LTC2922 Linear Technology, LTC2922 Datasheet
LTC2922
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LTC2922 Summary of contents
Page 1
... Capacitance at the TIMER pin programs the delays in the monitoring sequence. The LTC2921 includes three remote sense switches in a 16-pin narrow SSOP package, while the LTC2922 includes five remote sense switches in a 20-pin TSSOP package. Both parts are available for V 3 ...
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... Supply Voltage ...................................... –0. V1, V2, V3, V4 Voltages ............................... –0. SENSE Voltage ............................................ –0. TIMER Voltage ............................. –0. Charge Pumped Output Voltages GATE, PG ............................................ –0.3V to 12.2V Switch Voltages S0, D0, S4, D4 (LTC2922 Series) ............ –0. S1, D1, S2, D2, S3, D3 ............................ –0. PACKAGE/ORDER I FOR ATIO TOP VIEW ...
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... ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T LTC2921-3.3/LTC2922-3.3, and V = 2.5V for LTC2921-2.5/LTC2922-2.5, unless otherwise noted. CC SYMBOL PARAMETER V Supply Undervoltage Lockout CC(UVLO) V Supply Undervoltage Hysteresis CC(UVH) Electronic Circuit Breaker V Circuit Breaker Trip Voltage SENSE I SENSE Pin Input Current SENSE t Circuit Breaker Trip Delay Time ...
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... LTC2921/LTC2922 Series W U TYPICAL PERFOR A CE CHARACTERISTICS Specifications are unless otherwise noted. A Supply Current vs Supply Voltage 3.00 PG SIGNAL ASSERTED 2.75 2.50 LTC2921 LTC2922 LTC2921-3.3 2.25 LTC2922-3.3 2.00 LTC2921-2.5 LTC2922-2.5 1.75 1.50 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 V (V) CC 2921/2 G01 Monitor Input Threshold vs Temperature 0.505 0.500 0.495 –50 – –30 70 TEMPERATURE ( C) ...
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... G10 GATE Pull-Up Current vs Temperature 11 GATE CC 11.0 10.5 10.0 9.5 9.0 8.5 –50 –30 – TEMPERATURE ( C) 2921/2 G13 LTC2921/LTC2922 Series Gate Voltage vs Temperature 12 11 LTC2921 LTC2922 10 LTC2921-3.3 LTC2922-3.3 9 GATE LOAD = 1000pF || 10M PG LOAD = BYPASS CAP = LTC2921-2.5 7 LTC2922-2 –50 – ...
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... The pins are interchangeable, either switch pin can be tied to the load side. Tie both pins to ground if unused. S4, D4 (Pins 7, 8 [LTC2922]): Remote Sense Switch 4. Tie to GND if unused. S3, D3 (Pins 5, 6/Pins 9, 10): Remote Sense Switch 3. Tie to GND if unused ...
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... MONITOR ENABLE OVERVOLTAGE – CIRCUIT + BREAKER MONITOR RESET PULSE TIMER ENABLE (LTC2922 ONLY (LTC2922 ONLY) Figure 1. LTC2921 and LTC2922 Functional Diagram www.DataSheet4U.com V PUMP PUMP REMOTE SENSE SWITCH GATE V PUMP 10 A GATE GATE + ...
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... LTC2921/LTC2922 Series U OPERATIO General Operation The LTC2921 and LTC2922 track multiple supplies, moni- tor multiple inputs, and provide integrated switches for remote sensing. Once all input voltages lie between moni- toring and overvoltage threshold levels, in-line FETs are turned on to simultaneously ramp power to the loads. The automatic remote sense switches are then activated, and the power good signal is asserted ...
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... DIAGRA S The timing of a typical start-up sequence for the LTC2921/ LTC2922 is shown in Figure 2. V exceeds the undervoltage CC lockout level at time 0. All monitor inputs settle between the 0.5V monitor threshold and the 0.7V overvoltage threshold by time 1, then a TIMER cycle starts ...
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... Desktop PC motherboards, instrumenta- tion circuits and plug-in boards of all kinds often require tracking and control of several supply voltages. The LTC2921 and LTC2922 ramp and monitor up to five supply voltages in such systems. External resistive volt- age dividers independently program four monitor levels, ...
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... U U APPLICATIO S I FOR ATIO Setting the Supply Monitor Levels The LTC2921 and LTC2922 series both feature low 0.5V monitoring thresholds with tight 1% accuracy. To set a supply monitoring level tightly, design a precision ratio resistive divider to relate the lowest valid supply voltage to the maximum specified monitor threshold voltage. Use resistors with 1% tolerance or better to limit the error due to mismatch ...
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... LTC2921/LTC2922 Series U U APPLICATIO S I FOR ATIO voltage specifications. On-resistance is a critical param- eter when choosing power MOSFETs. The integrated remote sense switches compensate for IR drops, but minimizing V leaves more margin for designing the Q(MAX) resistive voltage divider for the monitors. ...
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... In applications not requiring the current sensing circuit breaker, tie the SENSE pin to the V Configuring the PG Pin Output The LTC2921 and LTC2922 each include a power good indicator, the PG pin. During the turn-on sequence, and upon detection of errors, a strong FET pulls PG to ground with > ...
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... LTC2921/LTC2922 Series U U APPLICATIO S I FOR ATIO R SENSE Q0 V SRC0 V SENSE CC GATE V PUMP ENABLE GND LTC2922 2921/22 F08 Figure 8. PG Pin as Logic Output V SRC5 R SENSE Q0 V SRC0 V SENSE CC GATE V PUMP ENABLE GND LTC2922 2921/22 F09 Figure 9. PG Pin as Sequenced N-Channel Gate Driver pin has fully ramped up ...
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... The terminals of each switch are interchangeable; choose the connections to optimize the board layout. Ground all unused switch pins. Design Example Consider the design of a three-supply monitoring system, as shown in Figure 12, with specifications as listed in Table 1. LTC2921/LTC2922 Series W U Table 1. Design Example Electrical Specifications Supply Specifications 5V 7.5% R ...
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... LTC2921/LTC2922 Series U U APPLICATIO S I FOR ATIO 5V = 7.5% V OUT V FB DC/DC CONVERTER 3.3V = 7.5% V OUT 100 DC/DC CONVERTER 2.5V = 7.5% V OUT 100 DC/DC CONVERTER QRST Si1012R CBRST R1 100k CIRCUIT BREAKER RESET CONTROL Figure 12. Design Example of a Three-Supply Tracker and Monitor (5V, 3.3V, 2.5V) Selecting R = 243k satisfies the range restrictions be- ...
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... A LTC2921/LTC2922 Series W U Select a precision power sense resistor, such as the Vishay Dale WSL1206 series. They can be specified to 1%, and exhibit <1% variation over the LTC2921/LTC2922 operating range; choose R ances, the circuit breaker trip current threshold variation will be: I TRIP MIN ( I supply path. ...
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... LTC2921/LTC2922 Series U U APPLICATIO S I FOR ATIO 10 V – • 150 m • 100 – – • 150 m • 100 – – • 150 m • 100 – ...
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... 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC2921/LTC2922 Series U F Package 20-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1650) 4.30 – ...
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... LTC2921/LTC2922 Series U TYPICAL APPLICATIO Early-Late Supply Sequencer with Early Supplies LED Indicator 5V 10% V OUT 100 DC/DC CONVERTER 2. OUT 100 DC/DC CONVERTER 1. OUT 100 DC/DC CONVERTER 3.3V 10% V OUT V FB DC/DC CONVERTER 2.5V 10% V OUT V FB DC/DC CONVERTER QRST Si1012R CBRST ...