XC9290/91

THE WORLDS SMALLEST 600mA BUCK DC/DC CONVERTER

 

XC9290/91 6.0V 600mA Step-Down Sychronous DC/DC Converter with HiSAT-COT control

The XC9290/91 is an ultra-small synchronous step-down DC/DC which can operate from 2.5V to 6.0V and deliver loads up to 600mA. HiSAT-COT control ensures ultra-fast load transient response performance whilst maintaining a stable switching frequency.  Two versions are available, with switching frequencies of either 4.0MHz or 6.0MHz.

 

 

Series XC9290 XC9291
Output Current 600mA
ON
Resistance
P-Ch 0.26Ω (typ)
N-Ch 0.32Ω (typ)
Input Voltage Range 2.5V ~ 6.0V
Output Voltage Range 0.7V ~ 3.6V
Switching Frequency 4.0MHz or 6.0MHz
Quiescent Current (typ.) 700μA 11μA
  PWM PWM/PFM
Max Duty Cycle 100%
Protection Circuits Current Limit
UVLO
Additional Features Soft-start
Optional CL Discharge
Package LGA-6B01 or WLP-5-08

 

TYPICAL APPLICATION CIRCUIT

 

EFFICIENCY vs. OUTPUT CURRENT

 

LOW OUTPUT RIPPLE

 

STABLE SWITCHING FREQUENCY

 

LOAD TRANSIENT RESPONSE

 

Utilising HiSAT-COT, Torex’s Constant ON Time architecture ensures extremely fast load transient response performance when compared with standard DC/DC solutions.

HiSAT-COT also provides less fluctuation in oscillation frequency against load and input voltage when compared to traditional COT control architectures.

IOUT = 1mA ⇔ 300mA (tr, tf = 5μs)
L = 0.47μH(LSCNB1005EETR47MB) 
CIN = 4.7μF(GRM035R60J475ME15)
CL = 4.7μF(C1005X5R0J475K)

 

LOW ELECTROMAGNETIC INTERFERENCE (EMI) 

 

The PCB area and subsequently the length of copper tracks is minimised due to the use of ultra-small packaging and smaller external components.

This results in extremely low radiated noise and excellent EMI performance as illustrated in the graph.

The XC9290/91 passes EN55032 (CISPR 32) CLASS B with good margin.

 

ANY OUTPUT CAPACITOR

 

As shown in the graph, the CL capacitance value will reduce to 2μF at 1.8V and this will further decrease at higher temperatures.

The XC9290/91 is designed to operate with lower capacitance values which will occur under DC bias conditions.

As a result, designers can safely use smaller, lower cost, 0603 sized (0.6 x 0.3 x 0.5mm) multilayer capacitors without sacrificing performance.