SMM605
Preliminary Information
APPLICATIONS INFORMATION (CONTINUED)
The SMM605 and the DC-DC Converter
VDD (+2.7V to +5.5V)
+12VIN (+6V to +14V)
Can Operate with either 12V or VDD
If 12V is used, VDD can be left floating
If VDD is used, 12V can be left floating
J2
Supply
C8
If the SMM605 internal VREF
is used, the VREF_CNTL pin
becomes an output
0.1uF
C3
C2
C4
C7
J1
Vdd
U4
5
0.01uF
0.01uF
0.1uF
0.1uF
LM4121
4
3
VOut
Ref
VIn
EN
Ext VRef
R4 10K
1
10K
R3
C6
0.1uF
R2 10K
U1
R1 10K
C6 1uF
START
READY
4
7
START
READY
TRIM_CAPX
TRIMX
VOUT
VMX
U2
DC-DC Converter
1
D1
SMM605
2
1
7
8
SCL
SDA
+Vin
+Vin
+Vout
2
DIODE
15
FILT_CAP
+Vout
4
11
9
Enable
+Vin
+Vout
Sense
3
SMX3200 I2C
Programming
Connector 10
pin Header
3
A2
10
Trim
C5
0.02uF
0.1uF
C1
1
3
5
7
9
2
Gnd
SCL
SDA
MR
4
Gnd3
Rsrv5
DC-DC ENABLE
6
8
+10V Rsrv8
+5V Rsrv10
10
J1
Figure 7 – SMM605 Applications schematic. The accuracy of the external (U4) or internal reference sets the
accuracy of the ADOC function. Total accuracy with a ±0.1% external reference is ±0.2% and ±0.5% with the
internal reference. The 12V supply can go as low as 6V if the internal regulator is set to 3.6V.
Summit Microelectronics, Inc
2064 1.1 09/16/03
11
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
