A8450KLB-DS, Rev. 1
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.
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.
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 R
θJA
of 35°C/W on a 4-layer board (see chart
on p. 4).
Use the following complete part number when ordering:
AB SO LUTE MAX I MUM RAT INGS
Part Number Package Description
A8450KLB 24-pin, SOIC Webbed Leadframe
Load Supply Voltage, V
BB
..................................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 V
BB
Operating Temperature Range
Ambient Temperature, T
A
............ –40°C to 135°C
Junction Temperature, T
J(MAX)
.....................150°C
Storage Temperature, T
S
.................... –55°C to 150°C
FEATURES
Package LB 24-pin SOIC
Approximate Scale 1:1
3
4
5
6
7
8
2
1
22
21
20
19
18
17
23
24
10
9
11
15
14
13
16
12
VBB
CP2
CP1
VCP
VREG11
GND
GND
ENB
LX
ENBAT
V33
V33BD
CL33
GND
GND
VREG
CPOR
CLADJ
VADJBD
FB
V5D
NFAULT
NPOR
V5A
1.2Vto
3.3 V
Lin Reg
Control
5V
Dig/Anlg
Lin Reg
5 V Reg
Track
Control
3.3 V
Lin Reg
Control
Charge
Pump
Buck
Converter
Soft
Start
null 6 V to 45 V input range
null dc-to-dc buck converter with 5.7 V output
null Overcurrent protection with foldback, and undervoltage lockout (UVLO)
null Dual 5 V outputs
– 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
null 3.3 V linear regulator, with foldback current limit
null Adjustable 1.2 V to 3.3 V linear regulator, adjustable foldback current limit
null Ignition switch enable; Sleep mode
null 100% duty cycle operation for low input voltages
null Power OK output
null –40°C to 135°C ambient operating temperature range