A8672 Datasheet, PDF (7/24 Pages) Allegro MicroSystems – Fixed Frequency High Current Synchronous Buck Regulator With Fault Warnings and Power OK

A8672
Fixed Frequency High Current Synchronous Buck Regulator
With Fault Warnings and Power OK
ELECTRICAL CHARACTERISTICS¹ (continued) Valid at T_J = –20°C to 125°C and V_IN = 12 V; unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit
Power OK
Power Good Threshold (Rising)
V_POK(HI)
Feedback voltage relative to reference voltage,
POK = high
92
95
98
%
Power Good Threshold (Falling)
V_POK(LO)
Feedback voltage relative to reference voltage,
POK = high
107
110
113
%
Power Good Hysteresis
POK Rising Delay
POK Output Voltage
POK Leakage Current
Fault Reporting
V_POKHYS
t_dPOK
V_POK
I_POK
POK= low
I_POK = 10 mA, POK asserted
V_POK = 5.5 V, POK not asserted
–
5
–
%
–
90
–
µs
–
–
500
mV
–
–
1
μA
¯F¯ ¯A ¯U¯¯L¯ ¯T¯ Overtemperature
¯F¯ ¯A ¯U¯¯L¯ ¯T¯ Overtemperature Hysteresis
¯F¯ ¯A ¯U¯¯L¯ ¯T¯ Output Voltage
¯F¯ ¯A ¯U¯¯L¯ ¯T¯  _Leakage
Protection
T_OT
T_OTHYS
V_FAULT
I_FAULT
Temperature rising
Fault release = T_OT – T_OTHYS
I_FAULT = 10 mA, fault asserted
V_FAULT = 5.5 V, fault not asserted
–
140
–
°C
–
20
–
°C
–
–
500
mV
–
–
1
µA
Undervoltage Threshold (Falling)
V_UVFB Feedback voltage relative to reference voltage
–
75
–
%
Undervoltage Hysteresis
V_UVHYS
–
5
–
%
Overvoltage Threshold (Rising)
V_OVFB Feedback voltage relative to reference voltage
115
120
125
%
Overvoltage Hysteresis
V_OVHYS
–
5
–
%
Valley Current Limit Voltage Range
I_LIMVR
1.0
–
2.75
V
Valley Current Limit
ILIM resistor = 169 kΩ
I_LIM
ILIM resistor = 249 kΩ
3.0
4.0
5.0
A
6.0
8.0
10.0
A
Hiccup On Period¹
t_HICOC
Either valley current limit or overvoltage
condition reached
–
50
–
µs
Hiccup Shutdown Period¹
C_SS = 10 nF, first shutdown event
–
10
–
ms
t_HICSD
C_SS = 10 nF, second and subsequent shutdown
events
-
1.2
-
ms
Pulse-by-Pulse Negative Valley
Current Limit
I_NLIM FCCM selected
–2.4
–1.9
–1.4
A
FB Overvoltage Duration
t_UVFB High-side MOSFET off, low-side MOSFET on
–
50
–
μs
High-Side MOSFET Protection Current I_HIPRO LX node short-circuited to GND
–
25
–
A
High-Side MOSFET Protection Voltage V_HIPRO LX node short-circuited to GND
450
650
850
mV
VDD Undervoltage Lockout (Rising)
V_UVLO
–
4.2
4.45
V
VDD Undervoltage Lockout Hysteresis V_UVLOHYS
–
300
–
mV
Thermal Shutdown Threshold
T_SD
Temperature rising
–
165
–
°C
Thermal Shutdown Hysteresis
T_SDHYS Recovery = T_SD – T_SDHYS
–
15
–
°C
1_{Specifications throughout the junction temperature, TJ , range of –20ºC to 125ºC are assured by design and characterization unless otherwise noted.}
2_{Positive current is into the node or pin, negative current is out of the node or pin.}
Allegro MicroSystems, LLC
6
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com