A4411 Datasheet, PDF (1/45 Pages) Allegro MicroSystems – Automotive AEC-Q100 qualified

A4411
Adjustable Frequency Buck or Buck-Boost Pre-Regulator with a
Synchronous Buck, 3 LDOs, Pulse-Width Window Watchdog, NPOR, and POK5V
FEATURES AND BENEFITS
• Automotive AEC-Q100 qualified
• 3.5 to 36 V_IN operating range, 40 V_IN maximum
• Buck or buck-boost pre-regulator (VREG)
• Adjustable PWM switching frequency: 250 kHz to 2.4 MHz
• PWM frequency can be synchronized to external clock
• Synchronous buck regulator (ADJ) delivers 0.8 to 3.3 V
• Two 5 V LDOs for “local” sensors (V5_SNR) and
communications (V5_CAN) with foldback short-circuit
protections
• 5 V internal tracking LDO for remote sensors with foldback
short-circuit and short-to-battery protections (V5P)
• TRACK sets FB_ADJ or V5_SNR as the reference for V5P
• Programmable pulse-width window watchdog (PWWD)
with scalable activation delay and selectable tolerance
• Internal Watchdog (WD) CLK with ±5% accuracy
• Accepts external WD CLK for improving accuracy
• Active-low Watchdog Enable pin (WD_ENn)
• Dual bandgaps for increased reliability: BG_VREF, BG_FAULT
• Power-on reset (NPOR) with fixed delay of 2 ms
• Power OK output for 5 V LDOs UV/OV (POK5V)
• Logic enable input for microprocessor control (ENB)
Continued on next page...
APPLICATIONS
□□Electronic power steering (EPS) modules
□□Automotive power trains
□□CAN power supplies
□□High-temperature applications
PACKAGE: 38-Pin eTSSOP (suffix LV)
DESCRIPTION
The A4411 is a power management IC that can be configured
as a buck or buck-boost pre-regulator to efficiently convert
automotive battery voltages into a tightly regulated intermediate
voltage complete with control, diagnostics, and protections.
The output of the pre-regulator supplies a 5 V / 150 mA_MAX
LDO for “local” sensors (V5_SNR), a 5 V / 200 mA_MAX LDO
for communications (V5_CAN), a 5 V / 120 mA_MAX tracking/
protected LDO for remote sensors (V5P), and a 0.8 to
3.3 V / 800 mA_MAX adjustable synchronous buck regulator
(ADJ). Designed to supply CAN or microprocessor power
supplies in high-temperature environments, the A4411 is ideal
for underhood applications.
The A4411 can be enabled by its logic level (ENB) or high-
voltage (ENBAT) input. The A4411 includes a TRACK pin to
set the reference of the V5P tracking regulator to either V5_SNR
or the buck FB_ADJ pin, so the A4411 can be adapted across
multiple platforms with different sensors and supply rails.
Diagnostic outputs from the A4411 include a power-on-reset
output (NPOR) with a fixed delay, an ENBAT status output,
and a Power OK output for the 5 V LDOs (POK5V). Dual
bandgaps, one for regulation and one for fault checking,
improve long-term reliability of the A4411.
TheA4411 contains a Pulse-Width Window Watchdog (PWWD)
that can be programmed to detect pulse widths from 1 to
2 ms (WD_ADJ). The watchdog has an activation delay that
scales with the pulse-width setting to accommodate processor
startup. The tolerance of the Watchdog’s Window can be set to
±8%, ±13%, or ±18% using the WD_TOL pin. The watchdog has
an active-low enable pin (WD_ENn) to facilitate initial factory
programming or field reflash programming.
Continued on next page...
Not to scale
5.35 V
(VREG)
Buck-Boost
Pre-Regulator
5 V LDO
Communications
(V5_CAN)
with Foldback
Protection
5 V LDO
Local Sensor(s)
(V5_SNR)
with Foldback
Protection
Dual
Bandgaps
Charge
Pump
Thermal
Shutdown
(TSD)
POK5V
Output
Adjustable (ADJ)
Sync. Buck
Regulator
0.8 to 3.3 V_OUT
Programmable
Pulse Width
Window Watchdog
with Selectable
Tolerance
NPOR
Output
FB_ADJ
V5_SNR
Tracking
Control
2:1 MUX
5 V Protected
LDO (V5P) for
Remote Sensors
with Tracking,
Foldback, and
Short to V_BAT
Protection
REF
A4411-DS, Rev. 6
A4411 Simplified Block Diagram
October 12, 2016