STMicroelectronics LEO3910 Datasheet
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LEO3910
LEO3910
Datasheet
2 A positive low drop voltage regulator
Features
• Operating input voltage from 3 V to 12 V
• Adjustable output voltage from 1.23 V to 9 V
• Low-dropout voltage: 0.35 V @ I
O
= 400 mA
• Overtemperature protection
• Overcurrent protection
• Adjustable current limitation
• Inhibit (ON/OFF) TTL-compatible control
• Gold bonding
• Nickel/palladium/gold-lead-finished (NiPdAu), whisker-free
• RML <1% and CVCM <0.1% guaranteed outgassing
• Compliant with ST-LEO-specification
• Target radiation performace:
– 50 krad(Si) total ionizing dose
– SEL free up to 62.5 MeV.cm²/mg
Application
• Low earth orbit (LEO) applications
Description
The LEO3910 is a positive adjustable voltage regulator housed into a Power-SO 20L slug-down package, which is able to provide a maximum output current up to 2 A.
It can operate over a large temperature range of -40 °C to +125 °C.
DS13691 - Rev 1 - May 2021
For further information contact your local STMicroelectronics sales office.
www.st.com
1
Block diagram
Figure 1. Block diagram
LEO3910
Block diagram
AMG081120161300MT
DS13691 - Rev 1 page 2/21
2
LEO3910
Pin configuration
Pin configuration
Pin
16
2, 3, 8, 9, 13, 14, 15, 18
4, 6
5
7
12
17
19
EP (1, 10, 11, 20)
Figure 2. Pin configuration
1
2
3
6
7
4
5
8
9
10
EP
20
19
18
17
16
15
14
13
12
11
Table 1. Pin connection table
Pin name
GND
NC
VO
VI
ISC
OCM
INH
ADJ
EP
Description
Ground
Not connected
Output voltage
Input voltage
Current limit setting
Over current monitoring
Inhibit
Adjustable pin
Exposed pad, to be connected to GND.
1, 10, 11, 20 internally connected to EP
DS13691 - Rev 1 page 3/21
3
Note:
Maximum ratings
Symbol
V
I
VO
V
ADJ
V
OCM
V
ISC
V
INH
I
O
P
D
T stg
Table 2. Absolute maximum ratings
Parameter
DC input voltage
DC output voltage range
ADJ pin voltage
Over current monitor pin voltage
Current limit pin voltage
INHIBIT input voltage
Output current
Power dissipation
Storage temperature range
Value
-0.3 to 14
-0.3 to (VI + 0.3)
-0.3 to (VO + 0.3)
-0.3 to (VI + 0.3)
-0.3 to (VI + 0.3)
-0.3 to (VI + 0.3)
Internally limited
Internally limited
-65 to +150
Exceeding maximum ratings may damage the device. All values are referred to GND.
Symbol
R thJC
R thJA
Table 3. Thermal data
Parameter
Thermal resistance junction-case
Thermal resistance junction-ambient
2s2p board jedec board
Value
2
25
LEO3910
Maximum ratings
Unit
°C/W
°C/W
Unit
V
V
V
V
V
V
°C
DS13691 - Rev 1 page 4/21
4
LEO3910
Application circuit
Application circuit
V
IN
C
In
Figure 3. Typical application circuit
V
I
ON
OFF
INHIBIT
I
SC
GND
V
O
ADJ
OCM
R
2
R
1
C byp
C
Out
V
OUT
DS13691 - Rev 1 page 5/21
5
LEO3910
Electrical characteristics
Electrical characteristics
V
I
= V
O
+ 2.5 V, T j
= +25 °C, C
I
= 10 µF, C
O
= 10 µF tantalum, unless otherwise specified.
Symbol
V
I
V
ADJ
∆V
O
/∆V i
∆V
O
/∆VI
O
I
SHORT
V d
I q
SVR
V
INH (OFF)
V
INH (ON)
I
INH
V
OCML
V
OCMH eN
Parameter
Input voltage
Reference voltage
Line regulation
Load regulation
Dropout voltage
Quiescent current
Inhibit turn-off voltage
Inhibit turn-on voltage
Shutdown input current
Overcurrent monitor voltage low
Table 4. Electrical characteristics
Overcurrent monitor voltage high
Test conditions
I
O
= 1 A, T
J
= -40 to 125 °C
I
O
= 5 mA, V
O
= V
ADJ
,T
J
= -40 to 125 °C
V
I
= V
O
+2.5 V to 12 V, I
O
= 5 mA
V
I
= V
O
+2.5 V, I
O
= 5 mA to 1 A
Adjustable by external resistor
I
O
= 400 mA, V out
= 3 V, T
J
= -40 to 125 °C
I
O
= 1 A, V out
= 3 V, T
J
= -40 to 125 °C
I
O
= 2 A, V out
= 3 V, T
J
= -40 to 125 °C
V
I
= V
O
+2.5 V to 12 V,
I
O
= 5 mA, on mode
V
I
= V
O
+2.5 V to 12 V,
I
O
= 30 mA, on mode
V
I
= V
O
+2.5 V to 12 V,
I
O
= 300 mA, on mode
V
I
= V
O
+2.5 V to 12 V,
I
O
= 1 A, on mode
V
I
= 12 V V
INH
= 3 V, off mode
V
I
= V
O
+2.5 V ± 1 V,
I
O
= 5 mA,
V
O
=3 V, f = 33 kHz
I
O
= 5 mA, T
J
= -40 to 125 °C
I
O
= 5 mA, T
J
= -40 to 125 °C
V
INH
= 5 V
I
OCM
= 10 mA (sunk current), V
I
= 12 V
I
OCM
= -10 µA (sourced current)
V
I
= V
O
+2.5 V to 12 V
B= 10 Hz to 100 kHz
I
O
= 5 mA to 2 A
1. These values are guaranteed by design.
Min. Typ. Max.
3 12
1.19 1.23 1.27
0.07
-
-
1
0.4
3.8
-
-
-
0.35
0.7
0.5
1
0.75
1.5
-
-
-
-
-
-
1.6
2.7
11
32
0.3
-
50
-
-
2.4
-
-
120
0.4
-
V
I
40
6
8
25
62
-
-
-
0.8
-
-
-
-
mA mA mA mA mA dB
µA
V
V
V
V
µVrms/V
Unit
V
V
%
%
A
V
V
V
DS13691 - Rev 1 page 6/21
6
6.1
6.2
6.3
6.4
6.5
LEO3910
Device functional description
Device functional description
The LEO3910 adjustable voltage regulator contains a PNP type power element controlled by a signal resulting from an amplified comparison between the internal temperature-compensated band-gap and the fraction of the desired output voltage value obtained from an external resistor divider bridge. The device is protected by several functional blocks.
ADJ pin
The output voltage feedback comes through an external resistor divider (R1, R2 as in the typical application schematic), whose mid-point connected to the ADJ pin (allowing all possible output voltage settings as per user requirements).
INHIBIT
By setting the INHIBIT pin TTL high, the device switches off the output current and voltage. The device is ON when the INHIBIT pin is set low. Since the INHIBIT pin is pulled down internally, it can be left floating in cases where the inhibit function is not used.
Overtemperature protection
The LEO3910 is protected by a junction temperature detection circuit, turning the device “OFF” when the temperature attains 175 °C. The recovery of the ON mode occurs with a hysteresis of 40 °C. Combined with the other protection blocks, the device is protected from destructive junction temperature excursions in all load conditions. It should be noted that when the internal temperature detector reaches 175 °C, the active power element can be as high as 225 °C. Prolonged operation under these conditions far exceeds the maximum operating ratings and the device reliability cannot be guaranteed.
Overcurrent protection
The device is equipped with a circuit having the purpose of limiting the maximum load current, in order to protect the output stage against possible overcurrent-related damages. By denoting ISHORT the maximum current available at output, this value can be modified externally by a resistor between the pins ISC and Vin, with a typical value range of 17 kΩ to 200 kΩ.
As the behavior of the overcurrent protection, when the load current approaches the mentioned ISHORT, the regulation is inhibited.
To maintain optimal VO regulation and at the same time an acceptable accuracy for ISHORT, it is necessary:
• to set an ISHORT> = 1 A
• to set ISHORT 1.6 times greater than the maximum desired application I
O
to fix enough margins from the regulation range.
When IO reaches typically ISHORT – 300 mA, the current limiter overrules the regulation, VO starts to drop and the OCM flag rises. When no current limitation adjustment is required, the ISC pin can be left unbiased.
OCM pin
In the event of an overcurrent at the output, a voltage level of 0.4 V is present at the OCM pin. In other conditions, this voltage equals V
I
. The OCM pin is internally pulled up by a 5 kΩ resistor up to V
I
. It is buffered and can sink up to 10 mA.
DS13691 - Rev 1 page 7/21
7
LEO3910
Application information
Application information
To adjust the output voltage, the R
2
resistor must be connected between the V
O
and ADJ pins. The R
1
resistor must be connected between ADJ and ground. Resistor values can be derived from the following formula:
VO = VADJ (R
1
+ R
2
) / R
1
The V
ADJ
is typically 1.23 V, controlled by the internal temperature-compensated band gap block.
The minimum input voltage is 3 V. The LEO3910 is designed to operate for V
I
- V
O
> of the minimum specified dropout. The value of R
1
, the resistance between ADJ pin and GND, must not be greater than 10 kΩ, in order to keep the output feedback error below 0.2%. A minimum of 0.5 mA I
O
must be set to ensure perfect no-load regulation. It is advisable to dissipate this current into the divider bridge resistor.
The inhibit function switches off the output current very quickly. According to Lenz’s law, the external circuitry reacts with LdI/dt terms which can be of high amplitude in case somewhere a serial coil inductance exists. Large transient voltage would develop on both device terminals. It is advisable to protect the device with Schottky diodes to prevent negative voltage excursions. In the worst case, a 14 V Zener diode could protect the device input.
All available VO pins should always be externally interconnected, otherwise the stability and reliability of the device cannot be guaranteed.
To ensure regulator stability, input and output capacitors with a minimum 10 μF are mandatory. These capacitors must be connected as close as possible to the device terminals.
In the case of high-current operation, an important factor to look at for the reliability target of the space application is the sustainable surge current of the capacitors used. The surge current is known to be one of the major failure mechanisms for these parts, especially when the equipment is turned ON. Tantalum capacitors manufactured per military specifications (MIL-PRF-55365) are established reliability parts targeted for less than 0.001% of failures per 1000 hours (failure rate< 10 FIT).
Derating is a means for application engineers of space systems to further reduce the probability of failures by limiting the level of stresses to capacitors during application. Typical derating requirements for solid tantalum capacitors limit the maximum applied voltage to 50% of the rated voltage (VR) and the inrush currents are bounded by additional resistors used in series with the capacitors.
In addition, a ceramic capacitor of at least 100nF in parallel to the input and output bulk capacitors must be used for decoupling purposes. A 470 nF polyester capacitors, put close to the regulator between input and ground, helps further improving the LEO3910 reliability by filtering potentially dangerous over voltages spikes coming out during particular conditions.
A separate kelvin voltage sensing line provides the ADJ pin with exact load "high potential" information (see
Figure 4. Application diagram for remote sensing operation). But variable remote load current consumption induces variable Iq current (Iq is roughly the IO current divided by the hFE of the internal PNP series power element) routed through the parasitic series line resistor RW2. To compensate for this parasitic voltage, resistor
RW1 can be introduced to provide the necessary compensating voltage signal to the ADJ pin. A ceramic or polyester 47nF CBYP capacitor between ADJ and VO pins is recommended when the remote sensing technique is implemented.
Since the LEO3910 adjustable voltage regulator is manufactured with very high speed bipolar technology (6 GHz fT transistors), the PCB layout must be designed with exceptional care, with very low inductance and low mutually coupling lines. Otherwise, high frequency parasitic signals may be picked up by the device resulting in system self-oscillation. The benefit is an SVR performance extended to far higher frequencies.
DS13691 - Rev 1 page 8/21
DS13691 - Rev 1
LEO3910
Application information
Figure 4. Reference voltage vs. temperature
(V
IN
=V
OUT
+2.5 V)
1.3
1.28
1.26
1.24
1.22
1.2
1.18
1.16
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80
Vin=Vout+2.5V, Vout= Vadj, Cin=0.1Fµ,
Cout=1µF (tant), Iout=5mA
100 120 140
Figure 5. Line regulation vs. temperature
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Vout+2.5 V<Vin <12V, Vout= Vadj, Cin=0.1Fµ
Cout=1µF (tant), Iout=5mA
Figure 6. Load regulation vs. temperature ( I
OUT
= 5 mA to 1 A)
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Vin=Vout+2.5V, Vout=Vadj, Cin=0.1µF,
Cout=1µF (tant), 5mA<Iout<1A
Figure 7. Inhibit threshold vs. temperature
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-60
Vin=Vout+2.5V
Vin=12V
-40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Vout =Vadj, Cin=0.1 μF, Cout =1 μF(tant ), No load
Figure 8. Output voltage vs input voltage (I
OUT
=0 mA,T=25 °C and T=125 °C)
1.4
1.2
1
0.8
0.6
0.4
0.2
125°C
25°C
0
0 1 2
V
IN
3
[V]
4 5
Vout = Vadj , Cin =0.1μF, Cout =1μF(tant), No load,
T=25 °C, T=125 °C
6
Figure 9. Output voltage vs input voltage (I
OUT
=0 mA,T=0 °C and T=-55 °C)
1.4
1.2
1
0.8
0.6
0.4
0.2
0°C
-55°C
0
0 1 2 3 4 5
V
IN
[V]
Vout = Vadj , Cin =0.1μF, Cout =1μF(tant), No load,
T= 55 °C
6 page 9/21
DS13691 - Rev 1
LEO3910
Application information
Figure 10. Quiescent current vs. temperature (I
OUT
= 5 mA)
Figure 11. Quiescent current vs. temperature (I
OUT
= 30 mA)
5
4.5
4
3.5
3
2.5
2
1.5
Vin=Vout+2.5V
Vin=12V
1
0.5
0
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Vout = Vadj ,Cin =0.1μF, Cout =1μF(tant), Iout=5 mA
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
-60
Vin=Vout+2.5V
Vin=12V
-40 -20 0 20 40 60
Temperature [ °C]
80 100 120 140
Vout = Vadj ,Cin =0.1μF, Cout =1μF(tant), Iout=30 mA
Figure 12. Quiescent current vs. temperature (I
OUT
= 300 mA)
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-60
Vin=Vout+2.5V
Vin=12V
-40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Vout = Vadj ,Cin =0.1μF, Cout =1μF(tant), Iout=300 mA
Figure 13. Quiescent current vs. temperature (I
OUT
= 1 A)
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-60
Vin=Vout+2.5V
Vin=12V
-40 -20 0 20 40 60 80 100 120 140
Temperature [ ° C]
Vout = Vadj ,Cin =0.1μF, Cout =1μF(tant), Iout=1 A
Figure 14. Dropout voltage vs. temperature (V
OUT
=3
V, I
OUT
=400 mA)
Figure 15. Dropout voltage vs. temperature (V
OUT
=3
V, I
OUT
=1 A)
400
380
360
340
320
300
280
260
500
480
460
440
420
240
220
200
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
800
760
720
680
640
600
560
520
480
440
400
360
320
280
240
200
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140 page 10/21
DS13691 - Rev 1
LEO3910
Application information
Figure 16. Dropout voltage vs. temperature (V
OUT
=3
V, I
OUT
=2 A)
1300
1250
1200
1150
1100
1050
1000
950
900
850
800
750
700
650
600
550
500
450
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Figure 17. SVR vs. frequency
1300
1250
1200
1150
1100
1050
1000
950
900
850
800
750
700
650
600
550
500
450
-60 -40 -20 0 20 40 60
Temperature [ ° C]
80 100 120 140
Iout=5 mA,T=25°C
Figure 18. Output noise spectrum (V
OUT
=V adj
,
C
OUT
=1 μF)
400.0
350.0
300.0
250.0
200.0
150.0
100.0
50.0
0.0
10 100 1000 10000
V IN = 3.5V,
Frequency [Hz]
V out
=V
ADJ
,
Iout=2A
Iout=5mA
100000 1000000
Figure 19. Short-circuit current vs. dropout voltage,
(V
OUT
=V adj
)
3.5
3
2.5
2
1.5
1
0.5
5
4.5
4
T=25
T=-55
T=125
0
0 2 4 6
V
Drop
[V]
8 10 12
C
IN
= 0.1μF, Cout =1μF(tantalum), T=25°C, No R
SH
14
4
3.5
3
2.5
2
1.5
1
0.5
0
0
Figure 20. Short-circuit current vs. R
SH
Vout=Vadj
50 100
R
150
SH
[Kohm]
200
C
IN
= 0.1μF, Cout =1μF(tantalum)
250 300
Figure 21. Stability plan
100
10
1
0.1
STABILITY AREA
0.01
0.001
1
V
IN from 3 to 12V; I
OUT
10
C
OUT
[µF] (nominal value) from 5mA to 2A; V
OUT
= V
ADJ
; C
100
IN
=1µF ; T=25 ° C page 11/21
8
LEO3910
Radiations
Radiations
Total ionizing dose (TID):
•
•
The LEO3910 is tested and characterized according to condition A of MIL-STD-883.
All parameters provided in Table 4. Electrical characteristics
apply to both pre- and post-irradiation, as follows:
•
Total ionizing dose (TID) are performed in accordance with MIL-STD-883
The initial characterization is performed in qualification only on both biased and unbiased parts
Each new production lot is tested at high dose rate, in the worst bias case condition, based on the results obtained during the initial qualification.
Heavy-ions:
The behavior of the product when submitted to heavy-ions is not tested in production. Heavy-ion trials are performed on qualification lots only.
Table 5. Radiations
Symbol
TID
•
•
Characteristics
High-dose rate (50-to-300 rad (Si)/s)
Low-dose rate (10 mrad (Si)/s) with a particle angle of 0 ° at 125 °C and a fluence of 1 x 10 7 n/cm² SEL
1. A total ionizing dose (TID) of 50 krad(Si) is equivalent to 500 Gy(Si), (1 gray = 100 rad).
2. SEL: single event latchup.
Value
50
62.5
Unit krad
MeV.cm²/mg
DS13691 - Rev 1 page 12/21
9
Outgassing
1. RML < 1%.
2. CVCM < 0.1%.
Specification (tested per ASTM E 595)
Recovered mass loss (RML)
Collected volatile condensable material (CVCM) (2)
LEO3910
Outgassing
Value
0.06
0.00
Unit
%
%
DS13691 - Rev 1 page 13/21
10
10.1
LEO3910
Package information
Package information
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com
. ECOPACK is an ST trademark.
POWER-SO 20 package information
Figure 22. POWER-SO 20 package outline
Bottom view
DS13691 - Rev 1
Top view
page 14/21
DS13691 - Rev 1
Figure 23. POWER-SO 20 detail A
LEO3910
POWER-SO 20 package information
Figure 24. POWER-SO 20 detail B page 15/21
DS13691 - Rev 1
LEO3910
POWER-SO 20 package information
Symbol e
E
E1
E2
E3 c
D
D1
D2
D3
A2
A3
A4 b b1
θ
θ1
θ2
A
A1 h
L
L1
L2
N
R
R1
S
Min.
3.10
0.00
0.83
0.40
0.40
0.23
0 ̊
5 ̊
0 ̊
-
0.20
Table 6. POWER-SO 20 mechanical data
-
-
-
-
0.85
0.20
0.20
0.25
Milimeters
Typ.
-
15.90 BSC
Variation
-
5.00
1.27 BSC
14.20 BSC
11.00 BSC
Variation
-
-
-
-
-
0.45
-
-
-
-
-
-
-
1.60 REF
0.35 BSC
20
-
-
-
Symbol aaa bbb ccc ddd eee ggg
Note
Table 7. Tolerance of form and position
Drawing
0.10
0.30
0.10
0.25
0.10
0.25
1.2
Max.
3.20
0.075
0.95
0.53
0.50
0.32
8 ̊
10 ̊
-
3.50
0.275
1.10
-
2.85
1.10
1.05
-
-
page 16/21
Symbol
D1
D2
Min.
9.00
5.60
LEO3910
POWER-SO 20 package information
Table 8. Variations
Drawing
Typ.
-
-
Max.
13.00
6.20
Opt.
A
DS13691 - Rev 1 page 17/21
11
LEO3910
Ordering information
Ordering information
Order code
LEO3910PDT-D
1. Under development
•
Table 9. Ordering information
Quality level
Engineering sample
Flight model
Package
POWER-SO 20
POWER-SO 20
Merking includes:
1.
ST logo
2.
date code in YYWWA (year, week and lot index of the week)
3.
Country of origin
Lead-finish
NiPdAu
NiPdAu
Marking Packing
Tape and reel
Tape and reel
LEO
LEO qualification
3910
Product
Table 10. Order code
PD
POWER-SO 20 package
T
Tape and reel
DS13691 - Rev 1 page 18/21
Revision history
Date
17-May-2021
Version
1
Table 11. Document revision history
Changes
Initial release.
LEO3910
DS13691 - Rev 1 page 19/21
LEO3910
Contents
Contents
DS13691 - Rev 1 page 20/21
LEO3910
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DS13691 - Rev 1 page 21/21
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