micrf004 Micrel Semiconductor, micrf004 Datasheet - Page 10

• Manufacturer Part Number: micrf004
• Description: Micrf004/micrf044 Qwikradio? Low-power Vhf Receiver
• Manufacturer: Micrel Semiconductor

MICRF004/RF044
SEL0, SEL1, SWEN, and SHUT Pins
Control input circuitry is shown in Figures 6a and 6b. The
standard input is a logic inverter constructed with minimum
geometry MOSFETs (Q2, Q3). P-channel MOSFET Q1 is a
large channel length device which functions essentially as a
“weak” pullup to VDDBB. Typical pullup current is 5 A,
leading to an impedance to the VDDBB supply of typically
1M .
MICRF004
Figure 6a. SEL0, SEL1, SWEN
SWEN
SHUT
SHUT
SEL0,
SEL1,
VSSBB
VSSBB
Figure 6b. SHUT
VDDBB
VDDBB
Q1
Q1
Q4
VSSBB
VSSBB
Q2
Q3
Q2
Q3
to Internal
Circuits
to Internal
Circuits
10
February 9, 2000
Micrel