Rainbow Electronics MAX8805Z - Manual (Page 11)

MAX8805Y/MAX8805Z
600mA PWM Step-Down Converters in
2mm x 2mm WLP for WCDMA PA Power
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Pin Description
PIN NAME FUNCTION
A1 REFBP
Reference Noise Bypass. Bypass REFBP to AGND with a 0.22µF ceramic capacitor to reduce noise on the
LDO outputs. REFBP is internally pulled down through a 1k
Ω resistor during shutdown.
A2 AGND Low-Noise Analog Ground
A3 REFIN
DAC-Controlled Input. The output of the PA step-down converter is regulated to 2 x V REFIN . When V REFIN
reaches 0.465 x V IN2 , bypass mode is enabled.
A4 PGND Power Ground for PA Step-Down Converter
B1 LDO2
200mA LDO Regulator 2 Output. Bypass LDO2 with a 1µF ceramic capacitor as close as possible to LDO2
and AGND. LDO2 is internally pulled down through a 1k
Ω resistor when this regulator is disabled.
B2 PA_EN
PA Step-Down Converter Enable Input. Connect to IN_ or logic-high for normal operation. Connect to GND
or logic-low for shutdown mode.
B3 EN2
LDO2 Enable Input. Connect to IN2 or logic-high for normal operation. Connect to AGND or logic-low for
shutdown mode.
B4 LX Inductor Connection. Connect an inductor from LX to the output of the PA step-down converter.
C1 IN2
Supply Voltage Input for LDO1, LDO2, and Internal Reference. Connect IN2 to a battery or supply voltage
from 2.7V to 5.5V. Bypass IN2 with a 2.2µF ceramic capacitor as close as possible to IN2 and AGND.
Connect IN2 to the same source as IN1A and IN1B.
C2 HP
High-Power Mode Set Input. Drive HP high to invoke forced bypass mode. Bypass mode connects the
input of the PA step-down converter directly to its output through the internal bypass MOSFET. Drive HP
low to disable the forced bypass mode.
C3, C4
IN1B,
IN1A
Supply Voltage Input for PA Step-Down Converter. Connect IN1_ to a battery or supply voltage from 2.7V to
5.5V. Bypass the connection of IN1_ with a 2.2µF ceramic capacitor as close as possible to IN1_, and
PGND. IN1A
and IN1B are internally connected together. Connect IN1_ to the same source as IN2.
D1 LDO1
200mA LDO Regulator 1 Output. Bypass LDO1 with a 1µF ceramic capacitor as close as possible to LDO1
and AGND. LDO1 is internally pulled down through a 1k
Ω resistor when this regulator is disabled.
D2 EN1
LDO1 Enable Input. Connect to IN2 or logic-high for normal operation. Connect to AGND or logic-low for
shutdown mode.
D3, D4 PAB, PAA
PA Connection for Bypass Mode. Internally connected to IN1_ using the internal bypass MOSFET during
bypass mode. PA_ is connected to the internal feedback network. Bypass PA_ with a 2.2µF ceramic
capacitor as close as possible to PA_ and PGND.