SMB110

Preliminary Information

Summit Microelectronics, Inc

2099 2.3 3/1/2005

15

AC OPERATING CHARACTERISTICS (CONTINUED)

(Over recommended operating conditions, unless otherwise noted. All voltages are relative to GND.)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

Inverting Output Block Channel 0

HS Driver output rise time

10

ns

HS Driver output fall time

10

ns

Boost Output Block Channel 1

LS Driver output rise time

10

ns

LS Driver output fall time

10

ns

Buck Output Block Channels 2 and 3

LS Driver output rise time

10

ns

LS Driver output fall time

10

ns

HS Driver output rise time

15

ns

HS Driver output fall time

5

ns

High to low transition on HSDRV

20

Driver non-overlap delay

Low to high transition on buck HSDRV

10

ns

V

V

% n= 1,2,3,4

Ch 0 P

1 -

Channel MOSFET source voltage, L = inductance, Vd = forward diode drop (0.6V silicon, 0.3V Schottky). Lesser values may exist

source voltage, L = inductance, and Vd = forward diode drop (0.6V silicon, 0.3V Schottky. Lesser values may exist

6. The Channel 0 programmable over voltage setting is calculated from the following formula: where VREF_OUT is the voltage o the VREF_OUT pin

and R1 and R2 are the upper and lower resistors in the external voltage divider, n corresponds to the available user programmable settings

5. The Channel 0 programmable under voltage setting is calculated from the following formula: where VREF_OUT is the voltage o the VREF_OUT

pin and R1 and R2 are the upper and lower resistors in the external voltage divider, n corresponds to the available user programmable settings

V

V

% n= 1,2,3,4

Ch 0 P

1 -

2*L*Vout *(Vout - Vd)

Rmax =

2*L*Vout*(Vout - VIN + Vd)

Rmax =

1. The total current drawn when all supplies are switching will not equal the sum of the buck, boost, and inverting buck-boost channels current

consumption when switching independently. This is due to current overhead to commence sequencing.

2. Guaranteed by design.