general description the MAX2232/max2233 low-voltage, silicon rf power amplifiers (pas) are designed for use in the 900mhz ism band. they operate from a single +2.7v to +5.5v supply, allowing them to be powered directly from a 3- cell nicd or a 1-cell lithium-ion battery. the devices typically deliver 250mw (+24dbm) of output power at 915mhz from a single +3.6v supply, or 150mw (+22dbm) from a single +2.7v supply. at +24dbm out- put power, power-added efficiency (pae) is 44%. the MAX2232/max2233 provide 24db of gain, which is adjustable over a continuous 24db span via the analog gain-control pin of the MAX2232 or in two 10db steps via the 2-bit programmable gain-control dac of the max2233. an external capacitor sets the rf output power envelope ramp time, reducing spurious emis- sions during power-up and power-down by providing a gradual change in output power (MAX2232). the MAX2232/max2233 feature a low-power shutdown mode, which typically draws less than 1? of supply current, saving power during ?dle slots?in time-division multiple-access (tdma) systems. the ? vswr of the rf input in shutdown mode relative to normal operation is 1.2:1. the devices also feature a thermal shutdown function, enabling the pa to protect itself from excessive temperature conditions that could damage the ic. a capacitor to ground limits thermal cycling by setting a thermal shutdown timeout period. the MAX2232/max2233 are available in a space-sav- ing, thermally enhanced 16-pin power-qsop (pqsop) package. applications 900mhz ism band digital cordless phones wireless data fm analog transmitters 868mhz european ism band features 800mhz to 1000mhz frequency range 250mw (+24dbm) output power at 915mhz from +3.6v supply +2.7v to +5.5v single-supply operation 44% power-added efficiency 24db power gain 24db analog gain-control range (MAX2232) three levels of digitally programmed power gain in 10db steps (max2233) programmable rf power envelope ramping (MAX2232) thermal shutdown programmable thermal shutdown timeout period 0.2a low-power shutdown mode low ? vwsr in standby and shutdown modes MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control ________________________________________________________________ maxim integrated products 1 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 rfin v cc gnd ramp+ (n.c.) ramp- (n.c.) v cc v cc tset n.c. top view MAX2232 max2233 pqsop gnd shdn (d1) gnd ctrl (d0) gnd gnd rfout ground of output stage connected to package slug. ( ) are for max2233. 19-1470; rev 1; 6/00 part MAX2232 eee max2233 eee -40? to +85? -40? to +85? temp. range pin-package 16 pqsop 16 pqsop pin configuration ordering information functional diagrams appear at end of data sheet. for price, delivery, and to place orders, please contact maxim distribution at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com.
MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control 2 _______________________________________________________________________________________ absolute maximum ratings dc electrical characteristics (v cc = +2.7v to +5.5v, v ctrl = +2.2v, v shdn = v d0 = v d1 = +2v, t a = -40? to +85?. no input signal applied, unless otherwise noted. typical values are at v cc = +3.6v and t a = +25?.) ac electrical characteristics (MAX2232/max2233 evaluation kit, v cc = +3.6v, v ctrl = +2.2v, shdn = v cc (MAX2232), d0 = d1 = v cc (max2233), p rfin = 0dbm, rfin = 915mhz, t a = +25?, unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v cc to gnd ...........................................................-0.3v to +6.5v shdn , ctrl, d0, d1 to gnd ....................-0.3v to (v cc +0.3v) i rfin ....................................................................................10ma rfin power (50 ? ac-coupled source). .........................+10dbm output load vswr. ................................................................6:1 continuous power dissipation (t a = +70?) 16-pin pqsop (derate 80mw/? above +70?) ................3w operating temperature range ...........................-40? to +85? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? v ctrl 0.4v (MAX2232) v shdn = 0.6v, v d0 = v d1 = 0.6v v ctrl = gnd v shdn = gnd (MAX2232), v d0 = v d1 = gnd (max2233) v shdn = 2.0v (MAX2232), v d0 = v d1 = 2.0v (max2233) MAX2232 shdn (MAX2232), d0, d1 (max2233) shdn (MAX2232), d0, d1 (max2233) MAX2232 v ctrl = 2.2v conditions 1.5 ma 20.3 25 i cc standby supply current 0.2 10 i cc v 2.7 5.5 v cc supply voltage range shutdown supply current ? -1.5 1 ctrl input current -1 1 i il ? -1 10 i ih logic input current v 0.6 v ctrl ctrl input for gain-control mode v 2.0 v ih logic input high v 0.6 v il logic input low v 0.4 v ctrl ctrl input for standby mode units min typ max symbol parameter ? 120 v cc 3.6v v cc = 5.5v v cc = 4.8v (notes 1, 2) d0 = gnd, d1 = v cc (max2233 only) v cc = 3.6v (note 1) v cc = 3.0v v cc = 2.7v t a = t min to t max (note 1) conditions 25.4 db 23.9 g p mhz 902 928 in frequency range power gain dbm 15.8 p out output power, medium-power mode 22.9 23.9 24.9 dbm 22.5 21.6 p out output power db 1.9 3.2 ? p out output power variation over temperature units min typ max symbol parameter
MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control _______________________________________________________________________________________ 3 ac electrical characteristics (continued) (MAX2232/max2233 evaluation kit, v cc = +3.6v, v ctrl = +2.2v, shdn = v cc (MAX2232), d0 = d1 = v cc (max2233), p rfin = 0dbm, rfin = 915mhz, t a = +25?, unless otherwise noted.) note 1: guaranteed by design. note 2: operation outside this range is possible, but not characterized. note 3: gain is monotonic with v ctrl . note 4: input vswr relative to input impedance in operating mode. note 5: harmonics measured on evaluation kit, which provides some harmonic attenuation in addition to the rejection provided by the ic. the combined suppression is specified. note 6: time measured from shdn (MAX2232) low-to-high transition to when output power is within 1db of final value. includes effects of 1% tolerance capacitor. note 7: time measured from shdn (MAX2232) high-to-low transition to when output power is -20db of final value. includes effects of 1% tolerance capacitors. note 8: time from die temperature dropping below thermal shutdown temperature, t th , to when the device turns itself back on. c ramp = 0.22? (notes 1, 6) (MAX2232 only) (note 5) any load phase angle, p rfin = +5dbm, t a = t min to t max v cc = +2.7v to +5.5v, 6:1 vswr at any phase angle, p rfin = +5dbm ctrl = gnd (MAX2232 only) shdn = d0 = d1 = gnd MAX2232 only 0.6v < v ctrl < 2.2v (MAX2232 only) z source = 50 ? (note 1) d0 = v cc , d1 = gnd (max2233 only) d0 = v cc , d1 = gnd (max2233 only) d0 = gnd, d1 = v cc (max2233 only) ctrl adjusted to give p rfout = +21dbm (MAX2232 only) conditions ms 0.9 autoramping rise time dbc 29 harmonic suppression 6:1 maximum output load vswr without damage (note1) dbc -60 maximum nonharmonic spurious output due to load mismatch db 38 52 off-isolation 1.2:1 ? vswr input vswr change, standby mode (notes 1, 4) 1.4:1 ? vswr input vswr change, shutdown mode (notes 1, 4) 1.5:1 vswr input vswr ma 44.0 i cc supply current, low-power mode ma 78.5 i cc supply current, medium-power mode % 29 pae power-added efficiency at +21dbm output power % 44 pae power-added efficiency db 23.6 ? g p gain-control range (note 3) dbm 6.5 p out output power, low-power mode units min typ max symbol parameter p rfin = 0dbm, v cc = +3.6v ramp+ = ramp- = unconnected (note 6) c ramp = 0.22? (notes 1, 7) (MAX2232 only) c tset = 0.22? (note 8) ? 145 t th thermal shutdown temperature ? 0.4 ms 3.2 autoramping fall time output power rise time ms 900 t th thermal shutdown timeout period
linear scale 0 3v 1ms/div MAX2232 output power vs. shutdown control MAX2232/33 toc10 c ramp = 0.22 f output power shutdown MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control 4 _______________________________________________________________________________________ typical operating characteristics (MAX2232/max2233 evaluation kit, v cc = +3.6v, ctrl = v cc , shdn = d0 = d1 = v cc , p rfin = 0dbm, f rfin = 915mhz, t a = +25?, unless otherwise noted.) 0.001 0.01 1 0.1 10 100 2.5 3.5 3.0 4.0 4.5 5.0 5.5 shutdown supply current vs. supply voltage MAX2232/33 toc01 supply voltage (v) shutdown supply current ( a) t a = -40? t a = +25? t a = +85? 0 10 5 20 15 25 30 2.5 3.5 4.0 3.0 4.5 5.0 5.5 MAX2232 standby supply current vs. supply voltage MAX2232/33 toc02 supply voltage (v) supply current (ma) t a = -40 c t a = +25 c t a = +85 c v shdn = v cc v ctrl = gnd rfin = unconnected 22 23 24 25 26 27 28 20 21 2.5 3.5 3.0 4.0 4.5 5.0 5.5 output power vs. supply voltage MAX2232/33 toc03 supply voltage (v) output power (dbm) t a = +85 c t a = -40 c t a = +25 c 0 5 10 15 20 25 30 0.6 1.0 0.8 1.2 1.4 1.6 .1.8 2.0 2.2 2.4 MAX2232 output power vs. gain control voltage MAX2232/33 toc06 v ctrl (v) output power (dbm) t a = -40 c t a = +25 c t a = +85 c 10 0 20 40 30 50 60 2.5 3.5 3.0 4.0 4.5 5.0 5.5 power-added efficiency vs. supply voltage MAX2232/33 toc04 supply voltage (v) power-added efficiency (%) t a = -40 c t a = +25 c t a = +85 c 5 10 15 20 25 30 902 915 928 output power vs. frequency MAX2232/33 toc05 frequency (mhz) output power (dbm) max2233 (d0 = 0, d1 = 1) max2233 (d0 = d1 = 1), and MAX2232 max2233 (d0 = 1, d1 = 0) 3 8 18 13 23 28 10 25 55 40 70 85 -20 -10 -15 -5 0 5 10 15 output power and power-added efficiency vs. input power MAX2232/33 toc07 input power (dbm) output power (dbm) pae (%) t a = -40 c t a = -40 c t a = +25 c p out pae t a = +25 c t a = +85 c t a = +85 c 1.0 1.2 1.4 1.6 1.8 2.0 902 915 928 MAX2232 rfin port vswr vs. frequency MAX2232/33 toc08 frequency (mhz) vswr shutdown mode normal operation standby mode
MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control _______________________________________________________________________________________ 5 pin description pin function MAX2232 max2233 13 negative terminal of output power ramp capacitor. connect capacitor, c ramp , between ramp+ and ramp- to control the rise and fall time of the output power ramp. 12 12 input stage supply voltage. bypass with appropriate capacitors to gnd. 11 11 second stage supply voltage. bypass with appropriate capacitors to gnd. 10 10 thermal shutdown timeout capacitor terminal. connect a capacitor from tset to ground to limit thermal cycling. 9 9, 13, 14 no connection. do not make a connection to this pin. 14 positive terminal of output power ramp capacitor. connect capacitor, c ramp , between ramp+ and ramp- to control the rise and fall time of the output power ramp. 15 15 bias circuitry ground. connect directly to low-inductance ground plane. if vias are used, separate them from other gnd pin vias. 16 16 bias circuitry supply voltage. bypass with appropriate capacitors to gnd. slug slug output stage ground. provides additional thermal conduction, as well as a low-inductance path to ground. connect directly to low-inductance ground plane. name ramp- v cc v cc tset n.c. ramp+ gnd v cc gnd 8 8 open-collector, rf output port. connect output matching network to this pin. rfout 5, 6 5, 6 second stage ground. connect directly to low-inductance ground plane. if vias are used, separate them from other gnd pin vias. gnd 7 7 output stage ground. connect directly to low-inductance ground plane. if vias are used, separate them from other gnd pin vias. gnd 4 analog gain-control input. apply a voltage between 0.6v and 2.2v to vary the gain of the pa. drive ctrl below 0.4v to place the device in standby mode. drive ctrl above 2.2v to place the device in peak output power mode. ctrl 3 shutdown control input. drive s hdn low to place the device in shutdown mode. drive high for normal operation. shdn 3 digital gain/shutdown control input. msb of the 2-bit digital output power control. d0 and d1 set the output power to one of three discrete levels. to place the device in shutdown, drive d0 and d1 low (table 2). d1 4 digital gain/shutdown control input. lsb of the 2-bit digital output power control. d0 and d1 set the output power to one of three discrete levels. to place the device in shutdown, drive d0 and d1 low (table 2). d0 1 1 rf input port. requires external matching network and blocking capacitor. rfin 2 2 input stage ground. connect directly to low-inductance ground plane. if vias are used, separate them from other gnd pin vias. gnd
MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control 6 _______________________________________________________________________________________ detailed description the MAX2232/max2233 are nonlinear power amplifiers (pas) intended for constant envelope applications (fm, fsk, gmsk). the devices operate over the 902mhz to 928mhz frequency range and provide typically 250mw of output power and 44% efficiency from a single +2.7v to +5.5v supply. both devices typically provide 24db of gain, which is adjustable over a continuous 24db range through an analog voltage on ctrl of the MAX2232 or in two 10db steps through the 2-bit programmable gain inputs (d0, d1) on the max2233. a low-power shutdown mode on both devices reduces supply current to 0.2?. all bias, gain control, and temperature-sensing circuitry is provided on-chip to save board space and reduce component count. the signal path includes a variable gain amplifier (vga), an output driver, and an output power transistor. on-chip interstage matching networks are provided for optimal loading and power transfer. internal bias circuitry responds to ctrl and shdn of the MAX2232, or to the 2-bit gain/shutdown control dac of the max2233, providing optimum biasing and efficiency as well as shutdown and ramp control func- tions. a unique temperature-sensing circuit protects the device from overheating by shutting down the pa until a safe temperature is resumed. the devices come in a 16-pin pqsop package, which incorporates a slug on the bottom of the device to increase heat conduction and provide a low induc- tance path to ground. rf input stage (variable gain amplifier) the input stage includes a variable gain amplifier (vga) with 24db gain-control range. with the appropri- ate matching network, the input vswr is nominally 1.5:1 during operation and the change in vswr is only 1.2:1, relative to normal operation. this stage remains active during standby mode (MAX2232) to provide a constant input impedance but is off during shutdown mode (MAX2232/max2233). ac-couple this port with a dc-blocking capacitor. rf second stage (driver) the driver provides gain to overcome interstage match- ing losses and to produce a signal large enough to drive the output power transistor into saturation. the driver stage is off during standby (MAX2232) and shut- down (MAX2232/max2233) modes. rf output stage (output power transistor) the output power transistor delivers +24dbm of output power from a single +3.6v supply. the transistor? open-collector output requires a pull-up inductor to v cc for proper biasing, as well as a proper output matching network to ensure optimum output power. connect the output matching network to rfout (pin 8). see the typical application circuit for bias and matching components suitable for 900mhz operation. the ground of the output stage is connected to a metal slug on the bottom of the MAX2232/max2233? 16-pin pqsop package. the metal slug increases heat con- duction and provides a low-inductance path to ground. solder the metal slug to the pc-board ground plane. ___________________________MAX2232 analog gain control and power management shutdown mode drive the shutdown ( shdn ) pin below 0.6v to place the MAX2232 in shutdown mode. the vga, driver, and out- put transistor are off in shutdown mode and the supply current is typically reduced to 0.2?. when shdn is above 2.0v, the device is enabled. standby mode drive shdn above 2.0v and ctrl below 0.4v to place the MAX2232 in standby mode. in standby mode, the vga remains biased while the driver and output tran- sistor are disabled. supply current is typically 20ma in standby mode. this mode allows the device to maintain a good input vswr while maintaining 38db of isolation. this is useful to users who drive the pa with a direct modulated vco, where pulling of the vco results from changes in the input vswr. analog gain control the voltage applied to the gain-control (ctrl) pin varies the output power of the MAX2232 continuously over a 24db range. an internal comparator holds the pa to a constant peak output power if v ctrl is above 2.2v. for v ctrl below 0.4v, the pa is in standby mode. ctrl pre- sents a high input impedance, allowing the v ctrl voltage to be set with a resistor-divider or a voltage output dac. output power autoramping the internal bias circuitry of the MAX2232 automatically ramps the output power of the pa down or up at a con- stant rate (in w/sec) when switched in or out of shut- down mode. the output power is ramped to the level set by v ctrl on the MAX2232. the output power rise and fall time ramp is set by placing a capacitor, c ramp , between ramp+ and ramp-. this provides an easy means of avoiding spectral splatter and complying with transmit mask requirements, without using a separate controller. the output power rise and fall time is set by the value of c ramp .
___________________________max2233 digital gain control and power management the max2233 responds to logic-level signals at the device? 2-bit dac inputs, d0 and d1, placing the device in shutdown mode or into one of three discrete output power levels. see table 2 for operating modes and output power levels. setting d0 and d1 to a logic- level low places the device in shutdown mode and reduces supply current to 0.2?. the vga, driver, and output stage are off in shutdown mode, while the input impedance is only slightly changed. setting d0 and d1 to one of the other three modes adjusts the output power to one of three discrete levels in 10db steps. thermal shutdown the MAX2232/max2233 feature a thermal shutdown mode that helps to protect the device from damage when the die temperature becomes excessive. if the temperature of the die exceeds the thermal shutdown temperature, t th , the vga is forced into a low-gain mode and output power is reduced to a minimum. after the pa? die temperature drops below t th , the device remains in thermal shutdown mode for the thermal shut- down timeout period, t th . a single capacitor, c tset , from tset to ground sets t th . the thermal shutdown timeout period helps to limit device thermal cycling that results if the source of the excessive temperature is not removed. t th is set by the value of c tset . applications information proper attention to voltage supply bypassing is essen- tial for high-frequency rf circuit stability. bypass v cc with 0.1?, 10nf, and 100pf capacitors in parallel with each other to ground. use separate vias to the ground plane for each of the bypass capacitors and minimize trace length to reduce inductance. use separate vias to the ground plane for each ground pin. use low-induc- tance ground connections. decouple shdn , ctrl, d0, and d1 with 0.1? capaci- tors to ground to minimize noise on the internal bias cell. use a series resistor (typically 100 ? ) to further reduce coupling of high-frequency signals into the control pins. MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control _______________________________________________________________________________________ 7 mode standby > 2.0v < 0.6v v shdn v ctrl x 0.4v output power (p rfin = 0dbm, v cc = +3.6v) < -35dbm < -35dbm variable gain > 2.0v 0.6v v ctrl < 2.2v 0dbm to +24dbm maximum gain > 2.0v > 2.2v +24 dbm shutdown table 1. MAX2232 operating modes x = don? care table 2. max2233 operating modes truth table mode shutdown low power 0 0 d1 d0 0 1 output power (p rfin = 0dbm, v cc = +3.6v) < -35dbm +6.5dbm medium power 1 0 +15dbm high power 1 1 +24dbm functional diagrams MAX2232 vga driver temp sensor rfout tset 2 16 15 5, 6 7, slug 8 10 shdn ramp+ 14 3 11 12 1 13 ramp- v cc v cc 4 ctrl rfin bias gnd v cc gnd gnd gnd tset max2233 vga driver temp sensor rfout 2 16 15 5, 6 7, slug 10 d0 4 3 11 12 1 d1 v cc v cc rfin bias gnd v cc gnd gnd gnd 8 2-bit dac
MAX2232/max2233 900mhz ism-band, 250mw power amplifiers with analog or digital gain control maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2000 maxim integrated products printed usa is a registered trademark of maxim integrated products. 16 15 14 13 1 2 3 4 12 11 10 9 rfin 27nh 2.55nh 5 6 7 8 gnd gnd shdn (d1) ctrl (d0) rfin v cc v cc v cc v cc gnd rfout rfout gnd gnd ramp+ (n.c.) ramp- (n.c.) tset n.c. 100pf 10nf 0.1 f c ramp 0.22 f 3.6pf 15nh notes: ( ) applies to max2233. backside slug must be soldered to groundplane. MAX2232 max2233 c tset 0.22 f v cc 10nf 0.1 f 100pf v cc 10nf 0.1 f 100pf v cc 10nf 0.1 f 0.22 f 0.22 f 100pf 100pf 100pf 68pf typical application circuit package information pssopps.eps
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