Document
19-0238; Rev 2; 4/96
Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias
_______________General Description
The MAX850–MAX853 low-noise, inverting, chargepump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers. The MAX850–MAX852 offer both preset (-4.1V) and adjustable (-0.5V to -9.0V) output voltages. The MAX853 uses an external positive control voltage to set the negative output voltage. Input voltage range for all four devices is 4.5V to 10V. Output current is 5mA. An internal linear regulator reduces the output voltage ripple to 2mVp-p. With a well-filtered control voltage (VCTRL), the MAX853 achieves typical output ripple of less than 1mVp-p. Supply current is 3mA max, and shutdown current is less than 1µA max over temperature (5µA max for MAX851).
NUAL KIT MA ATION U EET L H A S V A E T WS DA FOLLO
____________________________Features
o Fixed -4.1V or Adjustable -0.5V to -9V Output at 5mA o 4.5V to 10V Input Voltage Range o 2mVp-p Output Voltage Ripple (MAX850–MAX852) 1mVp-p Output Voltage Ripple (MAX853) o 100kHz Charge-Pump Switching Frequency (MAX850/MAX851/MAX853) o External Synchronizing Clock Input (MAX852) o Logic-Level Shutdown Mode: 1µA Max Over Temperature (MAX850/MAX852/MAX853) o Low Cost, 8-Pin SO Package
MAX850–MAX853
______________Ordering Information ________________________Applications
Cellular Phones Negative Regulated Power Supplies Personal Communicators, PDAs Wireless Data Loggers Continuously Adjustable GaAsFET Bias LCD-Bias Contrast Control
PART MAX850C/D MAX850ISA MAX850ESA MAX851C/D MAX851ISA MAX851ESA MAX852C/D TEMP. RANGE 0°C to +70°C -25°C to +85°C -40°C to +850°C 0°C to +70°C -25°C to +85°C -40°C to +85°C 0°C to +70°C PIN-PACKAGE Dice* 8 SO 8 SO Dice* 8 SO 8 SO Dice* 8 SO 8 SO Dice* 8 SO 8 SO
__________Typical Operating Circuit
VIN = 4.5V to 10.0V (4 CELLS)
MAX852ISA -25°C to +85°C MAX852ESA -40°C to +85°C MAX853C/D 0°C to +70°C MAX853ISA -25°C to +85°C MAX853ESA -40°C to +85°C * Dice are specified at TA = +25°C only.
ise*
C3 IN C1+ C1 C1VOUT = -4.1V (VGG of GaAsFET) OUT C4
__________________Pin Configuration
TOP VIEW
MAX850 MAX851 MAX852
NEGOUT C2 SHDN* SHDN OSC GND * MAX850: SHDN MAX851: SHDN MAX852: OSC
C1+ 1 C1- 2 NEGOUT 3
8
IN GND OUT FB** (MAX850–852)
FB
SHDN* 4 (MAX850/853)
MAX850 MAX851 MAX852 MAX853
SO
7 6 5
* SHDN (MAX851) OSC (MAX852)
** CONT (MAX853)
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
http://www.Datasheet4U.com/
Low-Noise, Regulated, Negative Charge-Pump Power Supplies for GaAsFET Bias MAX850–MAX853
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VIN to GND ..................................-0.3V to 10.5V VNEGOUT to GND ...................................................-10.5V to 0.3V VIN to VNEGOUT .........................................................-0.3V to 21V VOUT to GND (Note 1) ........................................VNEGOUT to 0.3V SHDN or OSC (pin 4) Voltage to GND.........-0.3V to (VIN + 0.3V) Continuous Power Dissipation (TA = +70°C) SO (derate 5.88mW/°C above +70°C) ........................471mW Operating Temperature Ranges MAX85_ISA ......................................................-25°C to +85°C MAX85_ESA.....................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C
Note 1: The output may be shorted to NEGOUT or GND if the package power dissipation is not exceeded. Typical short-circuit current to GND is 50mA.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(+5V ≤ VIN ≤ +10V, GND = 0V, VOUT = -4.1V, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. A 100kHz, 50% duty cycle square wave between GND and VIN is applied to OSC on the MAX852.) PARAMETER Supply Voltage Range (Note 2) SYMBOL VIN MAX850–MAX852, VFB = 0V, RL = ∞ or 820Ω, Figure 2a MAX853, VCTRL = 4.1V, RL = ∞ or 820Ω, Figure 2c CONDITIONS MIN 5 -4.3 -4.2 -0.5 to -(VIN - 1) VFBset IQ MAX850/MAX853, VIN = 10V, SHDN = 0V Shutdown Supply Current ISHUT MAX851, SHDN = 2V MAX852, OSC low MAX850–MAX852, VFB = 0V, RL = ∞ or 820Ω, Figure 2a VOUT Load Regulation MAX853, VCTRL = 4.1V, RL = ∞ or 820Ω, Figure 2c VOUT Ripple Oscillator Frequency (Note 3) Input High Voltage Input Low Voltage Input Current Input Capacitance fOSC VIH VIL IIN CIN MAX850–MAX852 MAX853 MAX850/MAX851/MAX853, TA = +25°C Pin 4 Pin 4 Pin 4 Pin 4 10 80 2.0 0.5 ±1 3 2 1 100 120 8 4 MAX.