LTC2925CUF Linear Technology, LTC2925CUF Datasheet
LTC2925CUF
Specifications of LTC2925CUF
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LTC2925CUF Summary of contents
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... L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. MASTER 0.1μ ...
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... LTC2925CGN LTC2925CGN#TR LTC2925IGN LTC2925IGN#TR LTC2925CUF LTC2925CUF#TR LTC2925IUF LTC2925IUF #TR Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. For more information on lead free part marking, go to: For more information on tape and reel specifi cations, go to: ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER V Input Supply Range CC I Input Supply Current CC V Input Supply Undervoltage Lockout CC(UVL) ΔV Input Supply Undervoltage Lockout Hysteresis CC(UVL, HYST) ΔV External N-Channel Gate ...
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LTC2925 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. TYPICAL PERFORMANCE CHARACTERISTICS I ...
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TYPICAL PERFORMANCE CHARACTERISTICS SDx(OL) CC 1.0 0.8 0.6 0 5mA SDx 0 10μA SDx (V) CC 2925 G07 PIN FUNCTIONS GN/UF Packages V (Pin 1/Pin ...
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LTC2925 PIN FUNCTIONS GN/UF Packages profi OUTx (see Applications Information). TRACKx pulls up to 0.8V and the current supplied at TRACKx is mirrored at FBx. The TRACKx pin is capable of supply- ing at least 1mA when V ...
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PIN FUNCTIONS GN/UF Packages SCTMR (Pin 24/Pin 21): Circuit Breaker Timer. A capacitor from SCTMR to GND programs the maximum time that a short circuit can be sustained before GATE is pulled low. When (SENSEP – SENSEN) > 50mV, SCTMR ...
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LTC2925 APPLICATIONS INFORMATION Power Supply Tracking and Sequencing The LTC2925 handles a variety of power-up profi les to satisfy the requirements of digital logic circuits including FPGAs, PLDs, DSPs and microprocessors. These require- ments fall into one of the four ...
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APPLICATIONS INFORMATION Tracking Cell The LTC2925’s operation is based on the tracking cell shown in Figure 5, which uses a proprietary wide-range current mirror. The tracking cell shown in Figure 5 servos the TRACK pin at 0.8V. The current supplied ...
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LTC2925 APPLICATIONS INFORMATION Optional External FET Figure 7 illustrates how an optional external N-channel FET can ramp up a single supply that becomes the mas- ter signal. When used, the FET’s gate is tied to the GATE pin and its ...
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APPLICATIONS INFORMATION pin is pulled low, the supplies are latched off, and the FAULT pin is held low until the fault is cleared by taking the ON pin below 0.4V. The PGI pin, which is normally connected to the RST ...
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LTC2925 APPLICATIONS INFORMATION Status Output The STATUS pin provides an indication that the supplies are fi nished ramping up. This pin is an open-drain output that pulls low until the GATE has been fully charged. Since the GATE pin drives ...
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APPLICATIONS INFORMATION 3-Step Design Procedure The following 3-step design procedure allows one to choose the TRACK resistors, R and R , and the gate capacitor, TAx TBx C , that give any of the tracking or sequencing profi les GATE ...
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LTC2925 APPLICATIONS INFORMATION 1V/DIV Coincident Tracking Example A typical four supply application is shown in Figure 12. The master signal is a 3.3V module. The slave 1 supply is a 1.8V switching power supply, the slave 2 supply is a ...
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APPLICATIONS INFORMATION 1V/DIV Ratiometric Tracking Example This example converts the coincident tracking example to the ratiometric tracking profi le shown in Figure 13, using three supplies without an external FET. The ramp rate of the master signal remains unchanged (step ...
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LTC2925 APPLICATIONS INFORMATION 1V/DIV Offset Tracking Example Converting the circuit in the coincident tracking example to the offset tracking shown in Figure 15 is relatively simple. Here the 1.8V slave 1 supply ramps up 1V below the master. The ramp ...
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APPLICATIONS INFORMATION 1V/DIV Supply Sequencing Example In Figure 17, the three slave supplies are sequenced in- stead of tracking the coincident tracking example, the 3.3V master supply ramps up at 100V/s through an external FET, so step 1 ...
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LTC2925 APPLICATIONS INFORMATION Final Sanity Checks The collection of equations below is useful for identifying unrealizable solutions. As stated in step 2, the slave supply must fi nish ramping before the master signal has reached its fi nal voltage. This ...
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APPLICATIONS INFORMATION Load Requirements When the supplies are ramped down quickly, either the load or the supply itself must be capable of sinking enough current to support the ramp rate. For example, if there is a large output capacitance on ...
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LTC2925 APPLICATIONS INFORMATION Layout Considerations Be sure to place a 0.1μF bypass capacitor as near as pos- sible to the supply pin of the LTC2925. To minimize the noise on the slave supplies’ outputs, keep the traces connecting the FBx ...
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TYPICAL APPLICATION 1V 3. TB1 8.66k R TA1 48.7k R TA2 215k External FET Controls 1V Supply Q1 0.015Ω Si4412ADY 0.1μF C GATE 0.1μF 10Ω R ONB V SENSEP SENSEN GATE RAMP 138k CC ON ...
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LTC2925 PACKAGE DESCRIPTION .254 MIN .0165 ± .0015 RECOMMENDED SOLDER PAD LAYOUT .0075 – .0098 (0.19 – 0.25) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE ...
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... ON THE TOP AND BOTTOM OF PACKAGE 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. UF Package 24-Lead Plastic QFN (4mm × ...
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... Controls Two Supplies Without FETs, MSOP-10 and DFN-12 Packages www.linear.com ● 3.3V IN OUT 1.8V SLAVE1 R FB1 16.5k 3.3V IN 2.5V SLAVE2 R FB2 88.7k 3.3V IN 0.015W 1.5V OUT SLAVE3 R FB3 86.6k 2925 TA03b LT 1207 REV C • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2004 2925fc ...