MIC2184 Micrel, Inc. MIC2184 Low Voltage Buck PWM Control IC General Description Features Micrels MIC2184 is a high efficiency PWM buck control IC. Input voltage range: 2.9V to 14V With its wide input voltage range of 2.9V to 14V, the MIC2184 >90% efficiency can be used to efficiently step voltages down in 1- or 2-cell Li Oscillator frequency of 400kHz Ion battery powered applications, as well as in fixed 3.3V, 5V, Frequency divide-by-two pin or 12V systems. Frequency sync to 600kHz FrequOut oscillator output allows simple charge pump Efficiencies over 90% are achievable over a wide range of implementation in low voltage systems load conditions with the MIC2184s PWM control scheme. 1.245V reference output The operating frequency can be divided by two by raising the Front edge blanking FREQ/2 pin to V . This allows the user to optimize efficiency DD 5 output driver versus board space. It also allows the MIC2184 to be exter- Soft start nally synchronized to frequencies below its nominal 400KHz. PWM current mode control The MIC2184 features an oscillator output, FreqOut, which 1A shutdown current can be used to implement a simple charge pump in low Cycle-by-cycle current limiting voltage applications. The output of the charge pump can be Frequency foldback short circuit protection fed into the gate drive power circuitry via the V P pin, IN Adjustable under-voltage lockout allowing enhanced gate drive, hence higher efficiencies, 16 pin narrow-body SOIC and QSOP package options despite low input voltages. Applications MIC2184 features a 1A shutdown mode, and a program- mable undervoltage lockout, making it well suited for portable 3.3V to 2.5V/1.8V/1.5V conversion applications. DC power distribution systems Wireless Modems The MIC2184 is available in 16 pin SOP and QSOP package ADSL line cards options with a junction temperture range range from 40C 1-and 2-cell Li Ion battery operated equipment to +125C. Satellite Phones Typical Application V = 3.3V IN 16 15m 120F (x2) MIC2184 EFFICIENCY VINP 6.3V 100 1 9 VINA CSH 95 7 8 90 EN/UVLO CSL 2 14 85 FreqOut OUTP Q3 80 V OUT Si9803DY(x2) 16 2.5V 5A FREQ/2 75 MIC2184 10 4.7H 70 VDD V = 3.3V IN 65 4 COMP V = 2.5V 60 OUT 3 12 220F(x2) f = 200kHz 55 SS PGND S 6.3V 13 6 50 VREF 012345 FB OUTPUT CURRENT (A) SYNC SGND 11 5 Adjustable Output Buck Converter Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC2184 Micrel, Inc. Ordering Information Part Number Output Junction Standard Pb-Free Voltage Frequency Temp. Range Package MIC2184BM MIC2184YM Adj. 400KHz 40C to +125C 16-lead SOP MIC2184BQS MIC2184YQS Adj. 400KHz 40C to +125C 16-lead QSOP Pin Configuration VINA 1 16 VINP FreqOut 2 15 FREQ/2 SS 3 14 OUTP COMP 4 13 VREF SGND 5 12 PGND FB 6 11 SYNC EN/UVLO 7 10 VDD CSL 8 9 CSH 16 Lead SOIC (M) M9999-042205 2 April 2005