code, whose maximum values is the same as for integral nonlinearity error. In general, only two values of output may be calibrated exactly; all others must tolerate some error. Choosing the extreme end points (plus and minus full scale) minimizes this distributed error for all other codes. CODE INPUT 7 -VEE PWR GND 24 . . . . . 13 MSB LSB FIGURE 2. UNIPOLAR VOLTAGE OUTPUT 4 FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Settling Time This is a challenging measurement, in which the result depends on the method chosen, the precision and quality of test equipment and the operating configuration of the DAC (test conditions). As a result, the different techniques in use by converter manufacturers can lead to consistently different results. An engineer should understand the advantage and limitations of a given test method before using the specified settling time as a basis for design. The approach used for several years at Intersil calls for a strobed comparator to sense final perturbations of the DAC output waveform. This gives the LSB a reasonable magnitude (814mV) for the HS-565BRH, HS-565BEH, which provides the comparator with enough overdrive to establish an accurate ±0.50 LSB window about the final settled value. Also, the required test conditions simulate the DACs environment for a common application - use in a successive approximation A/D converter. Considerable experience has shown this to be a reliable and repeatable way to measure settling time. The usual specification is based on a 10V step, produced by simultaneously switching all bits from off-to-on (tON) or on-to-off (tOFF). The slower of the two cases is specified, as measured from 50% of the digital input transition to the final entry within a window of ±0.50 LSB about the settled value. Four measurements characterize a given type of DAC: (a) tON, to final value +0.50 LSB (b) tON, to final value -0.50 LSB (c) tOFF, to final value +0.50 LSB (d) OFF, to final value -0.50 LSB (Cases (b) and (c) may be eliminated unless the overshoot exceeds 0.50 LSB). For example, refer to Figures 4A and 4B for the measurement of case (d). Procedure As shown in Figure 4B, settling time equals tX plus the comparator delay (tD = 15ns). To measure tX, • Adjust the delay on generator number 2 for a tX of several microseconds. This assures that the DAC output has settled to its final wave. • Switch on the LSB (+5V) • Adjust the VLSB supply for 50% triggering at COMPARATOR OUT. This is indicated by traces of equal brightness on the oscilloscope display as shown in Figure 4B. Note DVM reading. • Switch to LSB to Pulse (P) • Readjust the VLSB supply for 50% triggering as before, and note DVM reading. One LSB equals one tenth the difference in the DVM readings noted above. • Adjust the VLSB supply to reduce the DVM reading by 5 LSBs (DVM reads 10X, so this sets the comparator to sense the final settled value minus 0.50 LSB). Comparator output disappears. • Reduce generator number 2 delay until comparator output reappears, and adjust for “equal brightness”. • Measure tX from scope as shown in Figure 4B. Settling time equals tX + tD, i.e., tX + 15ns. TABLE 1. OPERATING MODES AND CALIBRATION CIRCUIT CONNECTIONS MODE Unipolar (See Figure 2) Bipolar (See Figure 3) CALIBRATION OUTPUT RANGE PIN 10 TO PIN 11 TO RESISTOR (R) APPLY INPUT CODE ADJUST TO SET VO 0 to +10V VO Pin 10 1.43k All 0’s All 1’s R1 R2 0V +9.99756V 0 to +5V VO Pin 9 1.1k All 0’s All 1’s R1 R2 0V +4.99878V ±10V NC VO 1.69k All 0’s All 1’s R3 R4 -10V +9.99512V ±5V VO Pin 10 1.43k All 0’s All 1’s R3 R4 -5V +4.99756V ±2.5V VO Pin 9 1.1k All 0’s All 1’s R3 R4 -2.5V +2.49878V 5 FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH SYNC PULSE PULSE IN GENERATOR GENERATOR TRIG NO. 1 NO. 2 OUT OUT OUT C 20V ± 20% BIAS A HS-565BRH ~100 kHz P 24 8 23 . . . . . . . . . . . . . 14 11 13 TURN ON TURN OFF 5k 9.95k +3V 10 NC 0V 5k -0.50LSB STROBE IN B 9 COMPARATOR OUT - B -400mV (TURN OFF) 5 5V LSB 2V 12 90 DVM 10 200k 0.1µF DIGITAL INPUT DAC OUTPUT 0V D + 2.5k 2mA 50% A tX COMP. STROBE 50% C VLSB SUPPLY SETTLING TIME tD = COMPARATOR DELAY 0.8V “EQUAL BRIGHTNESS” 4V COMP. OUT D . 0V FIGURE 4A. FIGURE 4B. Other Considerations Grounds Layout The HS-565BRH, HS-565BEH has two ground terminals, pin 5 (REF GND) and pin 12 (PWR GND). These should not be tied together near the package unless that point is also the system signal ground to which all returns are connected. (If such a point exists, then separate paths are required to pins 5 and 12). Connections to pin 9 (IOUT) on the HS-565BRH, HS-565BEH are most critical for high speed performance. Output capacitance of the DAC is only 20pF, so a small change of additional capacitance may alter the op amp’s stability and affect settling time. Connections to pin 9 should be short and few. Component leads should be short on the side connecting to pin 9 (as for feedback capacitor C). See the “Settling Time” section on page 5. The current through pin 5 is near zero DC (Note); but pin 12 carries up to 1.75mA of code - dependent current from bits 1, 2, and 3. The general rule is to connect pin 5 directly to the system “quiet” point, usually called signal or analog ground. Connect pin 12 to the local digital or power ground. Then, of course, a single path must connect the analog/signal and digital/power grounds. NOTE: Current cancellation is a two step process within the HS-565BRH, HS-565BEH in which code dependent variations are eliminated, the resulting DC current is supplied internally. First an auxiliary 9-bit R-2R ladder is driven by the complement of the DACs input code. Together, the main and auxiliary ladders draw a continuous 2.25mA from the internal ground node, regardless of input code. Part of the DC current is supplied by the zener voltage reference, and the remainder is sourced from the positive supply via a current mirror which is laser trimmed for zero current through the external terminal (pin 5). 6 Bypass Capacitors Power supply bypass capacitors on the op amp will serve the HS-565BRH, HS-565BEH also. If no op amp is used, a 0.01µF ceramic capacitor from each supply terminal to pin 12 is sufficient, since supply current variations are small. FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Die Characteristics DIE DIMENSIONS: ASSEMBLY RELATED INFORMATION 179 mils x 107 mils x 19 mils Substrate Potential: Tie Substrate to VREF GND INTERFACE MATERIALS: ADDITIONAL INFORMATION: Glassivation: Type: AlCu Thickness: 8kÅ ±1kÅ Worst Case Current Density: 2.0 x 105 A/cm2 Top Metallization: Transistor Count: Type: Al/Copper Thickness: 16kÅ ±2kÅ 200 Substrate: Bipolar DI, Backside Finish: Silicon Metallization Mask Layout HS-565BRH, HS-565BEH VCC NC 3 3 NC 1 A (MSB) BIT 1 BIT 2 VREF OUT BIT 3 VREF GND BIT 4 BIT 5 VREF IN -VS BIT 6 BIPOLAR 12 BIT 7 IDAC OUT BIT 8 BIT 9 10V SPAN BIT 10 20V SPAN 7 POWER GND BIT 12 (LSB) BIT 11 FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Ceramic Dual-In-Line Metal Seal Packages (SBDIP) -DBASE METAL E -BC A-B S SECTION A-A D S D BASE PLANE Q S2 -C- SEATING PLANE A L S1 eA A A b2 b ccc M C A - B S e eA/2 c aaa M C A - B S D S D S INCHES (c) b1 M (b) M bbb S D24.6 MIL-STD-1835 CDIP2-T24 (D-3, CONFIGURATION C) 24 LEAD CERAMIC DUAL-IN-LINE METAL SEAL PACKAGE LEAD FINISH c1 -A- NOTES: 1. Index area: A notch or a pin one identification mark shall be located adjacent to pin one and shall be located within the shaded area shown. The manufacturer’s identification shall not be used as a pin one identification mark. 2. The maximum limits of lead dimensions b and c or M shall be measured at the centroid of the finished lead surfaces, when solder dip or tin plate lead finish is applied. 3. Dimensions b1 and c1 apply to lead base metal only. Dimension M applies to lead plating and finish thickness. 4. Corner leads (1, N, N/2, and N/2+1) may be configured with a partial lead paddle. For this configuration dimension b3 replaces dimension b2. 5. Dimension Q shall be measured from the seating plane to the base plane. SYMBOL MILLIMETERS MIN MAX MIN MAX A - 0.225 b 0.014 0.026 0.36 b1 0.014 0.023 b2 0.045 0.065 b3 0.023 c 0.008 c1 D - 5.72 - 0.66 2 0.36 0.58 3 1.14 1.65 - 0.045 0.58 1.14 4 0.018 0.20 0.46 2 0.008 0.015 0.20 - 1.290 E 0.500 e 0.610 12.70 NOTES 0.38 3 32.77 - 15.49 - 0.100 BSC 2.54 BSC - eA 0.600 BSC 15.24 BSC - eA/2 0.300 BSC 7.62 BSC - L 0.120 0.200 3.05 5.08 - Q 0.015 0.075 0.38 1.91 5 S1 0.005 - 0.13 - 6 S2 0.005 - 0.13 - 7 α 90o 105o 90o 105o - aaa - 0.015 - 0.38 - bbb - 0.030 - 0.76 - ccc - 0.010 - 0.25 - M - 0.0015 - N 24 0.038 24 2 8 Rev. 0 4/94 6. Measure dimension S1 at all four corners. 7. Measure dimension S2 from the top of the ceramic body to the nearest metallization or lead. 8. N is the maximum number of terminal positions. 9. Braze fillets shall be concave. 10. Dimensioning and tolerancing per ANSI Y14.5M - 1982. 11. Controlling dimension: INCH. For additional products, see www.intersil.com/product_tree Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 8 FN4607.4 May 7, 2012 HS-565BRH, HS-565BEH Ceramic Metal Seal Flatpack Packages (Flatpack) K24.A MIL-STD-1835 CDFP4-F24 (F-6A, CONFIGURATION B) A e 24 LEAD CERAMIC METAL SEAL FLATPACK PACKAGE A INCHES PIN NO. 1 ID AREA -A- D -B- S1 b MILLIMETERS SYMBOL MIN MAX MIN MAX NOTES A 0.045 0.115 1.14 2.92 - b 0.015 0.022 0.38 0.56 - b1 0.015 0.019 0.38 0.48 - c 0.004 0.009 0.10 0.23 - c1 0.004 0.006 0.10 D - 0.640 0.15 - 16.26 3 E1 0.004 M H A-B S D S Q 0.036 M H A-B S D S C E -D- A -C- E 0.350 0.420 E1 - 0.450 9.14 E2 0.180 - 4.57 - - E3 0.030 - 0.76 - 7 0.015 0.20 - 10.67 - 11.43 3 -HL E2 E3 SEATING AND BASE PLANE - c1 L E3 e k LEAD FINISH BASE METAL (c) b1 M 0.050 BSC 0.008 1.27 BSC - 0.38 2 L 0.250 0.370 6.35 9.40 - Q 0.026 0.045 0.66 1.14 8 S1 0.005 - 0.13 M - 0.0015 - - 0.04 6 - M (b) SECTION A-A N 24 24 Rev. 0 5/18/94 NOTES: 1. Index area: A notch or a pin one identification mark shall be located adjacent to pin one and shall be located within the shaded area shown. The manufacturer’s identification shall not be used as a pin one identification mark. Alternately, a tab (dimension k) may be used to identify pin one. 2. If a pin one identification mark is used in addition to a tab, the limits of dimension k do not apply. 3. This dimension allows for off-center lid, meniscus, and glass overrun. 4. Dimensions b1 and c1 apply to lead base metal only. Dimension M applies to lead plating and finish thickness. The maximum limits of lead dimensions b and c or M shall be measured at the centroid of the finished lead surfaces, when solder dip or tin plate lead finish is applied. 5. N is the maximum number of terminal positions. 6. Measure dimension S1 at all four corners. 7. For bottom-brazed lead packages, no organic or polymeric materials shall be molded to the bottom of the package to cover the leads. 8. Dimension Q shall be measured at the point of exit (beyond the meniscus) of the lead from the body. Dimension Q minimum shall be reduced by 0.0015 inch (0.038mm) maximum when solder dip lead finish is applied. 9. Dimensioning and tolerancing per ANSI Y14.5M - 1982. 10. Controlling dimension: INCH. 9 FN4607.4 May 7, 2012