TB7100F

TB7100F Toshiba BiCD Integrated Circuit Silicon Monolithic TB7100F Step-down DC-DC Converter IC The TB7100F is a single-chip step-down DC-DC converter IC. Equipped with a built-in high-speed and low on-resistance power MOSFET, and utilizing a chopper circuit, this IC can achieve a high efficiency in a wide load current range. Features • Capable of high current drive (IOUT = maximum of 700 mA), using only a few external components • High efficiency (η = 90% or higher) (@VIN = 5V, VOUT = 3.3V, and IOUT = 300 mA). • Operating voltage (VIN) range: 3 to 5.5 V • Low on-resistance (RDS(ON)): 0.27 Ω (typ.) if VIN = 5 V • High oscillation frequency of 550 kHz (typ.), making it possible to use small external components. • Uses external phase compensation, assuring a high degree of design freedom in selecting external components and determining a loop response. • Employs a current mode architecture with excellent fast load response. • A small surface mount-type ceramic capacitor can be used as an output smoothing capacitor. • Housed in a small surface-mount package (PS-8) with a low thermal resistance. SON8-P-0303-0.65A(PS-8) Weight: 0.016 g (Typ.) Pin Assignment Marking Part number COMP 1 8 FB 7100 ※ ・The dot (•) on the top surface indicates pin 1. *: Lot number RT 2 7 ENB PGND 3 6 VIN SGND 4 5 SW Due to its MOS structure, this product is sensitive to electrostatic discharge. Handle with care. 1 2004-09-10 TB7100F Block Diagram VIN (pin 6) ENB (pin 7) RT (pin 2) Reference voltage supply 1.2 V Current detection + - Oscillator Control logic Driver SW (pin 5) FB (pin 8) Temperature detection Error amplifier + Reference voltage (0.8 V) SGND (pin 4) PGND (pin 3) COMP (pin 1) Pin Descriptions Pin No. 1 2 3 4 5 6 7 8 Pin Symbol COMP RT PGND SGND SW VIN ENB FB Pin Description Pin for connecting an error amplifier phase compensation resistor and capacitor. Oscillation frequency setting pin for connecting a resistor to the internal oscillation circuit. Connecting 120 kΩ to this pin operates the oscillation circuit at 550 kHz (typ.). Power ground Signal ground Switching pin. A P-channel MOSFET is connected between the VIN and SW pins. The peak switch current corresponding to the voltage that is generated at the COMP pin flows through the power MOSFET. The rating of this peak switch current is 1.0 A (min). Input pin. This pin is placed in the standby state if VENB = low. 1 μA or lower operating current Enable pin. This pin is connected to the CMOS inverter. Applying 3.5 V or higher (@ VIN = 5 V) to this pin starts the internal circuit to perform switching control. Output voltage feedback pin. This is connected to the internal error amplifier, which is supplied with a reference voltage of 0.8 V (typ.). 2 2004-09-10 TB7100F Timing Chart OSC 0 IOUT 0 VOUT 0 VCOMP 0 The peak switch current is determined according to the VCOMP. IL 0 VSW 0 TON T Overheat state operation OSC 0 Tch increase Hysteresis: 25°C (typ.) Tch VSW Low Voltage operation VIN 0 OSC 0 VSW Hysteresis: 0.1 V (typ) 0 OSC : Internal oscillator output voltage IOUT : Load current VOUT : Output voltage VCOMP : COMP pin voltage IL : Inductor current : SW pin voltage VSW VIN : Input pin voltage Tch : Channel temperature 3 2004-09-10 TB7100F Maximum Ratings (Ta = 25°C) Characteristics Input voltage Switch pin voltage Feedback pin voltage Enable pin voltage Input-enable pin voltage Power dissipation (Note 1) Operating temperature Channel temperature Storage temperature Symbol VIN VSW VFB VENB VENB-VIN PD Topr Tch Tstg Rating -0.3～6 -0.3～6 -0.3～6 -0.3～6 VENB-VIN