MICRF022BM-FS24 TR Micrel Inc, MICRF022BM-FS24 TR Datasheet - Page 13
![](/photos/31/26/312664/5768soic_sml.jpg)
MICRF022BM-FS24 TR
Manufacturer Part Number
MICRF022BM-FS24 TR
Description
Manufacturer
Micrel Inc
Datasheet
1.MICRF022BM-FS24_TR.pdf
(17 pages)
Specifications of MICRF022BM-FS24 TR
Operating Band Frequency
300 to 440MHz
Operating Temperature (min)
-40C
Operating Temperature (max)
85C
Operating Temperature Classification
Industrial
Modulation Type
ASK/OOK
Product Depth (mm)
3.94mm
Product Height (mm)
1.48mm
Operating Supply Voltage (min)
4.75V
Operating Supply Voltage (typ)
5V
Operating Supply Voltage (max)
5.5V
Lead Free Status / Rohs Status
Not Compliant
C
Figure 3 illustrates the C
control voltage is developed as an integrated current into a
capacitor C
the decay current is a 1/10th scaling of this, nominally
1.5µA, making the attack/decay time constant ratio a fixed
10:1. Signal gain of the RF/IF strip inside the IC diminishes
as the voltage at C
attack/decay ratio is possible by adding resistance from the
C
Both the push and pull current sources are disabled during
shutdown, which maintains the voltage across C
improves recovery time in duty-cycled applications. To
further improve duty-cycle recovery, both push and pull
currents are increased by 45 times for approximately 10ms
after release of the SHUT pin. This allows rapid recovery of
any voltage droop on C
DO and WAKEB Pins
The output stage for DO (digital output) and WAKEB
(wakeup output) is shown in Figure 4. The output is a 10µA
push and 10µA pull switched-current stage. This output
stage is capable of driving CMOS loads. An external buffer-
Micrel, Inc.
July 2008
AGC
AGC
pin to either V
Pin
Timout
AGC
Compa-
rator
Figure 4. DO and WAKEB Pins
. The attack current is nominally 15µA, while
DDBB
Compa-
rator
Figure 3. CAGC Pin
1.5µA
AGC
15µA
AGC
or V
AGC
decreases. Modification of the
while in shutdown.
SSBB
VDDBB
VSSBB
pin interface circuit. The AGC
, as desired.
VDDBB
VSSBB
67.5µA
675µA
10µA
10µA
DO
CAGC
AGC
, and
13
driver is recommended for driving high-capacitance loads.
REFOSC Pin
The REFOSC input circuit is shown in Figure 5. Input
impedance is high (200kΩ). This is a Colpitts oscillator with
internal 30pF capacitors. This input is intended to work with
standard ceramic resonators connected from this pin to the
V
frequency accuracy is required. The nominal dc bias
voltage on this pin is 1.4V.
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 V
leading to an impedance to the V
1MΩ.
SSBB
pin, although a crystal may be used when greater
Figure 6a. SEL0, SEL1, SWEN Pins
SWEN
SHUT
SHUT
SEL0,
SEL1,
REFOSC
Figure 5. REFOSC Pin
VSSBB
VSSBB
Figure 6b. SHUT Pin
30pF
30pF
VDDBB
VDDBB
DDBB
VSSBB
Q1
Q1
Q4
. Typical pull-up current is 5µA,
Active
Bias
250
VSSBB
VSSBB
200k
Q2
Q3
Q2
Q3
30µA
DDBB
to Internal
Circuits
to Internal
Circuits
VDDBB
VSSBB
MICRF002/RF022
supply of typically
M9999-070808