ST8R00PUR

ST8R00 Micropower 1 A synchronous step-up DC-DC converter Features ■ Output voltage adjustable from 6 V to 12 V ■ Output voltage accuracy: ± 2% ■ Output current up to 1 A ■ Low ripple voltage: 5 mV (typ.) ■ Synchronous rectification ■ High 90% efficiency: VO = 9 V (typ.) ■ Few external components ■ Thermal shutdown protection ■ Very small DFN8 (4 x 4 mm) package DFN8 4 x 4 mm Description The ST8R00 is a synchronous PWM step-up DCDC converter. The device is able to provide an output voltage in the range of 6 to 12 V with an input voltage from 4 to 6 V. The high switching frequency (1.7 MHz) permits the use of tiny surface-mount components. In addition to the resistor divider to set the output voltage value, only an inductor and two capacitors are required. Moreover, a low output ripple is guaranteed by the current mode PWM topology and by the use of low ESR SMD ceramic capacitors. The device is available in a very small DFN8 (4 x 4 mm) package. Table 1. Device summary Part number Order code Output voltage ST8R00 ST8R00WPUR ADJ February 2012 Doc ID 13449 Rev 2 1/18 www.st.com 18 Contents ST8R00 Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2/18 Doc ID 13449 Rev 2 ST8R00 1 Block diagram Block diagram Figure 1. Schematic diagram LX Thermal OUT INH Inhibit PGND PWM Control FB IN VREF PGND Doc ID 13449 Rev 2 GND 3/18 Pin configuration 2 4/18 ST8R00 Pin configuration Figure 2. Pin connections (top view) Table 2. Pin description Pin n° Symbol Name and function 1 LX 2 PGND Power ground 3 GND Analog ground 4 IN Power input for analog circuit 5 FB Feedback 6 INH Inhibit. Connecting the pin to a voltage higher than 2 V = device ON. Connecting the pin to a voltage lower than 0.8 V = device OFF, resulting in no current flow to the load 7 HV Trimming (floating or connected to GND) 8 OUT Output voltage EXP pad GND Exposed pad. Must be connected to GND Switching output Doc ID 13449 Rev 2 ST8R00 3 Typical application circuit Typical application circuit Figure 3. Application circuit VI L=4.7µH IN VO LX OUT INH R1 ST8R00 CI=10µF GND PGND Doc ID 13449 Rev 2 FB R2 CO=10µF 5/18 Maximum ratings ST8R00 4 Maximum ratings Table 3. Absolute maximum ratings Symbol Parameter Unit VO Output voltage 16 V VI Input voltage 6 V VINH Inhibit voltage 6 V VLX LX pin voltage 16 V ILX LX pin output current Internally limited TSTG Storage temperature range -50 to 150 °C TOP Operating junction temperature range -25 to 125 °C Value Unit Table 4. Thermal Data Symbol Parameter RthJC Thermal resistance junction-case 10 °C/W RthJA Thermal resistance junction-ambient 50 °C/W Table 5. Symbol 6/18 Value ESD Performance Parameter Test conditions Value Unit ESD ESD protection voltage HBM 4 KV ESD ESD protection voltage MM 500 V Doc ID 13449 Rev 2 ST8R00 5 Electrical characteristics Electrical characteristics VI = 5 V, VINH = 2 V, IO = 100 mA, TJ = - 25 °C to 125 °C, CI = CO = 10 µF(X7R), L = 4.7 µH unless otherwise specified. Table 6. Electrical characteristics Symbol VO Parameter Output voltage VSTART-UP Start-up voltage VI Test conditions (1) Min. Typ. 6 IO = 400mA, VI rising Input voltage range 3 4 VFB Feedback voltage IO = 50mA VFB_OFF Feedback voltage IO = 0, VINH = 0 IFB Feedback current Supply current 1.195 1.22 Max. Unit 12 V 3.5 V 6 V 1.245 V 0 V VFB = 0, VINH = 2V 600 nA To be measured at VI, VO = 7V, no load 10 mA RDSON_N Internal N channel RDSON ILX = 400mA 300 RDSON_P Internal P channel RDSON ILX = 400mA 300 ISUPPLY mΩ ILX(leak) Internal leakage current VLX = 4V, VFB = 2V, VINH = 0 ILX(LIM) LX current limitation VLX = 4V fOSC Oscillator frequency To be measured on LX pin DTY Max. oscillator duty cycle To be measured on LX pin 90 IO = 50mA, VO = 7V 85 IO = 500mA, VO = 9V 90 IO = 1A, VO = 9V 90 Eff Efficiency VINH_H Inhibit threshold high VINH_L Inhibit threshold low VI = 4 to 6V, IO = 50mA Inhibit pin current VINH = VI = 5V IINH TSHDN THYS 0.5 3 0.8 1.2 µA A 1.4 MHz % % 2 V Thermal shut down (2) 0.8 2 130 Thermal shut down hysteresis (2) µA 150 °C 15 °C ΔVO/ΔVI Line transient response VI from 4 to 5.5V, IO= 500mA (2) -5 5 %VO ΔVO/ΔIO Load transient response VI = 5V, IO from 10mA to 500mA, VO = 7V (2) -5 5 %VO ΔVO/ΔVI Start-up transient VI from 0 to 5V, IO = 500mA -10 10 %VO TSTART Start-up time VINH from 0 to 5V, IO = 100mA 500 µs 1. For VO higher than 9 V the maximum output current capability is reduced according to LX current limitation 2. Guaranteed by design Doc ID 13449 Rev 2 7/18 Typical characteristics ST8R00 Typical characteristics Figure 4. L = 4.7 µH, CI = CO = 10 µF. Voltage feedback vs. temperature Figure 5. Feedback current vs. temperature 700 1.3 1.28 1.26 1.24 1.22 1.2 1.18 1.16 1.14 1.12 1.1 VI=5V, VINH=2V, No Inductor, No Bridge 600 500 IFB [nA] VFB [mV] 6 400 300 200 100 VI=VINH=5V, IO=50mA 0 -100 -75 -50 -25 0 25 50 75 -75 100 125 150 175 -50 -25 0 25 Supply current vs. temperature (VI = VINH = 5 V) 20 VI=VINH=5V, No Load 18 16 14 12 10 8 6 4 2 0 -75 -50 -25 0 25 50 Figure 7. @VO=7V 15 10 5 VI=5,VINH=2V,No Load, VO@ 7V 0 -75 75 -50 -25 0 25 100 125 150 175 Supply current vs. temperature (VFB = 2 V) Figure 9. 750 ILX [A] I SUPPLY [ µA ] 700 650 600 550 VI = VINH = 5 V, VFB = 2 V 450 No resistors bridge and inductor directly to VI 400 - 75 - 50 - 25 0 25 50 75 100 125 150 175 75 100 125 150 175 LX current limitation vs. temperature 4 3.5 3 2.5 2 1.5 1 0.5 0 VIN=VINH=5V, @VO