LTC1645CS8 Linear Technology, LTC1645CS8 Datasheet
LTC1645CS8
Specifications of LTC1645CS8
Available stocks
Related parts for LTC1645CS8
LTC1645CS8 Summary of contents
Page 1
... An additional spare com- parator is available for monitoring a second supply voltage. The LTC1645 is available in the 8- and 14-pin SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. V 0.005 * IRF7413 OUT2 3 ...
Page 2
... Operating Temperature Range CC1 LTC1645C ............................................... 0.3V) LTC1645I ............................................ – CC1 + 0.3V) Storage Temperature Range ................. – 150 C CC2 Lead Temperature (Soldering, 10 sec).................. 300 ORDER PART NUMBER V 1 CC2 SENSE2 2 LTC1645CS8 GATE2 3 LTC1645IS8 FAULT 4 RESET 5 S8 PART MARKING FB 6 GND 7 1645 14-LEAD PLASTIC SO 1645I T JMAX CONDITIONS ...
Page 3
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T 2.375V V 12V, 1.2V V 12V unless otherwise noted (Note 2). CC1 CC2 SYMBOL PARAMETER V TIMER Pin Voltage Threshold TM ...
Page 4
LTC1645 W U TYPICAL PERFOR A CE CHARACTERISTICS GATE Voltage vs Supply Voltage HIGHEST V (V) CC 1645 ...
Page 5
CTIO S (14-Lead Package/8-Lead Package) V (Pin 1/Pin 1): Positive Supply Input. V CC2 from 1.2V to 12V for normal operation. I 0.2mA. An undervoltage lockout circuit disables the LTC1645 whenever the voltage at V ...
Page 6
LTC1645 CTIO S (14-Lead Package/8-Lead Package) Whenever the timer is inactive, an internal N-channel FET shorts the TIMER pin to ground. Activating the timer connects current source from V and the voltage ...
Page 7
U U APPLICATIO S I FOR ATIO Hot Circuit Insertion When a circuit board is inserted into a live backplane, the supply bypass capacitors on the board can draw huge transient currents from the backplane power bus as they charge. ...
Page 8
LTC1645 U U APPLICATIO S I FOR ATIO Power Supply Ramping The power supplies on a board are controlled by placing external N-channel pass transistors in the power paths as shown in Figure 2. Consult Table 1 for a selection ...
Page 9
U U APPLICATIO S I FOR ATIO No bulk capacitance is present to slow the rate of rise and heavily damp the parasitic resonance. Instead, the fast edge shock excites a resonant circuit formed by a combi- nation of wiring ...
Page 10
LTC1645 U U APPLICATIO S I FOR ATIO D1* POWER LEADS + 12V – ON SEMICONDUCTOR * 1SMA12CAT3 + 12V – 12V 0V 1 s/DIV (a) V Waveform Damped by a Snubber (15 , 6.8nF ...
Page 11
U U APPLICATIO S I FOR ATIO Supply Glitching LTC1645 Hot Swap circuits on the backplane are generally used to provide power-up/down sequence at insertion/ removal as well as overload/short-circuit protection short-circuit occurs at supply ramp-up, the circuit ...
Page 12
LTC1645 U U APPLICATIO S I FOR ATIO nearly unlimited current flow. The LTC1645 discharges the GATE pin in a few microseconds, but during this discharge time current on the order of 150 amperes flows from the V power supply. ...
Page 13
U U APPLICATIO S I FOR ATIO voltage on the external capacitor C TIMER with a slope dv/ A/C . When the voltage reaches TIMER the trip point (1.23V), the timer is reset by pulling the TIMER pin ...
Page 14
LTC1645 U U APPLICATIO S I FOR ATIO An external hard reset is initiated at time point 6. The ON pin is forced below 0.8V but above 0.4V, and the GATE n pin voltages start to ramp down. V OUT ...
Page 15
U U APPLICATIO S I FOR ATIO V IN2 5V/DIV V IN1 5V/DIV V OUT2 5V/DIV V OUT1 5V/DIV TIMER 2V/DIV RESET 5V/DIV Figure 16. Ramping 3.3V and 2.5V Up and Down Together This circuit guarantees that: ( ...
Page 16
LTC1645 U U APPLICATIO S I FOR ATIO BOTH CURRENT LIMITS: 10A V IN2 3.3V 0.005 * V IN1 5V D1 1N4148 13k 10k 47.5k V SENSE1 CC1 10k 1% 4 FAULT FAULT ...
Page 17
U U APPLICATIO S I FOR ATIO Using the LTC1645 as a Linear Regulator This application uses the LTC1645 to Hot Swap one primary supply and generate a secondary low dropout regulated supply. Figure 19 shows how to switch a ...
Page 18
LTC1645 U U APPLICATIO S I FOR ATIO Switching Regulator Supply Sequencing Figure 21 shows the LTC1645 sequencing two power supplies, the lower of which is generated by the LTC1430A switching regulator. Connecting the regulator’s FB pin resistor divider (R1 ...
Page 19
U U APPLICATIO S I FOR ATIO W U LTC1645 1645fa 19 ...
Page 20
LTC1645 U U APPLICATIO S I FOR ATIO 1645fa ...
Page 21
U U APPLICATIO S I FOR ATIO ON 2V/DIV V REGIN 2V/DIV V REGOUT 2V/DIV V OUT2 2V/DIV V OUT1 2V/DIV RESET 5V/DIV Figure 24. Switching Regulator Hot Swap its FB or SENSE pin. In the case of the LTC1649, ...
Page 22
LTC1645 PACKAGE DESCRIPTIO .050 BSC .245 MIN .030 .005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 (0.254 – 0.508) .008 – .010 (0.203 – 0.254) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT ...
Page 23
... MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 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. ...
Page 24
... Supply Tracking Mode 1.7V to 16.5V, Active Inrush Limiting, Fast Comparator www.linear.com V OUT1 3. 2.5A C 1N4002 LOAD1 D3 D2 MBR0530T1 1N4002 V OUT2 2.5V + 2.5A C LOAD2 10k 0.1 F 25V 1.18k 1% 1.37k 1% P RESET 1645 F15 LT/TP 0404 1K REV A • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1999 1645fa ...