1A high-speed LDO regulator supporting a 0.5V low input voltage New Product Leaflet XC6602/XC6603/XC6604 Series Digital Camera Smartphone Notebook PC The XC6602/XC6603/XC6604 series is capable of operation from an input voltage of 0.5V and has a low on-resistance, making these products ideal for applications that require high current output with high efficiency at a low voltage range. Each series has a soft-start function, and the XC6603 series enables the rise time of the soft-start function to be adjusted with an external capacitor. The XC6604 series has an externally adjustable current limiting circuit, enabling adjustment of the current limit using an external resistor. USP-6C, SOT-26W SOT-89-5 Low input voltage, low dropout voltage, and low output voltage are achieved with an N-channel MOS driver 1 Fig.䋱 P-ch MOS Driver LDO Fig.3 TYPICAL APPLICATION CIRCUIT VIN 3.3V 3.3V VGS + AM P - 1.2V Pch VOUT VREF CFB R1 CL R2 XC9236 Step-Down DC/DC Converter CBIAS 䋱.0㱘F VSS 1.2V 1.0V core2 SS ILIM CE VSS CIN 䋱.0㱘F core1 System LSI VBIAS XC6602 XC6603 XC6604 VIN VOUT Input I/O CSS RLIM CL 2.2㱘F 䃂Low Input Voltage 䃂Low Dropout Voltage 䃂Low Output Voltage Can be used with the XC6603 Fig.2 N-ch MOS Driver LDO VIN VBIAS + AM P - Nch VOUT VGS VREF CFB R1 CL R2 VSS Can be used with the XC6604 As shown in Fig.1, previous LDOs used a P-channel MOS transistor as a driver transistor. In this case, VGS of the driver transistor can reach as a maximum the voltage between VIN and VSS, and VGS falls as VIN falls, causing the on-resistance to grow higher as the voltage becomes lower. In addition, VIN cannot be lowered below the voltage required for the IC to operate. By contrast, when an N-channel MOS transistor is used as the driver transistor as shown in Fig.2, VGS of the driver transistor can reach as a maximum the voltage between VBIAS and VOUT. As such, VBIAS is biased from a high level such as a 3V or 5V system, and VGS grows higher as VOUT becomes lower, making operation at a low on-resistance possible. Using an N-channel MOS transistor for the driver transistor, a large current can be supplied at a low dropout voltage such as VIN=1.2V and VOUT=1.0V. (Fig.3) Features Maximum Output Current 1A (1.3A Limit) ON Resistance Bias Voltage Range 0.15㱅@VBIAS=3.6V, VOUT=1.2V 2.5V䌾6.0V Input Voltage Range Output Voltage Range 0.5V䌾3.0V 0.5V䌾1.8V (0.1V increments) Output Voltage Accuracy ±0.015V@VOUT䋼1.2V ±0.020V@VOUT҈1.2V 60dB @ 䌦 =1kHz (VBIAS) Ripple Rejection 75dB @ 䌦 =1kHz (VIN) Low Power Consumption Stand-by Current 100㱘A (VBIAS), 6.5㱘A (VIN)@VOUT=1.2V 0.01㱘A (VBIAS), 0.01㱘A (VIN) Function Soft-start (Please refer to Table. 1), CL High Speed Discharge CE Pull-Down (Active High) Packages USP-6C, SOT-26W, SOT89-5 (XC6602 only) www.torex.co.jp/english October 2011 䃂 Values shown in this sheet can be changed without any prior notice. New Product Leaflet 1A high-speed LDO regulator supporting a 0.5V low input voltage䇭XC6602/XC6603/XC6604 Series 2 XC6603 series: Soft-start can be adjusted externally Because the soft-start circuit prevents rush current from VIN to VOUT when the IC starts, voltage fluctuations in the VIN line due to rush current can be held down. In a circuit like the example shown in Fig.3, there is no concern that over-current protection will activate due to rush current in the front end IC, and the sequence can be controlled. Even with a low on-resistance, smooth power-on is achieved with no adverse effects on other ICs due to rush current. The soft-start time of the XC6602 type A and XC6604 type A is set internally to 430㱘s (TYP.). The soft-start time of the XC6603 series can be adjusted by external capacitor (CSS), enabling optimization of the soft-start time for the rush current. Fig.4 Soft-start Characteristics (XC6603 Series) CE Rise Transient Response Css=0.1nF Css=0.47nF Css=1nF 6 1200 4 VCE 2 2.5 1000 2.0 0 -2 tss [ms] 800 VOUT IIN [mA] VCE, VOUT [V] Fig.5 Soft-start Time vs. Capacitor Capacitance 600 400 IIN -4 -6 Time [100㱘s/div] 1.5 1.0 0.5 200 0.0 0.0 0 2.0 4.0 6.0 8.0 10.0 Css [nF] Test Condition:VBIAS=3.6V, VIN=1.5V, VOUT=1.2V, VCE=0V㸢3.6V(tr=5㱘s), IOUT=100mA, CBIAS=CIN=1.0㱘F, CL=10㱘F, Ta=25㷄 Table.1 Soft-start Function Selection Guide SERIES XC6602 XC6603 XC6604 TYPE A B A A B Soft-start Function Soft-start Internal Fixed Without Soft-start Soft-start External Setting* * When the SS pin is open, the soft-start circuit does not Soft-start Internal Fixed operate and operation is the same as the non soft-start Without Soft-start product. When VSS is shorted, VOUT does not rise. XC6604 series: The current limit value can be set as desired 3 When the maximum output current is exceeded and the current reaches a specific value, the current limiting circuit (foldback current limiting characteristic) of the XC6602/XC6603/XC6604 series activates and gradually reduces the current to prevent IC damage. The current limit value of each series is set internally to 1.3A (TYP.), and the XC6604 series further allows the value to be set with an external resistor (RLIM) to match the required current range. Fig.6 Current Limiting Characteristics (XC6604 Series) RLIM=0k㱅 RLIM=56k㱅 Fig.7 Current Limit Value vs. External Resistance VOUT=0.5V VOUT=1.8V RLIM=22k㱅 RLIM=120k㱅 1.4 1.0 ILIM [A] V㩷 OUT [V] 1.2 0.8 0.6 0.4 0.2 0 0.0 0.5 1.0 IOUT [A] 1.5 VOUT=1.2V 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 50 100 150 200 RLIM [k㱅] Test Condition:VBIAS=3.6V, VIN=1.5V, VOUT=1.2V, VCE=VBIAS, CBIAS=CIN=1.0㱘F, CL=2.2㱘F, Ta=25㷄 www.torex.co.jp/english/ October 2011 䃂 Values shown in this sheet can be changed without any prior notice.