Analog Integrated Circuit Device Data
3
Freescale Semiconductor
33998
PIN CONNECTIONS
PIN CONNECTIONS
Figure 3. 33998 Pin Connections
Table 1. Pin Definitions
Pin Number
Pin
Name
Definition
1
VKAMOK
Keep-Alive Output Monitoring. This pin is an "open-drain" output that will be used with a discrete pull-up
resistor to VKAM. When the supply voltage to the 33998 is disconnected or lost, the VKAMOK signal goes
low.
2
KA_VPWR
Keep Alive Power Supply Pin. This supply pin is used in modules that have both direct battery connections
and ignition switch activated connections.
3
CRES
Reservoir Capacitor. This pin is tied to an external "reservoir capacitor" for the internal charge pump.
4
VPWR
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.
5 8
GND
Ground of the integrated circuit.
9
VSW
Internal P-Channel Power MOSFET Drain. VSW is the "switching node" of the voltage buck converter. This
pin is connected to the VPWR pin by an integrated p-channel MOSFET.
10
PWROK
Power OK Reset Pin. This pin is an "open-drain" output that will be used with a discrete pull-up resistor to
VKAM, VDDH, or VDDL. When either VDDH or VDDL output voltage goes out of the regulation limits this
pin is pulled down.
11
FBKB
Step-Down Switching Regulator Feedback Pin. The FBKB pin is the VDDH feedback signal for the
switching regulator.
12
VSUM
Error Amplifier "Summing Node". The VSUM pin is connected to the inverting input of the error amplifier.
This node is also the "common" point of the integrated feedback resistor divider.
13
DRVL
Drive for VDDL (2.6 V) Regulator. The DRVL pin drives the base of an external NPN pass transistor for the
VDDL linear post regulator. The collector of the VDDL pass transistor is connected to VDDH. An example
of a suitable pass transistor is BCP68.
14
FBL
Feedback for VDDL (2.6 V) Regulator. The FBL pin is the voltage feedback sense signal from the VDDL
(2.6 V) linear post regulator.
15
VDDH
VDDH 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 VDDH pin is supplied from the switching regulator output, capable of
providing 5.0 V @ 1400 mA total output current.
16
VREF2
Sensor Supply #2 Output. The VREF2 pin is sensor supply output #2.
17 20
GND
Ground of the integrated circuit.
21
VREF1
Sensor Supply #1 Output. The VREF1 pin is sensor supply output #1.
VKAM
GND
GND
GND
GND
VREF2
VDDH
FBL
DRVL
EN
SNSEN
VREF1
VKAMOK
GND
GND
GND
GND
VSW
PWROK
VSUM
KA_VPWR
CRES
VPWR
FBKB
5
6
7
8
9
10
11
12
2
3
4
24
20
19
18
17
16
15
13
23
22
21
14
1