ST ISA053V1 User Manual
STEVAL-ISA053V1
Demonstration board for the PM6680 dual step-down controller
with adjustable output voltage for notebook power system
Features
■ Constant on-time control allows very fast load
transients
■ 6 V to 28 V input voltage range
■ 5 V auxiliary output voltage
■ Accurate current limit with sense resistor
■ Adjustable switching outputs
■ Lossless current sensing
■ Negative current limit
■ Soft-start internally fixed at 2.8 ms
■ Soft-end for output discharge
■ 200 kHz / 300 kHz, 300 kHz / 400 kHz, 400 kHz
/ 500 kHz (5 V / 3 V selectable switching
frequency)
■ Selectable pulse skip and no-audible skip
modes at light loads
■ Independent Power Good signals
STEVAL-ISA053V1
Data Brief
Description
The PM6680 is a dual step-down controller with
adjustable output voltages for notebook computer
power systems. The STEVAL-ISA053V1
demonstration board is designed to test the
performance of the PM6680 by employing a
typical application circuit which allows testing of
all PM6680 device functions. The board features
two switching sections, with (typically) 1.5 V and
1.05 V outputs, from a 6 V to 28 V input battery
voltage. The operating switching frequency of the
two switching sections is 200 kHz / 300 kHz,
respectively. Each switching section delivers more
than 5 A of output current. Moreover, an internal
linear regulator can provide 5 V @ 100 mA peak
current.
September 2008 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
www.st.com
4
Circuit schematic STEVAL-ISA053V1
LDO_FB
BOOT2
BOOT1
BOOT2
BOOT1
FB1
FB1
LDO_FB
PGND
PGND
VIN
V5SW
OUT5V
OUT5V
SGND
V+
V+
VIN
SGND
SGND
V+
SGND
SGND
SGND
SGND
SGND
PGND
PGND
SGND
V+
V+
V+
SGND
SGND
SGND
PGND
PGND
VIN
SGND
OUT5V
V5SW
PGND
SGND
SGND
PGND
PGND
PGND
SGND
SGND
SGND
V+
SGND
SGND
SGND
SGND
SGND
LIKE 4-PIN JUMPER
A - S12 CLOSED
B - S14 CLOSED
C - S12.1 TO S14.2
M1
MOSFET-N-SO8
M1
MOSFET-N-SO8
C9
100n
C9
100n
C17
NM
C17
NM
J3
LDO5V+
J3
LDO5V+
C27
1uF
C27
1uF
J10
PGND
J10
PGND
500R
500R
3V3L1L1
3V3
C4
15u
C4
15u
R251K1K
R251K1K
D2
SMA
D2
SMA
R1
100K
R1
100K
R6
NM
R6
NM
J9
OUT2-
J9
OUT2-
C19
100n
C19
100n
C12
330uF
C12
330uF
C13
NM
C13
NM
C24
100n
C24
100n
M2
MOSFET-N-SO8
M2
MOSFET-N-SO8
C20
1uF
C20
1uF
J6
PGOOD1
J6
PGOOD1
R31
R31
C5
100n
C5
100n
CIN
NM
CIN
NM
C22
220nF
C22
220nF
R27
R27
R4
NM
R4
NM
C3
15u
C3
15u
R29
R29
C15
150pF
C15
150pF
C8
NM
C8
NM
R32
R32
R10
10R
R10
10R
15uC1C1
15u
PGOOD2J7J7
PGOOD2
R33
R33
CREF
100n
CREF
100n
L2
5V
L2
5V
S1
JP2SO
S1
JP2SO
S10
JP4I
S10
JP4I
C26
4u7
C26
4u7
R24
1K
R24
1K
R16
100K
R16
100K
C6
100n
C6
100n
R9
47R
R9
47R
J4
OUT1+
J4
OUT1+
JP3SO
JP3SO
R17
560K
R17
560K
C25
100n
C25
100n
15uC2C2
15u
C16
100pF
C16
100pF
R14
100K
R14
100K
C10
100n
C10
100n
C21
4u7
C21
4u7
RLD5V
100K
RLD5V
100K
D3
SMA
D3
SMA
R28
R28
R30
R30
C14
NM
C14
NM
D1
BAT54A/SOT
D1
BAT54A/SOT
R8
500R
R8
500R
C11
330uF
C11
330uF
S11
JP4I
S11
JP4I
-VINJ2J2
-VIN
R11
10R
R11
10R
M4
MOSFET-N-SO8
M4
MOSFET-N-SO8
R20
0R
R20
0R
S4
JP2SO
S4
JP2SO
J8
OUT1-
J8
OUT1-
R3
NM
R3
NM
S3
JP4I
S3
JP4I
R22
0R
R22
0R
S1
JP2SO
S1
JP2SO
R26
3R9
R26
3R9
R18
560K
R18
560K
S9
JP3SO
S9
JP3SO
C18
NM
C18
NM
M3
MOSFET-N-SO8
M3
MOSFET-N-SO8
J11
EXT5V
J11
EXT5V
C7
NM
C7
NM
+VINJ5J5
+VIN
S5
JP2SO
S5
JP2SO
LDO_ADJ
LDO_ADJ
C28
4u7
C28
4u7
JP3SOS8S8
JP3SO
R23
0R
R23
0R
R19
560K
R19
560K
U1
PM6681_VFQFPN32
U1
PM6681_VFQFPN32
BOOT1
23
HGATE1
22
PHASE1
21
CSENSE1
20
V5SW
17
OUT1
29
COMP1
30
LDO_FB
16
LGATE1
15
PGOOD1
26
PGOOD2
27
SHDN
SKI
FSE
LDO
BOOT2
HGATE2
10
PHASE2
11
CSENSE2
12
PGND
14
SGND
OUT2
COMP2
FB2
FB1
28
LDO
LGATE2
13
C23
10pF
C23
10pF
R5
NM
R5
NM
R15
100K
R15
100K
R2
0R
R2
0R
S2
SWDIP-4
S2
SWDIP-4
J1
OUT2+
J1
OUT2+
R1
100K
R1
100K
1 Circuit schematic
Figure 1. Schematic diagram
J10
OUT2+
OUT2+
J1
J1
1
3
VIN
VCC
S4
S4
NM
NM
NM
NM
M1
M1
100n
100n
C5
C5
LDO
R22
R22
100n
100n
M2
M2
NM
NM
NM
NM
S5
S5
OUT5V
JP2SO
JP2SO
L1L13V3
MOSFET-N-SO8
MOSFET-N-SO8
4
R20
R20
9
BOOT2
BOOT1
23
4
MOSFET-N-SO8
MOSFET-N-SO8
L2
L2
JP2SO
JP2SO
J4
J4
0R
0R
1 2
3
2
10
22
2
3
1 2
2
1
HGATE2
HGATE1
12
1
1
3V3
8
7
6
51
0R
0R
11
PHASE2
PHASE1
21
M4
M4
51
6
7
8
5V
5V
VIN
2/4
LDO5V+
LDO5V+
J3
J3
1
1
PGND
CIN
CIN
NM
NM
+
+
PGND
R5
R5
NM
NM
C13
C13
C2C215u
15u
C1C115u
15u
3R9
3R9
R26
R26
4u7
4u7
C26
C26
+
+
100n
100n
C19
C19
RLD5V
RLD5V
100K
100K
4u7
4u7
C21
C21
+
+
C20
1uF
C20
1uF
47R
47R
R9
R9
V+
BOOT2
BOOT1
2
1
D1
D1
3
V+
VIN
PGND
PGND
SGND
SGND
SGND
SGND
SGND
BAT54A/SOT
BAT54A/SOT
15u
15u
C4
C4
15u
15u
C3
C3
R3
R3
8
7
6
51
BOOT2
R11
R11
10R
10R
U1
U1
19
5
18
V+
31
C22
C22
220nF
220nF
SGND
10R
10R
R10
R10
C6
C6
BOOT1
51
6
7
8
PGND
PGND
R4
R4
R6
R6
NM
NM
C14
C14
J2J2-VIN
-VIN
J5J5+VIN
+VIN
S8S8JP3SO
JP3SO
C8
C8
+
+
C7
C7
+
+
C24
C24
560K
560K
R18
R18
12
M3
M3
MOSFET-N-SO8
MOSFET-N-SO8
4
1 0R
1 0R
R2
R2
13
LGATE2
LGATE1
15
R23
R23
4
MOSFET-N-SO8
MOSFET-N-SO8
R19
R19
12
S9
S9
JP3SO
JP3SO
3
1
OUT1+
OUT1+
J9
J9
1
2
NM
NM
NM
NM
100n
100n
100n
100n
C9
C9
D3
D3
SMA
SMA
3
2
PGND
R7 500R
R7 500R
12
14
PGND
CSENSE2
V5SW
CSENSE1
20
17
V5SW
R8
R8
500R
500R
0R
0R
2
3
100n
100n
C10
C10
560K
560K
D2
D2
SMA
SMA
C12
C12
330uF
330uF
+
+
C11
C11
330uF
330uF
+
+
C25
C25
100n
100n
2
J10
PGND
OUT2-
OUT2-
R25
R25
PGND
C15
C15
SGND
1
8
OUT2
SGND
COMP1
OUT1
29
30
OUT5V
1
J8
J8
PGND
1
PGND
R30
?
R30
?
?
?
R29
R29
SGND
LDO_ADJ
LDO_ADJ
NM
NM
SGND
A - S12 CLOSED
LIKE 4-PIN JUMPER
B - S14 CLOSED
FB1
28
FB1
PGOOD2
27
3 100K
3 100K
R1
R1
V+
C18
C18
100pF
100pF
1K
1K
+
+
C - S12.1 TO S14.2
12
3 JP2SO
3 JP2SO
S1
S1
7
LDO
SHDN
5
PGOOD1
PGOOD1
J7J7PGOOD2
J6
J6
NM
NM
VIN
R28
R28
?
?
1
R32
R32
?
?
R31
R31
?
?
SGND
R33
R33
?
?
SGND
4u7
4u7
C28
C28
SGND
S1S1JP3SO
S1S1JP3SO
C27
C27
1uF
1uF
SGND
FSE
L
3
SKI
P
24
VREF
32
EN1
25
EN2
4
PGOOD2
SGND
560K
560K
R17
R17
FB1
?
?
R27
R27
SGND
1
3
2
LDO_FB
PM6681_VFQFPN32
PM6681_VFQFPN32
R15
R15
100K
100K
V+V+V+
SGND
V+
JP4I
JP4I
S3
S3
4
31
2
4
31
2
CREF
CREF
4
5
3
6
2
7
1
8
S2
S2
SWDIP-4
SWDIP-4
R14
R14
100K
100K
R16
R16
100K
100K
SGND
C23
10pF
C23
10pF
SGND
SGND
JP4I
JP4I
S10
S10
SGND
SGND
100n
100n
SGND
J11
J11
EXT5V
EXT5V
4
31
2
V5SW
OUT5V
SGND
S11
S11
JP4I
JP4I
150pF
150pF
C17
C17
1
2 JP2SO
2 JP2SO
S1
S1
2
2
6
FB2
COMP2
LDO_FB
PGOOD1
26
16
LDO_FB
2 100K
2 100K
R1
R1
V+
C16
C16
R24
R24
PGND
OUT1-
OUT1-
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