PT7681—5V 30-A Programmable ISR With Margin Up/Down Controls SLTS177B - DECEMBER 2002 - REVISED JULY 2006 Features • 5V Input Voltage • 30A Output Current • 4-bit Programmable Output: 2V to 3.5V • 95% Efficiency • Margin Up/Down Controls • Differential Remote Sense • • • • • Description Over-Current Protection Over-Temperature Protection 27-Pin Solderable Copper Case 1.57in² PCB Area (‘N’ Suffix) IPC Lead-Free 2 Ordering Information The PT7681 Excalibur™ is a high performance integrated switching regulator (ISR), which is housed in a 27-pin space-saving solderable copper package. Operating from a +5V input source, the PT7681 delivers up to 30A of output current over the adjustable output voltage range of 2V to 3.5V. The high output current and relatively small size makes the PT7681 suitable for powering high-end DSP, microprocessor, and ASIC circuits requiring core or I/O logic supply voltages as low as 2V. The output voltage is programmable via a 4-bit input code. PT7681o = 2 to 3.5 Volts A special feature of the PT7681 is the Margin Up and Margin Down controls. These controls provide a convenient method for testing the load circuit over its supply voltage margins during production and qualification test programs. Other features include output shortcircuit and over-temperature protection, a standby on/off control, and a differential remote sense to compensate for voltage drop between the regulator and load. PT Series Suffix (PT1234 x ) Case/Pin Order Configuration Suffix N A C Vertical Horizontal SMD Package Code (ENE) (ENF) (ENG) (Reference the applicable package code drawing for the dimensions and PC board layout) Standard Application VID0 VID1 VID2 VID3 PROGRAMMING PINS SENSE(+) 4 3 2 1 26 L1 VIN 7-11 1µH CIN + 5 13-19 6 VOUT 20-25 PT7681 27 12 L O A D + COUT GND GND STBY SENSE(–) MARG DN MARGUP MARG UP MARGDN For technical support and more information, see inside back cover or visit www.ti.com Cin = Required 1500µF electrolytic Cout = Required 330µF electrolytic L 1 = Optional 1µH input choke PT7681—5V 30-A Programmable ISR With Margin Up/Down Controls SLTS177B - DECEMBER 2002 - REVISED JULY 2006 Pin-Out Information Programming Information Pin Function Pin Function 1 VID0 15 GND 2 VID1 16 GND 3 VID2 17 GND 4 5 VID3 STBY * 18 19 GND GND 6 MARGDN 20 7 Vin Vin Vin 21 Vout Vout 22 23 Vout Vout Vin Vin 24 11 25 Vout Vout 12 13 Sense(–) GND 26 27 Sense(+) MARGUP 14 GND 8 9 10 * For STBY pin: VID3 VID2 VID1 VID0 1 1 1 1 1 1 1 0 1 1 0 1 1 1 0 0 1 0 1 1 1 0 1 0 1 0 0 1 1 0 0 0 0 1 1 1 0 1 1 0 0 1 0 1 0 1 0 0 0 0 1 1 0 0 1 0 0 0 0 1 0 0 0 0 Vout 2.00V 2.10V 2.20V 2.30V 2.40V 2.50V 2.60V 2.70V 2.80V 2.90V 3.00V 3.10V 3.20V 3.30V 3.40V 3.50V Logic 0 = Pin 12 potential (Rem Sense Gnd) Logic 1 = Open circuit (no pull-up resistors) VID 3 must not be changed while the unit is operating. open =output enabled ground =output disabled. Pin Descriptions Vin: The positive input voltage power node to the module, which is referenced to common GND. GND: This is the common ground connection for the ‘Vin’ and ‘Vout’ power connections. It is also the 0VDC reference for the ‘STBY’ control input. STBY: The STBY pin is an open-collector/drain negative logic input that is referenced to GND. Applying a ground signal to this input will disable the module’s output and place the regulator in “standby” mode. When in standby, the input current drawn by the regulator is significantly reduced. If the STBY input is left open circuit, the module will produce an output whenever a valid input source is applied. VID0–VID3: Selects the set-point output voltage of the regulator according to the applicable program code (See programming information). Each input, VID0 through VID3, must either be connected to ‘Sense(–)’ or left open circuit. Vout: The regulated positive power output with respect to the GND node. The set point voltage at this node is defined by the status of the pins VID0 through VID3. Sense(+): Provides the regulator with the capability to regulate the set-point voltage at the load. When used with ‘Sense(–)’, the regulation circuitry will compensate for voltage drop between the converter and the load. This pin may be left open circuit, but connecting it to ‘Vout’ will improve load regulation. Sense(–): This is the logic ‘0’ reference for the inputs VID0 through VID3. It also provides the regulator with a differential remote sense capability when used with the ‘Sense(+)’ input. For optimum output voltage accuracy this pin should always be connected to GND. MARGDN: This is an open-collector/drain negative logic input. Applying a ground signal to this input increases the output voltage of the module by up to 5%. The control provides a convenient method for testing the operation of the load circuit over its supply voltage tolerance margins. MARGUP: An open-collector/drain negative logic input that operates similar to the MARGDN control. Applying a ground signal to this input automatically decreases the output by up to 5%. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT7681—5V 30-A Programmable ISR With Margin Up/Down Controls SLTS177B - DECEMBER 2002 - REVISED JULY 2006 Specifications (Unless otherwise stated, Ta =25°C, Vin =5V, Cin =1,500µF, Cout =330µF, Vo =3.3V, and Io =Iomax) PT7681 Characteristics Symbols Conditions Min Output Current Io Ta = 60°C, 200LFM, pkg N Ta = 25°C, Natural convection Input Voltage Range Vin Over Io range 4.5 — 5.5 Set-Point Voltage Tolerance Vo tol All output voltages — ±10 ±25 Temperature Variation Regtemp –40°C =Ta =+85°C, I o =Iomin — ±1 — Line Regulation Regline Over Vin range — ±5 — mV Load Regulation Regload Over Io range — ±5 — mV Total Output Voltage Variation . Vo tol Includes set-point, line, load, –40°C =T a =+85°C — ±1.5 ±3 %Vo Efficiency . Io =15A Vo =3.3V Vo =2.5V Vo =1.8V — — — 93 92 89 — — — % Io =30A Vo =3.3V Vo =2.5V Vo =1.8V — — — 90 87 83 — — — % mVpp 0 0 Typ — — Max Units 30 29 A V (1) mV %Vo Vo Ripple (pk-pk) Vr 20MHz bandwidth — 40 — Transient Response ttr 1A/µs load step, 50% and 100% Io max — 25 — µSec Vos Vo over/undershoot — ±200 (2) — mV Over-Current Threshold I TRIP Reset followed by auto-recovery — 38 — A Output Margin Adjust Switching Frequency Vo adj ƒs Pin 6 or 26 connected to pin 12 Over Vin range — 250 ±5 300 — 350 % kHz STBY* Input Requirements Input High Voltage Input Low Voltage Input Low Current VIH VIL I IL Referenced to GND — — 0.3 Open (3) 0.8 — V Pin 5 to GND 2.0 -0.2 — Standby Input Current Iin standby Pin 5 to GND — 6 — mA 330 mA External Capacitance Cout — 15,000 µF Operating Temperature Range Ta Over Vin Range –40 — 85 (5) °C Solder Reflow Temperature Treflow Surface temperature of module pins or case — — 215 (6) Storage Temperature Ts — –40 — 125 °C Mechanical Shock — Per Mil-STD-883D, Method 2002.3 1 msec, Half Sine, mounted to a fixture — 500 — G’s Mechanical Vibration — Mil-STD-883D, Method 2007.2 20-2000 Hz — — 20 (7) TBD (7) — — G’s Weight — Vertical/Horizontal — 36 — grams Flammability — Materials meet UL 94V-0 Suffix A Suffixes N,C (4) °C Notes: (1) If the remote sense ground is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy. (2) The transient response may be improved by placing additional capacitors with low equivalent series resistance (ESR) on the output. (3) The STBY* control (pin 5) has an internal pull-up. If it is left open-circuit, the module will operate when input power is applied. A low-leakage (<1µA) MOSFET must be used to control this pin. The open-circuit voltage may be as high as Vin. (4) For operation below 0°C, Cin and Cout must have stable characteristics. Use either low ESR tantalum or Oscon® capacitors. (5) See safe Operating Area curves or consult factory for the appropriate derating. (6) During reflow of SMD package version do not elevate the module case, pins, or internal component temperatures above a peak of 215°C. For further guidance refer to the application note, “Reflow Soldering Requirements for Plug-in Power Surface Products,” (SLTA051). (7) The case pins on the through-hole package types (suffixes N & A) must be soldered. For more information see the applicable package outline drawing. External Capacitors: The regulator require a minimum output capacitance of 330µF for proper operation. An input capacitance of 1500µF is also required. This must be rated for a minimum of 1.1Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For further information refer to the application note regarding capacitor selection for this product. Input Filter: An input filter inductor is optional for most applications. The inductor must be sized to handle 30ADC with a typical value of 1µH. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT7681—5V 30-A Programmable ISR With Margin Up/Down Controls SLTS177B - DECEMBER 2002 - REVISED JULY 2006 Performance Characteristics; VOUT =3.3V Safe Operating Area Curves (See Note A) Efficiency vs Output Current; VIN =5V (See Note B) PT7681, VIN =5VDC, VOUT =3.3V 100 90 80 Ambient Temperature (°C) Efficiency - % 90 80 70 60 Airflow 70 400LFM 200LFM 60LFM Nat conv 60 50 40 30 50 20 0 5 10 15 20 25 30 0 5 10 Iout (A) Ripple vs Output Current 20 25 30 PT7681, VIN =5VDC, VOUT =2.5V 90 60 VIN 40 5.5V 5.0V 4.5V 30 20 10 Ambient Temperature (°C) 80 50 Ripple - mV 15 Iout (A) Airflow 70 400LFM 200LFM 60LFM Nat conv 60 50 40 30 20 0 0 5 10 15 20 25 0 30 5 10 15 20 25 30 Iout (A) Iout (A) Power Dissipation vs Output Current; V IN =5V 12.00 10.00 Pd - Watts 8.00 6.00 4.00 2.00 0.00 0 5 10 15 20 25 30 Iout (A) Note A: All characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical for the ISR. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT7680 Series Operating Features and System Considerations for the PT7680 Series of ISRs Power up & Soft-Start Timing Following either the application of a valid input source voltage, or the removal of a ground signal to the STBY control pin (with input power applied), the regulator will initiate a soft-start power up. The soft start slows the rate at which the output voltage rises, and also introduces a short time delay of approx. 10ms. Figure 1-1 shows the power-up characteristic of a PT7681 with a 15-A load, and with the output voltage programmed to 3.3V. Figure 1-1 Vo (2V/Div) Iin (10A/Div) Vin (2V/Div) HORIZ SCALE: 10ms/Div Over-Current Protection To protect against load faults, the PT7680 series of regulators incorporates output over-current protection. Applying a load that exceeds the regulator’s over-current threshold (see data sheet specifications) will cause the regulated output to shut down. Following shutdown the ISR will periodically attempt to recover by initiating a soft-start power-up. This is often described as a “hiccup” mode of operation, whereby the module continues in a cycle of shutdown and power up until the load fault is removed. During this period, the average current flowing into the fault is significantly reduced. Once the fault is removed, the converter automatically recovers to normal operation. Differential Remote Sense Connecting the Sense(+) and Sense(-) pins to the load circuit allows the regulator to compensate for limited amounts of ‘IR’ voltage drop. This voltage drop is caused by current flowing through the trace resistance between the power converter and the ‘point of regulation’ some distance away. Although not recommended, leaving the sense pins disconnected will not damage the regulator. An internal 15. resistor, connected between each sense pin and its corresponding output node, keeps the output voltage in regulation. If the remote sense feature is not used it is important to at least connect the Sense(–) pin to GND locally, as this provides a return path for the regulator’s internal bias currents. With the sense leads connected, the difference between the voltage measured between the Vout and GND pins, and that measured between the Sense(+) and Sense(–) pins, is the amount of IR drop being compensated by the regulator. This should be limited to 0.6V. (0.3V maximum between pins 25 & 26, and also between pins 12 & 13). Note: The remote sense feature is not designed to compensate for the forward drop of non-linear or frequency dependent components that may be placed in series with the converter output. Examples include OR-ing diodes, filter inductors, ferrite beads, and fuses. When these components are enclosed by the remote sense connections they are effectively placed inside the regulation control loop, which can adversely affect the stability of the regulator. Margin Up/Margin Down The MARGUP/MARGDN controls allow up to a 5% momentary adjustment of the regulator’s output voltage set point. This adjustment is independent of the VID control inputs and provides a convenient method for testing the load circuit’s supply voltage margins. A 5% adjustment is made by simply connecting either control input directly to the remote sense ground. Adjustments of less than 5% can be accommodated by grounding the input through a suitably sized padding resistor. Note: These inputs must be controlled with a low-leakage (<1µA) open-collector/open-drain transistor. Do not add pullup resistors or use a push-pull logic gate to drive these pins. Over-Temperature Protection The PT7680 series of ISRs incorporates an on-board temperature sensor, which protects the module’s internal circuitry against excessively high temperatures. A rise in the temperature of the internal components may be the result of a drop in airflow, or a high ambient temperature. If the module’s internal temperature exceeds its OTP threshold (see data sheet specifications), the regulator output is disabled and the output voltage is reduced to zero. The recovery is automatic, and begins with a softstart power up. It occurs when the the sensed temperature decreases by about 10°C below the trip point. Note: The over-temperature protection is a last resort mechanism to prevent thermal stress to the regulator. Operation at or close to the thermal shutdown temperature is not recommended and will reduce the long-term reliability of the module. Always operate the regulator within the specified Safe Operating Area (SOA) limits for the worst-case conditions of ambient temperature and airflow. For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT7680 Series Capacitor Recommendations for the PT7680 Series of 30-A Switching Regulators Input Capacitor: The recommended input capacitance is determined by 1.1A minimum ripple current rating and 1500µF minimum capacitance. Ripple current and <100m. equivalent series resistance (ESR) values are the major considerations, along with temperature, when designing with different types of capacitors. Tantalum capacitors have a recommended minimum voltage rating of twice the maximum DC voltage + AC ripple. This is necessary to insure reliability for input voltage bus applications. Output Capacitors: The ESR of the required capacitors is less than 100m. . Electrolytic capacitors have marginal ripple performance at frequencies greater than 400kHz but excellent low frequency transient response. Above the ripple frequency, ceramic capacitors are necessary to improve the transient response and reduce any high frequency noise components apparent during higher current excursions. Preferred low ESR type capacitor part numbers are identified in Table 2-1. Tantalum Capacitors( Optional Output Capacitors) Tantalum type capacitors can be used for the output but only the AVX TPS series, Sprague 593D/594/595 series or Kemet T495/T510 series. These capacitors are recommended over many other tantalum types due to their higher rated surge, power dissipation, and ripple current capability. As a caution the TAJ series by AVX is not recommended. This series has considerably higher ESR, reduced power dissipation, and lower ripple current capability. The TAJ series is also less reliable than the AVX TPS series when determining power dissipation capability. Tantalum or Oscon® types are recommended for applications where ambient temperatures fall below 0°C. Capacitor Table Table 2-1 identifies the characteristics of capacitors from a number of vendors with acceptable ESR and ripple current (rms) ratings. The number of capacitors required at both the input and output buses is identified for each capacitor type. This is not an extensive capacitor list. Capacitors from other vendors are available with comparable specifications. Those listed are for guidance. The RMS ripple current rating and ESR (Equivalent Series Resistance at 100kHz) are critical parameters necessary to insure both optimum regulator performance and long capacitor life. Table 2-1: Input/Output Capacitors Capacitor Vendor/ Series Capacitor Characteristics Quantity Working Voltage Value(µF) (ESR) Equivalent Series Resistance 105°C Maximum Ripple Current(Irms) Physical Size(mm) Input Bus Output Bus Panasonic FK (SMT) 25V 35V 2200 330 0.038. 0.080. 1800mA 850mA 16x16.5 10x10.2 1 1 1 EEVFK1E222M EEVFK1V331P FC (Radial) 16V 16V 470 1500 0.090. 0.043. 755mA 1690mA 10x12.5 16x15 1 1 1 EEUFC1C471 EEUFC1C152S United LXZ Chemi -Con FX 25V 16V 10V 330 1500 680 0.090. 0.038. 0.015. 760mA 1660mA 4735mA 10x12.5 12.5x20 10x10.5 1 2 1 1 1 LXZ25VB331M10X12LL LXZ16VB152M12X20LL 10FX680M Nichicon PL Series NX (SM) 25V 10V 10V 390 1500 330 0.080. 0.050. 0.024. 720mA 1330mA 3770mA 12.5x15 16x15 10x8 1 5 1 1 1 UPL1E391MHH6 UPL1A152MHH6 PNX1A331MCR1GS Oscon SP (Radial) SVP (SMT) 10V 10V 470 330 0.015. 0.017. >4510mA >3950mA 10x10.5 9x12x8.3 3 4 1 1 10SP470M 10SVP330M AVX Tanatalum TPS- Series 10V 10V 330 330 0.10. 0.060. 1414mA 1826mA 7.3Lx 4.3Wx 4.1H 5 5 1 1 TPSV337M010R0100 TPSV337M010R0060 Sprague Tantalum 595D/594D 10V 10V 330 680 0.045. 4 =0.011. 0.09. >4500mA >1510mA 7.3L x 5.7W x 4.0H 5 2 1 1 594D337X0010R2T 595D687X0010R2T (Surface Mount) Kemet Tantalum T510/T495 Series 10V 330 0.035. 2000mA 5 1 510X337M010AS 10V 220 0.07. 2 =0.035. 4.3Wx7.3L x4.0H >2000mA 6 2 T495X227M010AS (Surface Mount) 10V 220 0.04. 3000mA 6 2 10TPB220M (Surface Mount) Sanyo Poscap TPB 7.2L x 4.3W x 3.1H Vendor Number For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT7680 Series Using the Standby Function on the PT7680 Series of 30-A Switching Regulators For applications requiring On/Off control of the output voltage, the 30-A rated PT7680 series of Excalibur ISRs incorporate an on/off “Standby” function. This feature may be used for power-up/shutdown sequencing, or to change the output voltage while input power is applied. See related notes: “Pin-Coded Output Voltage Adjustment of the PT7680 Series of 30-A ISRs.” Figure 3-2 Vo (2V/Div) Iin (5A/Div) The standby function is provided by the STBY* control, pin 5. If pin 5 is left open-circuit the regulator operates normally, providing a regulated output whenever a valid supply voltage is applied to Vin (pins 7-11) with respect to GND (pins 13-19). Connecting pin 5 to ground 1 will disable the regulator output 2. This places the regulator in standby mode, and reduces the input current to typically 6mA. If a ground signal is applied to pin 5 prior to powerup, the regulator output will remain inactive during the period that input power is applied. The standby input must be controlled with an opencollector (or open-drain) discrete transistor (See Figure 3-1). Table 3-1 gives the input requirements. 2V –0.2V Open Cct. 0.8V 0.5mA HORIZ SCALE: 5ms/Div Notes: 1. The Standby input of the PT7680 series of regulators must be controlled using an open-collector (or open-drain) discrete transistor. Do Not use a pull-up resistor. The control input has an open-circuit voltage equal to Vin. To set the regulator output to zero, the control pin must be “pulled” to less than 0.8Vdc with a 0.5mA sink to ground. Table 3-1 Standby Control Input Requirements Parameter Min Typ Max Enable Disable Istby (low) Vstby (o/c) Vstby (5V/Div) 1 2. In the standby mode the output of the regulator is tristate, and the output voltage falls at the rate that the load circuit discharges the output filter capacitors. Vin Turn-On Time: Turning Q1 in Fig. 3-1 off, removes the low-voltage signal at pin 5 and enables the output 3. After a delay of less than 5ms, the output voltage rises to full regulation within 30ms 4. Fig. 3-2 shows the typical output voltage waveform of a PT7681 following the turn-off of Q1 at time t =0 secs. In the circuit of Fig. 3-1, the output voltage is set to 3.3V. The waveform was measured with a +5V input source voltage, and 15-A output load. 3. When the ground signal to the Standby pin is removed, the regulator output initiates a soft-start cycle by first asserting a low impedance to ground. If an external voltage is applied to the output bus, it will sink current and possibly over-stress the part. 4. The turn-off time of Q1, or rise time of the standby input is not critical. Turning Q1 off slowly will not affect regulator operation. However, a slow turn-off time will increase both the initial delay and rise-time of the output voltage. Figure 3-1 26 Senes(+) 4 3 2 1 VID3 - VID0 7–11 5V PT7681 Vin STBY 5 GND 13–19 Vo 20–25 Senes(–) 12 + + C in Inhibit V o =3.3V C out L O A D Q1 BSS138 COM For technical support and more information, see inside back cover or visit www.ti.com COM Application Notes PT7680 Series Pin-Coded Output Voltage Adjustment of the PT7680 Series of 30-A Switching Regulators The PT7680 Excalibur™ family of converters use a pin code to adjust the output voltage. This feature uses the control inputs, VID0–VID3 (pins 1–4). When these pins are left open-circuit, the ISR regulates at its default output voltage. Each of the programming pins are internally connected to a precision resistor, and when pulled low 1 applies a weighted change to the output voltage. By selectively connecting VID0–VID3 to Sense(–) 2, the output voltage of these ISRs can be programmed in incremental steps over their specified output voltage range. The program codes and output voltages offered by these ISRs are compatible with the Voltage ID specifications used by popular microprocessors. See Figure 4-1 for the connection schematic, and the respective device data sheet for the programming code information. 4. If active devices are used to ground the voltage control pins, low-level open drain MOSFET devices should be used over bipolar transistors. The inherent Vce(sat) in bipolar devices introduces errors in the device’s internal divider network. Discrete transistors such as the BSS138, 2N7002, or IRLML2402 are examples of appropriate devices. Active Voltage Programming: Special precautions should be taken when making changes to the output voltage progam code while the unit is powered. This activity can induce current transients through the device as a result of the electrolytic output capacitors being either charged or discharged to the new output voltage set-point. The transient current can be minimized by making only incremental changes to the binary code, i.e. one LSB at a time. A minimum of 100µs settling time between each program state is also recommended. Making non-incremental changes to VID3 is discouraged. Notes: 1. The programming convention is as follows:Logic 0: Connect to pin 12; Sense(–). Logic 1: Open circuit/open drain (See Note 2) When active devices are used to program the output voltage, their state should be asserted prior to the input power being applied. One approach is to pull STBY (pin 5) control to GND prior to power up. After the host board has then asserted the program code, the ground signal to pin 5 can be removed. This will allow the regulator to intiate a clean soft-start power-up to the desired program voltage. For more information on the use of the Standby function, consult the related application note, “Using the Standby Function on the PT7680 Series of 30-A Switching Regulators.” 2. For optimal output voltage accuracy Sense(–) (pin 12) should always be used as the logic ‘0’ reference. The input/output ground (pins 13-19) can also be used if pin 12 is connected to pin 13 external to the module. 3. Do not connect pull-up resistors to the voltage programming pins. Figure 4-1 4 3 2 1 +5V 26 VID3 - VID0 L1 7–11 1µH (Optional) SNS(+) PT7681 V IN STBY GND 5 13–19 SNS(–) 12 + + Cin STBY VOUT 20–25 V OUT Cout Q1 L O A D Sense(–) COM Power GND For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT7680 Series Using the Up/Down Margin Adjust Controls on the PT7680 Series of 30-A Regulators The PT7680 series of integrated switching regulator modules incorporate MARGUP (pin 27) and MARGDN (pin 6) control inputs. These controls allow the output voltage set point to be momentarily adjusted 1, either up or down, by a nominal 5%. The adjustment is independent of the VID control inputs and provides a convenient method for dynamically testing the load circuit’s power supply voltage over its operating margin or range. The 5% adjustment is made by driving the appropriate margin control input to the ground reference at Sense(-) (pin 12) 2. An open drain, low-leakage (<1µA), logic-level MOSFET or p-channel JFET is recommended for this purpose. Adjustments of less than 5% are also possible using a series resistor (See Figure 5.1). The value of the resistor can be selected from Table 5.1, or calculated using the following formulas. Notes: 1. The MARGUP and MARGDN controls were not intended to be activated simultaneously. If they are their affects on the output voltage may not completely cancel, resulting in a slight shift in the output voltage set point. 2. When possible use the Sense(-) (pin 12) as the ground reference. This will produce a more accurate adjustment of the output voltage at the load circuit terminals. GND (pins 13-19) can be used if the Sense(-) pin is connected to GND near the regulator. Table 5.1; Margin Up/Down Adjust Resistor Values PADDING RESISTOR VALUES Resistor Value Calculation To reduce the margin adjustment to a value less than 5%, series padding resistors are required (See RD and RU in Figure 5.1). For the same amount of adjustment, the resistor value calculated for RU and RD will be different. RU = 100 ( 6 – 1.2 . %) .% RD = 4.99 (100 – . %) .% % Adjust RU (Margin Up) RD (Margin Dn) 0.0k. 30.0k. 80.0k. 180.0k. 480.0k. 0.0k. 24.9k. 66.5k. 150.0k. 399.0k. 5 4 3 2 1 k. –94.81 k. Where: . % = The required margin adjust in percent Figure 5.1; Margin Up/Down Application Schematic +V o 4 3 2 1 26 VID3 - VID0 +5V 7–11 PT7681 VIN STBY 5 + C in 0V SNS(+) GND 13–19 MARG DN 6 +VOUT 20–25 VOUT MARG UP 27 RD RU SNS(–) 12 + C out L O A D Q1 Margin Dn Q2 Margin Up Sense(–) PWR GND For technical support and more information, see inside back cover or visit www.ti.com Power GND 0V (No resistor) PACKAGE OPTION ADDENDUM www.ti.com 28-Jul-2006 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing PT7681N ACTIVE SIP MOD ULE ENE Pins Package Eco Plan (2) Qty 27 10 TBD Lead/Ball Finish Call TI MSL Peak Temp (3) Level-1-215C-UNLIM (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 MECHANICAL DATA MMSI031 – SEPTEMBER 2001 ENE (R–MSIP–T27) METAL SINGLE-IN-LINE MODULE Suffix N 0.66 (16,76) MAX. 0.500 (12,70) 3.00 (76,20) MAX. 1 Note G 0.025 (0,63) TYP. 1.02 (25,90) MAX. 0.017 (0,43) TYP. 0.100 (2,54) TYP. 0.050 (1,27) TYP. 0.050 (1,27) TYP. 0.160 (4,06) TYP. 0.140 (3,55) MIN. See Note F 3.028 (76,91) 2.928 (74,37) 0.050 (1,27) Note E 0.110 (2,79) 0.70 (17,78) 0.040 (1,01) 0.54 (13,71) 1 ø0.045 (1,14) MIN. 27 Places Plated through 0.100 (2,54) 26 Places 0.164 (4,16) 0.350 (8,89) 0.090 (2,28) 2 Places ø0.093 (2,36) MIN. 4 Places Plated through holes. See Note G. PC Layout 4203526/A 08/01 NOTES: A. B. C. D. E. F. G. All linear dimensions are in inches (mm). This drawing is subject to change without notice. 2 place decimals are 0.030 (0,76mm). 3 place decimals are 0.010 (0,25mm). Recommended mechanical keep out area. Electrical pin length mounted on printed circuit board, from seating plane to pin end. The case may be electrically connected to power ground plane. 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