Microchip Technology MIC2125, MIC2126 General Description Manual
MIC2125/6
MIC2125/6
16-Pin 3 mm x 3 mm QFN (ML)
28V Synchronous Buck Controllers
Featuring Adaptive ON-Time Control
Features
• Hyper Speed Control Architecture Enables:
- High delta V operation (V
= 0.6V)
- Any Capacitor™ stable
• 4.5V to 28V Input Voltage
• Adjustable Output Voltage from 0.6V to 24V
• 200 kHz to 750 kHz Programmable Switching
Frequency
®
• HyperLight Load
• Hyper Speed Control® (MIC2126)
• Enable Input and Power Good Output
• Built-in 5V Regulator for Single-Supply Operation
• Programmable current limit and “hiccup” mode
short-circuit protection
• 7 ms internal soft-start, internal compensation,
and thermal shutdown
• Supports Safe Start-Up into a Prebiased Output
• –40°C to +125°C Junction Temperature Range
• Available in 16-pin, 3 mm × 3 mm QFN Package
(MIC2125)
= 28V and V
IN
OUT
Applications
• Networking/Telecom Equipment
• Base Stations, Servers
• Distributed Power Systems
• Industrial Power Supplies
General Description
The MIC2125 and MIC2126 are constant-frequency
synchronous buck controllers featuring a unique
adaptive ON-time control architecture. The MIC2125/6
operate over an input voltage range from 4.5V to 28V
and can be used to supply load current up to 25A. The
output voltage is adjustable down to 0.6V with a
guaranteed accuracy of ±1%. The device operates with
programmable switching frequency from 200 kHz to
750 kHz.
®
HyperLight Load
efficiency and ultra-fast transient response as the
Hyper Speed Control® architecture under medium to
heavy loads. It also maintains high efficiency under
light load conditions by transitioning to variable
frequency, discontinuous conduction mode operation.
The MIC2125/6 offer a full suite of features to ensure
protection of the IC during fault conditions. These
include undervoltage lockout to ensure proper
operation under power-sag conditions, internal
soft-start to reduce inrush current, “hiccup” mode
short-circuit protection, and thermal shutdown.
architecture provides the same high
Package Type
FB
PG
EN
VIN
16 15 14 13
2015 Microchip Technology Inc. DS20005459B-page 1
VDD
PVDD
ILIM
DL
1
2
EP 17
3
4
56 78
FREQ
PGND
DH
SW
12
11
10
9
AGND
NC
OVP
BST
MIC2125/6
MIC2125/6
3x3 QFN
4.7μF
MIC2125/26
EN
VDD
EN
g
m
EA
COMP
CL
DETECTION
CONTROL
LOGIC
TIMER
SOFT–START
FIXED T
ON
ESTIMATE
UVLO
LDO
THERMAL
SHUTDOWN
SOFT
START
PVDD
COMPENSATION
MODIFIED
T
OFF
PG
49.9kΩ
VDD
PG
VDD
8%
92%
100kΩ
V
IN
HSD
LSD
90.9kΩ
V
OUT
3.3V/20A
0.1μF
SW
FB
470pF
DL
DH
BST
Q1
Q3
VIN
AGND
PGND
220μF
0.1μF
100μF
2.2μF
×2
0.72μH
R1
10kΩ
R2
2.26kΩ
1.2kΩ
V
IN
4.5V TO 28V
R19
R20
FREQ
ILIM
OVP
V
REF
0.6V
V
REF
0.6V
PVDD
470μF
Typical Application Circuit
PVDD
VDD
4.7μF
EN
AGND
EN
MIC2125/6
FREQ
VIN
BST
DH
SW
0.1μF
0.72μH
V
4.5V TO 28V
2.2μF
×3
IN
V
OUT
3.3V/20A
220μF
PG
V
OUT
PG
DL
56.2kΩ
OVP
PGND
90.9kΩ
0.1μF
10kΩ
470pF
100μF 470μF
10kΩ
FB
ILIM
2.26kΩ
1.2kΩ
Functional Block Diagram
DS20005459B-page 2 2015 Microchip Technology Inc.
MIC2125/6
1.0 ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
VIN.............................................................................................................................................................. –0.3V to +30V
V
, P
DD
V
SW
V
BST
V
BST
V
PG
V
FB
P
GND
ESD Rating
Operating Ratings ‡
Supply Voltage (VIN) ...................................................................................................................................... 4.5V to 28V
V
SW
† Notice: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the device at those or any other conditions above those indicated
in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended
periods may affect device reliability.
‡ Notice: The device is not guaranteed to function outside its operating ratings.
Note 1: Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5 k in series
.................................................................................................................................................... –0.3V to +6V
VDD
, V
FREQ
, V
, VEN....................................................................................................................–0.3V to (VIN +0.3V)
ILIM
to VSW................................................................................................................................................... –0.3V to 6V
............................................................................................................................................................. –0.3V to 36V
................................................................................................................................................. –0.3V to (VDD + 0.3V)
................................................................................................................................................. –0.3V to (VDD + 0.3V)
, V
to A
FREQ
........................................................................................................................................... –0.3V to +0.3V
GND
(1)
.............................................................................................................................................................2 kV
, V
, VEN......................................................................................................................................0V to V
ILIM
with 100 pF.
IN
2015 Microchip Technology Inc. DS20005459B-page 3
MIC2125/6
TABLE 1-1: ELECTRICAL CHARACTERISTICS
Electrical Characteristics: V
–40°C T
+125°C. (Note 1).
J
Parameters Min. Typ. Max. Units Conditions
Power Supply Input
Input Voltage Range (VIN)
(Note 2)
Quiescent Supply Current
(MIC2125)
Quiescent Supply Current
(MIC2126)
Shutdown Supply Current — 0.1 5 µA SW unconnected, V
VDD Supply
V
Output Voltage 4.8 5.2 5.4 VV
DD
V
UVLO Threshold 3.7 4.2 4.5 V
DD
VDD UVLO Hysteresis — 400 — mV —
Load Regulation 0.6 2 3.6 % IDD = 0 to 40 mA
Reference
Feedback Reference Voltage 0.597 0.6 0.603 V T
FB Bias Current — 0.01 0.5 µA V
Enable Control
EN Logic Level High 1.6 —— V—
EN Logic Level Low — — 0.6 —
EN Hysteresis — 120 — mV —
EN Bias Current — 6 30 µA V
Oscillator
Switching Frequency — 750 — kHz V
Maximum Duty Cycle — 85 — % —
Minimum Duty Cycle — 0 — VFB > 0.6V
Minimum On-Time — 100 — ns —
Minimum Off-Time 150 220 300 —
Soft-Start
Soft-Start Time — 7 — ms —
Short-Circuit Protection and OVP
Current-Limit Comparator
Offset
Current-Limit Source Current 32 36 40 µA VFB = 0.6V
Note 1: Specification for packaged product only.
2: The application is fully functional at low V
low voltage VTH.
= 12V, V
IN
OUT
= 1.2V, V
– VSW = 5V; T
BST
= 25°C, unless noted. Bold values indicate
A
4.5 — 5.5 VV
4.5 — 28 —
—340750 µA V
—1.1 3 mA V
0.594 0.6 0.606 –40°C T
—375 — V
–15 –4 7 mV V
(supply of the control section) if the external MOSFETs have
DD
= V
DD
IN
= 1.5V
FB
= 1.5V
FB
= 7V to 28V, IDD = 10 mA
IN
rising
DD
= 25°C (±0.5%)
J
+125°C (±1%)
J
= 0.6V
FB
= 12V
EN
= V
FREQ
FREQ
FB
IN
= 50% x V
= 0.6V
= 0V
EN
IN
DS20005459B-page 4 2015 Microchip Technology Inc.
TABLE 1-1: ELECTRICAL CHARACTERISTICS (CONTINUED)
Electrical Characteristics: V
–40°C T
+125°C. (Note 1).
J
Parameters Min. Typ. Max. Units Conditions
= 12V, V
IN
OUT
= 1.2V, V
– VSW = 5V; T
BST
= 25°C, unless noted. Bold values indicate
A
MIC2125/6
Overvoltage Protection
—— 0.62 — V —
Threshold
FET Drivers
DH, DL Output Low Voltage — — 0.1 VI
DH, DL Output High Voltage V
PVDD
-0.1
—— I
= 10 mA
SINK
SOURCE
= 10 mA
or
V
-0.1
BST
DH On-Resistance, High State — 2.5 — —
DH On-Resistance, Low State — 1.6 — —
DL On-Resistance, High State — 1.9 — —
DL On-Resistance, Low State — 0.55 — —
SW, BST Leakage Current — — 50
µA —
Power Good (PG)
PG Threshold Voltage 85 89 95 %V
Sweep VFB from low to high
OUT
PG Hysteresis — 6 — Sweep VFB from high to low
PG Delay Time — 80 —
PG Low Voltage — 60 200 mV V
µs Sweep V
< 90% x V
FB
from low to high
FB
, IPG = 1 mA
NOM
Thermal Protection
Overtemperature Shutdown — 150 — °C T
Overtemperature Shutdown
—15 — °C—
Rising
J
Hysteresis
Note 1: Specification for packaged product only.
2: The application is fully functional at low V
(supply of the control section) if the external MOSFETs have
DD
low voltage VTH.
2015 Microchip Technology Inc. DS20005459B-page 5
MIC2125/6
TEMPERATURE SPECIFICATIONS
Parameters Sym. Min. Typ. Max. Units Conditions
Temperature Ranges
Junction Operating Temperature T
Storage Temperature Range T
Junction Temperature T
Lead Temperature — — — +260 °C Soldering, 10s
Package Thermal Resistances
Thermal Resistance 3 mm x 3 mm
QFN-16LD
Note 1: The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable
junction temperature and the thermal resistance from junction to air (i.e., TA, TJ, JA). Exceeding the
maximum allowable power dissipation will cause the device operating junction temperature to exceed the
maximum +125°C rating. Sustained junction temperatures above +125°C can impact the device reliability.
J
S
J
JA
JC
–40 — +125 °C Note 1
–65 — +150 °C —
— — +150 °C —
—50.8 —°C/W—
—25.3 —°C/W—
DS20005459B-page 6 2015 Microchip Technology Inc.
MIC2125/6
2.0 TYPICAL PERFORMANCE CURVES
Note: The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note: Unless otherwise noted, V
FIGURE 2-1: VIN Operating Supply Current vs. Input Voltage (MIC2125).
= 12V, FREQ = 350 kHz.
IN
FIGURE 2-4: VIN Shutdown Current vs. Input Voltage (MIC2125).
FIGURE 2-2: Feedback Voltage vs. Input Voltage (MIC212 5).
FIGURE 2-3: Output Voltage vs. Input Voltage (MIC212 5).
2015 Microchip Technology Inc. DS20005459B-page 7
FIGURE 2-5: Switching Frequency vs. Input Voltage.
FIGURE 2-6: Switching Frequency vs. Temperature (MIC2126).
MIC2125/6
Note: Unless otherwise noted, V
= 12V, FREQ = 350 kHz.
IN
FIGURE 2-7: VDD Voltage vs. Input Voltage (MIC212 5).
.V
FIGURE 2-10: VIN Operating Supply Current vs. Temperature (MIC2125).
FIGURE 2-8: Enable Threshold vs. Input Voltage (MIC212 5).
FIGURE 2-9: Output Peak Current Limit vs. Input Voltage (MIC2125).
FIGURE 2-11: Feedback Voltage vs. Temperature (MIC2125).
FIGURE 2-12: Load Regulation vs. Temperature (MIC2125).
DS20005459B-page 8 2015 Microchip Technology Inc.
MIC2125/6
Note: Unless otherwise noted, V
FIGURE 2-13: VIN Shutdown Current vs.
Temperature (MIC2125)
.
= 12V, FREQ = 350 kHz.
IN
FIGURE 2-16: EN Bias Current vs.
Temperature (MIC2125)
.
FIGURE 2-14: VDD UVLO Threshold vs.
Temperature (MIC2125)
FIGURE 2-15: Enable Threshold vs. Temperature (MIC2125).
.
FIGURE 2-17: VDD Voltage vs.
Temperature (MIC2125)
FIGURE 2-18: Current-Limit Source
Current vs. Temperature (MIC2125)
.
.
2015 Microchip Technology Inc. DS20005459B-page 9
MIC2125/6
Note: Unless otherwise noted, V
*Note: For Case Temperature graphs: The temperature measurement was taken at the hottest point on the MIC2125/6
case mounted on a 5 square inch PCBn. Actual results will depend upon the size of the PCB, ambient temperature and
proximity to other heat emitting components.
FIGURE 2-19: Line Regulation vs. Temperature (MIC2125).
= 12V, FREQ = 350 kHz.
IN
FIGURE 2-22: Output Regulation vs. Input Voltage (MIC2125).
FIGURE 2-20: Feedback Voltage vs. Output Current (MIC2125).
FIGURE 2-21: Line Regulation vs. Output Current (MIC2125).
FIGURE 2-23: Case Temperature* vs. Output Current (MIC2125).
FIGURE 2-24: Case Temperature* vs. Output Current (MIC2125).
DS20005459B-page 10 2015 Microchip Technology Inc.
MIC2125/6
Note: Unless otherwise noted, V
*Note: For Case Temperature graphs: The temperature measurement was taken at the hottest point on the MIC2125/6
case mounted on a 5 square inch PCBn. Actual results will depend upon the size of the PCB, ambient temperature and
proximity to other heat emitting components.
FIGURE 2-25: Case Temperature* vs. Output Current (MIC2125).
= 12V, FREQ = 350 kHz.
IN
FIGURE 2-28: Efficiency (V
Output Current (MIC2125).
= 18V) vs.
IN
FIGURE 2-26: Efficiency (V
Output Current (MIC2125).
FIGURE 2-27: Efficiency (V
Output Current (MIC2125).
= 5V) vs.
IN
= 12V) vs.
IN
FIGURE 2-29: Efficiency (V
Output Current (MIC2126).
FIGURE 2-30: Efficiency (V
Output Current (MIC2126).
= 5V) vs.
IN
= 12V) vs.
IN
2015 Microchip Technology Inc. DS20005459B-page 11
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