MAX8794 19-0584 Rev 2 3/10 Low-Voltage DDR Linear Regulator General Description Features The MAX8794 DDR linear regulator sources and sinks up Internal Power MOSFETs with Current Limit (3A typ) to 3A peak (typ) using internal n-channel MOSFETs. This Fast Load-Transient Response linear regulator delivers an accurate 0.5V to 1.5V output from a low-voltage power input (V = 1.1V to 3.6V). The External Reference Input with Reference IN MAX8794 uses a separate 3.3V bias supply to power the Output Buffer control circuitry and drive the internal n-channel MOSFETs. 1.1V to 3.6V Power Input The MAX8794 provides current and thermal limits to pre- 15mV (max) Load-Regulation Error vent damage to the linear regulator. Additionally, the Thermal-Fault Protection MAX8794 generates a power-good (PGOOD) signal to Shutdown Input indicate that the output is in regulation. During startup, PGOOD remains low until the output is in regulation for 2ms Power-Good Window Comparator with 2ms (typ) (typ). The internal soft-start limits the input surge current. Delay The MAX8794 powers the active-DDR termination bus Small, Low-Profile, 10-Pin, 3mm x 3mm TDFN that requires a tracking input reference. The MAX8794 Package can also be used in low-power chipsets and graphics Ceramic or Polymer Output Capacitors processor cores that require dynamically adjustable output voltages. The MAX8794 is available in a 10-pin, Ordering Information 3mm x 3mm, TDFN package. PIN- TOP PART TEMP RANGE Applications PACKAGE MARK Notebook/Desktop Computers 10 TDFN-EP* MAX8794ETB+ -40C to +85C ASW DDR Memory Termination (3mm x 3mm) Active Termination Buses 10 TDFN-EP* MAX8794ETB/V+ -40C to +85C ASW (3mm x 3mm) Graphics Processor Core Supplies +Denotes a lead(Pb)-free/RoHS-compliant package. Chipset/RAM Supplies as Low as 0.5V /V denotes an automotive qualified part. *EP = Exposed pad. Pin Configuration Typical Operating Circuit V IN (1.1V TO 3.6V) V = V OUT TT IN OUT TOP VIEW OUTS + REFOUT 1 10 IN V BIAS MAX8794 2 9 V OUT CC (2.7V TO 3.6V) V PGND CC 3 8 AGND PGND MAX8794 REFIN 4 7 SHDN SHDN AGND EP* 5 6 PGOOD OUTS PGOOD V DDQ TDFN (2.5V OR 1.8V) V = V REFOUT TTR 3mm x 3mm REFIN REFOUT *EXPOSED PAD. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Low-Voltage DDR Linear Regulator ABSOLUTE MAXIMUM RATINGS IN to PGND............................................................-0.3V to +4.3V Continuous Power Dissipation (T = +70C) A OUT to PGND ..............................................-0.3V to (V + 0.3V) 10-Pin 3mm x 3mm TDFN IN OUTS to AGND............................................-0.3V to (V + 0.3V) (derated 24.4mW/C above +70C)...........................1951mW IN V to AGND.........................................................-0.3V to +4.3V Operating Temperature Range CC REFIN, REFOUT, SHDN, PGOOD to AGND...-0.3V to (V + 0.3V) MAX8794ETB...................................................-40C to +85C CC PGND to AGND.....................................................-0.3V to +0.3V Junction Temperature......................................................+150C REFOUT Short Circuit to AGND .................................Continuous Storage Temperature Range .............................-65C to +150C OUT Continuous RMS Current Lead Temperature (soldering, 10s) .................................+300C 100s ................................................................................1.6A Soldering Temperature (reflow) .......................................+260C 1s....................................................................................2.5A Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = 1.8V, V = 3.3V, V = V = 1.25V, SHDN = V , circuit of Figure 1, T = -40C to +85C, unless otherwise noted. IN CC REFIN OUTS CC A Typical values are at T = +25C.) (Note 1) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS V Power input 1.1 3.6 IN Input Voltage Range V V Bias supply 2.7 3.6 CC Quiescent Supply Current (V)I Load = 0, V > 0.45V 0.7 1.3 mA CC CC REFIN SHDN = AGND, V > 0.45V 350 600 REFIN Shutdown Supply Current (V )I A CC CC(SHDN) SHDN = AGND, REFIN = AGND 50 100 Quiescent Supply Current (V)I Load = 0 0.4 10 mA IN IN Shutdown Supply Current (V)I SHDN = AGND 0.1 10 A IN IN(SHDN) T = +25C -4 0 +4 REFIN to OUTS, A Feedback-Voltage Error V mV OUTS I = 200mA OUT T = -40C to +85C -6 +6 A Load-Regulation Error -1A I +1A -15 +15 mV OUT Line-Regulation Error 1.4V V 3.3V, I = 100mA 1 mV IN OUT OUTS Input Bias Current I -1 +1 A OUTS OUTPUT Output Adjust Range 0.5 1.5 V High-side MOSFET (source) (I = 0.1A) 0.10 0.169 OUT OUT On-Resistance Low-side MOSFET (sink) (I = -0.1A) 0.10 0.20 OUT Output Current Slew Rate C = 100F, I = 0.1A to 2A 3 A/s OUT OUT OUT Power-Supply Rejection 10Hz < f < 10kHz, I = 200mA, OUT PSRR 80 dB Ratio C = 100F OUT OUT to OUTS Resistance R 12 k OUTS Discharge MOSFET On- R SHDN = AGND 8 DISCHARGE Resistance 2 MAX8794