STMICROELECTRONICS GS

GS-R12F
2A DC/DC converter modules
Features
■
MTBF 1 000 000 hours (TA = 25° C)
■
2A max output current
■
16V max input voltage
■
1.5V max drop-out voltage
■
Remote logic inhibit/enable
■
Synchronization
■
Not-latching overload and short circuit
protection
■
Thermal shutdown
■
Fixed or adjustable output
■
No heatsink required
■
Operating temperature range -25°C ÷ 85°C
Description
The GS-R12F series is a family of high efficiency
step down switching voltage regulator, designed
to replace linear regulators.
Based on ST L5973 device, these non isolated
regulators are suitable for various applications,
including telecom, industry, computer and
distributed power supply system having a wide
range input voltage.
Order codes
Output Voltage
Input Voltage
Output Ripple
Efficiency
[V]
[V]
[mVpp]
[%]
GS-R12F0182.0
1.8 ± 4%
4.5 ÷ 15
20
72
Fixed output voltage
GS-R12F0252.0
2.5 ± 4%
4.5 ÷ 15
20
76
Fixed output voltage
GS-R12F0332.0
3.3 ± 4%
4.5 ÷ 15
20
82
Fixed output voltage
GS-R12F0502.0
5.0 ± 4%
6.6 ÷ 15
20
85
Fixed output voltage
GS-R12F0002.0
1.235 ÷ 5.5
4.5 ÷ 15
20
68 ÷ 85
Progr. output voltage
Part number
October 2006
Rev 1
Notes
1/12
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12
Contents
GS-R12F
Contents
1
2
Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1
Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2
Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3
Thermal de-rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
4.1
Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2
Reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3
Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.4
Multiple units synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.5
Current limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.6
Thermal shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.7
Output voltage programming (GS-R12F0002.0 only) . . . . . . . . . . . . . . . . . 7
4.8
Loop compensation (GS-R12F0002.0 only) . . . . . . . . . . . . . . . . . . . . . . . . 7
Additional features and protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1
Output overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6
Ordering scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2/12
GS-R12F
Pin settings
1
Pin settings
1.1
Pin connection
Figure 1.
1.2
Pin connection and mechanical data (dimensions in mm)
Pin description
Table 1.
Pin description
Name
Function
Description
1
INH
A logic high level disables the device. When the pin is open, an
internal pull up disables the device
2
Vref
3.3V reference voltage
3
Input +
DC input voltage
4
Input +
DC input voltage
5
Input GND
Return for input voltage source
6
Input GND
Return for input voltage source
7
Output GND
Return for output voltage source
8
Output GND
Return for output voltage source
9
Vout
Regulated power output
10
Vout
Regulated power output
11
FB
Feedback input, available on adjustable device and on request for
additional compensation
12
Sync
Master/Slave synchronization
3/12
Maximum ratings
GS-R12F
2
Maximum ratings
2.1
Absolute maximum ratings
Table 2.
Absolute maximum ratings
Symbol
2.2
Parameter
16
V
DC input voltage
Iout
Maximum output current
V1
INH
-0.3 to Vi
V
V12
Sync
-0.3 to 4
V
V11
FB
4
V
Value
Unit
internally limited
Thermal data
Absolute maximum ratings
Symbol
Parameter
Tstg
Storage temperature range
-40 ÷ 105
°C
Top
Operating ambient temperature
-25 ÷ 85
°C
Test condition
Value
Unit
Vi = 4.5 ÷ 16V, TA = 60°C (Max)
1.95
Vi = 4.5 ÷ 16V, TA = 65°C (Max)
1.85
Vi = 4.5 ÷ 16V, TA = 70°C (Max)
1.75
Vi = 4.5 ÷ 16V, TA = 75°C (Max)
1.65
Vi = 4.5 ÷ 16V, TA = 80°C (Max)
1.55
Vi = 4.5 ÷ 16V, TA = 85°C (Max)
1.45
Thermal de-rating
Table 4.
Symbol
Io
4/12
Unit
Vi
Table 3.
2.3
Value
Thermal de-rating for free air condition (all versions)
Parameter
Output current
A
GS-R12F
3
Electrical characteristics
Electrical characteristics
TA = 25°C, unless otherwise specified
Table 5.
Symbol
Vr
Electrical characteristics (all version)
Parameter
Test condition
Min
Typ
Max
Unit
20
35
mVpp
Ripple voltage
Vi = 12V, Io = 2A
Temperature stability
Vi = Vo + 1.5V, Io = 2A
Io
Output current
Vi = 4.5 ÷ 16V
IoL
Current limit
Vi = 4.5 ÷ 16V
2.5
Iq
Quiescent current
Vi = 12V, Io = 0A
1.8
2.5
mA
Total stand-by quiescent
current
Vinh > 2.2V
50
100
µA
Switching frequency
Vi = 12V, Io = 2A
225
250
275
kHz
Reference voltage
Vi = 4.5 ÷ 15V
Iref = 0 ÷ 5mA
3.234
3.3
3.366
V
8
10
30
mA
0.8
V
Iqst-by
fs
Vref
Short circuit current
TBD
0
2
Device ON
INH
mV/°C
A
A
INH threshold voltage
VFB
Feedback voltage
SRV
Supply voltage rejection
Device OFF
2.2
Vi = 4.5 ÷ 15V IO=0 ÷ 2A
1.22
V
1.235
TBD
1.25
V
mV/V
5/12
Application information
4
Application information
4.1
Input voltage
GS-R12F
The recommended maximum operating DC Input Voltage is 15V including ripple voltage.
4.2
Reference voltage
No capacitor is required for stability.
4.3
Inhibit function
The inhibit feature allows to put the device in stand-by mode.
With INH pin 1 is higher than 2.2V the device is disabled and the current consumption is
reduced to less than 100µA for Vi = 15V.
With INH pin lower than 0.8V, the device is enabled.
If the INH pin is left floating, an internal pull up ensures that the voltage at the pin reaches
the inhibit threshold and the device is disabled.
The pin can be pulled to Vi to disable the device.
4.4
Multiple units synchronization
Using more than one unit on the same circuit, it is possible to synchronize the switching
frequency, connecting all pin 12 together (see Figure 4).
The unit with higher frequency becomes the master.
4.5
Current limitation
The device has two current limit protections, pulse by pulse and frequency fold back.
The current is sensed through a resistor and if it reaches the threshold, the on time is
reduced and consequently the output voltage, too.
Since the minimum switch ON time (necessary to avoid false overcurrent signal) is not
enough to obtain a sufficiently low duty cycle at 250Hz, the output current could increase
again, in strong overcurrent or short circuit conditions.
For this reason the switching frequency is also reduced to keep the inductor current within
its maximum threshold limit.
The frequency depends on the feedback voltage.
As the feedback voltage decreases (due to the reduced duty cycle), the switching frequency
decrease too.
6/12
GS-R12F
4.6
Application information
Thermal shutdown
The shutdown block generates a signal that turns off the power stage if the temperature of
the internal chip goes higher than a fixed internal threshold (150ºC min).
The sensing element of the chip is very close to the PDMOS area, so ensuring an accurate
and fast temperature detection.
An hysteresis of approximately 20° C avoids that the devices turns on and off continuously.
4.7
Output voltage programming (GS-R12F0002.0 only)
The GS-R12F0002.0 output voltage is 5.54V ±4%, to reduce this value connect a resistor
between pin 11 (FB) and pin 10 (Vout).
The resistor must be located very close to the proper pins, to minimize the injected noise
(see Figure 2).
The resistor value is calculated using the following formula:
Rv = [(Vout - 1.235) * 11.3] / 5.54 - Vout) --[kΩ]
Vout can be adjusted between 1.235V (Rv = 0 Ω) and 5.54V (Rv = open)
4.8
Loop compensation (GS-R12F0002.0 only)
If required by particular load conditions, it is possible to change the feedback loop
compensation, adding an external capacitor between pin 11 (FB) and pin 10 (Vout), which
will act as speed up (see Figure 3).
7/12
Additional features and protections
GS-R12F
5
Additional features and protections
5.1
Output overvoltage protection
The overvoltage protection, OVP, is realized by using an internal comparator, whose input is
connected to the feedback. It turns off the power stage when the OVP threshold is reached.
This threshold is typically 30% higher than the feedback voltage.
8/12
Figure 2.
Output voltage programming
Figure 4.
Multiple units synchronization
Figure 3.
Loop compensation
GS-R12F
Additional features and protections
Figure 5.
P.C.B. Footprint (dimensions in mm)
9/12
Ordering scheme
6
GS-R12F
Ordering scheme
Table 6.
Ordering information scheme
GS-
Input Voltage
12 = 12V
Output Voltage
018 = 1.8V
025 = 2.5V
033 = 3.3V
050 = 5.0V
000 = 1.235 ÷ 5.5V
Output Current
2.0 = 2A
10/12
R12
F018
2.0
GS-R12F
7
Revision history
Revision history
Table 7.
Revision history
Date
Revision
16-Oct-2006
1
Changes
Initial release
11/12
GS-R12F
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