TYPICAL APPLICATIO. LT3462/LT3462A Inverting 1.2MHz/2.7MHz DC/DC Converters with Integrated Schottky in ThinSOT FEATURES DESCRIPTIO APPLICATIO S

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1 FEATRES Integrated Schottky Rectifier Fixed Frequency 1.2MHz/2.7MHz Operation Very Low Noise: 1mV P-P Output Ripple Low V CESAT Switch: 27mV at 25mA 5V at 1mA from 5V Input 12V at 3mA from 3.3V Input Low Input Bias Current Based Input Low Impedance (4Ω) 1.265V Reference Output High Output Voltage: p to 38V Wide Input Range: 2.5V to 16V ses Tiny Surface Mount Components Low Shutdown Current: <1µA Low Profile (1mm) SOT-23 (ThinSOT TM ) Package APPLICATIO S CC Bias LC Bias GaAs FET Bias General Purpose Negative Voltage Supply, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation ESCRIPTIO LT3462/LT3462A Inverting 1.2MHz/2.7MHz C/C Converters with Integrated Schottky in ThinSOT The LT 3462/LT3462A are general purpose fixed frequency current mode inverting C/C converters. Both devices feature an integrated Schottky and a low V CESAT switch allowing a small converter footprint and lower parts cost. The LT3462 switches at 1.2MHz while the LT3462A switches at 2.7MHz. These high speeds enable the use of tiny, low cost and low height capacitors and inductors. The LT3462/LT3462A operate in a dual inductor inverting topology that filters both the input and output currents. Very low output voltage ripple approaching 1mV P-P can be achieved when ceramic capacitors are used. Fixed frequency switching ensures a clean output free from low frequency noise typically present with charge pump solutions. The 4V switch allows a to differential of up to 38V for dual inductor topologies. Both devices provide a low impedance 1.265V reference output to supply the feedback resistor network. A ground referenced, high impedance input allows high feedback resistor values without compromising output accuracy. The LT3462/LT3462A are available in a 6-lead SOT-23 package. TYPICAL APPLICATIO 5V to 5V, 1mA Inverting C/C Converter Efficiency 5V 22µH 22µH 75 = 5V LT3462A 68.1k 22pF 5V 1mA 1µF EFFICIENCY (%) 7 65 = 3.3V TA LOA CRRENT (ma) 3462 TA1b 1

2 ABSOLTE AXI RATI GS (Note 1) W W W Input Voltage ( )... 16V Voltage... 4V Voltage... 4V, Voltage V Operating Ambient Temperature Range (Note 3)... 4 C to 85 C Maximum Junction Temperature C Storage Temperature Range C to 15 C Lead Temperature (Soldering, 1sec)... 3 C W PACKAGE/ORER I FOR ATIO TOP VIEW S6 PACKAGE 6-LEA PLASTIC TSOT-23 T JMAX = 125 C θ JA = 15 C ON BOAR OVER GRON PLANE θ JC = 12 C/W ORER PART NMBER LT3462ES6 LT3462AES6 S6 PART MARKING LTBBV LTBGB Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at, = 3V, unless otherwise noted. PARAMETER CONITIONS MIN TYP MAX NITS Minimum Operating Voltage 2.5 V Maximum Operating Voltage 16 V Voltage 1µA > I 8µA V Pin Bias Current (Note 2) 15 5 na Minus Voltage 1µA > I 8µA V Error Amp Offset Voltage mv Reference Source Current >1.2V µa Supply Current =.5V, Not Switching ma = V, = Open, = 5V µa Line Regulation.7 %/V Switching Frequency (LT3462) MHz Switching Frequency (LT3462A) MHz Maximum uty Cycle (LT3462) 9 % Maximum uty Cycle (LT3462A) 77 % Switch Current Limit 3 42 ma Switch V CESAT I = 25mA mv Switch Leakage Current V = 5V.1 1 µa Rectifier Leakage Current V = 4V.3 4 µa Rectifier Forward rop I SCHOTTKY = 25mA 8 11 mv Voltage Low.2 V Off-State Pull-p Current µa Turn-Off Current 3 2 µa Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Current flows out of the pin. Note 3: The LT3462E is guaranteed to meet specifications from C to 7 C. Specifications over the 4 C to 85 C operating temperature range are assured by design, characterization and correlation with statistical process controls. 2

3 TYPICAL PERFOR A CE CHARACTERISTICS W 1.6 Oscillator Frequency (LT3462) Current Limit Minus Pin Voltage FREQENCY (MHz) CRRENT LIMIT (ma) LT3462A LT3462 MINS (V) TEMPERATRE ( C) TY CYCLE (%) TEMPERATRE ( C) 3462 G G G3 FREQENCY (MHz) Oscillator Frequency (LT3462A) BIAS CRRENT (na) Bias Current QIESCENT CRRENT (µa) Quiescent Current in Shutdown Mode = N/C TEMPERATRE ( C) TEMPERATRE ( C) SPPLY VOLTAGE (V) G G G6 PI F CTIO S (Pin 1): Switch Pin. Connect to external inductor L1 and positive terminal of transfer cap. (Pin 2): Ground. Tie directly to local ground plane. (Pin 3): Feedback Pin. Connect resistive divider tap here. Set according to = ( /1.265V). In shutdown, a proprietary shutdown bias current cancellation circuit allows the internal 3µA source to pull up the pin, even with residual negative voltage on. (Pin 4): ual Function Shutdown and 1.265V Reference Output Pin. Pull to with external N-FET to turn regulator off. Turn-off pull-down and a 2µA internal source will pull up to turn-on the regulator. At turnon, a 18µA internal source pulls the pin to the regulation voltage. The pin can supply up to 8µA at 1.265V to bias the feedback resistor divider. An optional soft-start circuit capacitor connects from this pin to. (Pin 5): Anode Terminal of Integrated Schottky iode. Connect to negative terminal of transfer cap and external inductor L2. (Pin 6): Input Supply Pin. Must be locally bypassed. 3

4 OPERATIO LT3462/LT3462A BLOCK IAGRA W 3 4 SHTOWN A1 E AMP SHTOWN BIAS CRRENT CANCELLATION OFF 3µA ON 18µA ISRC R C C C RAMP GENERATOR A2 COMP R S Q RIVER 1 Q1.1Ω 5 O LG 2 1.2MHz* OSCILLATOR *LT3462A IS 2.7MHz (EXTERNAL) C S1 (EXTERNAL) (EXTERNAL) C S2 (EXTERNAL) V REFERENCE Q2 C S1, C S2 OPTIONAL SOFT-START COMPONENTS 3462 F2 Figure 1. Block iagram The LT3462 uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the Block iagram in Figure 1. At the start of each oscillator cycle, the SR latch is set, turning on the power switch Q1. A voltage proportional to the switch current is added to a stabilizing ramp and the resulting sum is fed into the positive terminal of the PWM comparator. When this voltage exceeds the voltage at the output of the EAMP, the SR latch is reset, turning off the power switch. The level at the output of the EAMP is simply an amplified version of the difference between the feedback voltage and. In this manner, the error amplifier sets the correct peak current level to keep the output in regulation. If the error amplifier s output increases, more current is taken from the output; if it decreases, less current is taken. One function not shown in Figure 1 is the current limit. The switch current is constantly monitored and not allowed to exceed the nominal value of 4mA. If the switch current reaches 4mA, the SR latch is reset regardless of the output state of the PWM comparator. This current limit cell protects the power switch as well as various external components connected to the LT3462. is a dual function input pin. When driven low it shuts the part down, reducing quiescent supply current to less than 1µA. When not driven low, the pin has an internal pull-up current that turns the regulator on. Once the part is enabled, the pin sources up to 18µA nominally at a fixed voltage of 1.265V through external resistor to. If there is no fault condition present, will regulate to V, and will regulate to 1.265V ( /). An optional soft-start circuit uses the fixed pull-up current and a capacitor from to to set the dv/dt on. In shutdown, an bias current cancellation circuit supplies up to 15µA biasing current to external resistor while is lower than. This function eliminates loading of during shutdown. As a result, supply current in shutdown may exceed 1µA by the amount of current flowing in. 4

5 APPLICATIO S I FOR ATIO Inrush Current The LT3462 has a built-in Schottky diode. When supply voltage is applied to the pin, the voltage difference between and V generates inrush current flowing from input through the inductor and the Schottky diode to charge the flying capacitor to. The maximum nonrepetitive surge current the Schottky diode in the LT3462 can sustain is 1.5A. The selection of inductor and capacitor value should ensure the peak of the inrush current to be below 1.5A. The peak inrush current can be calculated as follows: I P V = IN W O. 6 π exp L L C C where L is the inductance between supply and, and C is the capacitance between and. Table 3 gives inrush peak currents for some component selections. Table 3. Inrush Peak Current (V) L (µh) C (µf) I P (A) Inductor Selection Each of the two inductors used with LT3462 should have a saturation current rating (where inductance is approximately 7% of zero current inductance ) of approximately.25a or greater. If the device is used in the charge pump mode, where there is only one inductor, then its rating should be.35a or greater. CR of the inductors should be less than 1Ω. For LT3462, a value of 22µH is suitable if using a coupled inductor such as Sumida CLS If using two separate inductors, increasing the value to 47µH will result in the same ripple current. For LT3462A, a value of 1µH for the coupled inductor and 22µH for two inductors will be acceptable for most applications. Capacitor Selection Ceramic capacitors are recommended. An X7R or X5R dielectric should be used to avoid capacitance decreasing severely with applied voltage and at temperature limits. The flying capacitor between the and pins should be a ceramic type of value or more. When used in the dual inductor or coupled inductor topologies the flying capacitor should have a voltage rating that is more than the difference between the input and output voltages. For the charge pump inverter topology, the voltage rating should be more than the output voltage. The output capacitor should be a ceramic type. Acceptable output capacitance varies from for high ( 36V), to 1µF for low ( 5V). The input capacitor should be a ceramic type and be placed as close as possible to the LT3462/LT3462A. Layout Hints The high speed operation of the LT3462 demands careful attention to board layout. You will not get advertised performance with careless layout. Figure 2 shows the recommended component placement. A ceramic capacitor of or more must be placed close to the IC for input supply bypassing. L L F3 Figure 2. Suggested Layout 5

TYPICAL APPLICATIO S 3.3V to 12V with Soft-Start Circuit 12V Efficiency 3.3V 4.7µF L1 47µH LT3462 L2 47µH OFF 27.4k 15pF M1 C S1 1nF 22nF 12V 3mA 2.2µF EFFICIENCY (%) 8 75 7 65 6 55 = 3.

Peaks at 3mA without C S1 Reaches 12V in 7.

6 TYPICAL APPLICATIO S 3.3V to 12V with Soft-Start Circuit 12V Efficiency 3.3V 4.7µF L1 47µH LT3462 L2 47µH OFF 27.4k 15pF M1 C S1 1nF 22nF 12V 3mA 2.2µF EFFICIENCY (%) = 3.3V : TAIYO YEN X5R JMK212BJ475MG : TAIYO YEN X5R EMK212BJ15MG : TAIYO YEN EMK316BJ225 L1, L2: MRATA LQH32CN TA2a LOA CRRENT (ma) 3462 TA2b Reaches 12V in 75µs; Input Current Peaks at 3mA without C S1 Reaches 12V in 7.5ms; Input Current Peaks at 125mA with C S1 = 1nF OFF OFF 1V/IV 1V/IV I IN 1mA/IV I IN 5mA/IV 2ms/IV 3462 TA2c 2ms/IV 3462 TA2d Li to 8V Supply 8V Efficiency 2.7V TO 4.2V 4.7µF L1A 22µH LT3462 L1B 22µH 42.2k 15pF 8V 4.7µF EFFICIENCY (%) = 3.3V : TAIYO YEN X5R JMK212BJ475MG : TAIYO YEN X5R EMK212BJ15MG : TAIYO YEN LMK316BJ475 L1: SMIA CLS62-22 OR 2X MRATA LQH32CN TA3a LOA CRRENT (ma) 3462 TA3b 6

7 TYPICAL APPLICATIO S 2.7V TO 4.2V 3.3V to 8V (LT3462A) L1A 1µH LT3462A L1B 1µH 42.2k 22pF 8V 35mA 4.7µF 5V 5V to 5V Supply (LT3462A) L1 22µH LT3462A L2 22µH 68.1k 22pF 5V 1mA 1µF : TAIYO YEN JMK17BJ15MA : TAIYO YEN EMK212BJ15MA : TAIYO YEN LMK316BJ475.. L1: WRTH TA4a : TAIYO YEN JMK17BJ15MA : TAIYO YEN EMK212BJ15MA : MRATA GRM219R6J16KE19B L1, L2: MRATA LQH32CN TA5a Switching Waveform INCTOR 5mA/IV V 1V/IV 1mV/IV AC COPLE 2ns/IV 3462 TA5b PACKAGE ESCRIPTIO S6 Package 6-Lead Plastic TSOT-23 (Reference LTC WG # ).62 MAX.95 REF 2.9 BSC (NOTE 4) 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.8 BSC (NOTE 4) PIN ONE I NOTE: 1. IMENSIONS ARE IN MILLIMETERS 2. RAWING NOT TO SCALE 3. IMENSIONS ARE INCLSIVE OF PLATING 4. IMENSIONS ARE EXCLSIVE OF MOL FLASH AN METAL BRR 5. MOL FLASH SHALL NOT EXCEE.254mm 6. JEEC PACKAGE REFERENCE IS MO BSC ATM A RECOMMENE SOLER PA LAYOT PER IPC CALCLATOR.9.2 (NOTE 3) 1. MAX.95 BSC PLCS (NOTE 3) REF 1.9 BSC Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. S6 TSOT

8 TYPICAL APPLICATIO S 12V to 36V C/C Converter 36V Efficiency 12V L1 47µH.47µF LT k 15k 1nF 5pF 36V 36mA 5V EFFICIENCY (%) = 12V : TAIYO YEN X5R EMK212BJ15 : MRATA GRM42-6X7R474K5 : MRATA GRM42-6X7R474K5 2 1: CENTRAL CMSH5-4-LTN L1: MRATA LQH32CN TA6a LOA CRRENT (ma) TA6b RELATE PARTS PART NMBER ESCRIPTION COMMENTS LT1617/LT mA/1mA (I ) High Efficiency : 1.2V to 15V, (MAX) = 34V, I Q = 2µA, I S <1µA Micropower Inverting C/C Converter ThinSOT Package LT1931/LT1931A 1A (I ), 1.2MHz/2.2MHz, High Efficiency : 2.6V to 16V, (MAX) = 34V, I Q = 5.8mA, I S <1µA Micropower Inverting C/C Converter ThinSOT Package LT1945 ual Output, Boost/Inverter, 35mA (I ), Constant : 1.2V to 15V, (MAX) = ±34V, I Q = 4µA, I S <1µA, Off-Time, High Efficiency Step-p C/C Converter MS1 Package LT1946/LT1946A 1.5A (I ), 1.2MHz/2.7MHz, High Efficiency : 2.45V to 16V, (MAX) = 34V, I Q = 3.2mA, I S <1µA Step-p C/C Converter MS8 Package LT3463 ual Output, Boost/Inverter, 25mA (I ), Constant : 2.3V to 15V, (MAX) = ±4V, I Q = 4µA, I S <1µA Off-Time, High Efficiency Step-p C/C Converter FN Package with Integrated Schottky iodes LT mA (I ), High Efficiency Step-p C/C Converter : 2.3V to 1V, (MAX) = 34V, I Q = 25µA, I S <1µA with Integrated Schottky and PNP isconnect ThinSOT Package 8 LT/TP 34 1K PRINTE IN SA Linear Technology Corporation 163 McCarthy Blvd., Milpitas, CA (48) FAX: (48) LINEAR TECHNOLOGY CORPORATION 24

FEATURES TYPICAL APPLICATIO LTC MHz to 3GHz RF Power Detector. in SC70 Package DESCRIPTIO APPLICATIO S

FEATURES TYPICAL APPLICATIO LTC MHz to 3GHz RF Power Detector. in SC70 Package DESCRIPTIO APPLICATIO S 300MHz to 3GHz RF Power Detector in SC70 Package FEATRES Temperature Compensated Internal Schottky Diode RF Detector Wide Input Frequency Range: 300MHz to 3GHz Wide Input Power Range: 30dBm to 6dBm Buffered