SMM605
Preliminary Information
APPLICATIONS INFORMATION (CONTINUED)
+12VIN(+6V to 14V)
VTRIMlow=0.3V, VOSENSE=0.8V
The current through R3 is
ITRIM=(0.8-0.3)/RTRIM
C3
0.1uF
(ITRIM)(R4) > 15% of VOUT
RTRIMmax should be no greater
then the calculated value
C4
C5
For Example, If Vout=3.3V, R4=63.4K
15% of Vout=0.5V
0.1uF
0.01uF
C1 should be as close
to the SMM105 as
ITRIM=8uA
R5 10K
R4 10K
RTRIM=62.5K so Rtrim should be
next value down from 62.5K
possible
U1
C1 1uF
START
READY
4
7
R3 RTRIM
START
READY
TRIM_CAPX
TRIMX
VOUT
VMX
LT3707 Switching Regulator
R4
RSET1
R2 10K
SMM605
2
1
SCL
SDA
+Vin
+Vout
15
FILT_CAP
R1 10K
3
A2
PGOOD
D1
VOSENSE
C2
0.02uF
DIODE
R5
U2
20k
C6
START
0.01uF
J1
1
3
5
7
9
2
Gnd
SCL
4
Gnd3
Rsrv5
SDA
MR
6
8
+10V Rsrv8
+5V Rsrv10
10
The SMM605 START pin must be inactive during power-up so
that the TRIM pin is high impedence. Once power is nominal,
the START pin can be active to start margin and ADOC
functions
SMX3200 I2C Programming
Connector 10 pin Header
R1 and R2 need only be
placed once on the I2C bus
Figure 8 – SMM605 Applications schematic for an adjustable switching regulator (Full regulator circuit not
shown).
Summit Microelectronics, Inc
2064 1.1 09/16/03
12
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
