A8450
Automotive Multioutput Voltage Regulator
The A8450 is a multioutput power supply intended for automotive
applications. The A8450 operates from a wide input supply range and
is designed to satisfy the requirements of high ambient temperature
environments.
Package LB 24-pin SOIC
Four regulated voltage outputs provide multiple options. The 3.3 V
regulator and the 1.2 to 3.3 V adjustable regulator can be used to power
microcontroller or DSP cores, or for I/O, sensing, and A-to-D conver-
sion. Two 5 V outputs, one digital and the other analog, feature output
tracking within 0.5% of each other over the operating temperature
range. In addition, the analog regulator is protected against short-to-
battery conditions. All four regulators feature foldback current limit
protection.
The device can be enabled or disabled using two input pins. The
high voltage input, on the ENBAT pin, allows enable/disable using an
engine ignition or battery switch signal. The logic-level input, on the
ENB pin, allows enable/disable by microcontroller or DSP signals.
When disabled, the A8450 draws less than 10 µA of current. A POR
(power-on-reset) block monitors the supply voltages and provides a
reset signal, with an adjustable delay, for microcontroller or DSP resets.
A separate fault pin signals TSD (thermal shutdown), 5 V analog short-
to-supply, and 5 V analog or digital undervoltage.
Buck
Converter
VBB
CP2
1
2
24 LX
23 ENBAT
22 V33
Charge
Pump
CP1
3
VCP
V33BD
CL33
4
21
20
19
18
17
16
15
VREG11
GND
5
Soft
Start
3.3 V
Lin Reg
Control
GND
6
GND
GND
7
5 V
Dig/Anlg
Lin Reg
ENB
VREG
V5D
8
CPOR
CLADJ
VADJBD
FB
9
10
11
12
NFAULT
1.2 V to
3.3 V
Lin Reg
Control
14 NPOR
13
5 V Reg
Track
Control
V5A
The A8450 is supplied in a 24-pin SOIC package (part number
suffix LB) with fused power ground pins for enhanced thermal perfor-
mance. This provides an RθJA of 35°C/W on a 4-layer board (see chart
on p.4).
Approximate Scale 1:1
FEATURES
ꢀ6 V to 45 V input range
ꢀdc-to-dc buck converter with 5.7 V output
ꢀOvercurrent protection with foldback, and undervoltage lockout (UVLO)
ꢀDual 5 V outputs
ABSOLUTE MAXIMUM RATINGS
– Digital 5 V ±2%, 200 mA
– Analog 5 V, 200 mA
– Short-to-supply protection on analog regulator
– Analog to digital regulator output tracking <0.5%, throughout
operating temperature range
ꢀ3.3 V linear regulator, with foldback current limit
ꢀAdjustable 1.2 V to 3.3 V linear regulator, adjustable foldback current limit
ꢀIgnition switch enable; Sleep mode
Load Supply Voltage, VBB ..................................45 V
Analog Output, Pin V5A........................–1 V to 45 V
Logic Input Signal
Pin ENBAT .................................–0.3 V to 45 V
Pin ENB .....................................–0.3 V to 6.5 V
Pin LX.................................................... –2 V to VBB
Operating Temperature Range
Ambient Temperature, TA............ –40°C to 135°C
Junction Temperature, TJ(MAX).....................150°C
Storage Temperature, TS .................... –55°C to 150°C
ꢀ100% duty cycle operation for low input voltages
ꢀPower OK output
ꢀ–40°C to 135°C ambient operating temperature range
Use the following complete part number when ordering:
Part Number
Package
Description
A8450KLB
24-pin, SOIC
Webbed Leadframe
A8450KLB-DS, Rev. 1