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L6932
February 2003
s
2V TO 14V INPUT VOLTAGE RANGE
s
200m
Rdson MAX.
s
200
A QUIESCENT CURRENT AT ANY LOAD
s
EXCELLENT LOAD AND LINE REGULATION
s
1.8V AND 2.5V FIXED VOLTAGE
s
ADJUSTABLE FROM 1.2V TO 5V (L6932D1.2)
s
1% VOLTAGE REGULATION ACCURACY
s
SHORT CIRCUIT PROTECTION
s
THERMAL SHUT DOWN
s
SO-8 (4+4) PACKAGE
APPLICATIONS
s
MOTHERBOARDS
s
MOBILE PC
s
HAND-HELD INSTRUMENTS
s
PCMCIA CARDS
s
PROCESSORS I/O
s
CHIPSET AND RAM SUPPLY
DESCRIPTION
The L6932 Ultra Low Drop Output linear regulator op-
erates from 2V to 14V and is able to support 2A. De-
signed with an internal 50m
N-channel
Mosfet, can be usefull for the DC-DC conversion be-
tween 2.5V and 1.8V at 2A in portable applications
reducing the power dissipation.
L6932 is available in 1.8V, 2.5V and adj version from
1.2V and ensure a voltage regulation accuracy of
1%.
The current limit is fixed at 2.5A to control the current
in short circuit condition within 8%. The current is
sensed in the power mos in order to limit the power
dissipation.
The device is also provided of a thermal shut down
that limits the internal temperature at 150C with an
histeresys of 20C. L6932 provides the Enable and
the Power good functions.
SO-8 (4+4)
ORDERING NUMBERS:
L6932D1.2 (SO-8)
L6932D1.2TR (T&R)
L6932D1.8 (SO-8)
L6932D1.8TR (T&R)
L6932D2.5 (SO-8)
L6932D2.5TR (T&R)
HIGH PERFORMANCE 2A ULDO LINEAR REGULATOR
TYPICAL OPERATING CIRCUIT
C1
C2
VOUT
1.8V or 2.5V
VIN
2V to 14V
2
IN
GND
3
OUT
L6932D
4
5,6,7,8
PGOOD
1
EN
C1
R1
R2
C2
VOUT
1.2V to 5V
VIN
2V to 14V
2
IN
GND
4
OUT
L6932D1.2
3
5,6,7,8
ADJ
1
EN
L6932
2/10
PIN CONNECTIONS
PIN FUNCTION
ABSOLUTE MAXIMUM RATINGS
THERMAL DATA
(*) Measured on Demoboard with about 4 cm
2
of dissipating area 2 Oz.
N
L6232D
1.2
L6232D
1.8/2.5
Description
1
EN
Enables the device if connected to Vin and disables the device if forced to gnd.
2
IN
Supply voltage. This pin is connected to the drain of the internal N-mos. Connect this
pin to a capacitor larger than 10
F.
3
ADJ
Connecting this pin to a voltage divider it is possible to programme the output voltage
between 1.2V and 5V.
OUT
Regulated output voltage. This pin is connected to the source of the internal N-mos.
Connect this pin to a capacitor of 10
F.
4
OUT
Regulated output voltage. This pin is connected to the source of the internal N-mos.
Connect this pin to a capacitor of 10
F.
PGOOD
Power good output. The pin is open drain and detects the output voltage. It is forced
low if the output voltage is lower than 90% of the programmed voltage.
5, 6, 7, 8
GND
Ground pin.
Symbol
Parameter
Value
Unit
V
in
VIN and Pgood
14.5
V
EN, OUT and ADJ
-0.3 to (V
in
+0.3)
V
Symbol
Parameter
Value
Unit
R
th J-amb
Thermal Resistance Junction to Ambient
62 (*)
C/W
T
max
Maximum Junction Temperature
150
C
T
stg
Storage Temperature Range
-65 to 150
C
1
3
2
4
L6932D1.2
EN
OUT
5
7
6
8
GND
ADJ
IN
GND
GND
GND
1
3
2
4
EN
PGOOD
5
7
6
8
GND
OUT
IN
GND
GND
GND
L6932D1.8
L6932D2.5
3/10
L6932
BLOCK DIAGRAM (Referred to the Fixed Voltage version)
ELECTRICAL CHARACTERISTCS (T
j
= 25C, V
IN
= 5V unless otherwise specified)
(*) Specification referred to T
j
from -25C to 125C.
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
in
Operating Supply Voltage
2
14
V
V
o
Output voltage L6932D1.2
I
o
= 0.1A; V
in
= 3.3V
1.188
1.2
1.212
V
Output voltage L6932D1.8
I
o
= 0.1A; V
in
= 3.3V
1.782
1.8
1.818
V
Output voltage L6932D2.5
I
o
= 0.1A; V
in
= 3.3V
2.475
2.5
2.525
V
L6932D1.2
Line Regulation
V
in
= 2.5V 10%; I
o
= 10mA
5
mV
V
in
= 3.3V 10%; I
o
= 10mA
5
mV
V
in
= 5V 10%; I
o
= 10mA
5
mV
L6932D1.8
Line Regulation
V
in
= 2.5V 10%; I
o
= 10mA
5
mV
V
in
= 3.3V 10%; I
o
= 10mA
5
mV
V
in
= 5V 10%; I
o
= 10mA
5
mV
L6932D2.5
Line Regulation
V
in
= 3.3V 10%; I
o
= 10mA
5
mV
V
in
= 5V 10%; I
o
= 10mA
5
mV
L6932D1.2 Load Regulation
V
in
= 3.3V; 0.1A < I
o
< 2A
15
mV
L6932D1.8 Load Regulation
V
in
= 3.3V; 0.1A < I
o
< 2A
15
mV
L6932D2.5 Load Regulation
V
in
= 3.3V; 0.1A < I
o
< 2A
15
mV
R
dson
Drain Source ON resistance
200
m
I
occ
Current limiting
2.3
2.5
2.7
A
I
q
Quiescent current
0.2
0.4
mA
I
sh
Shutdown current
2V < V
in
< 14V
*
25
A
Ripple Rejection
f = 120Hz, I
o
= 1A
V
in
= 5V,
V
in
= 2Vpp
60
75
dB
V
en
EN Input Threshold
0.5
0.65
0.8
V
REFERENCE
VREF=1.25V
CURRENT
LIMIT
THERMAL
SENSOR
ENABLE
EN
IN
OUT
PG
GND
CHARGE
PUMP
ERROR
AMPL.
DRIVER
VREF
0.9 VREF
+
-
-
+
D99IN1100
L6932
4/10
Pgood threshold
V
o
rise
90
%Vo
Pgood Hysteresis
10
%Vo
Pgood saturation
I
pgood
=1mA
0.2
0.4
V
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
Figure 1. Output Voltage vs. Junction
Temperature (L6932D1.2)
Figure 2. Output Voltage vs. Junction
Temperature (L6932D1.8)
Figure 3. Output Voltage vs. Junction
Temperature (L6932D2.5)
Figure 4. Quiescent Current vs. Junction
Temperature
Figure 5. Shutdown Current vs. Junction
Temperature
1.209
1.210
1.210
1.211
1.211
1.212
1.212
1.213
-60
-40
-20
0
20
40
60
80
100 120 140 160
Temp [C]
V
1.788
1.792
1.796
1.800
1.804
1.808
-60 -40 -20
0
20
40
60
80
100 120 140 160
Temp [C]
V
2.495
2.500
2.505
2.510
2.515
2.520
-60
-40
-20
0
20
40
60
80
100 120 140 160
Temp [C]
V
250
260
270
280
290
300
310
-40
-20
0
20
40
60
80
100
120
140
Temp [C ]
Iq
(uA)
Vin=5V
4
4.5
5
5.5
6
6.5
7
7.5
-40
-20
0
20
40
60
80
100
120
140
Temp [C ]
Ishdn
(uA)
Vin=5V
ELECTRICAL CHARACTERISTCS (continued)
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L6932
APPLICATION INFORMATIONS
APPLICATION CIRCUIT
In figure 6 the schematic circuit of the demoboards are shown.
Figure 6. Demoboards Schematic Circuit
COMPONENT LIST
Fixed version
Figure 7. Demoboard Layout (Fixed Version)
Reference
Part Number
Description
Manufacturer
C1
C34Y5U1E106Z
10uF, 25V
TOKIN
C2
C34Y5U1E106Z
10uF, 25V
TOKIN
VIN
C1
OUT
1
3
7
5
6
4
8
2
L6932D2.5
L6932D1.8
VOUT=2.5V/1.8V
GND
C2
PGOOD
IN
EN
VOUT=1.2V TO 5V
VIN
C1
OUT
1
3
7
5
6
4
8
2
L6932D1.2
GND
C2
IN
EN
ADJ
R1
R2
V
O U T
1.2
R2
--------
R1
R 2
+
(
)
=
L6932
6/10
Adjustable version
Figure 8. Demoboard Layout (Adjustable Version)
COMPONENTS SELECTION
Input Capacitor
The input capacitor value depends on a lot of factors such as load transient requirements, input source (battery
or DC/DC converter) and its distance from the input cap. Usually a 47
F is enough for any application but a
much lower value can be sufficient in many cases.
Output Capacitor
The output capacitor choice depends basically on the load transient requirements.
Tantalum, Speciality Polimer, POSCAP and aluminum capacitors are good and offer very low ESR values.
Multilayer ceramic caps have the lowest ESR and can be required for particular applications. Nevertheless in
several applications they are ok, the loop stability issue has to be considered (see loop stability section).
Below a list of some suggested capacitor manufacturers.
Reference
Part Number
Description
Manufacturer
C1
C34Y5U1E106Z
10uF, 25V
TOKIN
C2
C34Y5U1E106Z
10uF, 25V
TOKIN
R1
5.6K, 1%, 0.25W
Neohm
R2
3.3K, 1%, 0.25W
Neohm
Manufacturer
Type
Cap Value (
F)
Rated Voltage (V)
PANASONIC
CERAMIC
1 to 47
4 to 16
TAYO YUDEN
CERAMIC
1 to 47
4 to 16
TDK
CERAMIC
1 to 47
4 to 16
TOKIN
CERAMIC
1 to 47
4 to 16
SANYO
POSCAP
1 to 47
4 to 16
PANASONIC
SP
1 to 47
4 to 16
KEMET
TANTALUM
1 to 47
4 to 16
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L6932
Loop Stability
The stability of the loop is affected by the zero introduced by the output capacitor.
The time constant of the zero is given by:
This zero helps to increase the phase margin of the loop until the time constant is higher than some hundreds
of nsec, depending also on the output voltage and current.
So, using very low ESR ceramic capacitors could produce oscillations at the output, in particular when regulating
high output voltages (adjustable version).
To solve this issue is sufficient to add a small capacitor (e.g. 1nF to 10nF) in parallel to the high side resistor of
the external divider, as shown in figure 9.
Figure 9. Compensation Network
Thermal Considerations
Since the device is housed in a small SO(4+2+2) package the thermal issue can be the bottleneck of many ap-
plications. The power dissipated by the device is given by:
P
DISS
= (V
IN
- V
OUT
) I
OUT
The thermal resistance junction to ambient of the demoboard is approximately 62C/W. This mean that, consid-
ering an ambient temperature of 60C and a maximum junction temperature of 150C, the maximum power that
the device can handle is 1.5W.
This means that the device is able to deliver a DC output current of 2A only with a very low dropout.
In many applications, high output current pulses are required. If their duration is shorter than the thermal con-
stant time of the board, the thermal impedance (not the thermal resistance) has to be considered.
In figure 10 the thermal impedance versus the duration of the current pulse for the SO(4+2+2) mounted on board
is shown.
T
ESR C
O U T
=
F
ZER O
1
2
ESR C
O U T
--------------------------------------------
=
VOUT=1.2V TO 5V UP to 2A
VIN=2V TO 14V
C1
OUT
1
3
7
5
6
4
8
2
L6932D1.2
GND
C2
IN
EN
ADJ
R1
R2
C3
L6932
8/10
Figure 10. Thermal Impedance
Considering a pulse duration of 1sec, the thermal impedance is close to 20C/W, allowing much bigger power
dissipated.
Example:
Vin = 3.3V
Vout = 1.8V
Iout = 2A
Pulse Duration = 1sec
The power dissipated by the device is:
P
DISS
= (V
IN
- V
OUT
) I
OUT
= 1.5 2 3W
Considering a thermal impedance of 20C/W, the maximum junction temperature will be:
T
J
= T
A
+ Z
THJA
P
DISS
= 60 + 60 = 120C
Obviously, with pulse durations longer than approximately 10sec the thermal impedance is very close to the
thermal resistance (60C/W to 70C/W).
9/10
L6932
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
1.75
0.069
a1
0.1
0.25
0.004
0.010
a2
1.65
0.065
a3
0.65
0.85
0.026
0.033
b
0.35
0.48
0.014
0.019
b1
0.19
0.25
0.007
0.010
C
0.25
0.5
0.010
0.020
c1
45
(typ.)
D (1)
4.8
5.0
0.189
0.197
E
5.8
6.2
0.228
0.244
e
1.27
0.050
e3
3.81
0.150
F (1)
3.8
4.0
0.15
0.157
L
0.4
1.27
0.016
0.050
M
0.6
0.024
S
8
(max.)
(1) D and F do not include mold flash or protrusions. Mold flash or
potrusions shall not exceed 0.15mm (.006inch).
SO8
OUTLINE AND
MECHANICAL DATA
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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L6932
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