PowTech PT1502 Schematics

GENERAL DESCRIPTION

PT1502

PMU for Portable Applications

The PT1502 is a integrated power management unit for
small handheld portable applications. It contains a
single-cell Lithium Ion battery charger, a synchronous
step-down DC-DC converter and 2 Low Dropout
Regulators. It allows charging from both wall adapter
and USB port. When charging from wall adapter, the
PT1502 increases the charging current automatically.

The battery charger is a highly integrated charging
management device targeted at space limited portable
applications. It offers an integrated MOSFET and
current sensor, reverse blocking protection, high
accuracy current and voltage regulation, charge status
indication, and charge termination. It charges a battery
in three phases: trickle charging, constant current, and
constant voltage. No external sense resistor is needed,
and no blocking diode is required due to the internal
MOSFET architecture. The thermal feedback regulates
the charging current to limit the chip temperature
during high power operation or high ambient
temperature to maximize the charge rate without risk of
overheating. The charge voltage is fixed at 4.2V, and
the charge current can be programmed externally with a
single resistor. The PT1502 automatically terminates

the charge cycle when the charge current drops to 1/10
the programmed value after the final float voltage is
reached. The PT1502 automatically re-starts the charge
if the battery voltage falls below an internal threshold.

The step-down converter is a high efficiency monolithic
current mode synchronous buck regulator with a
constant operation frequency. A main switch and a
synchronous switch are integrated in PT1502, the
device has high efficiency and no external Schottky
diode needed. 100% duty cycle provides low dropout
operation, extending battery life in portable systems.
Automatic burst mode operation at light loads provides
high efficiency. Internal 1.5MHz switching frequency
allowing the use of small surface mount inductors and
capacitors. The output voltage can be adjusted by
external resistors.

The two low-dropout voltage regulators are designed
for portable and wireless applications. It can provides
better than 60dB PSRR at 1kHz. The output current can
be up to 200mA. One regulator’s output voltage is
fixed at 3.0V, and the other one is adjusted to

2.5V,2.8V,3.0V,3.3V by two control pins.

FEATURES

z Integrated switch for USB/AC Adapter supply
z 120uA quiescent supply current(includes

step-down DC-DC converters and two low dropout
regulators)

z Integrated single-cell lithium ion battery charger

 Auto thermal regulated
 Charging current up to 800mA
 Charging current adjusted by external

resistor

z Integrated step-down DC-DC converter

 Output voltage adjusted by external resistor
 Output current up to 600mA

APPLICATIONS

z MP3/4
z PDAs

 1.5M Hz fixed switching frequency
 Over-current and over-temperature protection

z Integrated two low dropout regulators

 LDO1: output voltage 3.0V，up to 200mA

output current

 LDO2: output voltage optional for

2.5V/2.8V/3.0V/3.3V，up to 200mA output
current

 PSRR: 60dB@1k Hz
 Over-current and over-temperature protection

z QFN20（4X4）package

z GSM/CDMA mobile phone
z Portable media players

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 1

PT1502_DS Rev EN_1.0

ORDERING INFORMATION

PT1502

PMU for Portable Applications

PACKAGE

TEMPERATURE

RANGE

ORDERING PART

NUMBER

QFN20 -40 oC to 85 oC PT1502EQFN

Note:

xxxxxX

Assembly Factory Code

Lot Number

TYPICAL APPLICATION CIRCUIT

10k

To Battery

1k

100k

USB_IN

CHGIN

AC_ IN

CHG_PROG

1K

PVDD

10uF

PLAY_ON

uP_ RESET

PWR_ HOLD

Enable

Control

Charger

DC -DC

REF

Buck

UVLO

USB

AC_ DC

To Battery

sw_pwr

100k

TRANSPORT

MEDIA

Tape and Reel 3000

3000 units

BAT

10uF

CHG_STAT

LX

BUCKFB

PGND

BAT_ LOW

LED

2.2 uH

300k/R2

330

core: 1. 2V 600mA

22pF

300k/R1

CHGIN

MARKING

PT1502
xxxxxX

4.7 uF

To Battery

PIN ASSIGNMENT

10uF

AVDD

AGND

LDO 1

LDO2

LDOOUT1

LDOOUT2

LDO2_SET0

LDO2_SET1

3.0V 200mA

1uF

2.5/ 2.8/3. 0/3.3 V

1uF

100k

100k

200mA

To Battery

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 2

PT1502_DS Rev EN_1.0

PIN DESCRIPTION

PIN No. PIN NAMES PIN DESCRIPTION

1 LDO2_SET0 LDO2 output voltage setting bit，LSB

2 LDO2_SET1 LDO2 output voltage setting bit，MSB

3 AGND Analog Ground

4 PLAY_ON System start up signal for Battery

5 PWR_HOLD feedback Chip enabled signal from CPU

6 BUCKFB Feedback port for step-down DC-DC converter

7 BAT_LOW Battery voltage lower than 3.3V signal

8 uP_RESET CPU RESET signal

9 PVDD supply port for step-down DC-DC converter

10 LX Switch port for step-down DC-DC converter

11 PGND Power Ground

12 USB_IN USB supply

PT1502

PMU for Portable Applications

13 AC_IN Indicator for AC Adapter connected

14 CHGIN AC Adapter input

15 CHG_STAT Indicator for charging status，Open-drain output

16 BAT Battery input

17 LDOOUT1 LDO1 output

18 CHG_PROG Charging current setting pin, connects resistor to AGND

19 AVDD Analog supply

20 LDOOUT2 LDO2 output

ABSOLOUTE MAXIMUM RATING (Note1)

SYMBOL ITEMS VALUE UNIT

VIN

VIO

Input supply voltage: USB_IN，CHGIN，AVDD，

PVDD

Input/Output signal: PLAY_ON，PWR_HOLD，

uP_RESET，BAT_LOW，LDO2_SET0，

LDO2_SET1，BUCKFB，LDO1OUT，

LDO2OUT，CHG_PROG，CHG_STAT，LX，

AC_IN

– 0.3 ~ 6 V

– 0.3 ~ VIN V

TJ Junction Temperature -40~125 °C

T

Storage Temperature Range – 65 ~ 150 °C

STG

T

Lead Temperature (Soldering, 10 sec) 260 °C

SOLDER

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 3

PT1502_DS Rev EN_1.0

PMU for Portable Applications

RECOMMENDED OPERATING RANGE(Note2)

SYMBOL ITEMS VALUE UNIT

PT1502

VIN

V

IN2

T

Operating Temperature Range – 40 ~ 85 °C

OPER

θJA

Input supply voltage: USB_IN，CHGIN

Input supply voltage: AVDD，PVDD

Thermal Resister 50 °C/W

4.25 ~ 5.5 V

3.5 ~ 5.5 V

Note1: Absolute Maximum Ratings are those values beyond which the life of the device maybe impaired.
Note2: Recommended operating Range indicates conditions for which the device is functional, but does not

guarantee specific performance limits.

ELECTRICAL CHARACTERISTICS

（VB=3.6V，TA=25℃, unless otherwise specified）

SYMBOL PARAMETER CONDITIONS MIN TYP MAX

CHGIN/USB_IN floating，

BUCK/LDO1/LDO2 no load

120 300 μA

CHGIN/USB_IN floating，

PLAY_ON=AGND,

1 5 μA

PWR_HOLD=AGND

AVDD = 3.0 to 5.5V 0.4 V

I

SHDN

VIL

IQ

Bat supply quiescent current

Bat supply Shut down current

Maximum Low

Input Level at

PLAY_ON, PWR_HOLD

UNITS

Minimum High

VIH

Input Level at PLAY_ON,

AVDD = 3.0 to 5.5V 1.4 V

PWR_HOLD

V

LBAT

T

LBAT

V

LBATHYS

TSD

Battery voltage Undervoltage

lockout threshold

Battery voltage Undervoltage
lockout comparator filter time

Battery voltage Undervoltage
lockout hysteresis

Thermal shutdown Temperature

Thermal shutdown

Hysteresis

VBAT high to low 3.135 3.3 3.465 V

1 ms

100 mV

160 °C

20 °C

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 4

PT1502_DS Rev EN_1.0

PT1502

PMU for Portable Applications

ELECTRICAL CHARACTERISTICS (continued)

Charger Characteristics

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

Input Charging Supply Voltage

CHG

V

V

V

Regulated Output Voltage

BAT_REG

I

CH_CC

I

TRIKL

TRIKL

TRHYS

VUV

V

UVHYS

I

Charging termination current

TERM

Const current mode Charging
current

Trickle Charge Current

Trickle Charge Threshold
Voltage

Trickle Charge Hysteresis
Voltage

Under voltage Lockout
Threshold

Under voltage Lockout
Hysteresis

I

= 50mA, R

CH_CC

R

=1K, USB mode

PROG

R

=1K, Adapter mode 750 mA

PROG

V

< V

BAT

V

from low to high

BAT

TRIKL

PROG

=5K

V

from high to low

CHGIN

4.25 5.5 V

4.158 4.2 4.242 V

445 470 495 mA

I

/10 mA

CH_CC

2.9 V

80 mV

3.8 V

200 mV

I

/10 mA

CH_CC

V

CHG_PROG pin voltage Const current mode 1.0 V

PROG

I

CHG_STAT Pin Weak

TATCHG

_

TATCHGV_

ΔV

RECHG

T

LIM

T

RECHG

I

PROG Pin Pull-Up Current

PROG

Pull-Down Current

CHG_STAT Pin Output Low

Voltage

Recharge Battery Threshold
Voltage

Junction Temperature in
Constant Temperature Mode

Recharge Comparator Filter

Time

I

V

BAT_REG

V

BAT

= 5V

STATCHGV_

= 5mA

STATCHG

_

- V

CHG

from high to low

20 μA

0.35 V

150 mV

120

℃

2 ms

3

μA

DC-DC step down converter Characteristics

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VFB Regulated Feedback Voltage 0.588 0.600 0.612 V

∆V

Line Regulation PVDD = 3.5V to 5.5V 0.04 0.4 %/V

OUT

I

LIMIT

Peak Inductor Current

1 A

V

LOADREG

Load Regulation

F

OSC

R

RDS(ON) of P-Channel FET ILX = 100mA 0.4 0.5 Ω

PFET

R

NFET

Oscillator Frequency

RDS(ON) of N-Channel FET ILX = –100mA 0.35 0.45 Ω

0.5 %

1.2 1.5 1.8 MHz

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 5

PT1502_DS Rev EN_1.0

PT1502

PMU for Portable Applications

ELECTRICAL CHARACTERISTICS (continued)

Low Dropout Regulator Characteristics

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

Output voltage 1 2.94 3.0 3.06 V

LDO1

ΔV

V

Output voltage 2

LDO2

OUT

Line Regulation Error AVDD=(V

Load Regulation Error I

I

Peak Output Current V

OUTMAX

Power Supply

PSRR

Rejection Ratio

LDO2_SET0=Low,

LDO2_SET1=Low

LDO2_SET0=High,

LDO2_SET1=Low

LDO2_SET0=Low,

LDO2_SET1=High

LDO2_SET0=High,

LDO2_SET1=High

LDO(nom)

= 1mA to 150 mA 15 50 mV

LDO_OUT

LDO≥VLDO(nom)

+ 0.5V) to 5.5V 0.1 0.5 %/V

f = 1k Hz

=

AV D D

LDO(nom)

+1.0V

V

f = 10k

Hz

2.45 2.5 2.55

2.744 2.8 2.856

V

2.94 3.0 3.06

3.234 3.3 3.366

– 2% 300 mA

I

=

OUT

50mA

I

OUT

150mA

60

=

60

dB

I

=

OUT

50mA

I

OUT

150mA

55

=

55

ΔV

V

Dropout Voltage

DIFF

ISC

LDO_OUT

V

OUT

Output Short Current

Limit

V

/

Temperature

OUT

Characteristics

I

I

Output Grounded 500 mA

Temperature = -40 to 125°C 100 ppm/°C

= 50mA 50 90 mV

LDO_OUT

= 100mA 100 180 mV

LDO_OUT

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 6

PT1502_DS Rev EN_1.0