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Simple Tracker TM ADM1200 Preliminary Technical Data FEATURES Enables Power Supply Tracking of multiple supplies Up/Down Tracking limits Supply Differences to ~100mV Capacitor Adjustable Slew Rate On Board Charge Pump Fully enhances FET Ability to Track Down Supplies (ADM1200-1) Emergency Shutdown Feature (ADM1200-2) Packaged in tiny 6-Lead SOT-23 Package APPLICATIONS Multi-Voltage Supply Rail Tracker Telecoms and Datacom s Systems Multi voltage Network Processors , FPGAs, ASICs, DSPs PC/Server Applications Functional Block Diagram Q1 VIN VOUT 2.7V - 16.5V VCC UP/DOWN (ADM1200-1) UP/STOP (ADM1200-2) CSLEW UP / DOWN DETECTOR SLEW RATE CONTROL VOUT ADM1200 GND The ADM1200 is a cascadable Simple Tracker TM device which ensures that voltage rails track within ~100mV of each other in multi supply systems. Any number of these devices can be cascaded to form a multi supply tracking solution. Applications Diagram Q1 3.3VIN 3.3VOUT Vcc ADM1200 Vcc GATE UP/DOWN The Slew Rate of the ramp is adjustable via an external capacitor on the CSLEW pin and can be programmed from 100V/s to 1000V/s. When multiple devices are cascaded the CSLEW pin of each subsequent device should be tied to the output rail(VOUTFB) of the previous device to ensure that supply will track up and down with the previous supply. GATE FET DRIVER LOGIC CSLEW GENERAL DESCRIPTION The ADM1200 requires 2.7V to 16.5V on its Vcc pin to operate. An on-board charge pump generates a high voltage GATE drive to fully enhance FETs in the power path. VFET CHARGE PUMP 20nF UP/DOWN V OUT C SLEW GND C SLEW Q2 2.5VIN 2.5VOUT V cc ADM1200 The ADM1200 is offered in two variants. The ADM1200-1 features an UP/DOWNb pin and the ADM1200-2 features an Up/STOPb pin. For both devices a high level on the this input will initiate tracking power up sequence. A low on the UP/DOWNb pin of the ADM1200-1 will initiate a tracking down of the supply rails, while a low on the UP/STOPb pin of the ADM1200-2 will initiate an emergency fast shutdown of all supply rails simultaneously. Vcc GATE 20nF UP/DOWN VOUT C SLEW GND Q3 1.5VIN 1.5VOUT V cc ADM1200 Vcc The ADM1200 is packaged in a tiny 6-pin SOT-23 package. GATE 20nF UP/DOWN VOUT C SLEW GND Rev. PrH Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 Fax: 781.326.8703 2003 Analog Devices, Inc. All rights reserved. ©©2005 Preliminary Technical Data ADM1200—SPECIFICATIONS Table 1. VCC = Full Operating Range, TA = -40°C to +85°C, unless otherwise noted. Parameter Min VCC Pin Operating Voltage Range Vcc Undervoltage Lockout, VUVLO UVLO Hysteresis Switched Voltage Range Quiesent Current Up/Downb Pin Input Threshold Input Threshold Hysteresis Input Current CSLEW Pin Slew up Current Slew down Current Tracking Gain Minimum Tracking Voltage Maximum Tracking voltage Slew Rate VOUTFB Pin Input Current Voltage Range GATE Pin Gate Pullup Current Gate Pulldown Current Gate Pulldown Current GATE Voltage, VGATE 2.7 2.4 Typ 2.525 25 0.65 0.65 0.58 0.6 60 Units 16.5 2.65 V V mV V mA 16.5 1.0 0.62 100 V mV nA 100 1000 µA µA V/V V V V/s -10 0 10 Vcc µA V 10 12 10 µA µA mA V V V -100 -10 10 1 0.1 Vcc – 0.3 5 6 5 12 12 2 6.5 8 6.5 NOTES: 1 Asserted when voltage on PFI pin exceeds threshold Absolute Maximum Ratings Table 2. ADM1200 Absolute Maximum Ratings Parameter VCC Pin UP/DOWNb, UP/STOPb CSLEW Pin Gate Pin VOUTFB Pin Power Dissipation Storage Temperature Operating Temperature Range Lead Temperature Range (Soldering 10 sec) Junction Temperature Max Rating 20V 20V 20V Vcc + 11V 20V TBD –65°C to +125°C –40°C to +85°C 300°C 150°C Rev. PrH | Page 2 of 6 Conditions Vcc Rising Rising VSLEW/VOUTFB Vslew – Vout > 100mV Vout – Vslew > 100mV ADM1200-2 only –vgate = 3.0V VGATE – VCC; VCC = 2.7V VGATE – VCC; VCC = 5.0V VGATE – VCC; VCC = 16.5V Preliminary Technical Data ADM1200 ENABLING A SINGLE SUPPLY Q1 3.3VIN The ADM1200 requires a supply voltage of 2.7V to 16.5V on its Vcc pin for operation. The device may be powered from the input supply rail that is being switched or from an auxiliary supply. ADM1200 Vcc GATE UP/DOWN 20nF UP/DOWN V OUT C SLEW An internal charge pump ensures that the ADM1200 is capable of fully enhancing an external FET via the GATE pin, turning on the output. An external capacitor may be required on the GATE node for stability. GND C SLEW Q2 2.5VIN 2.5VOUT V cc Power up can be externally initiated by driving the UP/DOWNb (ADM1200-1) or UP/STOPb (ADM1200–2) logic pin high. A low on this pin will initiate a power down. ADM1200 Vcc GATE 20nF UP/DOWN VOUT C SLEW The VOUTFB pin monitors the output voltage. GND A single ADM1200 device may be used where a single supply rail is required to switch on at a controlled slew rate (see Figure 1). The value of the slew rate capacitor, CSLEW, will dictate the slew rate of the GATE voltage at startup. An internal current 10µA source charges CSLEW and the GATE voltage is ramped at the same rate. Q3 1.5VIN 1.5VOUT V cc ADM1200 Vcc GATE 20nF UP/DOWN VOUT C SLEW Q1 3.3VIN 3.3VOUT Vcc GND 3.3VOUT Figure 2. ADM1200 Solution for Tracking 3 Supplies ADM1200-1 A low-to-high transition on the UP/DOWNb or UP/STOPb pin will initiate turn-on of the supplies. The ADM1200 will begin to source current into the CSLEW capacitor. The voltages on all GATE pins will begin to rise, or “track” up, at the same rate, as set by the value of CSLEW. All supply voltages will remain within 100mV of the CSLEW voltage until they level off at their full potentials. V cc GATE POWER ON/OFF 1nF UP/STOP VOUTFB C SLEW CSLEW GND Figure 1. ADM1200 Switching on a Single Supply A high-to-low on the UP/DOWNb pin of the ADM1200-1 will initiate a tracking down of the supply rails. The voltages will attempt to stay with ~100mV of each other assuming the load current will be sufficient to discharge the capacitors at the required rate. (See Figure 3.) MULTI-SUPPLY TRACKING The primary function of the ADM1200 is to provide a voltage tracking solution for multiple supply rails. The implementation in Figure 2 will provide this function. Each voltage rail has its own ADM1200 device driving a FET. The UP/DOWNb (ADM1200-1) or UP/STOPb (ADM1200-2) pins of all devices can be driven by a single logic input which will initiate a system power-up going high or power-down going low. A high-to-low on the UP/STOPb pin of the ADM1200-2 will initiate an emergency fast shutdown of all supply rails simultaneously. (See Figure 4.) Note that while the pass FETs will be turned off immediately the actual discharge rate of each supply rail will depend on the load. In figure 2, the ADM1200 is configured to control the ramp of the largest supply first. The output of the first device is connected to the slew pin on the second device to allow the rate of the first supply to control the rate of the second and so on. Rev. PrH | Page 3 of 6 ADM1200 Preliminary Technical Data UP/DO WN SLEW RATE CONTROL Voltage tracking is achieved by controlling the slew rate of a rising or falling supply by an external capacitor on the SLEW pin. Alternatively, this pin can be overdriven with a supply which will result in the output following this supply. The gate responds to maintain ~100mV between the VOUTFB pin and the SLEW pin. 3.3V 2.5V 1.5V OUTP UT V OLTAGE S Figure 3. ADM1200-1 Power-Up and Power-Down Waveforms UP/STOP 3.3V 2.5V 1.5V OUTP UT V OLTAGE S Figure 6. Tracking up Waveforms Figure 4. ADM1200-2 Power-Up and Power-Down Waveforms Rev. PrH| Page 4 of 6 Preliminary Technical Data ADM1200 PIN CONFIGURATIONS UP / DOWN 1 6 VCC UP / STOP 1 2 5 GATE GND 2 TOP VIEW (Not to Scale) VOUTFB 3 VCC ADM1200-2ARJ ADM1200-1ARJ GND 6 5 GATE TOP VIEW (Not to Scale) 4 CSLEW VOUTFB 3 4 CSLEW PIN FUNCTIONAL DESCRIPTIONS Pin No. 1 Name UP/DOWNb or UP/STOPb 2 3 4 GND VOUTFB CSLEW 5 6 GATE VCC Description Logic Pin. Drive high to initiate track up off all ADM1200 controlled rails. Drive low to initiate track down of output (ADM1200-1) or a fast shutdown of output (ADM1200-2). Chip Ground Pin. Monitors the Source of the external FET Connect to an external capacitor to control the slew rate of the output at turn on (and turn-off for ADM1200-1). Drives the GATE node of the external FET Chip Power Supply, 2.7V to 16.5V. Rev. PrH | Page 5 of 6 ADM1200 Preliminary Technical Data OUTLINE DIMENSIONS 0.122 (3.10) 0.106 (2.70) 0.071 (1.80) 0.059 (1.50) 6 5 4 1 2 3 0.118 (3.00) 0.098 (2.50) PIN 1 0.037 (0.95) BSC 0.075 (1.90) BSC 0.051 (1.30) 0.035 (0.90) 0.057 (1.45) 0.035 (0.90) 0.059 (0.15) 0.000 (0.00) 0.020 (0.50) SEATING 0.010 (0.25) PLANE 10° 0.009 (0.23) 0° 0.003 (0.08) 0.022 (0.55) 0.014 (0.35) Figure 5. 6-Lead SOT-23 Package (RJ-6)—Dimensions shown in millimeters ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Table 3. Ordering Guide Part Number ADM1200-1ARJ ADM1200-2ARJ Variant UP/DOWNb logic input UP/STOPb logic input Temperature Package –40°C to +85°C –40°C to +85°C 2005 003 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the Printed in the U.S.A. property of their respective companies. PR05128-0-2/05(PrH) Rev. PrH | Page 6 of 6 Package Description SOT-23 SOT-23 Package Outline RJ-6 RJ-6