LT1312CS8

LT1312 Single PCMCIA VPP Driver/Regulator OBSOLETE: FOR INFORMATION PURPOSES ONLY Contact Linear Technology for Potential Replacement DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ U ■ Digital Selection of 0V, VCC, 12V or Hi-Z 120mA Output Current Capability Internal Current Limiting and Thermal Shutdown Automatic Switching from 3.3V to 5V Powered from Unregulated 13V to 20V Supply Logic Compatible with Standard PCMCIA Controllers 1µF Output Capacitor 30µA Quiescent Current in Hi-Z or 0V Mode VPP Valid Status Feedback Signal No VPP Overshoot 8-Pin SO Packaging U APPLICATIONS ■ ■ ■ ■ ■ ■ The LT ® 1312 is a member of Linear Technology Corporation’s family of PCMCIA drivers/regulators. The LT1312 provides 0V, 3.3V, 5V, 12V and Hi-Z regulated power to the VPP pin of a PCMCIA card slot from a single unregulated 13V to 20V supply. When used in conjunction with a PC card interface controller, the LT1312 forms a complete minimum component-count interface for palmtop, pen-based and notebook computers. The VPP output voltage is selected by two logic compatible digital inputs which interface directly with industry standard PC card interface controllers. Automatic 3.3V to 5V switching is provided by an internal comparator which continuously monitors the PC card VCC supply and automatically adjusts the regulated VPP output to match VCC when the VPP = VCC mode is selected. Notebook Computers Palmtop Computers Pen-Based Computers Handi-Terminals Bar-Code Readers Flash Memory Programming An open-collector VPP VALID output is driven low when VPP is in regulation at 12V. The LT1312 is available in an 8-pin SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION U Typical PCMCIA Single Slot VPP Driver 13V TO 20V VS PCMCIA CARD SLOT CONTROLLER Linear Technology PCMCIA Product Family VPP1 EN1 LT1312 VPP2 PCMCIA CARD SLOT VALID VCC EN0 VPPOUT SENSE GND + 3.3V OR 5V COUT 1µF TANTALUM LT1312 TA1 LT1312 TRUTH TABLE EN0 EN1 0 0 1 0 0 1 0 1 1 1 X = DON’T CARE SENSE X X 3.0V TO 3.6V 4.5V TO 5.5V X VPPOUT 0V 12V 3.3V 5V Hi-Z VALID 1 0 1 1 1 DEVICE DESCRIPTION PACKAGE LT1312 SINGLE PCMCIA VPP DRIVER/REGULATOR 8-PIN SO LT1313 DUAL PCMCIA VPP DRIVER/REGULATOR 16-PIN SO* ® LTC 1314 SINGLE PCMCIA SWITCH MATRIX 14-PIN SO LTC1315 DUAL PCMCIA SWITCH MATRIX 24-PIN SSOP LTC1470 PROTECTED VCC 5V/3.3V SWITCH MATRIX 8-PIN SO LTC1472 PROTECTED VCC AND VPP SWITCH MATRIX 16-PIN SO* *NARROW BODY 1 LT1312 U W U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION Supply Voltage ........................................................ 22V Digital Input Voltage ........................ 7V to (GND – 0.3V) Sense Input Voltage ......................... 7V to (GND – 0.3V) Valid Output Voltage ...................... 15V to (GND – 0.3V) Output Short-Circuit Duration .......................... Indefinite Operating Temperature ................................ 0°C to 70°C Junction Temperature ................................ 0°C to 125°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER TOP VIEW GND 1 8 VPPOUT ENO 2 7 N.C. EN1 3 6 VS VALID 4 5 SENSE LT1312CS8 S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO 1312 TJMAX = 125°C, θJA = 150°C/ W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS VS = 13V to 20V, TA = 25°C, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX VPPOUT Output Voltage Program to 12V, IOUT ≤ 120mA (Note 1) Program to 5V, IOUT ≤ 30mA (Note 1) Program to 3.3V, IOUT ≤ 30mA (Note 1) Program to 0V, IOUT = – 300µA ● ● ● 11.52 4.75 3.135 12.00 5.00 3.30 0.42 12.48 5.25 3.465 0.60 ILKG Output Leakage Program to Hi-Z, 0V ≤ VPPOUT ≤ 12V ● – 10 IS Supply Current Program to 0V Program to Hi-Z Program to 12V, No Load Program to 5V, No Load Program to 3.3V, No Load Program to 12V, IOUT = 120mA Program to 5V, IOUT = 30mA Program to 3.3V, IOUT = 30mA ● ● ● ● ● ● ● ● ILIM Current Limit Program to 3.3V, 5V or 12V VENH Enable Input High Voltage ● VENL Enable Input Low Voltage ● IENH Enable Input High Current IENL Enable Input Low Current 0V ≤ VIN ≤ 0.4V VSEN5 VCC Sense Threshold VPPOUT = 3.3V to 5V ● 3.60 VSEN3 VCC Sense Threshold VPPOUT = 5V to 3.3V ● 3.60 ISEN VCC Sense Input Current VSENSE = 5V VSENSE = 3.3V VVALID TH VPP VALID Threshold Voltage Program to 12V IVALID VPP VALID Output Drive Current Program to 12V, VVALID = 0.4V VPP VALID Output Leakage Current Program to 0V, VVALID = 12V The ● denotes the specifications which apply over the full operating temperature range. 2 µA 30 30 230 75 55 126 31 31 50 50 360 120 90 132 33 33 µA µA µA µA µA mA mA mA 330 500 mA 0.4 V 50 µA 0.01 1 µA 4.05 4.50 V 4.00 4.50 V 38 18 60 30 µA µA 11 11.5 V V 20 ● 10.5 1 V V V V 10 2.4 2.4V ≤ VIN ≤ 5.5V UNITS 3.3 0.1 mA 10 µA Note 1: For junction temperatures greater than 110°C, a minimum load of 1mA is recommended. LT1312 U W TYPICAL PERFORMANCE CHARACTERISTICS Quiescent Current (0V or Hi-Z Mode) Quiescent Current (12V Mode) 500 40 30 20 10 0 5 0 15 20 10 SUPPLY VOLTAGE (V) 400 300 200 100 0 25 TJ = 25°C EN0 = 5V EN1 = 0V RL = ∞ QUIESCENT CURRENT (µA) TJ = 25°C EN0 = EN1= 0V OR EN0 = EN1= 5V QUIESCENT CURRENT (µA) QUIESCENT CURRENT (µA) 50 5 15 20 10 SUPPLY VOLTAGE (V) Ground Pin Current (12V Mode) RL = 200Ω IL = 60mA* 2 RL = 400Ω IL = 30mA* 15 20 10 SUPPLY VOLTAGE (V) 2.0 1.5 RL = 167Ω IL = 30mA* 1.0 0 25 Ground Pin Current RL = 500Ω IL = 10mA* *FOR VPPOUT = 5V 0 5 15 20 10 SUPPLY VOLTAGE (V) 6 4 20 RL = 110Ω IL = 30mA* 1.0 0 40 60 80 100 120 140 160 OUTPUT CURRENT (mA) LT1312 G7 RL = 330Ω IL = 10mA* *FOR VPPOUT = 3.3V 0 5 15 20 10 SUPPLY VOLTAGE (V) Current Limit TJ = 25°C VPPOUT = 0V 700 600 500 400 300 200 0 0 5 25 LT1312 G6 600 100 2 0 1.5 25 SHORT-CIRCUIT CURRENT (mA) SHORT-CIRCUIT CURRENT (mA) GROUND PIN CURRENT (mA) 8 0 2.0 Current Limit 10 25 TJ = 25°C EN0 = 0V EN1 = 5V VSENSE = 3.3V 0.5 800 12 15 20 10 SUPPLY VOLTAGE (V) LT1312 G5 16 TJ = 25°C VS = 15V 5 Ground Pin Current (3.3V Mode) TJ = 25°C EN0 = 0V EN1 = 5V VSENSE = 5V LT1312 G4 14 0 2.5 0.5 *FOR VPPOUT = 12V 5 0 VSENSE = 3.3V LT1312 G3 GROUND CURRENT (mA) GROUND CURRENT (mA) GROUND CURRENT (mA) 6 VSENSE = 5V 50 Ground Pin Current (5V Mode) RL = 100Ω IL = 120mA* 4 100 25 2.5 8 150 LT1312 G2 10 TJ = 25°C EN0 = 5V EN1 = 0V TJ = 25°C EN0 = 0V EN1 = 5V RL = ∞ 200 0 0 LT1312 G1 0 Quiescent Current (3.3V/5V Mode) 250 10 15 INPUT VOLTAGE (V) 20 VS = 15V VPPOUT = 0V 500 400 300 200 100 0 25 LT1312 G8 0 25 50 75 100 JUNCTION TEMPERATURE (°C) 125 LT1312 G9 3 LT1312 U W TYPICAL PERFORMANCE CHARACTERISTICS VS = 15V 2.5 ENABLE INPUT CURRENT (µA) 2.0 1.5 1.0 0.5 0 TJ = 25°C VS = 15V 40 30 20 10 0 125 25 50 75 100 JUNCTION TEMPERATURE (°C) 0 VCC Sense Threshold Voltage 5.5 0 1 5 2 3 4 ENABLE INPUT VOLTAGE (V) VALID OUTPUT VOLTAGE (V) VCC SENSE INPUT CURRENT (µA) 40 30 20 10 1 5 2 3 4 ENABLE INPUT VOLTAGE (V) TJ = 25°C VS = 15V EN0 = 5V EN1 = 0V 0.4 0.2 OUTPUT VOLTAGE CHANGE (mV) COUT = 1µF COUT = 10µF 11.6 2.5 1.0 1.5 2.0 0.5 VALID OUTPUT CURRENT (mA) 0.2 0.4 0.6 TIME (ms) 0.8 1.0 1.2 LT1312 G16 4 COUT = 1µF TANTALUM 40 20 3.0 100 10 1k 10k FREQUENCY (Hz) COUT = 1µF 0 COUT = 10µF –20 0.4 0.2 COUT = 1µF 0 COUT = 10µF –0.2 –0.4 15 13 –0.1 1M Load Transient Response (12V) 40 20 100k LT1312 G15 LOAD CURRENT (mA) 0 0 60 0 0 –40 5 –0.2 80 LT1312 G14 SUPPLY VOLTAGE (V) OUTPUT VOLTAGE (V) EN0 INPUT (V) 12.0 125 LT1312 G12 Line Transient Response (12V) VS = 15V 25 50 75 100 JUNCTION TEMPERATURE (°C) TJ = 25°C, 12V MODE VS = 15V + 100mVRMS RIPPLE 0.6 12V Turn-On Waveform 11.8 3.0 Ripple Rejection (12V) LT1312 G13 12.2 SWITCH TO 3.3V 3.5 100 0.8 0 6 12.4 SWITCH TO 5V 4.0 VALID Output Voltage 1.0 TJ = 25°C VS = 15V 0 4.5 0 RIPPLE REJECTION RATIO (dB) VCC Sense Input Current 0 5.0 LT1312 G11 LT1312 G10 50 TJ = 25°C VS = 15V 2.5 6 OUTPUT VOLTAGE CHANGE (V) INPUT THRESHOLD VOLTAGE (V) 3.0 Enable Input Current 50 VCC SENSE THRESHOLD VOLTAGES (V) Enable Input Threshold Voltage 0 0.1 0.2 0.3 TIME (ms) 0.4 0.5 0.6 LT1312 G17 100 50 –0.1 0 0.1 0.2 0.3 TIME (ms) 0.4 0.5 0.6 LT1312 G18 LT1312 U U U PIN FUNCTIONS Supply Pin: Power is supplied to the device through the supply pin. The supply pin should be bypassed to ground if the device is more than 6 inches away from the main supply capacitor. A bypass capacitor in the range of 0.1µF to 1µF is sufficient. The supply voltage to the LT1312 can be loosely regulated between 13V and 20V. See Applications Information section for more detail. VPPOUT Pin: This regulated output supplies power to the PCMCIA card VPP pins which are typically tied together at the card socket. The VPPOUT output is current limited to approximately 330mA. Thermal shutdown provides a second level of protection. A 1µF to 10µF tantalum output capacitor is recommended. See Applications Information section for more detail on output capacitor considerations. Input Enable Pins: The two digital input pins are high impedance inputs with approximately 20µA input current at 2.4V. The input thresholds are compatible with CMOS controllers and can be driven from either 5V or 3.3V CMOS logic. ESD protection diodes limit input excursions to 0.6V below ground. VALID Output Pin: This pin is an open-collector NPN output which is driven low when the VPPOUT pin is in regulation, i.e., when it is above 11V. An external 51k pullup resistor is connected between this output and the same 5V or 3.3V logic supply powering the PCMCIA compatible control logic. VCC Sense Pin: A built-in comparator and 4V reference automatically switches the VPPOUT from 5V to 3.3V depending upon the voltage sensed at the PCMCIA card socket VCC pin. The input current for this pin is approximately 30µA. For 5V only operation, connect the Sense pin directly to ground. An ESD protection diode limits the input voltage to 0.6V below ground. W BLOCK DIAGRAM LOW DROPOUT LINEAR REGULATOR VS VPPOUT + VCC SENSE – VALID 4V EN0 + VOLTAGE LOGIC CONTROL – EN1 11V LT1312 BD 5 LT1312 U OPERATION The LT1312 is a programmable output voltage, lowdropout linear regulator designed specifically for PCMCIA VPP drive applications. Input power is typically obtained from a loosely regulated input supply between 13V and 20V (see Applications Information section for more detail on the input power supply). The LT1312 consists of the following blocks: Low Dropout Voltage Linear Regulator: The heart of the LT1312 is a PNP-based low-dropout voltage regulator which drops the unregulated supply voltage from 13V to 20V down to 12V, 5V, 3.3V, 0V or Hi-Z depending upon the state of the two Enable inputs and the VCC Sense input. The regulator has built-in current limiting and thermal shutdown to protect the device, the load, and the socket against inadvertent short circuiting to ground. Voltage Control Logic: The LT1312 has five possible output modes: 0V, 3.3V, 5V, 12V and Hi-Z. These five modes are selected by the two Enable inputs and the VCC Sense input as described by the Truth Table. VCC Sense Comparator: When the VCC mode is selected, the LT1312 automatically adjusts the regulated VPP output voltage to 3.3V or 5V depending upon the voltage present at the PC card VCC supply pin. The threshold voltage for the comparator is set at 4V and there is approximately 50mV of hysteresis provided to ensure clean switching between 3.3V and 5V. VPP VALID Comparator: A voltage comparator monitors the output voltage when the 12V mode is selected and is driven low when the output is in regulation above 11V. U W U U APPLICATIONS INFORMATION The LT1312 is a voltage programmable linear regulator designed specifically for PCMCIA VPP driver applications. The device operates with very low quiescent current (30µA) in the 0V and Hi-Z modes of operation. In the Hi-Z mode, the output leakage current falls to 1µA. Unloaded quiescent current rises to only 55µA and 75µA when programmed to 3.3V and 5V respectively. In addition to the low quiescent currents, the LT1312 incorporates several protection features which make it ideal for PCMCIA applications. The LT1312 has built-in current limiting (330mA) and thermal shutdown to protect the device and the socket VPP pins against inadvertent short-circuit conditions. an auxiliary winding to the 5V inductor in a split 3.3V/5V LTC1142HV power supply system. A turns ratio of 1:1.8 is used for transformer T1 to ensure that the input voltage to the LT1312 falls between 13V and 20V under all load conditions. The 9V output from this additional winding is rectified by diode D2, added to the main 5V output and applied to the input of the LT1312. (Note that the auxiliary winding must be phased properly as shown in Figure 1.) AUXILIARY WINDING POWER SUPPLIES When the 12V output is activated by a TTL high on the Enable line, the 5V section of the LTC1142HV is forced into continuous mode operation. A resistor divider composed of R2, R3 and switch Q3 forces an offset which is subtracted from the internal offset at the Sense – input (pin 14) of the LTC1142HV. When this external offset cancels the built-in 25mV offset, Burst ModeTM operation is inhibited and the LTC1142HV is forced into continuous mode operation. (See the LTC1142HV data sheet for further detail). In this mode, the 14V auxiliary supply can be Because the LT1312 provides excellent output regulation, the input power supply may be loosely regulated. One convenient (and economic) source of power is an auxiliary winding on the main 5V switching regulator inductor in the main system power supply. LTC®1142HV Auxiliary Winding Power Supply Figure 1 is a schematic diagram which describes how a loosely regulated 14V power supply is created by adding 6 The auxiliary winding is referenced to the 5V output which provides DC current feedback from the auxiliary supply to the main 5V section. The AC transient response is improved by returning the negative lead of C5 to the 5V output as shown. Burst Mode is a trademark of Linear Technology Corporation. LT1312 U U W U APPLICATIONS INFORMATION VIN PDRIVE 10 D1 MBRS140 VIN 6.5V TO 18V + 9 1/2 LTC1142HV 20 NDRIVE 5V REG R4 22Ω C1 68µF Q1 Q2 D2 MBRS140 D3 MBRS130T3 T1 1.8T 30µH* R1 100Ω + 15 C4 1000pF SENSE C2 1000pF – 14 + C5 22µF + TO CARD VPP PIN 0V, 3.3V, 5V, 12V OR HI-Z VS VPPOUT EN0 R5 0.033Ω R2 100Ω + EN1 LT1312 5V OUTPUT SENSE R3 18k Q3 VN7002 14V AUXILIARY SUPPLY VALID 1µF SENSE GND C3 220µF FROM CARD VCC PIN EN0 EN1 LT1312 F1 VALID *LPE-6562-A026 DALE (605) 665-9301 Figure 1. Deriving 14V Power from an Auxiliary Winding on the LTC1142HV 5V Regulator loaded without regard to the loading on the 5V output of the LTC1142HV. Continuous mode operation is only invoked when the LT1312 is programmed to 12V. If the LT1312 is programmed to 0V, 3.3V or 5V, power is obtained directly from the main power source (battery pack) through diode D1. Again, the LT1312 output can be loaded without regard to the loading of the main 5V output. there is simply not enough time to transfer energy from the 5V primary to the auxiliary winding. For applications where heavy 12V load currents exist in conjunction with low input voltages (