LTC2921/LTC2922 Series Power Supply Tracker with Input Monitors FEATURES DESCRIPTIO n Tracks Multiple Supplies with MOSFET Switches The LTC 2921 and LTC2922 monitor up to five supplies n Monitors 5 Input Voltages Including V and force them to track on power-up in multiple supply CC n Guaranteed Threshold Accuracy: 1% at 0.5V systems. Using external N-channel pass transistors, the n Automatic Remote Sense Switching supplies can be ramped up at an adjustable rate. Auto- n Adjustable Supply Ramp Rate matic remote sense switching allows the DC/DC convert- n Overvoltage Monitor ers to compensate for series voltage drops in the wiring. n Adjustable Electronic Circuit Breaker An incorrect level on one or more of the supplies triggers n Adjustable Power-Good Delay disconnect of all supplies. Tight 1% accuracy and glitch n Available for V Supply Voltages of 5V, 3.3V and 2.5V immunity on the low 0.5V monitoring level ensure no false CC n Available in 16-Pin Narrow SSOP (LTC2921 Series) error disconnects. and 20-Pin TSSOP (LTC2922 Series) The LTC2921 and LTC2922 each feature an adjustable U electronic circuit breaker to protect the V supply against CC APPLICATIO S short circuits. Capacitance at the TIMER pin programs the delays in the monitoring sequence. n Desktop Computers n Plug-In Cards The LTC2921 includes three remote sense switches in a n Telecom Infrastructure 16-pin narrow SSOP package, while the LTC2922 includes n Supply Sequencing five remote sense switches in a 20-pin TSSOP package. n Instruments Both parts are available for V supply voltages of 5V, CC 3.3V, and 2.5V. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO Three-Supply Tracker and Monitor (5V, 3.3V, 2.5V) 5V SUPPLY 5V V OUT WSL1206 LOAD V FB Si2316DS 0.05 100 Load Voltage Ramp-Up and DC/DC 10 Power-Good Activation CONVERTER 3.3V SUPPLY 3.3V V OUT LOAD V Si2316DS 2.5V SUPPLY FB 100 2V/DIV DC/DC 10 5V LOAD CONVERTER 3.3V LOAD 2.5V SUPPLY 2.5V V OUT OUTPUTS LOAD Si2316DS 2.5V LOAD 2V/DIV V FB 100 DC/DC 10 CONVERTER PG 243k 169k 4.7k 2V/DIV V SENSE CC V1 GATE V2 0.47F 2921/22 TA01b LTC2921 V3 5V SUPPLY AT 5V 100ms/DIV 49.9k 49.9k V4 3.3V SUPPLY AT 3.3V Si1012R PG RESET CBRST S1 D1 S2 D2 100k S3 D3 GND TIMER t ~ 500ms GATE CIRCUIT BREAKER t ~ 130ms TIMER 0.22F RESET CONTROL 2921/22 TA01 29212fa 1 U ULTC2921/LTC2922 Series ABSOLUTE AXI U RATI GS (Note 1) V Supply Voltage...................................... 0.3V to 7V Switch Currents (DC, RMS) CC V1, V2, V3, V4 Voltages ............................... 0.3V to 7V S0, D0, S4, D4 (LTC2922 Series) ..................... 30mA SENSE Voltage ............................................ 0.3V to 7V S1, D1, S2, D2, S3, D3 ..................................... 30mA TIMER Voltage ............................. 0.3V to (V + 0.3V) Operating Ambient Temperature Range CC Charge Pumped Output Voltages LTC2921C/LTC2922C .............................. 0C to 70C GATE, PG............................................ 0.3V to 12.2V LTC2921I/LTC2922I ............................40C to 85C Switch Voltages Junction Temperature (Note 2)............................. 125C S0, D0, S4, D4 (LTC2922 Series) ............ 0.3V to 7V Storage Temperature Range ..................65C to 150C S1, D1, S2, D2, S3, D3 ............................ 0.3V to 7V Lead Temperature (Soldering, 10 sec).................. 300C UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART ORDER PART TOP VIEW SO 1 20 NUMBER D0 NUMBER V1 1 16 TIMER TIMER 2 19 V CC LTC2921CGN LTC2922CF V2 2 15 V V1 3 18 CC SENSE LTC2921CGN-3.3 LTC2922CF-3.3 V3 3 14 SENSE V2 4 17 GATE LTC2921CGN-2.5 LTC2922CF-2.5 V4 4 13 GATE V3 5 16 PG LTC2921IGN LTC2922IF S3 5 12 PG V4 6 15 GND LTC2921IGN-3.3 LTC2922IF-3.3 D3 6 11 GND S4 7 14 D1 LTC2921IGN-2.5 LTC2922IF-2.5 S2 7 10 D1 D4 8 13 S1 GN PART MARKING D2 8 9 S1 S3 9 12 D2 2921 D3 10 11 S2 GN PACKAGE 16-LEAD NARROW PLASTIC SSOP 292133 F PACKAGE T = 125C, = 110C/W JMAX JA 292125 20-LEAD PLASTIC TSSOP T = 125C, = 90C/W JMAX JA 2921I 921I33 921I25 Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. V = 5V for LTC2921/LTC2922, V = 3.3V for A CC CC LTC2921-3.3/LTC2922-3.3, and V = 2.5V for LTC2921-2.5/LTC2922-2.5, unless otherwise noted. CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Pin V Supply Voltage Typical Operating Range CC LTC2921/LTC2922 4.50 5.00 5.50 V LTC2921-3.3/LTC2922-3.3 2.97 3.30 3.63 V LTC2921-2.5/LTC2922-2.5 2.37 2.50 2.63 V I Supply Current 2mA CC V Supply Monitor Threshold Voltage LTC2921/LTC2922 l 4.285 4.350 4.415 V CC(MON) LTC2921-3.3/LTC2922-3.3 l 2.828 2.871 2.914 V LTC2921-2.5/LTC2922-2.5 l 2.265 2.300 2.335 V V Supply Overvoltage Threshold LTC2921/LTC2922 l 5.82 6.13 6.43 V CC(OV) LTC2921-3.3/LTC2922-3.3 l 3.84 4.04 4.24 V LTC2921-2.5/LTC2922-2.5 l 3.08 3.24 3.40 V 29212fa 2 U WWW