MICRF005BM TR Micrel Inc, MICRF005BM TR Datasheet - Page 7

• Manufacturer Part Number: MICRF005BM TR
• Manufacturer: Micrel Inc

Specifications of MICRF005BM TR

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Not Compliant

DO Pin
The output stage for DO (digital output) is shown in Figure 4.
The output is a 90 A push and 90 A pull switched-current
stage. This output stage is capable of driving CMOS loads.
An external buffer-driver is recommended for driving high-
capacitance loads.
REFOSC Pin
The REFOSC input circuit is shown in Figure 5. Input imped-
ance is high (300k ). This is a Colpitts oscillator with internal
capacitors. The nominal dc bias voltage on this pin is 1.4V.
SHUT Pin
Control input circuitry is shown in Figures 6. 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”
October 2001
MICRF005
SHUT
REFOSC
Figure 5. REFOSC Pin
Figure 6. SHUT Pin
VSSBB
Figure 4. DO Pin
Compa-
rator
7.5pF
15pF
VDDBB
VSSBB
Q1
Active
Bias
250
VSSBB
200k
VDDBB
VSSBB
Q2
Q3
30 A
to Internal
Circuits
VDDBB
80 A
80 A
VSSBB
DO
7
pullup to V
impedance to the V
T/R Pin
The transmit/receive function is controlled by the logic state
of T/R. T/R is internally tied to V
or in the low state, the MICRF005 functions in its normal
receive operating mode. The T/R pin may be pulled high to
Vdd, this will place the receiver in a “stand-by” operating
mode. This mode is intended for use during transmit cycles
in transceiver applications where the receiver is co-located
with a transmitter. In this “transmit” mode, the receiver
oscillator remains active but the AGC function is disabled and
the C
This function enables the MICRF005 to quickly resume
receive operation after a transmit cycle.
AGC
pin is tri-stated to hold the AGC capacitor voltage.
DDBB
. Typical pullup current is 8.5 A, leading to an
VDDBB
DDBB
Figure 7. T/R Pin
supply of typically 1M .
Q3
SS
VDDBB
VSSBB
. When T/R is open circuit
Q1
Q2
MICRF005
Micrel