MAX8620Y
µPMIC for Microprocessors or DSPs
in Portable Equipment
_______________________________________________________________________________________ 7
Pin Description
PIN NAME FUNCTION
1 SEL1
LDO Output-Voltage Select Input 1. SEL1 and SEL2 set the OUT1 and OUT2 voltages to one of nine
combinations (Table 1).
2 SEL2
LDO Output-Voltage Select Input 2. SEL1 and SEL2 set the OUT1 and OUT2 voltages to one of nine
combinations (Table 1).
3 EN2
OUT2 Enable Input. Drive EN2 low to enable OUT2. Drive EN2 high to disable OUT2. If the MAX8620Y
is placed into shutdown (PWR_ON = HF_PWR = low), OUT2 does not power regardless of the status
of EN2 (Table 2, Figure 4).
4 RESET
Open-Drain, Active-Low Reset Output. RESET asserts low when V
OUT1
drops below 87% (typ) of
regulation. RESET remains asserted for t
RP
after V
OUT1
rises above 87% (typ) of regulation. RESET
also asserts when OUT1 is disabled (Figure 4). RESET deasserts if OUT1 is enabled and V
OUT1
is
above 87% of regulation after t
RP
.
5BP
Reference Bypass Capacitor Node. Bypass BP with a 0.01µF capacitor to GND. BP is high
impedance when the MAX8620Y is disabled (PWR_ON = HF_PWR = low).
6 HF_PWR
Hands-Free Enable Input. Drive HF_PWR high or apply a pulse to enable the MAX8620Y. Power is
enabled for 1.31s (typ) following a rising edge at HF_PWR (Table 2, Figure 4).
7 PWR_ON
Power-Enable Input. Drive PWR_ON high to enable the MAX8620Y (Table 2, Figure 4). Drive PWR_ON
low to enter shutdown mode. In shutdown, the LX node is high impedance and both LDOs are
disabled (depending on the state of HF_PWR).
8FB
Step-Down Converter Output-Voltage Feedback Input. V
FB
regulates to 0.6V (typ). Connect FB to the
center of an external resistor-divider between LX and GND to set V
OUT3
between 0.6V and 3.3V (see
the Setting the Step-Down Output Voltage (OUT3) section).
9 GND Ground. Connect GND to the exposed pad.
10 LX
Inductor Connection. LX is internally connected to the drain of the internal p-channel power MOSFET
and the drain of the n-channel synchronous rectifier. LX is high impedance when OUT3 is disabled.
11 IN2 Power Input 2. Connect IN2 to IN1 as close to the device as possible.
12 IN1
Power Input 1. Connect IN1 to IN2 as close to the device as possible. Bypass IN1 to GND with a 10µF
ceramic capacitor, as close to the device as possible.
13 OUT1
300mA LDO Output 1. Bypass OUT1 to GND with a 4.7µF ceramic capacitor for 300mA applications,
or a 2.2µF ceramic capacitor for 150mA applications. OUT1 is high impedance when disabled.
14 OUT2
300mA LDO Output 2. Bypass OUT2 to GND with a 4.7µF ceramic capacitor for 300mA applications,
or a 2.2µF ceramic capacitor for 150mA applications. OUT2 is high impedance when disabled.
EP EP Exposed Pad. Connect EP to GND.
MAX8620Y
µPMIC for Microprocessors or DSPs
in Portable Equipment
8 _______________________________________________________________________________________
Detailed Description
The MAX8620Y µPMIC is designed to power low-core-
voltage microprocessors or DSPs in portable devices.
The µPMIC contains a fixed-frequency, high-efficiency
step-down converter; two low-dropout regulators
(LDOs); a 30ms (min) reset timer; and power-on/off
control logic (Figure 1).
Step-Down DC-DC Control Scheme
The MAX8620Y step-down converter is optimized for
high-efficiency voltage conversion over a wide load
range while maintaining excellent transient response,
minimizing external component size, and minimizing
output voltage ripple. The DC-DC converter (OUT3)
also features an optimized on-resistance internal
MOSFET switch and synchronous rectifier to maximize
efficiency. The MAX8620Y utilizes a proprietary hys-
teretic-PWM control scheme that switches with nearly
fixed frequency up to 4MHz, allowing for ultra-small
external components. The step-down converter output
current is guaranteed up to 500mA.
When the step-down converter output voltage falls
below the regulation threshold, the error comparator
begins a switching cycle by turning the high-side pFET
switch on. This switch remains on until the minimum on-
time (t
ON
) expires and the output voltage is in regula-
tion or the current-limit threshold (I
LIM3P
) is exceeded.
Once off, the high-side switch remains off until the mini-
mum off-time (t
OFF
) expires and the output voltage
again falls below the regulation threshold. During this
off period, the low-side synchronous rectifier turns on
and remains on until either the high-side switch turns
on or the inductor current reduces to the rectifier-off
current threshold (I
LXOFF
= 30mA (typ)). The internal
synchronous rectifier eliminates the need for an exter-
nal Schottky diode.
FB
LX
0.6V
STEP-DOWN
CONVERTER
CONTROL
pFET
nFET
LDO1
CONTROL
LDO2
CONTROL
OUT1
OUT2
REFERENCE
IN1
GND
OUTPUT-
VOLTAGE
SELECT
UVLO
CONTROL
LOGIC
ONE-
SHOT
TIMER
PWR_ON
HF_PWR
SEL1
SEL2
RESET
EN2
BP
RESET
ENABLE
R1
R2
L
V
IN
C
IN
C
OUT3
C
OUT1
R
PU
C
BP
C
OUT2
C
FF
OUT3
GND
OUT1
OUT2
EN2
RESET
IN2
IN1
MAX8620Y
Figure 1. Functional Diagram
Voltage-Positioning Load Regulation
As seen in Figure 2, the MAX8620Y uses a unique step-
down converter feedback network. By taking feedback
from the LX node through R1, the usual phase lag due
to the output capacitor is removed, making the loop
exceedingly stable and allowing the use of a very small
ceramic output capacitor. This configuration causes the
output voltage to shift by the inductor series resistance
multiplied by the load current. This output-voltage shift
is known as voltage-positioning load regulation.
Voltage-positioning load regulation greatly reduces
overshoot during load transients, which effectively
halves the peak-to-peak output-voltage excursions
compared to traditional step-down converters. See the
Load-Transient Response graph in the Typical
Operating Characteristics section.
Two low-dropout, low-quiescent-current, high-accuracy
linear regulators supply loads up to 300mA each. The
LDO output voltages are set using SEL1 and SEL2 (see
Table 1). As shown in Figure 3, the LDOs include an
internal reference, error amplifiers, p-channel pass tran-
sistors, internal-programmable voltage-dividers, and an
OUT1 power-good comparator. Each error amplifier
compares the reference voltage to a feedback voltage
and amplifies the difference. If the feedback voltage is
lower than the reference voltage, the pass-transistor
gate is pulled lower, allowing more current to pass to
the outputs and increasing the output voltage. If the
feedback voltage is too high, the pass-transistor gate is
pulled up, allowing less current to pass to the output.
MAX8620Y
µPMIC for Microprocessors or DSPs
in Portable Equipment
_______________________________________________________________________________________ 9
OUT1
OUT2
LX
FB
GND
IN1
BP
HF_PWR
2.6V
300mA
100k
PWR_ON
SEL1
RESET
SEL2
EN2
RESET IN
OUT3,
500mA
C
OUT2
4.7µF
C
OUT1
4.7µF
C
OUT3
2.2µF
C
IN
10µF
C
BP
0.01µF
C
FF
150pF
DSP
OR
µP
I/O
ANALOG
ON/OFF
CORE
R1
150k
L
2.2µH
Li+
CELL
2.6V
300mA
R2
75k
POWER-ON
KEY
V
BATT
1M
IN2
MAX8620Y
SEL1 SEL2 OUT1 OUT2
IN1 IN1 3.00V 2.50V
IN1 OPEN 2.85V 2.85V
IN1 GND 3.00V 3.00V
OPEN IN1 3.30V 2.50V
OPEN OPEN 2.80V 2.60V
OPEN GND 3.30V 1.80V
GND IN1 2.85V 2.60V
GND OPEN 2.60V 2.60V
GND GND 1.80V 2.60V
Figure 2. Typical MAX8620Y DSP or µP Application
Table 1. MAX8620Y Output-Voltage
Selection

MAX8620YETD+T

Mfr. #:
Manufacturer:
Maxim Integrated
Description:
Power Management Specialized - PMIC uPMIC for MPU/DSP in Portable Equipment
Lifecycle:
New from this manufacturer.
Delivery:
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