Advanced Power Electronics Corp. AP1280AMP 2A SINK/SOURCE BUS TERMINATION REGULATOR FEATURES DESCRIPTIOON Ideal for DDR-I, DDR-II and DDR-III VTT Applications The AP1280AMP is a simple, cost-effective and high-speed linear regulator designed to generate termination voltage in double data rate (DDR) memory system to comply with the JEDEC SSTL_2 and SSTL_18 or other specific interfaces such as HSTL, SCSI-2 and SCSI-3 etc. devices requirements. The regulator is capable of actively sinking or sourcing up to 2A while regulating an output voltage to within 40mV. The output termination voltage cab be tightly regulated to track 1/2VDDQ by two external voltage divider resistors or the desired output voltage can be pro-grammed by externally forcing the REFEN pin voltage. The AP1280AMP also incorporates a high-speed differential amplifier to provide ultra-fast response in line/load transient. Other features include extremely low initial offset voltage, excellent load regulation, current limiting in bi-directions and on-chip thermal shut-down protection.Built-in softstart function avoids a misoperation by inrush current. The AP1280AMP are available in the ESOP-8 (Exposed Pad) surface mount packages. Sink and Source up to 2Amp Integrated Power MOSFETs Generates Termination Voltage for SSTL_2, SSTL_18, HSTL, SCSI-2 and SCSI-3 Interfaces. High Accuracy Output Voltage at Full-Load Output Adjustment by Two External Resistors Built-in Soft-start Function Shutdown for Suspend to RAM (STR) Functionality with High-Impedance Output Current Limiting Protection On-Chip Thermal Protection Available in ESOP-8 (Exposed Pad) Packages VIN and VCNTL Under Voltage Protection RoHS Compliant and Halogen Free APPLICATION Desktop PCs, Notebooks, and Workstations Graphics Card Memory Termination Set Top Boxes, Digital TVs, Printers Embedded Systems Active Termination Buses DDR-I, DDR-II and DDR-III Memory Systems TYPICAL APPLICATION VIN VCNTL VIN CIN VCNTL R1 CCNTL AP1280AMP RTT VOUT REFEN Shutdown R2 CSS GND VOUT COUT RDUMMY Enable R1 = R2 = 100 KΩ , RTT = 50Ω / 33Ω / 25Ω COUT = 10uF ( + 100 uF under the worst case testing condition ) CSS = 1uF , CIN = 470 uF (Low ESR) , CCNTL = 47uF Data and specifications subject to change without notice 1 20130617V4.2 Advanced Power Electronics Corp. AP1280AMP ABSOLUTE MAXIMUM RATINGS(Note1) Input Voltage (VIN) ------------------------------------------ 6V CNTL Pin Voltage (VCNTL) -------------------------------- 6V Power Dissipation (PD) ------------------------------------ Internally Limited Storage Temperature Range (T ST) --------------------- -65 to +150°C Lead Temperature (Soldering, 10sec.) --------------Thermal Resistance from Junction to Case (R thjc) 260°C 28°C/W Note1 : Exceeding the absolute maximum rating may damage the device. OPERATING RATING(Note2) Input Voltage (VIN) ------------------------------------------ 2.5V to 1.1V +3% CNTL Pin Voltage (VCNTL) -------------------------------- 5.5V or 3.3V +5% Junction Temperature Range (T J) --------------------- -40 to +125°C Ambient Temperature Range (T A) --------------------- -40 to +85°C Note2 : The device is not guaranteed to function outside its operating conditions. ORDERING / PACKAGE INFORMATION ( Top View ) AP1280 AX Package Type VIN 1 8 GND 2 7 NC REFEN 3 VOUT 4 GND MP : ESOP-8 NC 6 VCNTL 5 NC ESOP-8 Rthja = 75oC/W ELECTRICAL SPECIFICATIONS (VIN=1.8V, VCNTL=3.3V, VREFEN=0.9V, COUT=10uF(Ceramic), T A =25oC, unless otherwise specified) Parameter SYM TEST CONDITION MIN TYP MAX UNITS Input VCNTL Operation Current ICNTL IOUT = 0A - 1 2.5 mA Standby Current ISTBY VREFEN= 0V (Shutdown) - 2 5 uA IVIN VREFEN= 0V (Shutdown) - - 5 uA 2.4 2.55 2.7 V - 0.35 - V 0.8 0.95 1.1 V - 0.15 - V IOUT = 10mA -20 - 20 VIN Shutdown Current UVP Function VCNTL UVP Rising Threshold VCOP VCNTL UVP Hysteresis VCHYS VIN UVP Rising Threshold VIOP VIN UVP Hysteresis VIHYS VCNTL Rising VIOP Rising Output (DDR / DDRII / DDRIII) Output Offset Voltage(Note3) Load Regulation (Note4) ΔVOS ΔVLoad IOUT = -10mA -20 - 20 VIN=1.8V, VREFEN=0.9V, IOUT=+10mA ~ +2A -20 - 20 VIN=1.5V, VREFEN=0.75V, IOUT=+10mA ~ +2A -20 - 20 VIN=1.2V, VREFEN=0.6V, IOUT=+10mA ~ +2A -20 - 20 VIN=1.1V, VREFEN=0.55V, IOUT=+10mA ~ +1.8A -20 - 20 mV 2 Advanced Power Electronics Corp. AP1280AMP ELECTRICAL SPECIFICATIONS (CONTINUED) Parameter Protection SYM TEST CONDITION MIN TYP MAX UNITS A Current Limit ILIM 2.2 - - Thermal Shutdown Temperature TSD 3.3V < VCNTL < 5V - 150 - ΔTSD 3.3V < VCNTL < 5V - 20 - 0.15 - 0.4 V - 0.8 - ms Thermal Shutdown Hysteresis o C ENABLE and Soft-Start REFEN Threshold VEN Soft-Start Interval TSS ∆VOUT=1V Note3. VOS offset is the voltage measurement defined as V OUT subtracted from VREFEN. Note4. Regulation is measured at constant junction temperature by using a 1ms(on) / 9ms(off) current pulse. Devices are tested for load regulation in the load range from 10mA to 2A for source and -10mA to -2A for sink capability. PIN DESCRIPTIONS PIN SYMBOL VIN PIN DESCRIPTION Power Input Voltage. GND Ground Pin VOUT Output Voltage VCNTL Gate Drive Voltage REFEN Reference Voltage Input and Chip Enable BLOCK DIAGRAM VCNTL UVP Function VIN OTP Function ENABLE FUNCTION REFEN Soft-Start Function OCP Function GATE CONTROL LOGIC ERROR AMPLIFIER VOUT GND 3 Advanced Power Electronics Corp. AP1280AMP APPLICATION INFORMATION Input Capacitor and Layout Consideration Place the input bypass capacitor as close as possible to the AP1280AMP. A low ESR capacitor larger than 470uF is recommended for the input capacitor. Use short and wide traces to minimize parasitic resistance and inductance. Inappropriate layout may result in large parasitic inductance and cause undesired oscillation between AP1280AMP and the preceding powe converter. Consideration while designs the resistance of voltage divider Make sure the sinking current capability of pull-down NMOS if the lower resistance was chosen so that the voltage on VREFEN is below 0.15V. In addition, the capacitor and voltage divider form the lowpass filter. There are two reasons doing this design; one is for output voltage softstart while another is for noise immunity. Thermal Consideration AP1280AMP regulators have internal thermal limiting circuitry designed to protect the device during overload conditions.For continued operation, do not exceed maximum operation junction temperature 125oC. The power dissipation definition in device is: PD = (VIN - VOUT) x IOUT + VIN x IQ The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula: PD(MAX) = ( TJ(MAX) -TA ) / Rthja Where TJ(MAX) is the maximum operation junction temperature 125oC, TA is the ambient temperature and the Rthja is the junction to ambient thermal resistance. The junction to ambient thermal resistance (Rthja is layout dependent) for ESOP-8 package (Exposed Pad) is 75oC/W on standard JEDEC 51-7 (4 layers, 2S2P) thermal test board. The maximum power dissipation at TA = 25oC can be calculated by following formula: PD(MAX) = (125oC - 25oC) / 75oC/W = 1.33W The thermal resistance Rthja of ESOP-8 (Exposed Pad) is determined by the package design and the PCB design. However, the package design has been decided. If possible, it's useful to increase thermal performance by the PCB design. The thermal resistance can be decreased by adding copper under the expose pad of ESOP-8 package. We have to consider the copper couldn't stretch infinitely and avoid the tin overflow 4 Advanced Power Electronics Corp. AP1280AMP MARKING INFORMATION ESOP-8 Part Number Package Code 1280AMP YWWSSS Date Code (YWWSSS) Y：Last Digit Of The Year WW：Week SSS：Sequence 5