MAX8662ETM+ Maxim Integrated Products, MAX8662ETM+ Datasheet - Page 27

• Manufacturer Part Number: MAX8662ETM+
• Description: IC POWER MANAGE 48-TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX8662ETM+

• Applications: Handheld/Mobile Devices
• Current - Supply: 900µA
• Voltage - Supply: 4.1 V ~ 8 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 6 shows a simplified version of the THM input.
Ensure that the physical size of the thermistor is such
that the circuit of Figure 6 does not cause self-heating.
OUT1 and OUT2 are high-efficiency, 1MHz, current-mode
step-down converters with adjustable output voltage.
The OUT1 regulator outputs 0.98V to V
while OUT2 outputs 0.98V to V
OUT1 and OUT2 have individual enable inputs. When
enabled, the OUT1 and OUT2 gradually ramp the out-
put voltage over a 400μs soft-start time. This soft-start
eliminates input inrush current spikes.
OUT1 and OUT2 can operate at a 100% duty cycle,
which allows the regulators to maintain regulation at the
lowest possible battery voltage. The OUT1 dropout volt-
age is 72mV with a 600mA load and the OUT2 dropout
voltage is 90mV with a 450mA load (does not include
inductor resistance). During 100% duty-cycle operation,
the high-side p-channel MOSFET turns on continuously,
connecting the input to the output through the inductor.
Figure 6. Thermistor Input
GND
Single-Cell, Li+ Battery-Operated Devices
Step-Down DC-DC Converters
______________________________________________________________________________________
THM
GND
10kΩ
IN
ESD
DIODE
at up to 900mA.
VL
(OUT1 and OUT2)
IN
SWITCH OPEN
WHEN CHARGER
DISABLED
55.71kΩ
97.71kΩ
54.43kΩ
6.43kΩ
at up to 1200mA
V
V
THM_H
THM_D
V
THM_C
= 0.9V FALLING (TYP)
= 0.1V FALLING (TYP)
= 2.4V RISING (TYP)
Power-Management ICs for
OUT1 and OUT2 can operate in either auto-PWM mode
(PWM low) or forced-PWM mode (PWM high). In auto-
PWM mode, OUT1 and OUT2 enter skip mode when
the load current drops below a predetermined level. In
skip mode, the regulator skips cycles when they are not
needed, which greatly decreases quiescent current
and improves efficiency at light loads. In forced-PWM
mode, the converters operate with a constant 1MHz
switching frequency regardless of output load. Output
voltage is regulated by modulating the switching duty
cycle. Forced-PWM mode is preferred for low-noise
systems, where switching harmonics can occur only at
multiples of the constant-switching frequency and are
easily filtered; however, regulator operating current is
greater and light-load efficiency is reduced.
Internal n-channel synchronous rectifiers eliminate the
need for external Schottky diodes and improve efficiency.
The synchronous rectifier turns on during the second
half of each switching cycle. During this time, the volt-
age across the inductor is reversed, and the inductor
current ramps down. In PWM mode, the synchronous
rectifier turns off at the end of the switching cycle. In
+
+
+
-
-
-
60mV HYST
60mV HYST
60mV HYST
ENABLE THM
COLD
HOT
Step-Down Converter Operating Modes
Synchronous Rectification
BAD TEMP
MAX8662
MAX8663
DISABLE CHARGER
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