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PDF MAX8834Y Data sheet ( Hoja de datos )
| Número de pieza | MAX8834Y | |
| Descripción | Adaptive Step-Up Converters | |
| Fabricantes | Maxim Integrated Products | |
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19-4421; Rev 0; 4/09
www.DataSheet4U.com
EVAALVUAAILTAIOBNLEKIT
Adaptive Step-Up Converters
with 1.5A Flash Driver
General Description
The MAX8834Y/MAX8834Z flash drivers integrate a
1.5A PWM DC-DC step-up converter and three pro-
grammable low-side, low-dropout LED current regula-
tors. The step-up converter features an internal
switching MOSFET and synchronous rectifier to
improve efficiency and minimize external component
count. An I2C interface provides flexible control of step-
up converter output voltage setting, movie/flash mode
selection, flash timer duration settings, and current reg-
ulator settings. The MAX8834Y/MAX8834Z operate
down to 2.5V, making them future proof for new battery
technologies.
The MAX8834Y/MAX8834Z consist of two current regula-
tors for the flash/movie mode. Each current regulator can
sink 750mA in flash mode and 125mA in movie mode.
The MAX8834Y/MAX8834Z also integrate a 16mA low-
current regulator that can be used to indicate camera
status. The indicator current regulator includes program-
mable ramp and blink timer settings. A programmable
input current limit, invoked using the GSMB control,
reduces the total current drawn from the battery during
PA transmit events. This ensures the flash current is set
to the maximum possible for any given operating condi-
tion. Additionally, the MAX8834Y/MAX8834Z include a
MAXFLASH* function that adaptively reduces flash cur-
rent during low battery conditions to help prevent system
undervoltage lockup.
Other features include an optional NTC input for finger-
burn protection and open/short LED detection. The
MAX8834Y switches at 2MHz, providing best overall
efficiency. The MAX8834Z switches at 4MHz, providing
smallest overall solution size. The MAX8834Y/
MAX8834Z are available in a 20-bump, 0.5mm pitch
WLP package (2.5mm x 2.0mm).
*Patent pending.
Ordering Information
PART
TEMP
PIN-PACKAGE
SWITCHING
FREQUENCY
RANGE
(MHz)
MAX8834YEWP+T -40°C to 20 WLP
+85°C (2.5mm x 2.0mm)
MAX8834ZEWP+T
-40°C to
+85°C
20 WLP
(2.5mm x 2.0mm)
2
4
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Pin Configuration appears at end of data sheet.
Features
♦ 2.5V to 5.5V Operation Range
♦ Step-Up DC-DC Converter
1.5A Guaranteed Output Current
Adaptive or I2C Programmable Output Voltage
2MHz and 4MHz Switching Frequency Options
♦ Two Flash/Movie LED Current Regulators
I2C Programmable Flash and Movie Current
Low-Dropout Voltage (110mV max) at 500mA
♦ LED Indicator Current Regulator
I2C Programmable Output Current
Ramp and Blink Timers for Indicator Mode
Low-Dropout Voltage (130mV max) at 16mA
♦ I2C Programmable Safety and Watchdog Timers
♦ GSM Blank Logic Input
♦ MAXFLASH System Lockup Protection
♦ Remote Temperature Sensor Input
♦ Open/Short LED Detection
♦ Thermal Shutdown Protection
♦ < 1µA Shutdown Current
♦ 20-Bump, 0.5mm Pitch, 2.5mm x 2.0mm WLP
Applications
Cell Phones and Smart Phones
PDAs, Digital Cameras, and Camcorders
Typical Operating Circuit
INPUT
2.5V TO 5.5V
10μF
1μH OR 2.2μH
LX
IN
AGND
PGND
COMP
MAX8834Y
MAX8834Z
PROGRAMMABLE
OUTPUT
3.7V TO 5.2V
OUT
10μF
FLED1
FLED2
1.5A TOTAL
FLASH
PA_TXON
FLASH ON
I2C
VLOGIC
0.1μF
GSMB
LED_EN
SCL
SDA
VDD
INDLED
FGND
16mA INDICATOR
NTC
FINGER-BURN
PROTECTION
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1 page  
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Adaptive Step-Up Converters
with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VAGND = VPGND = VFGND = 0V, VDD = 1.8V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at
TA = +25°C.) (Note 1)
PARAMETER
Watchdog Timer Accuracy
(4s setting)
Open LED Detection Threshold
CONDITIONS
TA = +25°C
TA = -40°C to +85°C
FLED1, FLED2, INDLED enabled
MIN TYP MAX UNITS
3.6 4 4.4
3.2 4.8
s
100 mV
Shorted LED Detection Threshold FLED1, FLED2, INDLED enabled
VOUT -
1V
V
Open and Short Debounce Timer From LED open or short detected until LED current
regulator is disabled
Thermal-Shutdown Hysteresis
Thermal Shutdown
MAXFLASH
30
20
+160
ms
°C
°C
Low-Battery Detect Threshold
Range
33mV steps
2.5 3.4 V
Low-Battery Voltage Threshold
Accuracy
±2.5
%
Low-Battery Voltage Hysteresis
Programmable Range
100 200 mV
Low-Battery Voltage Hysteresis
Step Size
100 mV
Low-Battery Reset Time
LB_TMR[1:0] = 00
LB_TMR[1:0] = 01
200 250 300
400 500 600
μs
Note 1: All devices are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by
design.
Note 2: LED current regulator dropout voltage is defined as the voltage when current drops 10% from the current level measured at
0.6V.
Note 3: Flash duration is from rising edge of LED_EN until IFLED = 0A (safety time in one-shot mode).
Note 4: The adaptive output voltage regulation threshold is individually set on each device to 75mV above the dropout voltage of
the LED current regulators. This ensures minimum power dissipation on the IC during a flash event. The dropout voltage
chosen is the highest measured dropout voltage of FLED1, FLED2, and INDLED.
_______________________________________________________________________________________ 5
5 Page 
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Adaptive Step-Up Converters
with 1.5A Flash Driver
PIN
A1, B1
A2, B2
A3, B3
A4
A5
B4
B5
C1
C2, D2
C3
C4
C5
D1
D3
D4
D5
Pin Description
NAME
OUT
LX
PGND
IN
VDD
SCL
AGND
COMP
FGND
LED_EN
GSMB
SDA
FLED2
FLED1
INDLED
NTC
FUNCTION
Regulator Output. Connect OUT to the anodes of the external LEDs. Bypass OUT to PGND with a 10μF
ceramic capacitor. OUT is connected to LX through an internal 10k resistor during shutdown.
Inductor Connection. Connect LX to the switched side of the inductor. LX is internally connected to
the drains of the internal MOSFETs. LX is connected to OUT through an internal 10k resistor during
shutdown.
Power Ground. Connect PGND to AGND and to the input capacitor ground. Connect PGND to the PCB
ground plane.
Analog Supply Voltage Input. The input voltage range is 2.5V to 5.5V. Bypass IN to AGND and PGND
with a 10μF ceramic capacitor as close as possible to the IC. IN is high impedance during shutdown.
Logic Input Supply Voltage. Connect VDD to the logic supply driving SCL, SDA, LED_EN, and GSMB.
Bypass VDD to AGND with a 0.1μF ceramic capacitor. When VDD is below the UVLO, the I2C registers
reset and the step-up converter turns off.
I2C Clock Input. Data is read on the rising edge of SCL.
Analog Ground. Connect AGND to PGND and to the input capacitor ground. Connect AGND to the PCB
ground plane.
Compensation Input. See the Compensation Network Selection section for details. COMP is internally
pulled to AGND through a 180 resistor in shutdown.
FLED1/FLED2 and INDLED Power Ground. Connect FGND to PGND.
LED Enable Logic Input. LED_EN controls FLED1, FLED2, and INDLED, depending on control bits
written into the LED_CNTL register. See the LED_EN Control register description for an explanation of
this input function. LED_EN has an internal 800k pulldown resistor to AGND.
GSM Blank Signal. Assert GSMB to reduce the current regulator settings according to the values
programmed into the GSMB_CUR register. The status of the flash safety timer and the flash/movie
mode values in the current regulator registers are not affected by the GSMB state. Connect GSMB to
the PA module enable signal or other suitable logic signal that indicates a GSM transmit is in
process. Polarity of this signal is set by a bit in the GSMB_CUR register (default is active-high).
GSMB has an internal 800k pulldown resistor to AGND.
I2C Data Input. Data is read on the rising edge of SCL and data is clocked out on the falling edge of
SCL.
FLED2 Current Regulator. Current flowing into FLED2 is based on the internal I2C registers
FLASH2_CUR and MOVIE_CUR. Connect FLED2 to the cathode of an external flash LED or LED
module. FLED2 is high impedance during shutdown. If unused, connect FLED2 to ground.
FLED1 Current Regulator. Current flowing into FLED1 is based on the internal I2C registers
FLASH1_CUR and MOVIE_CUR. Connect FLED1 to the cathode of an external flash LED or LED
module. FLED1 is high impedance during shutdown. If unused, connect FLED1 to ground.
INDLED Current Regulator. Current flowing into INDLED is based on the internal I2C registers
IND_CUR. Connect INDLED to the cathode of an external indicator LED. INDLED is high impedance
during shutdown. If unused, connect INDLED to ground.
NTC Bias Output. NTC provides 20μA to bias the NTC thermistor. The NTC voltage is compared to the
trip threshold programmed by the NTC_CNTL register. NTC is high impedance during shutdown.
Connect NTC to IN if not used. See the Finger-Burn Protection (NTC) section for details.
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet MAX8834Y.PDF ] | |
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