Datasheet

MAX2235
+3.6V, 1W Autoramping Power
Amplifier for 900MHz Applications
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0
400
200
800
600
1200
1000
1400
0406020 80 100 120
RISE TIME vs. RAMPING CAPACITANCE
MAX2235 toc10
CAPACITANCE (nF)
RISE TIME (µs)
FULL POWER = +20dBm
FULL POWER = +10dBm
FULL POWER = +30dBm
Typical Operating Characteristics (continued)
(MAX2235 Evaluation Kit, GC = unconnected, f
RFIN
= 836MHz, V
CC
= V
SHDN
= +3.6V, T
A
= +25°C, unless otherwise noted.)
0
400
200
800
600
1000
1200
0406020 80 100 120
FALL TIME vs. RAMPING CAPACITANCE
MAX2235 toc11
CAPACITANCE (nF)
FALL TIME (µs)
FULL POWER = +20dBm
FULL POWER = +10dBm
FULL POWER = +30dBm
NAME FUNCTION
1 RFIN
RF Input. A DC blocking capacitor in series with RFIN is required. The value of the capacitor depends on
the operating frequency.
PIN
Pin Description
2 GND
GND connection for the input stage (variable-gain amplifier). Connect to the circuit board ground plane
with a separate low-inductance path (via).
3 V
CC
Supply Voltage Input for the Input Stage. Bypass with its own 100pF low-inductance capacitor to GND.
4 V
CC
Supply Voltage Input for Bias Circuitry. Bypass with its own 100pF low-inductance capacitor and a 1000pF
capacitor to GND, to minimize RF signal coupling into the bias circuits.
5 V
CC
Supply Voltage Input for the Input Stage. Bypass with its own 22pF low-inductance capacitor to pins 6 and 7.
6, 7, 10 GND
GND Connection for the Second-Stage Amplifier (driver). Connect to the circuit board ground plane with a
separate low-inductance path (via).
8 V
CC
Supply Voltage Input for the Second Stage. Bypass with its own 220pF and 1000pF low-inductance
capacitors to GND.
9 V
CC
Supply Voltage Input for the Second Stage. Connect to pin 8.
11 RAMP
Power Ramp Pin. Connect a capacitor between RAMP and REF to provide a gradual linear power-up/down
ramp. See Detailed Description.
12 REF Reference Voltage for RAMP Capacitor. The reference is internally set to 1.9V.
13, 14,
17, 18,
SLUG
GND
GND Connection for the Power Stage. Solder the slug to the circuit board ground plane. Connect pins 13,
14, 17, and 18 to the slug with a straight board trace under the chip.
15 RFOUT
Power Amplifier Output. See Typical Operating Circuit for an example of a matching network, which pro-
vides optimal output power at 836MHz. Connect to pin 16.
16 RFOUT Power Amplifier Output. Connect to pin 15.
19
SHDN
Shutdown Pin. Drive SHDN low to turn the device off. Drive above 2.0V to turn the device on. Drive V
SHDN
> 2.0V and V
GC
< 0.4V for standby mode.
20 GC
Gain-Control Pin. Apply V
GC
between 0.6V and 2.3V to control the output power with a monotonic dB/V
relationship. See the Typical Operating Characteristics for a typical relationship.