How it Works
Datasheet
Loading...
MIC29510-3.3BT
Datasheet (MICREL)
8 pgs83.3 Kb0

Datasheet MIC29510-5.0BT, MIC29510-3.3BT, MIC29512BT Datasheet (MICREL)

Download
Page 1
MIC29510/29512 Micrel
MIC29510/29512
5A Fast-Response LDO Regulator
Preliminary Information
General Description
The MIC29510/2 is available in two versions: the three pin fixed output MIC29510 and the five pin adjustable output voltage MIC29512. All versions are fully protected against overcurrent faults, reversed input polarity, reversed lead insertion, overtemperature operation, and positive and nega­tive transient voltage spikes.
A TTL compatible enable (EN) control pin supports external on/off control. If on/off control is not required, the device may be continuously enabled by connecting EN to IN.
The MIC29510/2 is available in the standard three and five pin TO-220 package with an operating junction temperature range of 0°C to +125°C.
For applications requiring even lower dropout voltage, input voltage greater than 16V, or an error flag, see the MIC29500/ 29501/29502/29503.
Ordering Information
Features
• Fast transient response
• 5A current capability
• 700mV dropout voltage at full load
• Low ground current
• Accurate 1% guaranteed tolerance
• “Zero” current shutdown mode (MIC29512)
• Fixed voltage and adjustable versions
Applications
• Pentium™ and Power PC™ processor supplies
• High-efficiency “green” computer systems
• High-efficiency linear power supplies
• High-efficiency switching supply post regulator
• Battery-powered equipment
T ypical Application
MIC29510
V
IN
IN
GND
Fixed Regulator Configuration
OUT
Part Number Temp. Range* Voltage Current Package
MIC29510-3.3BT 0°C to +125°C 3.3V 5.0A TO-220-3 MIC29510-5.0BT 0°C to +125°C 5.0V 5.0A TO-220-3 MIC29512BT 0°C to +125°C Adj. 5.0A TO-220-5
* Junction Temperature
MIC29512
V
OUT
On Off
V
IN
EN
IN
V
OUT
GND
= 1.240
OUT
ADJ
R1
R2
R1
  
R2
 + 1
V
Adjustable Regulator Configuration
OUT
3-96 1997
Page 2
MIC29510/29512 Micrel
Pin Configuration
1 2 3
MIC29510BT
On all devices, the Tab is grounded.
Pin Description
3-Pin TO-220 (MIC29510)
Pin Number Pin Name Pin Function
1 IN Unregulated Input: +16V maximum supply. 2 GND Ground: Internally connected to tab (ground). 3 OUT Regulated Output
5-Pin TO-220 (MIC29512)
Pin Number Pin Name Pin Function
1 EN Enable (Input): Logic-level ON/OFF control. 2 IN Unregulated Input: +16V maximum supply. 3 GND Ground: Internally connected to tab (ground). 4 OUT Regulated Output 5 ADJ Output Voltage Adjust: 1.240V feedback from external resistive divider.
12345
MIC29512BT
3
Absolute Maximum Ratings
Input Supply Voltage (Note 1) ....................... –20V to +20V
Power Dissipation .................................... Internally Limited
Storage Temperature Range ................... –65°C to +150°C
Lead Temperature (Soldering, 5 sec.) ...................... 260°C
1997 3-97
Operating Ratings
Operating Junction Temperature ................. 0°C to +125°C
θJC (TO-220) .............................................................2°C/W
θJA (TO-220) ...........................................................55°C/W
Page 3
MIC29510/29512 Micrel
Electrical Characteristics
All measurements at TJ = 25°C unless otherwise noted. Bold values are guaranteed across the operating temperature range. Parameter Condition Min Typ Max Units
Output Voltage 10mA ≤ IO ≤ IFL, (V Line Regulation IO = 10mA, (V Load Regulation VIN = V
OUT
+ 1V, 10mA ≤ I
OUT
∆VO / ∆T Output VoltageTemperature Coefficient (Note 6) 20 100 ppm/°C Dropout Voltage ∆V
= – 1%, (Note 3)
OUT
MIC29510/29512 I
Ground Current MIC29510/29512 I
Ground Pin VIN = 0.5V less than specified V
I
GNDDO
Current at Dropout Current Limit MIC29510/29512 V
, Output Noise Voltage CL = 47µF 260 µV
e
n
(10Hz to 100kHz) IL = 100mA
+ 1V) ≤ VIN ≤ 8V (Note 2) –2 2 %
OUT
+ 1V) ≤ VIN ≤ 8V 0.06 0.5 %
≤ I
OUT
FULL LOAD
= 100mA 80 200 mV
O
= 750mA 200 mV
I
O
I
= 1.5A 320 mV
O
= 3A 500 mV
I
O
(Notes 2, 6) 0.2 1 %
IO = 5A 700 1000 mV
= 750mA, VIN = V
O
= 1.5A 10 mA
I
O
= 3A 36 mA
I
O
IO = 5A 100 150 mA
OUT
= 0V (Note 4) 5.0 6.5 A
OUT
+ 1V 3 20 mA
OUT
. I
= 10mA 2 3 mA
OUT
RMS
Reference (MIC29512 only)
Reference Voltage 10mA ≤ IO ≤ IFL, V
+ 1V ≤ VIN ≤ 8V (Note 2) 1.215 1.265 V
OUT
MAX
Adjust Pin Bias Current 40 80 nA
120 nA
Reference Voltage (Note 7) 20 ppm/°C Temperature Coefficient
Adjust Pin Bias Current 0.1 nA/°C Temperature Coefficient
3-98 1997
Page 4
MIC29510/29512 Micrel
Parameter Conditions Min Typical Max Units
Enable Input (MIC29512 only)
Input Logic Voltage Low (Off) 0.8 V
High (On) 2.4 V
Enable (EN) Pin Input Current V
Regulator Output (Note 8) 10 µA Current in Shutdown 20 µA
General Note: Devices are ESD sensitive. Handling precautions recommended. Note 1: The maximum continuous supply voltage is 16V. Note 2: Full Load current is defined as 5A for the MIC29510/29512. For testing, V Note 3: Dropout voltage is defined as the input-to-output differential when the output voltage drops to 99% of its nominal value with V
Note 4: For this test, VIN is the larger of 8V or V Note 5: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground
Note 6: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 7: V Note 8: VEN ≤ 0.8V and VIN ≤ 8V, V
to VIN.
pin current.
≤ V
REF
≤ (VIN – 1 V), 2.4V ≤ VIN ≤ 16V, 10mA < IL ≤ IFL, TJ ≤ T
OUT
= V
EN
IN
= 0.8V – 2 µA
V
EN
is programmed to 5V.
OUT
+ 3V.
OUT
J MAX.
OUT
= 0.
15 30 µA
75 µA
4 µA
+ 1V applied
OUT
3
Block Diagram
IN
Thermal
Shut­down
Bias
Reference
EN
On/Off
1997 3-99
28V
16V
O.V. I
LIMIT
Feed-
back
OUT
ADJ
GND
Page 5
MIC29510/29512 Micrel
Typical Characteristics
MIC29512 Load Transient Response
(See Test Circuit Schematic)
V
OUT
3.525V nominal
4 × 330µF
AVX
TPSE337M006R0100
tantalum
VIN = V
OUT
+ 1V
MIC29512
EN
IN
GND
OUT
0.1µF
ADJ
49.9k 1%
V
load (not shown):
OUT
Intel® Power Validator
93.1k 1%
MIC29512 Load Transient Response Test Circuit
MIC29512 Line Transient Response
with 5A Load, 10µF Output Capacitance
6.525V
4.525V
+20mV
3.525V
–20mV
5A
LOAD CURRENT OUTPUT VOLTAGE
200mA
0mA
MIC29512 Line Transient Response
with 5A Load, 100µF Output Capacitance
6.525V
4.525V
1ms/division
+20mV
3.525V
–20mV
OUTPUT VOLTAGE INPUT VOLTAGE
MIC2951x Dropout Voltage
vs. Output Current
1.0
0.8
0.6
0.4
0.2
DROPOUT VOLTAGE (V)
0
012345
OUTPUT CURRENT (A)
200µs/division
= 5A
I
OUT
C
= 10µF
OUT
+20mV
3.525V
–20mV
OUTPUT VOLTAGE INPUT VOLTAGE
MIC2951x Dropout Voltage
1.0
0.8
0.6
0.4
0.2
DROPOUT VOLTAGE (V)
vs. Temperature
I
= 5A
LOAD
0
-60 -30 0 30 60 90 120 150 TEMPERATURE (°C)
200µs/division
= 5A
I
OUT
C
= 100µF
OUT
MIC29510-3.3
Dropout Characteristics
5.0 VIN = 4.3V
4.0
I
= 10mA
LOAD
3.0
I
2.0
1.0
OUTPUT VOLTAGE (V)
0.0
0246
INPUT VOLTAGE (V)
LOAD
= 5A
3-100 1997
Page 6
MIC29510/29512 Micrel
0
50
100
150
200
250
02468
GROUND CURRENT (mA)
SUPPLY VOLTAGE (V)
0
2
4
6
8
-60 -30 0 30 60 90 120 150
GROUND CURRENT (mA)
TEMPERATURE (°C)
0
1
2
3
4
5
6
7
8
9
10
-60 -30 0 30 60 90 120 150
CURRENT (A)
TEMPERATURE (°C)
MIC2951x-3.3 Ground Current
vs. Supply Voltage
10
R
= 10mA
LOAD
8
6
4
2
GROUND CURRENT (mA)
0
02468
SUPPLY VOLTAGE (V)
MIC2951x Ground Current
0.8
0.6
0.4
0.2
GROUND CURRENT (mA)
0.0
vs. Temperature
I
= 10mA
OUT
-60 -30 0 30 60 90 120 150 TEMPERATURE (°C)
MIC2951x-3.3 Ground Current
vs. Supply Voltage
I
= 5A
LOAD
MIC2951x Ground Current
vs. Temperature
I
= 500mA
OUT
MIC2951x Ground
Current vs. Input Voltage
2.5 V
2.0
1.5
1.0
0.5
0.0
GROUND CURRENT (mA)
-0.5
= 3.3V
OUT
R
= 100Ω
LOAD
-20 -10 0 10 20
INPUT VOLTAGE (V)
MIC2951x-3.3 Ground Current
200
150
100
GROUND CURRENT (mA)
vs. Temperature
VIN = 4.3V I
= 5A
LOAD
50
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3
MIC2951x-3.3 Ground Current
vs. Output Current
150
125
VIN = 4.3V
100
75
50
25
GROUND CURRENT (mA)
0
012345
OUTPUT CURRENT (A)
MIC29512 Enable Current
50
40
30
1997 3-101
20
10
ENABLE CURRENT (µA)
vs. Temperaure
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
VEN = 5V
VEN = 2V
MIC29510-3.3 Output Voltage
3.40
3.38
3.36
3.34
3.32
3.30
3.28
3.26
3.24
OUTPUT VOLTAGE (V)
3.22
3.20
vs. Temperature
3 DEVICES
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
MIC29512 Adjust Pin Current
vs. Temperature
80
60
40
20
ADJUST PIN CURRENT (nA)
0
-60 -30 0 30 60 90 120 150
I
= 10mA
LOAD
TEMPERATURE (°C)
MIC2951x Short Circuit
Current vs. Temperature
V
= 0V
OUT
MIC2951x Output Impedance
10
1
0.1
0.01
OUTPUT IMPEDANCE (Ω)
0.001
vs. Frequency
0
0
10x10
100x10
FREQUENCY (Hz)
3
1x10
3
10x10
3
100x10
6
1x10
Page 7
MIC29510/29512 Micrel
Applications Information
A trade-off for the low dropout voltage is a varying base drive requirement. But Micrel’s Super ßeta PNP™ process re­duces this drive requirement to merely 2 to 5% of the load current.
MIC29510/512 regulators are fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current under overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating tem­perature. Transient protection allows device (and load) sur­vival even when the input voltage spike above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. The MIC29512 version offers a logic level ON/OFF control: when disabled, the devices draw nearly zero current.
An additional feature of this regulator family is a common pinout: a design’s current requirement may change up or down yet use the same board layout, as all of Micrel’s high­current Super ßeta PNP™ regulators have identical pinouts.
V
IN
Figure 3. The MIC29510 LDO regulator requires only
two capacitors for operation.
Thermal Design
Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires the following application-specific parameters:
• Maximum ambient temperature, T
• Output Current, I
• Output Voltage, V
• Input Voltage, V
OUT
OUT
IN
V
OUT
A
First, we calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet.
PD = I
Where the ground current is approximated by 2% of I
× (1.02VIN – V
OUT
OUT
)
OUT
Then the heat sink thermal resistance is determined with this formula:
T
– T
J MAX
A
θSA = —————— – (θJC + θCS)
P
D
Where T
≤ 125°C and θCS is between 0 and 2°C/W.
J MAX
The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. The low dropout properties of Micrel Super ßeta PNP regulators allow very significant reductions in regulator power dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least
0.1µF is needed directly between the input and regulator ground.
Please refer to Application Note 9 for further details and examples on thermal design and heat sink specification.
Capacitor Requirements
For stability and minimum output noise, a capacitor on the regulator output is necessary. The value of this capacitor is dependent upon the output current; lower currents allow smaller capacitors. MIC29510/2 regulators are stable with a minimum capacitor value of 47µF at full load.
This capacitor need not be an expensive low ESR type: aluminum electrolytics are adequate. In fact, extremely low ESR capacitors may contribute to instability. Tantalum ca­pacitors are recommended for systems where fast load transient response is important.
Where the regulator is powered from a source with a high AC impedance, a 0.1µF capacitor connected between Input and GND is recommended. This capacitor should have good characteristics to above 250kHz.
Transient Response and 5V to 3.3V Conversion
The MIC29510/2 have excellent response to variations in input voltage and load current. By virtue of their low dropout voltage, these devices do not saturate into dropout as readily as similar NPN-based designs. A 3.3V output Micrel LDO will maintain full speed and performance with an input supply as low as 4.2V, and will still provide some regulation with supplies down to 3.8V, unlike NPN devices that require 5.1V or more for good performance and become nothing more than a resistor under 4.6V of input. Micrel’s PNP regulators provide superior performance in “5V to 3.3V” conversion applications than NPN regulators, especially when all toler­ances are considered.
.
3-102 1997
Page 8
MIC29510/29512 Micrel
Adjustable Regulator Design
MIC29512BT
V
IN
4.75 to 5.25
10µF
R1
100k
R2
56.2k
V
= 1.240V × [1 + (R1 / R2)]
OUT
47µF
V
OUT
3.45V
Figure 4. Adjustable Regulator with Resistors
The adjustable regulator version, MIC29512, allows pro­gramming the output voltage anywhere between 1.25V and
the 16V maximum operating rating of the family. Two resis­tors are used. Resistors can be quite large, up to 100kΩ, because of the very high input impedance and low bias current of the sense comparator. The resistor values are calculated by:
V
OUT
R1 = R2 × ( –—— – 1 )
1.240
Where VO is the desired output voltage. Figure 4 shows component definition.
Enable Input
The MIC29512 versions features an enable (EN) input that allows ON/OFF control of the device. Special design allows “zero” current drain when the device is disabled—only micro­amperes of leakage current flows. The EN input has TTL/ CMOS compatible thresholds for simple interfacing with logic, or may be directly tied to VIN. Enabling the regulator requires approximately 20µA of current into the EN pin.
3
Resistor Value Table for the MIC29512 Adjustable Regulator
Voltage Standard (Ω)
R1 R2
2.85 100k 76.8k
2.9 100k 75.0k
3.0 100k 69.8k
3.1 100k 66.5k
3.15 100k 64.9k
3.3 100k 60.4k
3.45 100k 56.2k
3.6 100k 52.3k
3.8 100k 48.7k
4.0 100k 45.3k
4.1 100k 43.2k
1997 3-103
Loading...
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use