SMM105
Preliminary Information
APPLICATIONS INFORMATION (CONTINUED)
VDD (+2.7V to +5.5V)
The SMM105 and the DC-DC Converter
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
+12VIN (+10V to +15V)
C8
0.1uF
Vdd
D1
If the SMM105 internal VREF
is used, the VREF_CNTL pin
becomes an output
DIODE
C3
C2
0.1uF
C4
C7
0.01uF
0.01uF
0.1uF
J1
Vdd
U4
5
LM4121
4
3
VOut
VIn
Ext VRef
1
Ref
EN
C6
0.1uF
R8
R9
10K
10K
U1
C1 1uF
START
READY
FAULT#
3
5
18
START
READY
FAULT#
TRIM_CAP
TRIM
20
14
19
12
VOUT
11
VM
COMP1
U2
DC-DC Converter
1
SMM105 COMP2
C9
C10
0.01uF
1
28
6
7
8
RT2
~10K
SCL
SDA
A0
+Vin
+Vin
+Vout
2
10
8
FILT_CAP
+Vout
4
11
9
Enable
+Vin
+Vout
Sense
4
3
t t
A1
WP#
2
A2
10
Trim
C5
0.02uF
R1
10K
R2
10K
J1
1
DC-DC ENABLE
2
Gnd
3
SCL
4
Gnd3
5
SDA
MR
6
Rsrv5
7
8
+10V Rsrv8
+5V Rsrv10
9
10
SMX3200 I2C Programming
Connector 10 pin Header
Figure 6 – SMM105 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 8V if the internal regulator is set to 3.6V.
Summit Microelectronics, Inc
2068 1.8 09/20/05
10
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
