Freescale Semiconductor
Technical Data
Document Number: MC33998
Rev. 2.0, 8/2006
Switching Power Supply with
Linear Regulators
The 33998 is a medium-power, multi-output power supply
integrated circuit that is capable of operating over a wide input
voltage range, from 6.0 V up to 26.5 V with 40 V transient capability.
It incorporates a sensorless current mode control step-down
switching controller regulating directly to 5.0 V. The 2.6 V linear
regulator uses an external pass transistor to reduce the 33998 power
dissipation. The 33998 also provides a 2.6 V linear standby regulator
and two 5.0 V sensor supply outputs protected by internal low-
resistance LDMOS transistors.
There are two separate enable pins for the main and sensor supply
outputs and standard supervisory functions such as resets with
power-up reset delay.
The 33998 provides proper power supply sequencing for
advanced microprocessor architectures such as the MPC5xx and
683xx microprocessor families.
33998
SWITCHING REGULATOR
DW SUFFIX
EG SUFFIX (PB-FREE)
98ASB42344B
24-PIN SOICW
ORDERING INFORMATION
Features
• Operating Voltage Range 6.0 V up to 26.5 V (40 V transient)
Temperature
Device
Package
Range (T
A
)
• Step-Down Switching Regulator Output V
DDH
= 5.0 V @
1400 mA (total)
MC33998DW/R2
• Linear Regulator with External Pass Transistor V
DDL
= 2.6 V @
-40°C to 125°C
24 SOICW
MCZ33998EG/R2
400 mA
• Low-Power Standby Linear Regulator V
KAM
= 2.6 V @ 10 mA
• Two 5.0 V @ 200 mA (typical) Sensor Supplies V
REF
Protected
Against Short-to-Battery and Short-to-Ground with Retry Capability
• Undervoltage Shutdown on the V
DDL
, V
DDH
Outputs with Retry Capability
• Reset Signals
• Power-Up Delay
• Enable Pins for Main Supplies (EN) and Sensor Supplies (SNSEN)
• Power Sequencing for Advanced Microprocessor Architectures
• Pb-Free Packaging Designated by Suffix Code EG
33998
KA_VPWR
VPWR
VDDH
5.0 V
VREF1
DRVL
VREF2
FBL
VKAM
EN
SNSEN
GND
PWROK
VKAMOK
VSW
VDDH
5.0 V
MCU
VDDL
VKAM
5.0 V
2.6 V
2.6 V
Figure 1. 33998 Simplified Application Diagram
Freescale Semiconductor, Inc. reserves the right to change the detail specifications, as
may be required, to permit improvements in the design of its products.
© Freescale Semiconductor, Inc., 2007. All rights reserved.
INTERNAL BLOCK DIAGRAM
INTERNAL BLOCK DIAGRAM
33998
VPWR
VSW
5.0 V
I-lim
Drive
Sof t
Start
Ramp
Enb
Logic
&
Latch
FBKB
VSUM
Osc
KA_VPWR
V bg
VDDH
Retry
VREF1
Reg.
5.0 V
VREF1
Bandgap
Voltage
Snsenb Reference
Vbg
Enb
2.6V
Linear
Regulator
Driver
DRVL
FBL
2.6 V
Enb
Retry
Snsenb
VREF2
Reg.
5.0 V
VREF2
PwrOK
Snsenb
Enable
Control Enb
POR
V bg
2.6V
Standby
Reg.
VKAM
2.6 V
PWRO K
VKAMOK
Charge
Pump
VkamOK
CRES
SNSEN
EN
PGND
Figure 2. 33998 Simplified Internal Block Diagram
33998
2
Analog Integrated Circuit Device Data
Freescale Semiconductor
PIN CONNECTIONS
PIN CONNECTIONS
VKAMOK
KA_VPWR
CRES
VPWR
GND
GND
GND
GND
VSW
PWROK
FBKB
VSUM
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
VKAM
EN
SNSEN
VREF1
GND
GND
GND
GND
VREF2
VDDH
FBL
DRVL
Figure 3. 33998 Pin Connections
Table 1. Pin Definitions
Pin Number
1
Pin
Name
VKAMOK
Definition
Keep-Alive Output Monitoring. This pin is an "open-drain" output that will be used with a discrete pull-up
resistor to V
KAM
. When the supply voltage to the 33998 is disconnected or lost, the VKAMOK signal goes
low.
Keep Alive Power Supply Pin. This supply pin is used in modules that have both direct battery connections
and ignition switch activated connections.
Reservoir Capacitor. This pin is tied to an external "reservoir capacitor" for the internal charge pump.
Power Supply Pin. Main power input to the IC. This pin is directly connected to the switching regulator
power MOSFET. In automotive applications this pin must be protected against reverse battery conditions
by an external diode.
Ground of the integrated circuit.
Internal P-Channel Power MOSFET Drain. V
SW
is the "switching node" of the voltage buck converter. This
pin is connected to the V
PWR
pin by an integrated p-channel MOSFET.
Power OK Reset Pin. This pin is an "open-drain" output that will be used with a discrete pull-up resistor to
V
KAM
, V
DDH
, or V
DDL
. When either V
DDH
or V
DDL
output voltage goes out of the regulation limits this
pin is pulled down.
Step-Down Switching Regulator Feedback Pin. The FBKB pin is the V
DDH
feedback signal for the
switching regulator.
Error Amplifier "Summing Node". The V
SUM
pin is connected to the inverting input of the error amplifier.
This node is also the "common" point of the integrated feedback resistor divider.
Drive for V
DDL
(2.6 V) Regulator. The DRVL pin drives the base of an external NPN pass transistor for the
V
DDL
linear post regulator. The collector of the VDDL pass transistor is connected to V
DDH
. An example
of a suitable pass transistor is BCP68.
Feedback for V
DDL
(2.6 V) Regulator. The FBL pin is the voltage feedback sense signal from the V
DDL
(2.6 V) linear post regulator.
V
DDH
is an input supply pin providing power for the buffered sensor supplies and the drive circuitry for the
2.6 V linear power regulator. The V
DDH
pin is supplied from the switching regulator output, capable of
providing 5.0 V @ 1400 mA total output current.
Sensor Supply #2 Output. The V
REF2
pin is sensor supply output #2.
Ground of the integrated circuit.
Sensor Supply #1 Output. The V
REF1
pin is sensor supply output #1.
2
3
4
KA_V
PWR
C
RES
V
PWR
5–8
9
10
GND
V
SW
PWROK
11
12
13
FBKB
V
SUM
DRVL
14
15
FBL
V
DDH
16
17 – 20
21
V
REF2
GND
V
REF1
33998
3
Analog Integrated Circuit Device Data
Freescale Semiconductor
PIN CONNECTIONS
Table 1. Pin Definitions (continued)
Pin Number
22
23
24
Pin
Name
SNSEN
EN
V
KAM
Definition
Sensor Supply Enable Input. The SNSEN pin is an input, which enables the V
REF1
and V
REF2
supplies.
It allows the control module hardware / software to shut down the sensor supplies.
Enable Input. The EN pin is an input, which enables the main switching regulator and all other functions.
When this pin is low, the power supply is in a low quiescent state.
Keep-Alive (standby) 2.6 V Regulator Output. This is a 2.6 V low quiescent, low dropout regulator for Keep
Alive memory.
33998
4
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 2. Maximum Ratings
All voltages are with respect to ground unless otherwise noted.
Rating
Main Supply Voltage
Keep-Alive Supply Voltage
Switching Node
5.0 V Input Power
Sensor Supply
Symbol
V
PWR
KA_V
PWR
V
SW
V
DDH
V
REF1
V
REF2
Keep-Alive Supply Voltage
Maximum Voltage at Logic I/O Pins
V
KAM
EN
SNSEN
PWROK
VKAMOK
Charge Pump Reservoir Capacitor Voltage
Error Amplifier Summing Node
Switching Regulator Output Feedback
VDDL Base Drive
VDDL Feedback
ESD Voltage
Human Body Model (all pins)
(1)
Machine Model (all pins)
(1)
Power Dissipation (T
A
= 25°C)
(2)
Thermal Resistance, Junction to Ambient
(3)
,
(4)
Thermal Resistance, Junction to Board
(5)
Operational Package Temperature [Ambient Temperature]
(6)
V
ESD1
V
ESD2
P
D
R
θJA
R
θJB
T
A
±500
±100
800
60
20
-40 to 125
mW
°C/W
°C/W
°C
C
RES
V
SUM
FBKB
DRVL
FBL
Value
-0.3 to 45
-0.3 to 45
-0.5 to 45
-0.3 to 6.0
-0.3 to 18
-0.3 to 18
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 18
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
-0.3 to 6.0
V
V
V
V
V
V
V
V
Unit
V
V
V
V
V
Notes
1. ESD1 testing is performed in accordance with the Human Body Model (C
ZAP
= 100 pF, R
ZAP
= 1500
Ω).
ESD2 testing is performed in
accordance with the Machine Model (C
ZAP
= 200 pF, R
ZAP
= 0
Ω)
2.
3.
4.
5.
6.
Maximum power dissipation at indicated junction temperature.
Junction temperature is a function of on-chip power dissipation, package thermal resistance, mounting site (board) temperature,
ambient temperature, air flow, power dissipation of other components on the board, and board thermal resistance.
Per SEMI G38-87 and JEDEC JESD51-2 with the single layer board horizontal.
Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is measured on the top
surface of the board near the package.
The limiting factor is junction temperature, taking into account the power dissipation, thermal resistance, and heat sinking.
33998
5
Analog Integrated Circuit Device Data
Freescale Semiconductor
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