Data Brief
For further information contact your local STMicroelectronics sales office.
November 2008 Rev 1 1/4
4
STEVAL-ISA050V1
Monolithic VR for chipset and DDR2/3 demonstration board
based on the PM6641
Features
■ Switching section
– 0.8 V ±1% voltage reference
– 2.7 V to 5.5 V input voltage range
– Fast response, constant frequency, current
mode control
– Three independent, adjustable, SMPS For
DDR2/3 (VDDQ) and chipset supply
– S3-S5 states compliant DDR2/3 section
– Active soft-end for all outputs
– Selectable tracking discharge for VDDQ
– Separate Power Good signals
– Pulse skipping at light load
– Programmable current limit and soft-start
for all outputs
– Latched OVP, UVP protection
– Thermal protection
■ Reference and termination voltages (VTTREF
and VTT)
– ±2 Apk LDO for DDR2/3 termination (VTT)
with fold back
– Remote VTT output sensing
– High-Z VTT output in S3
– ±15 mA low noise DDR2/3 buffered
reference (VTTREF)
Application
■ Supply for ultra-mobile PC (UMPC)
Description
The STEVAL-ISA050V1 demonstration board is
based on the PM6641, that is a monolithic voltage
regulator module, with internal Power MOSFET,
specifically designed to supply DDR2/3 memory
and chipset in ultra-mobile PC and real estate
portable systems. It integrates three independent,
adjustable, constant frequency buck converters, a
±2 Apk low drop-out (LDO) linear regulator and a
±15 mA low noise buffered reference. Each
regulator is provided of basic under voltage (UV)
and over voltage (OV) protections, programmable
soft-start and current limit, active soft-end and
pulse-skipping at light loads.
STEVAL-ISA050V1
www.st.com
Circuit schematic STEVAL-ISA050V1
2/4
1 Circuit schematic
Figure 1. Schematic
C26
060
3-100p
C4
08
05-10u
C16
06
03-100n
C27
06
03-100p
R10
0603-
180k
TP8
GND
1
R20
0603-
68k
TP6
AGND
1
C28
06
03-10
0p
R2
06
03-4
R3
VIN
TP16
AGND
1
C18
0603
-33
n
VCC
TP15
LDOIN
1
C30
0603
-100
p
VCC
AV
CC
C19
06
03-22n
C7
B Case - 220u
TP4
PG_1
S05
1
C31
0603-1
00p
+
C13
EL SMD C-10
u
12
R33
0603
-join
AVCC
TP12
VOUT_1S05
1
C2
08
05-1
0u
AV
CC
R12
0603-
47k
R3
0603
-100
k
TP14
VTT
1
R4
0603
-68
k
C6
B Case - 220
u
C17
0603-1
00n
TP5
VCC
1
R11
0603
-100
k
+
C5
EL SMD C-10u
12
C21
0603
-22
n
R17
0603-
68k
C25
0603
-100
p
TP1
VTTREF
1
C32
0603
-15
p
JP1
STRIP 3
1 3
2
R31
0603-joi
n
C11
1206
-22
u
1
2
TP13
GND
1
JP3
STRIP 3
1 3
2
R34
06
03-joi
n
U1
PM66
41_Q
FPN
AGND_1
1
SE
T_SWF
2
VOUT_1S8
3
CSNS
4
SGND_1S8_1
5
SGND_1S8_2
6
VS
W_1S8_1
7
VS
W_1S8_2
8
VIN_1S8_1
9
VIN_1S8_2
10
VFB_1S8
11
COMP_1S8
12
SS_1S8
13
SS_1S05
14
COMP_1S05
15
VFB_1
S05
16
SGND
_1
S05_1
17
VSW_1S05_1
19
VSW_1S05_2
20
VIN_1
S05_2
22
PG_1
S05
23
PG_1
S8
24
EN_VTT
36
EN_1
S5
35
EN_1
S05
34
VIN_1
S5
33
VS
W_1
S5_2
32
VS
W_1
S5_1
31
SGND_1
S5_
2
30
SGND_1
S5_
1
29
VFB_1
S5
28
COMP_1
S5
27
SS_1
S5
26
PG_1
S5
25
SGND
_1
S05_2
18
VIN_1
S05_1
21
VCC
48
VTT_FB
47
DSCG
46
VTTREF
45
LDO_IN
44
VTT
43
VTT_GND
42
AVCC
41
AGND
_2
40
SE
T_PH1
39
AGND
_3
38
EN_1S8
37
THERMAL
49
AVCC
L2
2839
-1u
5
1 2
C23
0603-
470p
L3
283
9-1u
1 2
R19
060
3-68k
+
C8
EL SMD C-10u
12
TP18
AUX
1
C33
0603
-15
p
C12
0805
-10
u
TP2
PG_1S8
1
AV
CC
TP7
VIN
1
C15
B Case - 220u
C22
0603
-330
p
C20
060
3-22n
C1
0603
-1u
JP4
STRIP 3
1 3
2
L1
2839-
1u
1
2
R5
060
3-15
0k
JP5
STRIP 3
1 3
2
R7
0603
-100
k
R8
0603
-120
k
R32
06
03-joi
n
+
C14
EL SMD C-10u
1
2
AVCC
TP10
VOUT_1S5
1
TP3
PG_1S5
1
C34
06
03-1
5p
AUX
AUX
TP9
VOUT_1
S8
1
R21
0603
-68
k
R6
060
3-12
0k
R22
0603
-68
k
JP7
STRIP 2
1
2
R30
0603
-joi
n
R13
0603-
68k
AUX
TP17
GND
1
C3
0805
-10
u
R23
0603
-68
k
JP8
STRIP 2
1
2
SW1
SW DIP-4
1
2
3
4 5
6
7
8
VIN
C24
0603-
330p
C9
B Case - 220u
R18
060
3-68k
C10
B Case - 220
u
R1
06
03-4
R3
TP11
GND
1
VIN
C29
06
03-10
0p
JP6
STRIP 3
1 3
2
R9
0603-
56k
AM03286v1