LT1766-5 LINER [Linear Technology], LT1766-5 Datasheet
LT1766-5
Related parts for LT1766-5
LT1766-5 Summary of contents
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... A shutdown pin reduces supply current and the device can be externally synchronized from 228kHz to 700kHz with logic level inputs. The LT1766/LT1766-5 are available in a 16-pin fused-lead SSOP package or a TSSOP package with exposed backside for improved thermal performance. , LTC and LT are registered trademarks of Linear Technology Corporation. ...
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... LT1766/LT1766 ABSOLUTE AXI U RATI GS (Note 1) Input Voltage (V ) ................................................. 60V IN BOOST Pin Above SW ............................................ 35V BOOST Pin Voltage ................................................. 68V SYNC, SENSE Voltage (LT1766-5) ........................... 7V SHDN Voltage ........................................................... 6V BIAS Pin Voltage .................................................... 30V FB Pin Voltage/Current (LT1766) ................... 3.5V/2mA U PACKAGE/ORDER I FOR ATIO TOP VIEW GND 1 16 GND SHDN ...
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... Note 10: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125 C when overtemperature protection is active. Continuous operation above the specified maximum operating junction ): BIAS temperature may impair device reliability. = 2.9mA 2.4mA. TOTAL LT1766/LT1766 MIN TYP MAX = 4.1V 1 SENSE 0 ...
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... LT1766/LT1766 TYPICAL PERFOR A CE CHARACTERISTICS Switch Peak Current Limit 2 TYPICAL 2.0 GUARANTEED MINIMUM 1.5 1 100 DUTY CYCLE (%) 1766 G01 Lockout and Shutdown Thresholds 2.4 LOCKOUT 2.0 1.6 1.2 0.8 START-UP 0.4 SHUTDOWN 0 –50 – 100 125 JUNCTION TEMPERATURE ( C) 1766 G04 Error Amplifier Transconductance ...
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... NPN switch. This pin is driven up to the input pin voltage during switch on time. Inductor current drives the switch pin negative during switch off time. Negative volt- age is clamped with the external catch diode. Maximum negative switch voltage allowed is – 0.8V. NC (Pins 13): No Connection. LT1766/LT1766-5 BOOST Pin Current ...
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... LT1766/LT1766 CTIO S V (Pin 4): This is the collector of the on-chip power NPN IN switch. V powers the internal control circuitry when a IN voltage on the BIAS pin is not present. High dI/dt edges occur on this pin during switch turn on and off. Keep the path short from the V ...
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... R LIMIT – + CURRENT COMPARATOR SLOPE COMP ANTISLOPE COMP 200kHz S OSCILLATOR FOLDBACK V C(MAX) Q3 CURRENT CLAMP LIMIT CLAMP Figure 1. LT1766 Block Diagram LT1766/LT1766-5 R SENSE BOOST DRIVER S POWER FLIP-FLOP CIRCUITRY SWITCH 2 SW FREQUENCY FOLDBACK ERROR AMPLIFIER – 2000 Mho m + 1.22V ...
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... FB pin. Please read both parts before committing to a final design. The 5V fixed output voltage part (LT1766-5) has internal divider resistors and the FB pin is renamed SENSE, connected directly to the output. ...
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... Peak-to-peak output ripple voltage is the sum of a triwave (created by peak-to-peak ripple current (I and a square wave (created by parasitic inductance (ESL) and ripple current slew rate). Capacitive reactance is assumed to be small compared to ESR or ESL. V RIPPLE LT1766/LT1766 OUTPUT ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO where: ESR = equivalent series resistance of the output capacitor ESL = equivalent series inductance of the output capacitor dI/dt = slew rate of inductor ripple current = V Peak-to-peak ripple current (I ) through the inductor LP-P and into the output capacitor is typically chosen to be between 20% and 40% of the maximum load current ...
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... If the smallest inductor value is of most importance to a converter design, in order to reduce inductor size/cost, discontinuous mode may yield the smallest inductor solu- tion. The maximum output load current in discontinuous mode, however, must be calculated and is defined later in this section. LT1766/LT1766-5 ). The follow- LP – ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO Discontinuous mode is entered when the output load current is less than one-half of the inductor ripple current ( this mode, inductor current falls to zero before LP-P the next switch turn on (see Figure 8). Buck converters will be in discontinuous mode for output load current given by: ...
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... 4.7k Application Note 19 for further detail on techniques for proper loop compensation. LT1766/LT1766-5 . The formula RMS ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO INPUT CAPACITOR Step-down regulators draw current from the input supply in pulses. The rise and fall times of these pulses are very fast. The input capacitor is required to reduce the voltage ripple this causes at the input of LT1766 and force the switching current into a tight local loop, thereby minimiz- ing EMI ...
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... Minimum input voltage LT1766 + 2.38V IN – 5.5 A SHDN + – 0.4V GND Figure 4. Undervoltage Lockout LT1766/LT1766-5 10k or less. If shutdown LO can be raised to 100k, but the error 100k 25k suggested ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO Keep the connections from the resistors to the shutdown pin short and make sure that interplane or surface capaci- tance to the switching nodes are minimized. If high resistor values are used, the shutdown pin should be bypassed with a 1000pF capacitor to prevent coupling problems from the switch node ...
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... The path around switch, catch diode and input capacitor must be kept as short as possible to ensure reliable operation. When looking at this, a >100MHz oscilloscope must be used, and waveforms should be observed on the leads of the package. This LT1766/LT1766-5 CONNECT TO GROUND PLANE GND FOR THE FE PACKAGE, THE ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO SW RISE SW FALL 2V/DIV 50ns/DIV Figure 7. Switch Node Resonance switch off spike will also cause the SW node to go below ground. The LT1766 has special circuitry inside which mitigates this problem, but negative voltages over 0.8V lasting longer than 10ns should be avoided. Note that 100MHz oscilloscopes are barely fast enough to see the details of the falling edge overshoot in Figure 7 ...
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... P DISS BOOST ( Here it can be seen that boost power dissipation increases as the square below V C2 the voltage drop in the path of D2. Care should be taken that V C2 LT1766/LT1766-5 gives greater IN may generate greater losses due to switch DC and no switching IN V • • ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO voltage required for full saturation of the internal power switch. For output voltages of 5V During switch turn on, V will fall as the boost capacitor dicharged by the boost pin. In the previous Boost Pin section, the value of C2 was designed for a 0.7V droop in ...
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... C quired in the loop to increase phase margin for improved = 220pF. The output transient response. A zero can be added into the loop by placing a resistor the placing a capacitor, CFB, between the output and the FB pin. LT1766/LT1766 ERROR AMPLIFIER TANTALUM – ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO When using R , the maximum value has two limitations. C First, the combination of output capacitor ESR and R stop the loop rolling off altogether. Second, if the loop gain is not rolled off sufficiently at the switching frequency, output ripple will peturb the V ...
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... The ground pin must be tied to the regulated negative output. A resistor divider to the FB pin then provides the proper feedback voltage for the chip. The following equation can be used to calculate maximum load current for the positive-to-negative converter: I MAX LT1766/LT1766-5 D2 1N4148W C2 0.33 F L1A* BOOST ...
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... LT1766/LT1766 APPLICATIO S I FOR ATIO I = Maximum rated switch current Minimum input voltage Output voltage OUT V = Catch diode forward voltage F 0.3 = Switch voltage drop at 1.5A Example: with V = 5.5V, V IN(MIN) OUT V = 0.63V 1.5A 0.280A MAX OUTPUT DIVIDER Refer to Applications Information Feedback Pin Functions to calculate R1 and R2 for the (negative) output voltage (from Table 1) ...
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... IN(MAX) To increase usable V can be achieved by placing a zener diode V C2+) in series with D2. Note: A maximum limit on V ensure a minimum V ) capacitor; referred to as “V Characteristics OUT )( V ) OUT LT1766/LT1766-5 (GND pin – GNDPIN C2 – (D1 –12V. Absolute maximum ratings should OUT = 12V ...
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... LT1766/LT1766-5 PACKAGE DESCRIPTIO 6.60 0.10 4.50 0.10 SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 (.018 – .030) (.0036 – .0079) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. DIMENSIONS ARE IN 3. DRAWING NOT TO SCALE Package 16-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1663, Exposed Pad Variation BB) 3 ...
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... TYP .015 .004 45 .053 – .068 (0.38 0.10) (1.351 – 1.727) 0 – 8 TYP .008 – .012 (0.203 – 0.305) LT1766/LT1766-5 .189 – .196* (4.801 – 4.978) .009 (0.229 REF .150 – .157** (3.810 – 3.988) ...
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... LT1766/LT1766-5 RELATED PARTS PART NUMBER DESCRIPTION LT1074/LT1074HV 4. 100kHz, High Efficiency Step-Down DC/DC Converters OUT LT1076/LT1076HV 1. 100kHz, High Efficiency Step-Down DC/DC Converters OUT LT1616 500mA (I ), 1.4MHz, High Efficiency OUT Step-Down DC/DC Converter LT1676 60V, 440mA (I ), 100kHz, High Efficiency OUT Step-Down DC/DC Converter LT1765 25V, 2.75A (I ), 1.25MHz, High Efficiency ...
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