MIC28304
70V 3A Power Module
Hyper Speed Control™ Family
General Description
Micrel’s MIC28304 is synchronous step-down regulator
module, featuring a unique adaptive ON-time control
architecture. The module incorporates a DC-to-DC
controller, power MOSFETs, bootstrap diode, bootstrap
capacitor and an inductor in a single package. The
MIC28304 operates over an input supply range from 4.5V
to 70V and can be used to supply up to 3A of output
current. The output voltage is adjustable down to 0.8V with
a guaranteed accuracy of ±1%. The device operates with
programmable switching frequency from 200kHz to
600kHz.
Micrel’s HyperLight Load™ architecture provides the same
high-efficiency and ultra-fast transient response as the
Hyper Speed Control™ architecture under the medium to
heavy loads, but also maintains high efficiency under light
load conditions by transitioning to variable frequency,
discontinuous-mode operation.
The MIC28304 offers a full suite of protection features.
These include undervoltage lockout, internal soft-start,
foldback current limit, “hiccup” mode short-circuit
protection, and thermal shutdown.
Datasheets and support documentation are available on
Micrel’s web site at:
www.micrel.com.
Features
•
Easy to use
−
Stable with low-ESR ceramic output capacitor
−
No compensation and no inductor to choose
•
4.5V to 70V input voltage
•
Single-supply operation
•
Power Good (PG) output
•
Low radiated emission (EMI) per EN55022, Class B
•
Adjustable current limit
•
Adjustable output voltage from 0.9V to 24V
(also limited by duty cycle)
•
200kHz to 600kHz, programmable switching frequency
•
Supports safe start-up into a pre-biased output
•
–40°C to +125°C junction temperature range
•
Available in 64-pin, 12mm × 12mm × 3mm QFN
package
Applications
•
Distributed power systems
•
Industrial, medical, telecom, and automotive
Typical Application
Hyper Speed Control, HyperLight Load, and Any Capacitor are trademarks of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
March 25, 2014
Revision 1.1
Micrel, Inc.
MIC28304
Ordering Information
Part Number
MIC28304-1YMP
MIC28304-2YMP
Switching
Frequency
200kHz to 600kHz
200kHz to 600kHz
Features
HyperLight Load
Hyper Speed Control
Package
64-pin 12mm × 12mm QFN
64-pin 12mm × 12mm QFN
Junction
Temperature
Range
–40°C to +125°C
–40°C to +125°C
Lead
Finish
Pb-Free
Pb-Free
Pin Configuration
64-Pin 12mm × 12mm QFN (MP)
(Top View)
Pin Description
Pin Number
1, 2, 3, 54, 64
4
Pin Name
GND
ILIM
Pin Function
Analog Ground. Ground for internal controller and feedback resistor network. The analog ground
return path should be separate from the power ground (PGND) return path.
Current Limit Setting. Connect a resistor from SW (pin #4) to ILIM to set the over-current threshold
for the converter.
Supply Voltage for Controller. The VIN operating voltage range is from 4.5V to 70V. A 0.47μF
ceramic capacitor from VIN (pin # 60) to AGND is required for decoupling. The pin # 5 should be
externally connected to either PVIN or pin # 60 on PCB.
Switch Node and Current-Sense Input. High current output driver return. The SW pin connects
directly to the switch node. Due to the high-speed switching on this pin, the SW pin should be routed
away from sensitive nodes. The SW pin also senses the current by monitoring the voltage across
the low-side MOSFET during OFF time.
5, 60
VIN
6, 40 to 48, 51
SW
March 25, 2014
2
Revision 1.1
Micrel, Inc.
MIC28304
Pin Description (Continued)
Pin Number
7, 8
Pin Name
FREQ
Pin Function
Switching Frequency Adjust Input. Leaving this pin open will set the switching frequency to 600kHz.
Alternatively a resistor from this pin to ground can be used to lower the switching frequency.
Power Ground. PGND is the return path for the buck converter power stage. The PGND pin
connects to the sources of low-side N-Channel external MOSFET, the negative terminals of input
capacitors, and the negative terminals of output capacitors. The return path for the power ground
should be as small as possible and separate from the analog ground (GND) return path.
Power Input Voltage. Connection to the drain of the internal high-side power MOSFET.
Output Voltage. Connection with the internal inductor, the output capacitor should be connected
from this pin to PGND as close to the module as possible.
No Connection. Leave it floating.
Anode Bootstrap Diode Input. Anode connection of internal bootstrap diode, this pin should be
connected to the PVDD pin.
Bootstrap Capacitor. Connection to the internal bootstrap capacitor. Leave floating, no connect.
Bootstrap Resistor. Connection to the internal bootstrap resistor and high-side power MOSFET
drive circuitry. Leave floating, no connect.
Feedback Input. Input to the transconductance amplifier of the control loop. The FB pin is regulated
to 0.8V. A resistor divider connecting the feedback to the output is used to set the desired output
voltage.
Power Good Output. Open drain output, an external pull-up resistor to external power rails is
required.
Enable Input. A logic signal to enable or disable the buck converter operation. The EN pin is CMOS
compatible. Logic high enables the device, logic low shutdowns the regulator. In the disable mode,
the input supply current for the device is minimized to 4µA typically. Do not pull EN to PVDD.
Internal +5V Linear Regulator Output. PVDD is the internal supply bus for the device. In the
applications with VIN < +5.5V, PVDD should be tied to VIN to by-pass the linear regulator.
No Connection. Leave it floating.
9 to 13
PGND
14 to 22
23 to 38
39
49, 50
52, 53
55, 56
PVIN
VOUT
NC
ANODE
BSTC
BSTR
57
FB
58
PGOOD
59
EN
61, 62
63
PVDD
NC
March 25, 2014
3
Revision 1.1
Micrel, Inc.
MIC28304
Absolute Maximum Ratings
(1)
PVIN, VIN to PGND ...................................... –0.3V to +76V
PVDD, V
ANODE
to PGND .................................. –0.3V to +6V
V
SW
, V
FREQ
, V
ILIM
, V
EN
........................
−0.3V
to (PVIN +0.3V)
V
BSTC/BSTR
to V
SW
................................................
−0.3V
to 6V
V
BSTC/BSTR
to PGND ..........................................
−0.3V
to 82V
V
FB
, V
PG
to PGND .........................
−0.3V
to (PVDD + 0.3V)
PGND to AGND............................................
−0.3V
to +0.3V
Junction Temperature .............................................. +150°C
Storage Temperature (T
S
) .........................
−65°C
to +150°C
Lead Temperature (soldering, 10s) ............................ 260°C
(3)
ESD Rating ................................................. ESD Sensitive
Operating Ratings
(2)
Supply Voltage (PVIN, VIN) .............................. 4.5V to 70V
Enable Input (V
EN
) ................................................. 0V to VIN
V
SW
, V
FEQ
, V
ILIM
, V
EN
.............................................. 0V to VIN
Power Good (V
PGOOD
)..………………..……… ... 0V to PVDD
Junction Temperature (T
J
) ........................
−40°C
to +125°C
Junction Thermal Resistance
12mm × 12mm QFN-64 (θ
JA
) ............................ 20°C/W
12mm × 12mm QFN-64 (θ
JC
)............................... 5°C/W
Electrical Characteristics
(4)
PVIN = VIN = 12V, V
OUT
= 5V, V
BST
– V
SW
= 5V; T
A
= 25°C, unless noted.
Bold
values indicate
−40°C
≤ T
J
≤ +125°C.
Parameter
Power Supply Input
Input Voltage Range (PVIN, VIN)
Current into Pin 60; VFB = 1.5V (MIC28304-1)
Controller Supply Current
(5)
Condition
Min.
Typ.
Max.
Units
4.5
0.4
2.1
0.1
0.7
70
0.75
3
10
V
mA
µA
mA
Current into Pin 60;VFB = 1.5V (MIC28304-2)
Current into Pin 60;VEN = 0V
Operating Current
Shutdown Supply Current
PVDD Supply
(5)
I
OUT
= 0A (MIC28304-1)
I
OUT
= 0A (MIC28304-2)
PVIN = VIN = 12V, V
EN
= 0V
27
4
µA
PVDD Output Voltage
PVDD UVLO Threshold
PVDD UVLO Hysteresis
Load Regulation
Reference
(5)
VIN = 7V to 70V, I
PVDD
= 10mA
PVDD rising
4.8
3.8
5.2
4.2
400
5.4
4.7
V
V
mV
I
PVDD
= 0 to 40mA
0.6
2
3.6
%
Feedback Reference Voltage
FB Bias Current
Notes:
T
J
= 25°C (±1.0%)
−40°C
≤ T
J
≤ 125°C (±2%)
V
FB
= 0.8V
0.792
0.784
0.8
0.8
5
0.808
0.816
500
V
nA
1. Exceeding the absolute maximum ratings may damage the device.
2. The device is not guaranteed to function outside its operating ratings.
3. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
5. IC tested prior to assembly.
March 25, 2014
4
Revision 1.1
Micrel, Inc.
MIC28304
Electrical Characteristics
(4)
(Continued)
PVIN = VIN = 12V, V
OUT
= 5V, V
BST
– V
SW
= 5V; T
A
= 25°C, unless noted.
Bold
values indicate
−40°C
≤ T
J
≤ +125°C.
Parameter
Enable Control
EN Logic Level High
EN Logic Level Low
EN Hysteresis
EN Bias Current
Oscillator
Switching Frequency
Maximum Duty Cycle
Minimum Duty Cycle
Minimum Off-Time
Soft-Start
(5)
Condition
Min.
Typ.
Max.
Units
1.8
0.6
200
V
EN
= 12V
5
20
V
V
mV
µA
FREQ pin = open
RFREQ = 100kΩ (FREQ pin-to-GND)
400
600
300
85
750
kHz
%
%
260
ns
V
FB
> 0.8V
140
0
200
Soft-Start Time
Short-Circuit Protection
(5)
5
−30
−23
60
27
−14
−7
80
36
ms
Current-Limit Threshold (V
CL
)
Short-Circuit Threshold
Current-Limit Source Current
Short-Circuit Source Current
Leakage
SW, BSTR Leakage Current
Power Good
(5)
V
FB
= 0.79V
V
FB
= 0V
V
FB
= 0.79V
V
FB
= 0V
0
9
100
47
mV
mV
µA
µA
50
µA
Power Good Threshold Voltage
Power Good Hysteresis
Power Good Delay Time
Power Good Low Voltage
Thermal Protection
Overtemperature Shutdown
Overtemperature Shutdown Hysteresis
Sweep V
FB
from low-to-high
Sweep V
FB
from high-to-low
Sweep V
FB
from low-to-high
V
FB
< 90% x V
NOM
, I
PG
= 1mA
85
90
6
100
70
95
%V
OUT
%V
OUT
µs
200
mV
T
J
Rising
160
4
°C
°C
March 25, 2014
5
Revision 1.1
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
